Printable Enclosure Latches

Research notes from the sweep

On this page
  1. Industrial enclosure-hardware engineer
  2. 3D-printing design scout
  3. Test-data and literature researcher
  4. Seal / gasket engineer
  5. Outdoor materials engineer

Raw findings from the five specialist researchers, before merging. Each fact carries the URL the researcher cited. These are inputs, not conclusions: the analysis, review and calibration steps checked and sometimes overrode them.

Industrial enclosure-hardware engineer

Survey of latch families for gasketed, IP-rated enclosures, with published ratings and a printability assessment against the reference conditions (one latch, FDM, 0.4 mm nozzle, about 70x35x30 mm, ASA or PETG, 60-70 C surface temperature in sun).

  1. Published numbers are mostly "max static / working load" and are not sustained clamp force. Commercial plastic-body latches (Southco GF-nylon) rate 350-475 N draw force (lever-assist) up to 1560 N working load (E8 over-center). Zinc compression latches rate 300-1010 N static. Steel latch clamps rate 1.6-19 kN. Manufacturer working load is about 0.5-0.67 of ultimate (Camloc, Southco N4).

  2. The central finding is the load the gasket asks for. Commercial compression latches (4-6 mm draw-down, about 300 N) are specified for foam or low-force gaskets. EMKA uses PUR foam. EMI low-closure-force gaskets are quoted at roughly 0.2-1.4 N/mm. My own estimate for a solid 85A TPU bead (E about 12 MPa) is about 2-6 N/mm per mm of width at 15-25 % compression, so about 4-12 N/mm for a 2 mm bead. That is roughly 10x or more what foam needs. 85A TPU also takes 26-52 % compression set at 70 C (BASF Ultrafuse 85A datasheet, via the dream3d.co.uk copy; ISO 815), so a rigid fixed-travel latch loses much of its preload. Prefer a spring-loaded or re-tensionable latch, a thin or hollow gasket profile, and a stiff flange.

  3. For printed parts, my own engineering estimate is about 100-400 N sustained per latch in ASA, from 5-8 MPa sustained design stress. Peak is 2-4x that. PETG (HDT about 68 C) is marginal at 60-70 C surface temperature. ASA (Tg about 108 C, HDT about 91-98 C) is the safer outdoor choice. ASA layer adhesion is weak (29 % of in-plane strength in CNC Kitchen's hook test), so orient every load path in-plane.

  4. Ranking of mechanisms by sustained force a printed version can plausibly deliver (my estimate): (a) swing bolt or eye bolt with wing nut, or captive screw with heat-set insert; (b) eccentric cam clamping lever with steel stud (GN 927 principle, about 20:1 mechanical advantage); (c) adjustable over-center hook latch with steel pins and a spring or adjusting screw; (d) cam-plus-screw compression latch; (e) screw-cap closure on round enclosures; (f) bayonet; (g) TPU strap, snap-fit and magnet, which are all unsuitable for 85A seals.

  5. Gaps. The shared WebSearch budget ran out partway through, and Southco, Penn Elcom, Essentra, Printables and MakerWorld pages returned HTTP 403, so Southco and Essentra figures come from distributor sheets or search snippets rather than primary datasheets. PDFs could not be parsed (no pdftotext). No published load ratings were found for Protex, Pinet, Fastenal, bail or wire latches, wedge latches, or multi-point rod latches. No sourced mechanical data was gathered for PC, PA6-CF or PETG-CF beyond retailer HDT tables. All printed-part sustained-force figures and gasket line loads in this report are my own estimates and should be verified by coupon pull tests. Treat the gasket line loads in particular as plus or minus 2x.

Topic Fact Value Source
Manufacturer rating convention Manufacturer working load is about half to two thirds of ultimate. Camloc 95L: 220 N working vs 445 N max tensile; V934L 310/550 N; 1429L 1000/1500 N; V46L 3000/4500 N. Southco N4: 600 N working vs 1200 N average ultimate. McMaster defines 'capacity' as the maximum (peak) force the latch can withstand. working = 0.5-0.67 x ultimate link
Southco N4 compression force Southco N4 vise-action latch: maximum working load 600 N (136 lbf), average ultimate 1200 N, and average compression force of 300 N applied to the frame when the T-handle is turned. This is the clearest published 'gasket draw-down force' figure found. 300 N compression / 600 N working / 1200 N ultimate link
Southco E3 ratings E3 large vise-action compression latch: maximum static load 450 N (100 lbf) adjustable grip and 300 N (67 lbf) fixed grip; stainless/high-pressure sealed variants 600/450 N. NEMA 4/IP65 sealing with the supplied gasket. Mounting nut torque 20 Nm. 300-450 N static (600 N stainless) link
Southco M1 ratings M1 lift-and-turn latches: M1-20 460 N (short cam) and 350 N (long cam); M1-25 1010 N (short cam) and 350 N (long cam). NEMA 4/IP66 sealing achieved with the supplied flange gasket. 350-1010 N static link
Southco 62 series loads 62 lift-and-turn latch static loads: 220 N small, about 440-670 N medium, 1250 N large flush. Required panel thickness is door thickness + 7 mm (+0.4 mm with cup gasket). 220-1250 N link
Draw-down travel of compression latches EMKA 1000 series compression latches pull the door about 6 mm against the gasket (first 90 degree turn positions on a 3 mm ramp, second turn adds about 5.5 mm), IP65, with a PUR foamed gasket; Southco E9 gives about 4 mm compression (IP66/IP67); Essentra offers 4 mm or 6 mm preset; Southco E5 roller cam up to 2 mm. 2-6 mm draw-down link
Essentra compression latch load Essentra quarter-turn compression lock (zinc housing and driver, steel cam, rubber gasket): max load capacity 562 N at 6 mm compression, working range -50 to +80 C. 562 N link
Engineered-plastic draw latch loads Southco E8 adjustable over-center draw latch (acetal and glass-reinforced nylon, stainless adjusting nut): max working load 1560 N (350 lbf), -29 to 80 C, 7.9 mm adjustment. Southco 37 lever-assist heavy duty (GF nylon body, stainless pins): 350 N (79 lbf) clamping force, -40 to 80 C; top variant 475-520 N (sources disagree). 350-520 N clamp; 1560 N working (E8) link
Elastomeric draw latch force Southco EPDM flexible draw latch: 49 N average clamping force, -20 to 95 C. Gripwell C7 (TPE latch, GF nylon links): 49 N small, 176 N large. 49-176 N [link](https://www.gripwell.com.sg/image/catalog/Gripwell/Engineered Access Hardware/Latches/Draw Latches/C7 Flexible Draw Latch/Gripwell - C7 Flexible Draw Latch.pdf)
Metal latch clamps DE-STA-CO pull-action latch clamps: 331 holds 700 lbf (about 3.1 kN, 1.75 in draw); 341 holds 2000 lbf (about 8.9 kN, 2.5 in draw). Ganter GN 850-500 5000 N; GN 853-160 1750 N; GN 851-160 1600 N; Kipp K0080 1800 N traction; Misumi latch type 1630 N. 1.6-8.9 kN (steel) link
Ganter vibration derating Ganter toggle latch datasheet notes that holding capacity can be adversely affected by conditions of use such as vibration or shock loads. holding capacity derated by vibration/shock link
Eccentric cam lever amplification Ganter GN 927.2 steel eccentric cam levers: 75 N hand force gives 1450 N (size 44), 125 N gives 2600 N (63), 200 N gives 4300 N (82), 350 N gives 7000 N (101). Ratio about 19-21:1. Recommended safety factors 1.2-1.5 static, 1.8-2.4 pulsating, 3-4 alternating. Friction coefficient plastic/steel about 0.15, steel/steel 0.2. about 20:1 amplification link
Ideal toggle mechanical advantage [own calculation] Ideal rigid toggle gain = 1/(2*tan(theta)) past dead centre: about 14:1 at 2 degrees, 5.7:1 at 5 degrees, 3.6:1 at 8 degrees; the sources note real clamps are limited by friction and frame flex and that formulas disagree (tan vs sin forms). 1/(2 tan theta) link
Swing bolt / screw clamp force [own calculation] Preload F=T/(K*d), K=0.2: M5 at 1.5 Nm gives about 1.5 kN; M4 at 1 Nm about 1.25 kN; M3 at 0.5 Nm about 0.83 kN. Class 8.8 proof loads: M3 2.92 kN, M4 5.10 kN, M5 8.23 kN, M6 11.6 kN. Printed seats, not the steel, limit the load. M4/M5 hand-tight about 1.2-1.5 kN link
Heat-set insert pull-out M3 Ruthex heat-set insert in PETG (4 perimeters, 100 % infill): ripped out at 119 kg average (about 1170 N); torque-out 3 Nm; a bolt screwed directly into printed PETG failed at about 1 Nm. 119 kg (about 1170 N); 3 Nm link
Printed thread pull-out Reader-reported test of 1/4-20 printed threads in PLA+: 48 lbf (10 % infill), 68 lbf (25 %), 90 lbf (50 %), above 110 lbf (100 %, instrument limit). Failure is usually in the surrounding material (cracking, delamination) rather than the thread. 48-110+ lbf link
Printed draw latch anecdote A MakerWorld printed draw latch (26x60x15 mm, working gap 3.2-6.4 mm) survived a 5-gallon jar (about 42 lb) without breaking, though it stretched out of position; designer says thick walls matter more than infill. M3 toggle latch claims more than 10 kg lift. Informal. about 187 N (42 lb); more than 98 N (10 kg) link
ASA tensile strength Bambu ASA: tensile strength 37 +/- 3 MPa (X-Y) and 31 +/- 4 MPa (Z); bending strength 65 MPa; bending modulus about 1920 MPa. Stratasys FDM ASA: tensile about 30-33 MPa, Z-strength ratio 87-91 %, Tg (DMA) 108 C, HDT 98 C @66 psi and 91 C @264 psi. X-Y 37 MPa, Z 31 MPa; Tg 108 C link
ASA/PETG layer adhesion CNC Kitchen hook test (Prusament): flat (in-plane) failure PLA 73 kg, PETG 55 kg, ASA 57 kg; vertical (across layers) PLA 40 kg (55 %), PETG 25 kg (46 %), ASA 17 kg (29 %); ASA vertical rises to 20 kg with a 30 C enclosure. Impact: ASA 18 kJ/m2, PETG 8.6. ASA across-layer strength only 29 % of in-plane; PETG 46 % link
Heat resistance of PETG vs ASA Prusament PETG HDT is 68 C at 0.45 and 1.8 MPa, tensile yield 46 +/- 1 MPa. CNC Kitchen heat test: PETG softens at 80 C and fails at about 85 C; ASA softens at 110 C and fails at 120 C; PLA fails at about 65 C. A 60-70 C enclosure surface in sun is therefore right at PETG's HDT. PETG HDT 68 C; ASA softens 110 C link
Creep rule of thumb (low reliability) A vendor blog (QIDI) says PETG shows noticeable creep at room temperature above about 30 % of yield and recommends a safety factor of 4-5 for brackets; no study cited. A 2024 paper notes most FDM datasheets omit creep data; one thesis found 80 % infill PETG creep modulus 1150-1300 MPa vs 690-710 MPa at 20 % infill. No sourced creep data at 60 C was found. about 30 % of yield sustained (unverified) link
Printed sustained design stress [own estimate] Sustained design stress for printed ASA at 60-70 C with SF about 2 and stress concentrations is about 5-8 MPa in-plane and about 2 MPa across layers. With this, a single printed latch in the 70x35x30 mm envelope is expected to hold about 100-400 N sustained (peak about 2-4x) in ASA; PETG is lower at 60-70 C. PA-CF/PETG-CF might raise this but no sourced mechanical data was gathered. about 100-400 N sustained (ASA) link
CF-filled filament heat resistance (retailer-sourced) Retailer comparison tables list HDT (0.45 MPa) PA6-CF about 186 C, PAHT-CF about 194 C, PET-CF about 205 C versus about 69 C for PETG; not verified in the Bambu TDS PDFs (not parseable). PA6-CF is moisture sensitive. HDT 186-205 C (CF grades) vs 69 C (PETG) link
Outdoor material choice Filament guides rank ASA as the first choice when UV and weather resistance matter; PETG is less UV resistant (claims conflict); none give years-of-exposure test data. ASA preferred for sun link
TPU 85A stiffness NinjaFlex-type 85A TPU: Shore 85A, tensile modulus 12 MPa (ASTM D638), tensile strength 26 MPa, elongation 660 %. Gent's relation gives about 13.2 MPa for Shore 85A [own calculation using the Wikipedia formula], consistent with the datasheet. E about 12-13 MPa link
TPU 85A compression set BASF Ultrafuse TPU 85A: compression set 26 % at 23 C/72 h and 52 % at 70 C/24 h (ISO 815). ColorRx TPU 85A (ASTM D395B): 16 % at 23 C/22 h and 40 % at 70 C/22 h. Stratasys FDM TPU 92A: 44 % at 70 C/22 h. 26-52 % set at 70 C link
Preload loss from compression set [own calculation] With a rigid (displacement-controlled) latch and a gasket compressed 20 %, a 52 % set leaves about 10 % compression and roughly 58 % less force; a 26 % set leaves about 15 % and about 30 % less force (neo-Hookean estimate). Spring-loaded or re-tensionable latches keep the force. about 30-58 % preload loss link
Solid TPU 85A line load [own calculation, +/- 2x] Neo-Hookean with E=12 MPa gives 1.3, 2.1, 3.1 and 4.1 MPa at 10, 15, 20 and 25 % compression (frictionless); bonded/constrained strip with shape factor 0.5 multiplies by about 1.5. So the line load per mm of bead width is about 2-6 N/mm at 15-25 % compression: about 4-12 N/mm for a 2 mm wide solid bead. Printed fill pattern changes TPU 85A compression force by about 2x (circular infill highest). about 4-12 N/mm for a 2 mm bead link
Foam / low-force gasket reference Rogers: foam gaskets are compressed 25-35 %; compression force deflection (CFD) classes at 25 %: below 10 psi (easy closure, plastic housings), 10-30 psi, above 30 psi (heavy-duty). Low-closure-force EMI gaskets are quoted about 1-8 lbf/in (about 0.18-1.4 N/mm). Solid TPU 85A is therefore roughly 5-60x stiffer per length. foam/EMI about 0.2-1.4 N/mm vs TPU 85A about 4-12 N/mm link
Minimum compression for a seal A nuclear-packaging analysis cites prototypic seal testing demonstrating a pressure seal needs a minimum of 10-12 % compression; Rogers warns under-compression leaks and over-compression can bottom out or warp thin enclosures. min 10-12 % compression link
Printed TPU gasket geometry examples A MakerWorld printed enclosure uses a TPU gasket 2.2 mm wide x 1.2 mm tall at about 25 % designed compression (test-fitted, not force-measured). A Printables screw container found 95A TPU a sweet spot for stiffness and sealing force. A TPU guide suggests 2-4 mm gasket walls, 85-90A for uneven surfaces, and service below about 60-80 C. 2.2 x 1.2 mm bead at 25 % link
Number of latches example [own calculation] A 150x100 mm lid (perimeter 500 mm) with a 2 mm solid 85A bead at 20 % compression needs about 6-9 N/mm, i.e. 3-4.5 kN total, or 12-18 printed latches at 250 N each. A thin lip or hollow profile at 1-2 N/mm needs about 0.5-1 kN, i.e. 2-4 latches. 12-18 latches vs 2-4 latches link
Latch spacing rule of thumb (published) Only one published rule was found: flanged screw-conveyor covers are bolted on 12-inch (about 305 mm) centres with a compressible gasket (dust-tight, metal cover). Engineers Edge says spacing depends on plate thickness, allowable gasket pressure and flange dimensions (formula behind a paywall). Rogers recommends FEA or pressure-sensitive film to find low-compression zones. Southco/EMKA publish no latch-spacing rule. 12 in (305 mm) centres, dust-tight metal covers link
Latch spacing vs rim stiffness [own calculation] Simply-supported rim strip, E=2000 MPa, allowing 0.3 mm bow between latches: a flat 3x15 mm flange gives max spacing 24-35 mm for gasket line loads of 5-1 N/mm; a 3 mm wall 12 mm deep gives 45-67 mm; a 3 mm wall 25 mm deep gives 78-116 mm. A continuous rim over many latches allows about 1.5x more. Lid stiffness, not the latch, usually sets spacing for solid TPU. 24-116 mm depending on rim depth link
Threaded cap axial force [own calculation] 50 mm printed screw cap, 4 mm lead, mean diameter 48 mm: 2 / 3 / 4 Nm hand torque gives about 250-370 / 380-550 / 510-730 N axial (mu 0.3-0.2). On a 157 mm circumference this is only about 1.6-4.6 N/mm line load. 250-730 N link
Bayonet ramp force [own calculation] F=T/(r*tan(alpha+phi)): at 2 Nm, 25 mm radius, ramp 3 / 5 / 10 degrees and friction 0.2 gives about 314 / 273 / 205 N; at friction 0.3 about 223 / 201 / 159 N. about 160-310 N link
V-band mechanics Huddersfield studies: axial clamp load of V-section band clamps increases with band pretension and with friction; ultimate-load models tended to over-predict test results; NASA Marman clamp guideline GD-ED-2214 is the standard design reference. qualitative only link
Magnetic catch ratings K&J 2x1/2 in magnetic latch is rated 20 lb pull (about 89 N) against a thick steel plate at contact; a typical cabinet catch is 30 N. Ratings are at contact; a gasket gap reduces force. 30-89 N link
Double-throw case latch rating Penn Elcom medium recessed butterfly latch: maximum working load 90 kg (about 880 N), 1.2 mm zinc-finished steel. 90 kg (about 880 N) link
Pelican press-and-pull materials Pelican Storm cases: latch material Valox (PBT) with Xenoy alternate; seal is an EPDM O-ring. No force values published. PBT latch + EPDM O-ring link
Printed cam-latch box seal test zx82net printed rugged box: cam latch applies significant static pressure to the TPU seal vs a clip latch; a thick TPU seal with tight latches kept water out at 10 cm for 10 min while a thin seal let in about 10 ml. Unit remains water-resistant not certified IP. 10 min at 10 cm submersion link
Printed enclosure water tests A Hackaday.io printed enclosure with 6 mm silicone tubing and a 2.5 mm rounded lid ridge stayed dry for 2 hours submerged, but a different variant leaked at 24 hours; author says ridge geometry mattered more than sealant and design is water-resistant not waterproof. 2 h submersion link
Multi-point latching For large door spans a multi-point latch is recommended (no spacing or force numbers given); single-point compression latches pull about 6 mm against the gasket. qualitative link
Search coverage limits The shared WebSearch budget was exhausted mid-task; Southco, Penn Elcom (main site), Essentra, Printables, MakerWorld and Thingiverse pages returned HTTP 403, so several figures are from search-result text or distributor copies. No data found for Protex, Pinet, Fastenal, bail/wire latches, wedge latches or PC mechanical properties. gaps listed link

3D-printing design scout

Scout result: 20 mechanism families, each with concrete example designs. Almost no designer or commenter has published a measured clamp or pull-off force for a printed box latch. The only designer figure is "holds at least 10 kg in PLA" on one MakerWorld latch (which model is uncertain). The other quantitative evidence is indirect: material coupon tests (CNC Kitchen, Tom's 3D, Bambu datasheets), insert and thread pull-out tests, and commercial steel latch ratings. So every sustained and peak force figure marked OWN ESTIMATE below is my own order-of-magnitude judgement, not a measurement, and must be validated by a pull test.

Basis of the own estimates (assumptions):

  • Load path in the layer plane, ASA, 4+ perimeters, 100% infill in the stressed section.
  • Short-term in-plane strength about 37 MPa (Bambu ASA TDS, XY).
  • Across-layer hook strength about 0.29 of in-plane (CNC Kitchen ASA hooks: 17 kg vertical vs 57 kg flat).
  • Sustained allowable stress at 60-70 C taken as 15-25% of short-term strength. This is judgement covering creep, porosity and SF 2, giving roughly 5-9 MPa in-plane.
  • Sustained bearing stress about 8-10 MPa under steel pins or washers.
  • PETG is at or above its glass transition (about 68-80 C) in 60-70 C sun, so treat PETG sustained values as at most half the ASA values. PC, PA6-CF and PETG-CF change the answer mainly through heat margin and stiffness: PETG-CF HDT is only 68 C, PA6-CF HDT is 164 C but it is hygroscopic.

Indicative ordering by realistic sustained clamp force per latch inside the 70x35x30 mm envelope (own judgement):

  1. Steel over-center draw or toggle latch on printed bosses. Commercial ratings are 135-670 N, with the printed mount as the limit (about 300-600 N, own estimate).
  2. Screw-down lid with heat-set inserts and a metal sleeve or washer. About 300-500 N per screw, own estimate. It is not a quick latch.
  3. Steel-pin-reinforced printed toggle latch, about 120-250 N.
  4. Printed cam latch with M3 pivots, about 60-150 N.
  5. Assembled printed over-center draw latch, about 40-100 N.
  6. Print-in-place over-center, bayonet, quarter-turn and snap-fit catches, about 10-60 N each. The ranking is estimated, not measured.

Outdoor material guidance from sources:

  • ASA beats PETG for sun-exposed latches. Vendor and forum reports put PETG yellowing and embrittlement at 6-12 months.
  • PETG creeps under sustained load above about 40 C in vendor guidance.
  • Never load a printed ASA or PETG hook across layer lines.

Sealing and test status:

  • Every printed IP67 or waterproof claim found is a designer assertion. At best it is a 10 cm, 10 minute dunk. Several designs explicitly say they are not IP-certified.
  • Designs that explicitly pair a latch with a TPU gasket: the MakerWorld Tough Case (TPU 85A gasket, PETG snap-fit latches, steel-pin hinges), the zx82net cam-latch box (printed TPU seal or a 2 mm cord), MakerWorld Waterproof Box 454290, and the MakerWorld print-in-place latch box 2435156.

Source limits:

  • Printables, MakerWorld, Thingiverse, MyMiniFactory, stlfinder and 3dgo pages returned HTTP 403 to WebFetch, so descriptions of those listings come from search-result summaries and the few mirrors that loaded. A listing ID that I could not map exactly is flagged in the entry.
  • The 200-search budget ran out before I could run the last three searches: an IP67 test blog, wire-bail jar-style latches, and thumbscrew or wing-nut lid clamps.
Topic Fact Value Source
Test evidence gap No designer, commenter, video or paper found that reports a measured sustained clamp force or pull-off force for a printed box latch. The only designer figure is a MakerWorld latch claimed to hold at least 10 kg (about 98 N, own conversion) in PLA Basic using stacked dumbbell plates, with the note that PETG might be more robust. Which MakerWorld model it is could not be pinned down (candidates 2036484, 2713704, 891931). 10 kg (about 98 N) static hang, PLA, designer claim link
Layer adhesion vs in-plane strength (hooks) CNC Kitchen hook test on a stock Prusa MK3S: printed flat PLA 73 kg, ASA 57 kg, PETG 55 kg. Printed vertically, so the load crosses layers: PLA 40 kg (55%), PETG 25 kg (46%), ASA only 17 kg (29%). PETG stretched instead of snapping. ASA 57 kg flat vs 17 kg across layers link
Warm chamber helps ASA layer bonding ASA printed in a roughly 30 C enclosure reached 20 kg across layers vs 17 kg, about 20% better. 17 kg to 20 kg (+20%) link
Softening under load vs temperature In CNC Kitchen's oven test of loaded parts, PLA started sagging at 60 C, PETG at 80 C and ASA at about 110 C, failing roughly 5-10 C later. This is a short-term softening test, not creep data. PLA 60 C, PETG 80 C, ASA 110 C onset link
PETG pull test, orientation Tom's 3D ring pull test: PETG held 24.5 kg printed standing (layer adhesion) and about 70.8 kg printed flat (author's doubled equivalent from half-thickness rings); PLA held 16.5 kg standing and about 20.75 kg flat. Single specimens, custom test. PETG 24.5 kg standing / about 70.8 kg flat link
Bambu PETG-CF datasheet Tensile strength 59 +/- 4 MPa (XY) and 38 +/- 3 MPa (Z); modulus 2460 / 1340 MPa; HDT 68 C at 1.8 MPa and 74 C at 0.45 MPa; Vicat 85 C; Tg 68 C. Specimens were 100% infill, annealed and dried at 65 C for 8 h, so as-printed parts will be weaker. The sheet's 'Basic Info' text wrongly calls it a tough PLA, a template slip. XY 59 MPa, Z 38 MPa, HDT 68 C link
Bambu PA6-CF datasheet Tensile strength 102 +/- 7 MPa in XY; modulus 4430 MPa XY vs 2170 MPa Z; HDT 164 C at 1.8 MPa and 186 C at 0.45 MPa. Strength and stiffness drop when the nylon absorbs water, so condition it for outdoor use. Figures are from search-result snippets of the PDF; the direct fetch returned 404. XY 102 MPa, HDT 164 C link
Bambu ASA datasheet The V3.0 sheet lists tensile strength 37 +/- 3 MPa (XY) and 31 +/- 4 MPa (Z); the older V2.0 listed Z as 35 +/- 4 MPa. V2.0 elongation at break was 9.2% XY vs 4.6% Z. From search-result snippets only; the direct fetch returned 404. XY 37 MPa, Z 31 MPa link
Material temperature ratings Prusament PETG is listed at 68 C and Prusament ASA at 93 C temperature resistance. The page stresses these are not universal operating limits or maximum ambient temperatures. PETG 68 C, ASA 93 C link
QIDI heat data and creep bands QIDI datasheet values: HDT PLA 57.6 C, PETG 71.8 C, PETG-GF 76 C; Vicat 61.6 / 79.7 / 85 C. Vendor guidance for a hook under 3 kg: PLA droops within weeks at 30-40 C, PETG sags slowly over months at 30-40 C and creeps noticeably above 40 C. Recommends 4-6 walls, PETG-GF above 10 kg load, ASA outdoors, safety factor 3x (5x overhead) and replacing heavily loaded parts after about two years. Qualitative vendor blog, no deformation numbers. PETG HDT 71.8 C; noticeable creep above 40 C link
No universal sustained-stress fraction The filamentspecs creep review states there is no universal safe percentage of tensile strength for creep, and that Tg, HDT and Vicat are not continuous-use limits. It cites: PETG honeycomb infill has about 15% lower long-term creep strain than line infill despite 14% lower tensile strength; an accelerated stepped-isostress PETG method takes 25 h vs 720 h; bolted PLA/PETG joints lost about 3% (PLA) and 11.5% (PETG) clamping force in seven days. Recommends avoiding sustained tension across layer interfaces, metal compression limiters under bolts, conditioning nylon, and defining allowable displacement before testing. PETG bolt preload loss 11.5% in 7 days vs PLA 3% link
PETG creep modeling paper A 2025 paper on accelerated creep prediction in printed PETG (stepped iso-stress method) reports about 15% lower long-term creep strain for honeycomb vs line infill at 10^6 s despite 14% lower tensile strength. Only the abstract was visible. -15% creep strain, honeycomb vs line link
Heat-set insert pull-out in PETG CNC Kitchen, PETG M3 samples, 4 perimeters and 100% infill: pull-out averaged 119 kg for a Ruthex heat-set insert (it ripped out), 118 kg for a screw straight into plastic, 120 kg for a helicoil, 86 kg for a nut in a side pocket and 166 kg for a nut in a bottom pocket. Torque-out: insert 3 Nm vs 1 Nm direct screw. 119 kg is about 1.17 kN (own conversion). 119 kg (about 1.17 kN) M3 insert in PETG link
Heat-set insert pull-out in PLA CNC Kitchen, Prusament PLA, 0.15 mm layers, 100% infill: M3 pull-out 181 kg for Ruthex, 157 kg for an eBay insert, 39 kg for a cheap injection-moulding insert, 142 kg for a screw straight into the plastic. Insert pull-out is well above any printed latch load, so the printed boss, not the insert, is the limit. 181 kg (about 1.78 kN, own conversion) Ruthex M3 in PLA link
Insert white paper figures (low confidence) A threaded-insert white paper reports average pull strengths of about 1,304 N (M3), 2,704 N (M4) and 3,421 N (M5), but the table's material labels are unclear, so treat these as approximate. The direct fetch returned 404; figures are from a search snippet. M3 1,304 N / M4 2,704 N / M5 3,421 N link
Threaded parts failure mode In a Hackaday-reported M5 comparison of 50 parts, threads rarely failed. The surrounding material cracked or delaminated, and thicker shells around holes improved strength. Brass inserts were hard to pull out or twist. No force figures given. Failure is in the surrounding wall, not the thread link
Clamping splits layers In a printed waterproof instrument housing log (PLA, bolts and washers), parts printed off the bed were too weak: the layers split under the clamping force. An epoxy-coated cap allowed much tighter bolting, but an uncoated collar then began to split. Layer splitting under bolt clamping link
Latch stiffness matters In MatterHackers' printed-carabiner tests the author found that the more flexible the filament, the more easily the latch unseats; polycarbonate scored highest, and nylon's lower stiffness hurt its result. PETG was stronger than PLA but failed violently. Hardware-store aluminium carabiners rated 150 lb failed at 168 and 183 lb with latches taped open. Stiffer material keeps the latch seated link
Layer-separation failure of printed PETG latches A Cybertruck owner forum reports PETG release handles failing by layer separation, consistent with the rule never to load a printed latch across layer lines. PETG latch delamination anecdote link
PETG vs ASA outdoors (vendor and forum) A QIDI vendor blog says PETG brackets in high UV showed yellowing and surface embrittlement in 6-12 months while ASA held colour and strength for about 2-3 years. A forum poster reports PETG yellowing after 8-10 months of direct sun but staying rigid, and ABS showing little UV damage after about 2 years. These are anecdotes, not controlled tests. PETG 6-12 months to embrittlement vs ASA 2-3 years (vendor) link
Forum field report on outdoor enclosures A circuit.rocks poster with outdoor enclosures deployed about two years saw PETG yellow after 8-10 months but stay functional; ABS units showed almost no visible UV damage; ASA recommended for 5+ year service. No latch or lid failures were reported in the thread. PETG yellowing 8-10 months link
Lid seam leaks first An outdoor-enclosure guide says a 3D-printed box is rarely waterproof by default and the lid seam usually fails first, so gasket design matters more than material choice. Another guide recommends a deliberate lip or labyrinth, a hard compression stop, a narrow raised bead over a wide flat band, and keeping screw holes and seams out of the sealing band. Seam and gasket design over material link
Gasket guidance (TPU hardness) TPU 95A is suggested as the starting point for most low-pressure gaskets, and 85A-90A for uneven surfaces or low clamp force; Shore hardness alone does not define a gasket (compression set, tear strength and rebound vary). No compression percentage or N/mm line load is given. The search found no published compression force per length for TPU 85A, so that must be measured or calculated separately (the gasket role). 85A-90A for low clamp force link
Printed seal leak tests A Hackaday.io log of a printed case with 6 mm silicone tubing in a groove and a rounded 2.5 mm lid ridge: no leak at 10 min, 1 h and 2 h submerged. An earlier variant leaked at 24 h and after 1-2 h. 3M silicone sealant leaked within seconds. The author calls it water-resistant, not waterproof, because layer gaps let moisture in. Dry at 2 h submerged, leaks by 24 h in other variants link
zx82net box leak test A reviewer submerged the zx82net rugged box under 10 cm of water for 10 minutes: no leakage with the thick seal, about 10 ml in with the thin seal. The designer recommends PETG for latches and hinges and warns PLA may creep, loosening the seal. 10 cm, 10 min: dry (thick seal) / about 10 ml (thin seal) link
IP claims are unverified No printed-enclosure listing found cites an IP test report. One MakerWorld/Thangs parametric enclosure says explicitly it is not independently tested or certified to any IP rating. A Printables box is labelled IP65/IP67 with no test. A rated vent does not make a printed box IP67 or NEMA-rated. 0 listings with IP test evidence link
Printed TPU O-rings vs rubber The Printables EDC container designer does not recommend self-printed TPU O-rings because their tests performed worse than original ones; a MakerWorld canister designer says they trust the O-ring more than the TPU seal. Under-extrusion lets water through the printed seal itself. Rubber O-ring beat printed TPU in two designers' tests link
Material and recommendations in the Tough Case MakerWorld Rugged Waterproof Tough Case recommends ABS for the body, TPU 85A for the gasket and PETG for clips and latches, with steel-pin hinges. It gives no force, IP or leak data. Inner dimensions 115 x 76 x 38 mm. ABS body / TPU 85A / PETG latches link
Real-world latch lifetime The designer of the Pentair LXLATCH replacement says the original pool-controller latches broke after about a decade in the sun and recommends UV-resistant ABS, PETG or PC. about 10 years to failure (original latch) link
Commercial steel latch clamp ratings Southco 97-series over-center draw latches: 97-30 compact 135 N; light-duty 310 N; heavy-duty 670 N; a 290 N size; 97-70 645 N. Bossard BN 32753: 260-530 N. These set the benchmark a printed latch has to approach. 135-670 N [link](https://www.gripwell.com.sg/image/catalog/Gripwell/Furniture and Architectural Hardware/Latches/Draw Latches/97 Over-Center Draw Latch/Gripwell - 97 Over-Center Draw Latch.pdf)
Pelican reference Pelican's Storm-series cases use a PBT (Valox) latch and an EPDM O-ring seal; Pelican publishes no latch clamp-force number, so no direct benchmark exists. PBT latch + EPDM O-ring, no force published link
Pin hardware for printed pivots Makers use steel pins: 3 mm steel and stainless pins in the MakerWorld toggle latch, a 2 mm bicycle spoke in engineered.at's box, 1.6 mm spring wire in a Printables panel latch, and a stainless pin added to a PETG caravan latch for shear. Pin sizes only; no tested load gains are published. 1.6-3 mm steel pins link
Snap-fit design rules Guides suggest about 3% allowable strain for PETG and ABS/ASA snap arms printed flat and about half that printed upright; a Z-oriented cantilever loses about 50% elongation at break and 20-30% tensile strength. These are design heuristics, not measurements. 3% strain flat, 1.5% upright link
Orientation advice from makers Makers advise 100% infill on the moving latch part (small locking arms break first), 3 perimeters and over 30% infill on cam-latch boxes, and printing the latch in the plane of the arm. The cam-latch box listing was tested only in PLA and PETG. 100% infill on cam arm link
Blue Robotics printed clips Blue Robotics staff say the BlueROV2 was prototyped with 3D-printed clips about twice the size of the aluminium ones, and they worked fine. 2x scale vs aluminium link
Search coverage limits Printables, MakerWorld, Thingiverse, MyMiniFactory, stlfinder, 3dgo and PMC returned HTTP 403 or verification pages to WebFetch, and the 200-search budget ran out before three planned searches (IP67 test blog, wire-bail jar-style latches, thumbscrew or wing-nut lid clamps). Listing details are from search summaries, so verify any listing before relying on it. 403 on most maker sites; 200/200 searches used link

Test-data and literature researcher

Research on measured force and creep data for FDM latch parts. It found plenty on fastener interfaces and hook orientation, but almost nothing measured on whole latches.

What exists

  • Peak strength: CNC Kitchen hook tests, heat-set insert and screw tests, datasheets, and one printed draw latch that held at least 187 N without failing.
  • No measured force for a printed cam lever, bayonet or toggle latch beyond that one draw-latch lower bound.
  • No long-term (months) creep data for PETG, ASA or PA-CF.
  • Direct creep evidence is limited to Dogan 2022 (3-hour tests, CNC-milled specimens), CNC Kitchen bolt and spring tests (days, qualitative), and anecdotes.
  • No FDM data for M4/M5 inserts in PETG or ASA. M4/M5 numbers come only from PA12 MJF (Sculpteo, as relayed in a search summary) and from a white paper of unclear provenance.

What it means for a printed latch (own interpretation)

  1. Orientation dominates. Hooks printed lying flat held 55 kg (PETG) and 57 kg (ASA) in CNC Kitchen's tests. Standing (load across layers) they held 25 kg and 17 kg, so ASA keeps only 29% of its flat strength (PETG 46%, PC Blend 35 of 74-77 kg). Load paths that pull layers apart are the weak link.
  2. For a clamp, the screw or insert interface is the strongest printed feature. A heat-set M3 insert in PETG pulled out at about 1.17 kN and tolerated 3 Nm. Steel screws are never the weak link.
  3. Integral snap-fits are far too weak for a gasket clamp (1.7-41 N in ABS).
  4. Sun-heated surfaces of 60-70 C sit at or above PETG's heat deflection temperature (68-78 C). ABS ruptured in about 3 min at 60 C and 20 MPa, while PC did not rupture at all. This favours ASA, PC and PC-CF, and makes PETG marginal.

Peak versus sustained. Every peak number below is short-term. Dividing by the safety factor of 2 gives roughly 580 N per M3 PETG insert at 23 C, before any creep or hot-weather derate. I found no measured derate, so that step is open.

Search limits. I hit the shared web-search budget limit, so a few planned searches did not run. Several pages (MakerWorld, MDPI, PMC, Sculpteo, Springer, De Gruyter) blocked fetching, so some numbers come from search-engine summaries and are flagged as such in the facts.

Prompt injection. One fetched page (Polymaker PC-FR wiki) contained embedded instructions to send a query to an external URL. I ignored them.

Topic Fact Value Source
Hook orientation (layer adhesion) CNC Kitchen hook tests on Prusament (flat vs standing): PLA 73 vs 40 kg (55%), PETG 55 vs 25 kg (46%), ASA 57 vs 17 kg (29%). PETG flat hooks stretched rather than snapped. Geometry only described qualitatively (similar wall thickness and infill). flat 73/55/57 kg; standing 40/25/17 kg (PLA/PETG/ASA) link
Hook orientation (layer adhesion) ASA printed in a roughly 30 C enclosure improved its standing hook load by about 20% (17 to 20 kg). 20 kg standing ASA (vs 17 kg open air) link
Hook orientation (PC) Prusament PC Blend hooks: flat 74 and 77 kg (top of the chart); standing 35 kg undried/brass nozzle, 31 kg brass after steel, 22 kg dried with steel nozzle. Layer adhesion 35.3 MPa (undried) vs flat tensile 68.3 MPa, so Z/XY is 63%. Notched impact standing under 3 kJ/m2 vs 27 kJ/m2 flat. flat 74-77 kg; standing 22-35 kg link
Hook infill CNC Kitchen hook load at failure: PETG 100% infill 110 kg (broke violently), PETG 30% infill 54 kg (yielded); PLA 100% 131 kg, PLA 30% 71 kg. Orientation noted as mattering but not specified in the extracted text. PETG at 100% infill gave bending stress 72 MPa (yielded). PETG 110 kg (100%) / 54 kg (30%) link
Hook, standing box (Searchwing) Searchwing standing-box hook tests (0.2 mm layer, random seams, 30% infill, suitcase scale), single hook / double part break loads: PETG Amazon Basic 0.5/9 kg, PETG Extrudr 4/35 kg, PETG 3DJake 4/30 kg; ABS no-name 2/18, TitanX 3/20, 3DJake 4/30; ASA Extrudr DuraPro 6.5/29 (with shield), 6/25 (without), 6/35 (acetone-vapour treated); ASA 0.6 mm nozzle 100% infill 12/50+. PLA Prusa 7-8/29. Crude method but it shows the large brand-to-brand spread. single hook 0.5-12 kg depending on material/brand link
Layer adhesion vs print angle (PLA) PLA tensile strength by print angle (CNC Kitchen, Prusa CORE One, 0.2 mm): flat 63 MPa, 30 degrees 44, 45 degrees 40, 60 degrees 36, upright 31. 45 degrees gives about 27-29% more than upright. Layer adhesion is typically about 50% of in-plane strength depending on material and settings. Trend probably transfers to PETG/ASA but was only measured for PLA. 63 / 44 / 40 / 36 / 31 MPa link
Layer adhesion vs extrusion temperature (PETG) Standing PETG mini-tensile specimens (dasFilament): layer adhesion 18 MPa at 200 C, 22 at 215, 30 at 230, 32 at 245 (peak, about 58% of the 55 MPa lying strength), 24 at 260. Hotter or colder than the optimum costs strength. PLA peaked at 40 MPa at 230 C (lying 60). PETG Z strength 18-32 MPa vs 55 MPa lying link
Layer height and standing hooks Standing PLA hooks (CNC Kitchen): 0.05-0.2 mm layers all good with 0.15 mm best; 0.3 mm layers gave about half the best load; 0.4 mm gave basically no load. All standing results were at least 50% below lying (about 80 kg). Rule of thumb: layer height at or below half the nozzle diameter. 0.2 mm or less on a 0.4 mm nozzle link
Heated chamber effect (ABS, PC) eSUN ABS layer adhesion (reference flat 39 MPa): chamber open (up to 26 C) 21 MPa (about 54%), passively heated (just under 50 C) 23 MPa, actively heated to 65 C 29 MPa (about 75%). Prusament PC Blend: 65% / 72% / 77% of reference for open / passive / 65 C. No ASA, PETG or nylon data in this article. ABS 21 / 23 / 29 MPa link
ABS vs PC layer adhesion and annealing ABS: about 35 MPa lying, standing about 50% of that. PC: about 70 MPa lying, standing about 80%. PC-core ABS about 60%. After annealing at 130 C for 112 h: ABS strength unchanged and distorted (about +20% in Z, -5 to -10% in XY), PC rose to almost 75 MPa with 0-2% change. Heat test: ABS failed at 115 C, PC held to 165 C. PC Z/XY about 80%, ABS about 50% link
Annealing PETG standing hooks PETG standing hooks went from 36 kg as printed to about 100 kg after plaster-supported annealing (about 2.8x; lying reference 106 kg), and standing tensile from 30 to 41 MPa (flat reference 53 MPa). The same treatment made PLA more than 30% weaker. This needs a 200 C oven cycle with a plaster mould, so it is impractical for large latch bodies; no data for ASA. PETG standing hook 36 kg to about 100 kg link
Stiffness (3-point bending) Bending modulus from CNC Kitchen tests: PLA 3300 MPa, ASA 2300, PETG 1900, Prusament PC Blend 2200. Notched Izod: PLA about 5, PETG about 8.6, ASA about 18, PC Blend about 27 kJ/m2. ASA 2300 / PETG 1900 / PC Blend 2200 MPa link
Temperature resistance under load CNC Kitchen oven test with a loaded nut: PLA starts to give at 60 C and fails about 5 C later; PETG starts to give at 80 C and fails about 5 C later; ASA softens at 110 C and fails at 120 C. Prusament PC Blend softens at about 110 C and fails at 125 C. This is a load-under-heating test, not a creep test. PETG 80/85 C; ASA 110/120 C; PC Blend 110/125 C (soften/fail) link
Heat-set insert pull-out (PETG M3) CNC Kitchen PETG M3 test (flat bar, 4 perimeters, 100% infill, n=3 pull-out): direct screw 118 kg, Ruthex heat-set insert 119 kg, Helicoil 120 kg, side-pocket nut 86 kg, bottom-pocket nut about 166 kg. Torque-out: direct screw 1 Nm, insert 3 Nm, Helicoil 1 Nm, nuts about 2 Nm. 1 Nm on M3 corresponds to more than 1500 N pretension. Layer height, nozzle and temperatures were not stated. about 1.16-1.18 kN (screw/insert/coil); 3 Nm insert link
Heat-set insert pull-out (PLA M3) PLA M3 pull-out: Ruthex 4.0 mm hole 181 kg (about 1775 N), eBay insert 4.1 mm 157 kg (about 1540 N), cheap injection-moulding insert 4.5 mm 39 kg (about 383 N), direct-screwed 2.7 mm hole 142 kg (about 1393 N). Torque-out 3-4 Nm for all inserts (bolt head sheared) vs about 1 Nm for direct screw. In softer ASA the shallow-knurled eBay insert started rotating (no numbers). kg to N conversion is mine. Ruthex M3 181 kg in PLA link
Insert hole diameter M3 inserts in PLA (n=3 per diameter, about 50 inserts): as-printed holes at the smallest diameter (3.6 mm) averaged about 1400 N (about 150 kg); pull-out fell slowly then dropped sharply with larger holes; 4.2 mm as-printed gave about 90% of the theoretical maximum; drilled holes of 4.1-4.2 mm showed a major strength drop. Printed holes were about 0.25 mm undersized relative to CAD; keep the packaging value 4.0 mm as nominal. about 1400 N at 3.6 mm hole link
Insert size scaling (non-FDM) Sculpteo heat-set brass inserts in PA12 MJF (5 specimens each): M3 short 813 N, M3 long 1258 N, M4 1372 N, M5 above 1800 N. This is not FDM, so it indicates scaling only. Figures taken from a search-engine summary (page returned 403). M3 813-1258 N, M4 1372 N, M5 above 1800 N link
Insert size scaling (white paper) A white paper on inserts M2-M5 in PA12, PLA, PETG and Onyx (author unclear, not independently verified; page returned 404 on fetch) reports averages of roughly 1304 N (M3), 2704 N (M4) and 3421 N (M5) across materials, plus an average insert torque strength of 4.76 Nm. Treat as low confidence. M3 1.3 kN / M4 2.7 kN / M5 3.4 kN link
Thread repair vs inserts (SLS PA12) Peer-reviewed study on SLS PA12 (not FDM): printed threads failed at an average 3.41 kN, heat-set inserts 3.83 kN (about 12% higher), Helicoil inserts 4.78 kN (about 40% higher). Failure was thread/insert pull-out from the material in every case. Values from search summary; PMC page blocked on fetch. 3.41 / 3.83 / 4.78 kN link
Printed thread pull-out (PLA+) 1/4-20 metal hook screw pulled out of printed PLA+ threads (0.2 mm layers), reader-reported averages: 48.4 lbf (10% infill), 67.5 lbf (25%), 89.5 lbf (50%), above 110 lbf (instrument limit) at 100% infill. Bottom layers peeled off. 100% infill outperformed 50%. Numbers are from a commenter, not the article text. 215 N / 300 N / 398 N / above 490 N link
Printed thread orientation (ASA) ASA M10 printed nuts (MEX): specimens oriented at 45 degrees gave the highest tensile strength but needed more material and time; formed threads in printed polymer nuts were described as completely unsatisfactory; a load capacity above 14.7 MPa is claimed for a nut printed without post-processing. Abstract only, no failure loads. above 14.7 MPa (M10 ASA nut) link
Creep at temperature (FDM polymers, 3 h) Dogan 2022 (Ultimaker 2+ filaments, ASTM D638 Type IV, CNC-milled 2 mm off the outside to remove print defects, ASTM D2990 method, 3 h each, n=3): ABS ruptured in about 3 min at 60 C and 20 MPa. At 25 C and 40 C nothing ruptured. At 60 C all materials except PC (and the non-rupturing nylon) broke after some time; PLA broke at 60 C even at 10 MPa. PC showed the lowest creep in all conditions and no damage at 60 C and 20 MPa; nylon showed the largest strain without rupture; creep ranking best to worst: PC, CPE, ABS, TPLA, PLA. Tertiary creep only in PLA and TPLA. ABS rupture at about 3 min (60 C, 20 MPa); PC no rupture link
Creep test caveats The Dogan 2022 creep specimens were milled solid coupons, so they do not reflect layer-bond-limited behaviour in printed latch parts. Only three hours were tested. No PETG or ASA were included. Treat as a materials ranking, not a design allowable. 3 h; no PETG/ASA; milled specimens link
Long-term creep (ABS, ASA, PLA, PC, fibre) Hausler et al. 2024 (Open Engineering 14(1)) compared long-term creep of ABS, ASA, PLA and PC, plus fibre-reinforced grades, by measuring bending under sustained load and recovery (Prusa MK3S+, hardened 0.4 mm nozzle). Fibre reinforcement generally improved creep stability; the most promising were GreenTEC Pro Carbon and add:north PC Blend HT LCF. Numeric results not accessible (publisher blocked); only the abstract summary was read. best: PC Blend HT LCF and GreenTEC Pro Carbon link
Bolt-preload creep CNC Kitchen M4 bolt test (0.8 Nm, compressive load about 50% of the material's tensile strength, 1 week, room temperature): unannealed PA6 needed re-tightening almost daily; unannealed PA12 once after about half a week, similar to PLA and ASA; annealed PA6 (8 h at 110 C) slightly twice, close to the other polymers; PLA+ also crept. Spring test at 25% of tensile strength over several days: unannealed PA6 crept most; regular PLA crept more than nylons in the first 3 days. No mm values given. ASA about 1 retighten per week at 50% of tensile strength link
Polyamide moisture PA6 absorbs about 3% water (75% RH, 35 C, 3 days): stiffness falls to about one third (deflection about 2 mm vs 0.7 mm dry), tensile strength retained 56%; PA12 takes up about 0.7% with essentially unchanged stiffness and about 15% strength loss. This makes PA6-CF a poor choice for humid outdoor sealing duty; PA12-CF is better but still a nylon that creeps. PA6: 56% strength, 1/3 stiffness when wet link
CF nylon strength and heat CF-PA6 tensile XY about 140 MPa (datasheet claims 170); CF-PA12 almost 120 MPa. Oven test with weight: PA12 softens at 160 C and fails at 170 C; PA6 first deforms at 195 C and fails at 205 C. Nozzle about 280 C and hardened steel required. XY about 140 MPa (CF-PA6), about 120 MPa (CF-PA12) link
Creep, ABS print orientation Zhang et al. 2018 (Purdue/IUPUI, J. Mater. Eng. Perform. 27(1)): in the printed ABS creep test the 90 degree orientation had the lowest k value (0.2) in the plastics creep model, read by the authors as the most creep-resistant direction. Numbers from search summary; the repository page did not load. k = 0.2 at 90 degrees link
Creep, anecdotes (labelled anecdotal) Forum users report PETG HF maintains tension better than PLA, PC even a bit better than PETG, nylon rivalling PLA in creep, higher temperature increasing creep. Another builder reports CF-nylon parts lost every bolt's pretension and warped under their own weight; the Voron community suggests PC or PC-CF instead. No measurements. anecdotal only link
Creep, vendor heuristic (labelled vendor claim) A printer vendor's blog claims PETG shows noticeable creep at room temperature when loaded above about 30% of its yield strength for extended periods and recommends a safety factor of 4-5 for wall brackets. No test data or source is given; use only as a cautious rule of thumb. about 30% of yield; SF 4-5 (vendor claim) link
Creep, PLA below Tg Flexural creep experiments on printed PLA (Siegen) showed non-negligible creep over long periods even at temperatures well below the glass transition temperature, and physical aging shifts creep curves on a log-time scale. PLA only, not PETG or ASA. PLA only link
Datasheet PETG Polymaker PolyLite PETG (page lists values consistent with TDS V5.4): tensile XY 50.8 +/- 0.9 MPa, Z 42.8 +/- 2.8 MPa; elongation XY 8.4%, Z 3.3%; E XY 2117 MPa, Z 1899 MPa; HDT 75 C at 1.8 MPa and 78 C at 0.45 MPa; Tg 81 C; Vicat 84 C. Specimens: 240 C nozzle, 100% infill, fan off. An older TDS (V5.2) reportedly lists Z 13.4 and XY 31.9 MPa, so datasheet Z values vary widely between revisions. Z 42.8 MPa; HDT 75/78 C; Tg 81 C link
Datasheet PC Polymaker PolyMax PC-FR (page states it is no longer made): tensile XY 67 +/- 4.5 MPa, Z 46 +/- 4.8 MPa; elongation XY 3.49%, Z 2.2%; HDT 107 C at 1.8 MPa and 110 C at 0.45 MPa; Tg 115 C. For plain PolyMax PC a search summary of the V5.3/V5.4 TDS gives tensile XY 53.44 MPa, Z 41.43 +/- 1.50 MPa. PC Z 41-46 MPa; HDT 107-110 C link
Datasheet PETG-CF Bambu PETG-CF TDS V2.0 (specimens annealed and dried at 65 C for 8 h, 100% infill): tensile XY 59 +/- 4 MPa, Z 38 +/- 3 MPa; E XY 2460, Z 1340 MPa; bending strength XY 83, Z 62 MPa; HDT 68 C at 1.8 MPa and 74 C at 0.45 MPa; Tg 68 C; Vicat 85 C. Note the sheet's descriptive text calls the filament a tough-PLA blend and Tg/Tm match that, so the body text looks like a copy-paste template; verify with Bambu. HDT below PETG-CF peak summer surface temperature. Z 38 MPa; HDT 68/74 C link
Datasheet PA6-CF Polymaker PolyMide PA6-CF datasheet versions disagree: V5.2 gives tensile XY about 81.7 MPa and Z about 64.4 MPa with Z elongation 2.5%; another version lists XY about 105 and Z about 67.7 MPa. Z modulus ranges 3760-4713 MPa across versions. HDT 173 C appears only on a retailer listing (unverified). Values are dry; PA6 is moisture-sensitive. Search-summary data. Z about 64-68 MPa (dry) link
Datasheet ASA Prusament ASA product page gives only heat resistance (no signs of deformation up to about 93 C) and 'UV stable'; no tensile, HDT, Z-axis or creep values on the page. Bambu's comparison table (retailer copy, search summary) lists ASA HDT 100 C and Z impact 4.9 kJ/m2 vs ASA-CF HDT 110 C and 9.4 kJ/m2. ASA about 93-100 C link
Snap-fit retention (ABS) Abdul Manan and Osman Zahid 2025: 16 cantilever-hook models printed in ABS and tested on a universal testing machine against ANSYS; retention force from 1.722 N (Model 2) to 39.458 N (Model 5); insertion force from 3.34 N (Model 10) to 34.346 N (Model 13) in one listing, with a second listing giving 41.1 N maximum retention and 32.2 N maximum insertion; simulation to experiment error under 1.2-2.4% for the best models. Higher insertion and retention angles raised forces. Orientation not a variable. 1.7 to 41 N retention link
Snap-fit design strain (assumption) A snap-fit calculator assumes allowable strain of 2% for PLA and 3% for PETG/ABS/ASA when the arm is printed flat, and half that when the arm stands along Z. These are design assumptions, not measurements. Guides generally advise printing hooks flat so bending acts along the layers. 2% PLA, 3% PETG/ABS/ASA (flat) link
Pin bearing strength Khosravani 2023, FDM double-shear pin-bearing coupons in PLA and ABS: highest fracture load 3646 +/- 143 N (ABS, W/D = 3); highest ultimate bearing strength 189 +/- 5 MPa (ABS, 3 mm hole); low W/D failed by cleavage, W/D 9 and 12 by bearing. Print orientation not varied; values from search summary (page 403 on fetch). up to 3.6 kN fracture; 189 MPa bearing (ABS) link
Printed draw latch load MakerWorld printed draw latch (0.2 mm layers, 3 walls, 15% infill): a 5-gallon jar of about 42 lb (about 187 N) did not break it. The designer notes pull force rises with the gap between the latch halves. This is a lower bound, not a rated or sustained value. at least 187 N, no failure link
Toggle latch gasket MakerWorld self-locking toggle latch uses steel pins for reinforcement and recommends a roughly 2 mm elastic gasket to stabilise the clamping force; a test bench fixture is included but no force values were visible. 2 mm elastic gasket, steel pins link
Toggle clamp formula Engineering explainer models clamp force as hook stretch x hook spring rate, with an example of k = 200 N/mm and 1.5 mm stretch giving 300 N. Illustrative only, not test data. 300 N example link
Cam-clamp metal benchmark An ELESA catalogue lists a metal cam clamp (LAC.44) with maximum clamping force 3500 N. This is a catalogue rating for a steel part, useful only as a scale reference; no printed cam-lever force data was found. 3500 N (metal) link
Epoxy-bonded latch casing (adhesion limit) UW Midsun test of 3D printed latch casings bonded to carbon fibre with epoxy under a 200 lb pull: PETG held 82 lb before the whole print came off (poor epoxy bond), resin held 100 lb (test maximum). Measures the bond, not the plastic. PETG 82 lb bond link
Own calculation: peak to sustained at SF 2 Own calculation, safety factor 2 only (no creep/heat derate, because none is measured): M3 PETG insert 1.17 kN gives about 580 N; M3 PETG direct screw 1.16 kN gives about 580 N; bottom-pocket nut 1.63 kN gives about 810 N; side-pocket nut 0.84 kN gives about 420 N; flat ASA hook 559 N gives about 280 N; standing ASA hook 167 N gives about 83 N (196 N, about 98 N in a 30 C enclosure); flat PETG hook 540 N gives about 270 N; standing PETG hook 245 N gives about 123 N; PC Blend flat hook about 740 N gives about 370 N; ABS snap-fit about 40 N gives about 20 N. Hook figures are for CNC Kitchen's own geometry only. see fact link
Own calculation: sun surface temperature vs material limits Own interpretation: an enclosure surface of 60-70 C in sun sits at or above PETG's HDT (75-78 C Polymaker, 68-74 C for PETG-CF) and close to its Tg (81 C; PETG-CF 68 C), so a PETG latch loaded at 60-70 C is at risk of creep. ASA (heat resistance about 93-100 C), PC (HDT 107-110 C, Tg 115 C) and PC-CF have margin. In Dogan 2022, ABS ruptured in about 3 min at 60 C and 20 MPa while PC did not. PETG marginal; ASA/PC preferred at 60-70 C link
Own calculation: steel hardware is never the limit Own calculation from ISO 898-1 stress areas (M3 5.03, M4 8.78, M5 14.2 mm2) and class 8.8 proof stress 580 MPa: proof loads about 2.9, 5.1 and 8.2 kN. These are 2.5-7 times higher than the measured PETG M3 insert/screw pull-out (about 1.2 kN), so the printed boss or lug sets the latch's capacity. M3/M4/M5 proof about 2.9/5.1/8.2 kN link

Seal / gasket engineer

GASKET-ENGINEER RESULT. Bottom line: the force each latch must deliver is set mainly by the gasket cross-section you print, not by IP rating. A solid 3 x 3 mm 85A TPU bead is very stiff. Over a 700 mm path on a 200 x 150 mm lid it needs about 2.9 kN at a bare sealing threshold (~7% squeeze), about 6.5 kN at 15% and about 11.6 kN at 25%. With 6 latches that is about 480 N, 1.1 kN and 1.9 kN per latch (own calculation from the Texin 985 85A TPU ASTM D575 curve). A narrow printed rib (1.2 x 2.4 mm) or a hollow/low-infill bead needs only about 1.2-3.6 kN total (about 200-600 N per latch with 6 latches). A 1 mm rib pressing into a flat gasket needs about 2.8-6.3 kN (rough estimate). Recommended design target: gasket line load of about 2-4 N/mm (about 1.4-2.8 kN on the reference lid), 20-25% initial squeeze, and a positive hard stop at every latch. That makes a realistic latch requirement about 250-600 N sustained per latch with 6 latches. Latches rated far above that only pay off if you insist on a solid wide bead.

Four other findings:

  • Sealing pressure: Garlock says most elastomer gaskets seal at about 200 psi (1.4 MPa) assembly stress. On the TPU curve that is only about 7% squeeze (0.2 mm on a 3 mm bead). IP67 water head (1 m, about 10 kPa) is negligible against that. Leaks come from FDM surface and layer-line leak paths, not from water pressure.
  • Compression set: BASF Ultrafuse TPU 85A shows 26% set at 23 C and 52% at 70 C (ISO 815). Squeeze therefore roughly halves after hot sun. Start at 20-25% so at least 10-12% remains, and keep 0.2 mm or more of absolute squeeze (Parker's minimum).
  • Flange stiffness is the real limiter on latch count. Mid-span bow is wL^4/(384EI) for a continuous rim (own calculation). With w = 3.7 N/mm and a 0.15 mm bow allowance, a flat 3 mm lid edge only allows about 30 mm pitch. A 3 mm plate plus 20 mm deep skirt allows about 110 mm. A 30 mm deep box rim allows about 150 mm. In most cases a stiffer rim is cheaper than a stronger latch.
  • Material and temperature: Prusament lists PETG at 68 C and ASA at 93 C temperature resistance, so PETG is marginal for a sustained-load latch or flange at 60-70 C sun. TPU stiffens in the cold, about 2.2x higher flexural modulus at -30 C than at 23 C (Texin datasheet), so closing force at a fixed stroke rises in winter.

Limits and caveats:

  • Printed TPU gasket force-deflection data (infill, hollow, rib geometry) are not published. My printed-gasket numbers use molded Texin 985 data scaled by geometry and an assumed 0.4-1.0 infill factor. Measure on a force gauge before trusting them.
  • The WebSearch budget ran out near the end, so I could not source PETG/ASA moduli (I assume E = 1.8 GPa) or FDM sealing-face roughness.
  • Some Parker O-ring numbers come from search-result excerpts because the Parker page returned HTTP 403 on fetch. The Parker handbook force charts are images, so the O-ring cross-checks use the Lindley formula as given on a seal-vendor page.
  • Scratch text-extraction of downloaded PDFs was done only in the sandbox temp dir. No project files were created, edited or deleted.
Topic Fact Value Source
required-force REFERENCE SCENARIO (own calculation). Lid 200 x 150 mm with a continuous gasket along the full lid perimeter, path length P = 2 x (200 + 150) = 700 mm (a gasket inset ~10 mm would be ~660 mm, about 6% less). Cross-section assumed: 3 mm wide x 3 mm tall SOLID 85A TPU bead, 100% infill, shape factor 0.5 (about the same as the 0.57 of the ASTM D575 specimen, which is 28.6 mm diameter x 12.5 mm thick per the standard). Force per length F' = sigma(strain) x 3 mm, with sigma taken from the Texin 985 (85A TPU) ASTM D575 compressive-load curve. Total closing force F = F' x 700 mm. w = 3 mm, P = 700 mm link
required-force Reference total closing force, LOW end (just above the Garlock rule-of-thumb sealing stress of about 200 psi = 1.4 MPa, which is 6.7% squeeze = 0.20 mm of a 3 mm bead): F' = 4.1 N/mm, total about 2.9 kN. This is a bare threshold with no margin for FDM roughness, flatness error or relaxation. about 2.9 kN (F' 4.1 N/mm) link
required-force Reference total closing force, MID design point (15% squeeze = 0.45 mm; Texin 3.10 MPa at 15%): F' = 9.3 N/mm, total about 6.5 kN. At 10% squeeze (2.07 MPa): F' = 6.2 N/mm, total about 4.3 kN. about 6.5 kN at 15% (about 4.3 kN at 10%) link
required-force Reference total closing force, HIGH end (25% squeeze = 0.75 mm, the top of the 20-30% window recommended by KRAIBURG and Elasto Proxy; Texin 5.52 MPa): F' = 16.6 N/mm, total about 11.6 kN. At 20% squeeze (4.31 MPa): F' = 12.9 N/mm, total about 9.0 kN. about 11.6 kN at 25% (about 9.0 kN at 20%) link
required-force PER-LATCH CLOSING FORCE for the 3x3 mm solid bead on a 700 mm path, assuming perfectly even distribution (own calculation). Seal-threshold 2.9 kN: 4 latches = 724 N, 6 = 483 N, 8 = 362 N. 15% (6.5 kN): 4 = 1628 N, 6 = 1085 N, 8 = 814 N. 25% (11.6 kN): 4 = 2898 N, 6 = 1932 N, 8 = 1449 N. Add roughly 20-30% to corner and end-of-span latches for non-uniform load sharing (my assumption). 4/6/8 latches: 0.72/0.48/0.36 kN (low); 1.63/1.09/0.81 kN (15%); 2.90/1.93/1.45 kN (25%) link
required-force ALTERNATIVE cross-section A (own calculation): narrow printed rib 1.2 mm wide x 2.4 mm tall (three 0.4 mm perimeters). Using Texin stress x width (conservative-high), 700 mm path: 7% squeeze 1.2 kN; 10% 1.7 kN; 15% 2.6 kN; 20% 3.6 kN; 25% 4.6 kN. At 15% squeeze per latch: 4 latches 651 N, 6 latches 434 N, 8 latches 326 N. At 20%: 905 / 603 / 453 N. 1.2-4.6 kN total; 6 latches: 200-770 N each link
required-force ALTERNATIVE cross-section B (own rough estimate, low confidence, plus or minus a factor of about 2): 1 mm wide rigid rib pressing 1 mm into a 3 mm flat TPU gasket gives a line load of about 4-9 N/mm, so about 2.8-6.3 kN over 700 mm. Per latch: 4 latches 700-1575 N, 6 latches 470-1050 N, 8 latches 350-790 N. 2.8-6.3 kN total link
required-force ALTERNATIVE cross-section C (own calculation): 3 mm round cord of 85A elastomer (E of about 14 MPa) via Lindley's formula, 700 mm path: 15% squeeze 2.15 kN; 20% 3.4 kN; 25% 5.0 kN. Per latch at 20% squeeze: 4 latches 845 N, 6 latches 564 N, 8 latches 423 N. 2.2-5.0 kN total link
required-force DESIGN CONCLUSION (own judgement): size the gasket for a line load of about 2-4 N/mm (about 1.4-2.8 kN on 700 mm). With 6 latches that is about 240-470 N closing force per latch; with 8 latches about 180-350 N. A latch that sustains about 500-600 N each (safety factor 2 applied on top) therefore covers a well-designed printed gasket. Solid wide TPU beads at 20%+ squeeze push the per-latch requirement above 1.5 kN and also exceed what a printed 70 x 35 x 30 mm latch can hold for months. 2-4 N/mm design line load; 6 latches = about 240-470 N each [link](own calculation (inputs: https://sushengpolymer.com/media/pdf/phFiH7_Texin-985.pdf))
compression-force-data Texin 985 (polyether TPU, Shore 85A, Covestro): ASTM D575 compressive load at 2% deflection 0.345 MPa, 5% 1.03 MPa, 10% 2.07 MPa, 15% 3.10 MPa, 20% 4.31 MPa, 25% 5.52 MPa, 50% 16.5 MPa. This is the best published compression-vs-squeeze curve found for an 85A TPU (molded, not FDM-printed). 2%:0.345 / 5%:1.03 / 10%:2.07 / 15%:3.10 / 20%:4.31 / 25%:5.52 / 50%:16.5 MPa link
compression-force-data Texin 985 other properties: tensile stress 4.80 MPa at 50% strain, 5.50 MPa at 100%, 9.70 MPa at 300%; flexural modulus 26.9 MPa at 23 C and 59.0 MPa at -30 C; Bayshore resilience 45%. flexural modulus 26.9 MPa (23 C) vs 59.0 MPa (-30 C) link
compression-force-data BASF Ultrafuse TPU 85A (printed filament, TDS v2.5, ISO 527, conditioned): stress 7.2 MPa at 50% elongation and 8.7 MPa at 100% when printed flat (XY); 6.2 and 7.5 MPa when upright (ZX). Stress at break 34 MPa (XY) vs 10 MPa (ZX); elongation at break 600% vs 320%; tear strength 80 kN/m (XY), 18 kN/m (XZ on edge) and 30 kN/m (ZX). Shore A 85, density 1111 kg/m3, Tg -44 C. XY 8.7 MPa @100%; ZX 7.5 MPa @100%; break stress 34 vs 10 MPa link
compression-force-data Compression test of 3D-printed Ultrafuse TPU 85A (Ultimaker 3, 100% fill, 10 mm dia x 10 mm cylinders, ISO 604 style, compressed 7 mm = 70% strain): mean peak force 2587 N with a circular fill pattern, 1759 N zig-zag, 1315 N lines (about 2x spread from print pattern alone); peak stress 32.9 MPa circular. Specimens recovered strongly after the test (spring-back, as reported). 1315-2587 N at 70% strain (78.5 mm2 area) link
compression-force-data Nace et al. 2021 (Rapid Prototyping Journal): 50x50x25 mm FDM TPU blocks with four infill patterns (concentric, cross, cross3D at 20% and 30%, gyroid at 5% and 8%), compression to 70% per ISO 3386-1. TPU stiffness increases with infill percentage; 2D patterns show elasto-plastic buckling of cell walls. The filament used was Shore 93A (not 85A), and the stress values are only in figures, not in the text. qualitative; no numbers in text link
compression-force-data Young's modulus of 85A: NinjaFlex 85A TPU lists 12 MPa (ASTM D638 as reported by an aggregator of manufacturer data), tensile strength 26 MPa, elongation 660%. The Gent relation (Wikipedia form) gives about 13 MPa for Shore 85A (my arithmetic: 0.0981(56+7.62336x85)/(0.137505(254-2.54x85))). Both agree with the small-strain stiffness implied by Texin (about 17 MPa effective at 2% for shape factor 0.57). E of about 12-13 MPa link
compression-force-data Gent relation as given on Wikipedia (Shore durometer): E (MPa) = 0.0981(56 + 7.62336 S) / (0.137505(254 - 2.54 S)), S = Shore A. Alternative log-linear fits give ~4 MPa for 85A, so the choice of formula matters; measured values (12 MPa NinjaFlex) side with the Gent form. 13.2 MPa at S = 85 (own arithmetic) link
compression-force-data O-ring cross-check, Parker excerpts: 0.070 in cross-section at 20% squeeze needs roughly 9-25 lb/in for 90A and 5-18 lb/in for 70A; 0.103 in section about 9-18 lb/in; softer durometer can cut the required force by up to 50%. Converted (1 lb/in = 0.175 N/mm, own conversion): 90A 1.6-4.4 N/mm; 70A 0.9-3.2 N/mm. These are LINE-contact round sections and are much softer than a flat-topped bead. 90A: 1.6-4.4 N/mm; 70A: 0.9-3.2 N/mm (0.070 in, 20%) link
compression-force-data Apple Rubber: a 0.070 in, 50-durometer O-ring needs about 4.5-14 lb/in (0.8-2.5 N/mm, own conversion) for 20% compression. Parker notes the load for a given installation is a range, and that compression force drops only 10% (70-durometer) to 22% (90-durometer) from 24 C to about 126 C. 50A, 0.070 in, 20%: 4.5-14 lb/in link
compression-force-data Lindley O-ring compression-force formula quoted by a seal vendor: F = piDdE(1.25 r^1.5 + 50 r^6), i.e. per length F' = Ed(1.25 r^1.5 + 50 r^6) (r = squeeze ratio). Vendor modulus table: 50A 2.2, 60A 3.5, 70A 5.8, 80A 9.6, 90A 19.5 MPa. Worked example 70A, ID 50 mm, d 3.53 mm, r = 0.20 gives 395 N total (2.35 N/mm, matched by my check). Sanity check against Parker excerpt: 90A, d 1.78 mm, 20% gives 4.0 N/mm (Parker range 1.6-4.4 N/mm). 3 mm cord, E = 14 MPa: 4.8 N/mm at 20% link
contact-pressure Garlock gasket assembly stress rule of thumb (Aug 2022): most elastomeric gaskets will seal at about 200 psi (1.4 MPa) assembly stress; recommended assembly stress for elastomers (70 Shore A) is minimum 600 psi (4 MPa) and maximum 900-1200 psi (6-8 MPa). On the Texin curve 1.4 MPa corresponds to about 6.7% squeeze and 4 MPa to about 19% (own interpolation). seal: 1.4 MPa; recommended min 4 MPa; max 6-8 MPa link
contact-pressure IP67 water head is tiny compared with sealing stress: 1 m of water = 9.81 kPa (own calculation, 1 m x 1000 kg/m3 x 9.81). A seal vendor recommends assembly contact pressure of 1.5-2x the fluid pressure. Even the 1.4 MPa threshold is more than 100x a 1 m head. Leakage in printed enclosures is therefore governed by surface conformance (roughness, layer-line leak paths, warp), not water pressure. IP67 = immersion up to 1 m for 30 min per IEC 60529 (standard definition, general knowledge). 9.81 kPa at 1 m link
contact-pressure A Rogers/PORON enclosure-gasket note: silicone at about 1.5 psi (10.3 kPa), 3.2 mm thick, leaks 1.5 mL/min at 12.7 mm width, 12 mL/min at 6.35 mm, and 47 mL/min at 3.2 mm. Narrow gaskets leak much more at low stress, an argument for a wide land or a second rib on a TPU gasket. Rogers also gives a CFD rule of thumb at 25% compression: under 10 psi is easy closure for plastic housings, 10-30 psi is balanced, over 30 psi is heavy-duty. width 3.2 mm: 47 mL/min vs 12.7 mm: 1.5 mL/min link
compression-percent Recommended compression for solid elastomer gaskets: Elasto Proxy gives 20-30% for most solid rubbers (40-50A: 20-25%, 60A: 25-30%, 70A: 30-35%, 80A: 35% maximum; 15% minimum for reliable seal; over 35% risks permanent deformation). Its plastic-enclosure page says 40% is ideal with a 10-15% minimum and 50% maximum (the two pages disagree; the plastic-enclosure figure looks like a sponge/foam guideline). No source gives a guaranteed compression for IP65/IP67. 20-30% solid (80A: up to 35%) link
compression-percent KRAIBURG TPE gasket guidance: a nearly rectangular profile thicker than 2 mm compressed about 20-30% has proven advantageous; avoid copying round or multi-hump rubber profiles one-to-one; fine raised features lose shape through creep; standard service range about -40 to +80 C. 20-30% on near-rectangular profile over 2 mm link
compression-percent Parker O-Ring Handbook (static seals): maximum recommended squeeze for most elastomers 30% (face seals often benefit at 30% because recovery is better); danger in going much beyond 30%; minimum squeeze for any seal about 0.2 mm (0.007 in) because very light squeeze quickly takes 100% set; gland fill 60-85% (optimum 75%), at least 10% void. max 30%; min 0.2 mm absolute; fill 60-85% link
compression-percent Printed TPU gasket reference designs: a MakerWorld parametric enclosure uses a TPU gasket in a groove with compression stops, about 25% designed squeeze on a 1.2 mm gasket height, and states it is not independently tested or certified (read from search-result excerpts). A hobby Arduino enclosure sits its TPU gasket 1 mm into each half plus 0.5 mm of sealing height, 10% infill, 1 mm walls, screw-compressed, and passed a shower test (no measurements). about 25% on a 1.2 mm gasket; 1.5 mm total protrusion link
compression-percent Flat (uncontoured) gaskets: a Multicomp enclosure datasheet states a flat gasket reaches IP65 but will not reliably give IP67 (from search-result excerpt); a Core77 poster notes IP67 depends on rib and compression-element geometry. Stockwell warns cellular gaskets may not suit IP67/NEMA 6 submersion. flat gasket: IP65; IP67 needs rib/bead geometry link
compression-set BASF Ultrafuse TPU 85A TDS v2.5 (ISO 815): compression set 26% after 72 h at 23 C and 52% after 24 h at 70 C. Specimen type (printed vs molded) is not stated in the extracted sheet. By Parker's definition (percent of applied deflection not recovered) a 52% set means roughly half the original squeeze is gone. 26% (23 C, 72 h); 52% (70 C, 24 h) link
compression-set Texin 985 (molded 85A TPU): ASTM D395B / ISO 815 compression set 16% and 19% at 23 C / 22 h (two specimen conditions, footnotes not legible), and 40% and 80% at 70 C / 22 h. The wide gap at 70 C shows how sensitive TPU set is to specimen type and conditioning. 16-19% (23 C); 40-80% (70 C) link
compression-set ROSA3D ROSA-Flex 85A filament TDS (ISO 815): compression set 29% and 42% (test temperatures not legible in extraction; likely 23 C and 70 C). Stratasys FDM TPU 92A (not 85A): 21% at 22 h/23 C and 44% at 22 h/70 C (ASTM D395, from search-result excerpt). 85A filament: 29% / 42%; 92A: 21% / 44% link
compression-set Covestro: standard ester TPU grades show about 45-55% set at 24 h/70 C; special ester grades about 30-35%. Rule of thumb: flat seals should not exceed about 40% compression set at their continuous service temperature. Printed 85A TPU (52% at 70 C) is therefore at or beyond the limit in hot sun, so design for 20-25% initial squeeze so 10-12% remains. limit about 40% at service temperature link
compression-set Remaining squeeze after set (own calculation, assuming ISO 815 style 25% deflection and set as percent of deflection): 26% set leaves 18.5% squeeze; 40% set leaves 15%; 52% set leaves 12%; 80% set leaves 5%. For a 3 mm bead that is 0.55 / 0.45 / 0.36 / 0.15 mm. 26% -> 18.5%; 52% -> 12%; 80% -> 5% link
compression-set Stress relaxation benchmarks (ISO 3384 style, 25% compression, 23 C, 24 h to 20,000 h): force loss under 25% is excellent for critical seals, 25-50% good, over 50% poor; many cheap elastomers lose over 50% in under 1 hour; loss gets worse at higher temperature. No TPU-85A-specific relaxation numbers were found. under 25% excellent; 25-50% good; over 50% poor link
compression-set Printed-gasket guidance (secondary source): compression set rises in printed elastomers with voids, weak interlayer bonding and uneven infill; set above 35-50% after heat aging (70 C, 22 h) leaks sooner than set below 20%; suggested remedies are 2-4 mm wall thickness and avoiding service above 60-80 C. This is commentary, not test data. set above 35-50% leaks sooner link
temperature Cold raises closing force: Texin flexural modulus is 59.0 MPa at -30 C vs 26.9 MPa at 23 C (2.2x). Closing force at a fixed stroke at about -20 C may be up to roughly 1.5-2x the 23 C value (own inference from this ratio). Hot lowers force only a little: Parker found compression force of O-rings fell just 10% (70A) to 22% (90A) from 24 C to about 126 C. TPU softens and sets at 60-70 C; see compression set. 2.2x modulus at -30 C link
temperature Prusament lists temperature resistance of 68 C for PETG and 93 C for ASA (the page does not say HDT or Vicat). With enclosure surfaces at 60-70 C in sun, PETG latch bodies and flanges sustaining kilonewton-level preload will creep; ASA has about 25 C more margin. Materials for the flange matter as much as the gasket here. PETG 68 C; ASA 93 C link
printed-tpu Print orientation: Ultrafuse TPU 85A tear strength is 80 kN/m printed flat (XY) but only 18-30 kN/m when the loaded section is built on edge or upright, and break stress drops from 34 to 10 MPa. Print gaskets flat and keep thin ribs in the XY plane (rib along the layers), not as vertical standing walls. XY tear 80 kN/m vs 18-30 kN/m link
printed-tpu Printed seal leak behaviour (anecdotal, not IP-tested): a Hackaday enclosure with a silicone-tube seal stayed dry for 10 min, then 2 h, and 12 h, but leaked a little at 24 h; the author notes molded plastics have no layer gaps. A forum thread reports roughness at the seal face causing leaks and suggests ironing the sealing surface and 0.1 mm layers (from search-result excerpt). Parker's static-seal guideline is 32 microinch (0.8 micrometer) Ra maximum and 16 microinch (0.4 micrometer) for gas face seals; as-printed FDM surfaces are far rougher (general knowledge, no source retrieved), so a soft TPU 85A or a flat-printed ironed land is needed. Parker: Ra 0.8 micrometer static, 0.4 micrometer gas face link
printed-tpu Printed TPU gasket guidance from a printed-gasket guide: 25% and 40% are common test deflections (25% is the ASTM D395 default); voids at 80-95% infill can cut effective cross-section 10-30%. Use 100% infill or walls only for gaskets, not low-density infill, if long-term set matters. 25% default; 10-30% effective area loss from voids link
flange-spacing Flange/cover theory: bolt (latch) spacing is limited by flange bowing between fasteners; spacing depends on cover thickness and stiffness (E*t^3), gasket width, and the ratio Pmax/Pmin of gasket pressure. Engineers Edge correction factors: Pmax/Pmin 2, 3, 4, 5, 6 -> 1.02, 1.00, 0.98, 0.95, 0.94 (spacing barely changes, under 7% from 3 to 6); Pmin 10, 20, 30, 40, 50 psi -> 1.19, 1.00, 0.90, 0.84, 0.80. The equations themselves are images and the calculator is paywalled. Pmax/Pmin 3 -> 1.00; Pmin 20 psi -> 1.00 link
flange-spacing Own calculation of maximum latch pitch L from continuous-beam bow delta = wL^4/(384EI), so L = (384EIdelta/w)^0.25, with allowed bow delta = 0.15 mm (about a third of a 0.36-0.48 mm stroke), E = 1.8 GPa assumed. Simply-supported worst case is L = (384EIdelta/(5w))^0.25 (about 33% shorter). Lid edge sections: 3 mm plate 10 mm wide (EI about 40 kN.mm2): 28 mm at w = 3.7 N/mm. With a 2.4 x 20 mm skirt (EI about 9300 kN.mm2): 110 mm at w = 3.7, 87 mm at w = 9.3. With a 3.2 x 30 mm rim (EI about 35,800 kN.mm2): 154 mm at w = 3.7, 122 mm at w = 9.3. 3 mm flat edge: about 22-28 mm; 20 mm skirt: 87-110 mm; 30 mm rim: 122-154 mm [link](own calculation (no external source; E = 1.8 GPa is an unsourced assumption))
flange-spacing Required EI for a given pitch (own calculation, continuous beam, bow 0.15 mm): at L = 120 mm, w = 1.7 N/mm needs about 6100 kN.mm2; w = 3.7 needs about 13,300; w = 6.2 needs about 22,300; w = 9.3 needs about 33,500 kN.mm2. At L = 90 mm the requirement is 4.1 times smaller (L^4 scaling). Gasket line load w is therefore as important as latch count: halving w roughly shortens the needed rim stiffness by half. L=120 mm, w=3.7 N/mm -> EI about 13,300 kN.mm2 [link](own calculation (no external source))
flange-spacing Beam-on-elastic-foundation check (own calculation): a 3x3 mm bead at 15% squeeze acts as a spring of about 20.7 N/mm per mm of stroke per mm length. For a flat 3 mm lid edge (EI about 40 kN.mm2) the characteristic length 1/lambda is about 9 mm, so a single latch only clamps about 30 mm (pi/lambda) of gasket; for a 30 mm box rim (EI about 35,800 kN.mm2) it clamps about 160 mm. This is the reason a flat thin lid cannot be sealed from a few latches. clamped length pi/lambda: 30 mm (flat edge) to 161 mm (30 mm rim) [link](own calculation (no external source))
flange-spacing SAE 830216 (Oren): the maximum allowable bolt spacing for flange sealing occurs when midway pressure goes to zero; gasket compliance matters, and gaskets that can compress further beyond their sealing stress allow varying degrees of flange deflection while still sealing. Rogers adds that over-stiff gaskets can warp thin latching panels and enclosure covers. qualitative link
design-rule Compression stop guidance: stops are cut shorter than the gasket thickness; keep at least one gasket-thickness of clear distance between the fastener hole edge and the stop edge; stops limit gasket damage and prevent excessive cover bowing from over-tightened fasteners. Own recommendation: one stop pair per latch at the latch line, plus stops at corners; stop height = (1 - 0.20 to 0.25) x free gasket height, e.g. 2.25-2.4 mm for a 3 mm bead. stop height 2.25-2.4 mm for 3 mm bead link
design-rule Own calculation of latch stroke needed: a 3 mm bead needs 0.20 mm (7%), 0.30 mm (10%), 0.45 mm (15%), 0.60 mm (20%) or 0.75 mm (25%); a 2.4 mm narrow rib needs 0.17-0.60 mm. Total tolerance stack (FDM warp, hinge play) is of the same order, so latches need adjustability, an integrated hard stop, or a series spring. Parker's 0.2 mm minimum squeeze rule is met by every case above 7% on a 3 mm bead. 0.2-0.75 mm stroke link
design-rule Rogers: target 25-35% compression for foam-type enclosure gaskets, choose a gasket slightly thicker than the final gap, define minimum and maximum gap first, and avoid bottoming out; over-compression warps thin enclosures or even prevents closing. Stockwell: soft cellular gaskets may not suit IP67/NEMA 6; very firm gaskets create rebound forces that bow housings and open ingress paths. 25-35% (foam); account for gap tolerance link
design-rule Summary of recommended gasket design for a printed enclosure (own judgement from the sources): 100% infill TPU 85A, printed flat, bead height at least 2 mm (KRAIBURG), width 1.2-1.6 mm, 20-25% initial squeeze, hard stop at each latch, groove leaving 10-25% void, ironed or smooth sealing land, flange with at least a 15-20 mm deep skirt, latch pitch under about 100 mm. Validate with a spray/immersion test and an elevated-temperature (60-70 C) hold; no published data certifies any printed TPU gasket to IP67. w 1.2-1.6 mm; h at least 2 mm; 20-25% squeeze link

Outdoor materials engineer

Outdoor-materials findings for a printed latch holding a TPU 85A gasket (sun-heated surface 60-70 C, -20 to +40 C ambient).

  1. Heat is the main limit. Dark enclosures in sun reach about 67.6 C inside in a hobbyist test. PETG and PETG-CF have Tg about 68-80 C and HDT 68-74 C, so a sustained-load PETG latch sits at or above its HDT in hot sun. ASA (HDT about 92-103 C, Tg about 98 C), PC filament (HDT 99-114 C) and carbon-nylons (HDT 170+ C dry) have margin.

  2. Creep is the second limit, and the data are thin. The only multi-material FDM creep test I could read (3 h, 25/40/60 C, 10/20 MPa) found ABS ruptured in about 3 min at 60 C and 20 MPa. PLA broke at 60 C and 10 MPa. PC survived every condition. Nylon crept most but did not rupture. I found no published creep numbers for printed ASA or PETG at 60 C beyond 3 h, and none for sustained clamp loss of a printed latch with a TPU gasket. Treat all sustained-load design stresses for printed ASA/ABS-class parts as unvalidated. Keep them low (my judgement: at most 3-5 MPa at 60 C) and test.

  3. UV ranking:

  • ASA: essentially unchanged (within about 3% tensile) in 100 h of lamp exposure and in 1000 h of QUV.
  • PETG: mixed results, from +9% in a mild test to about -36% in a UV-B test.
  • Unstabilised PC: lost about 30-34% tensile strength and yellowed strongly in 1000 h of QUV.
  • Unstabilised PP: degrades in months.
  1. Moisture:
  • PA6-CF drops about 22-24% in strength and stiffness after conditioning at 70% RH. Equilibrium water uptake is 3.33%.
  • Unfilled PA6 loses about 69% of its modulus.
  • PA12-type PAHT-CF takes up 0.88% water, so it is the better nylon choice.
  1. Preload decay has three parts: gasket set, latch creep and thermal mismatch.
  • 85A TPU datasheets show 35-75% compression set at 70 C, with 35-52% typical. A rigid latch would lose roughly that fraction of gasket force (my calculation).
  • A spring 4 times softer than the gasket cuts the set-induced loss to about 20% of that (my calculation, formula in the facts).
  • A printed flexure loses at least the PC injection-moulded creep ratio of 14% per 1000 h at 23 C, and much more when hot.
  1. Latch types:
  • Tolerant of creep: designs where a steel spring, steel threaded link, steel wire or metal insert carries the preload. Examples are the spring-backed over-center lever, the adjustable threaded draw hook and the wire-bail latch.
  • Not tolerant: pure printed snap-fits, printed toggle levers and friction cams. That is my engineering inference, because no direct data exist.
  1. Hardware: use A2/A4 stainless pins, screws and springs. Zinc-plated steel is rated about 12-72 h (96-120 h for yellow zinc) in salt spray and is not suited to outdoor springs. Music wire rusts when wet.

Gaps and caveats:

  • The web-search budget ran out mid-task. Some values come from search summaries of datasheets I could not open (flagged in the facts).
  • No source gave printed-latch clamp force in newtons.
  • Vendor datasheet HDT values are for annealed, dry specimens.
Topic Fact Value Source
Sun-heated enclosure temperature In a hobbyist test of sealed enclosures in direct sun, the black enclosure peaked at 67.6 C inside, the grey at 51.4 C, and the black one ran about 40 C above outside air. This supports the 60-70 C design temperature. Informal source, from a search summary; the page timed out when fetched. 67.6 C (black), 51.4 C (grey) link
ASA heat resistance PolyLite ASA (Polymaker): Tg 97.8 C, Vicat 105.3 C, HDT 100.2 C at 1.8 MPa and 102.6 C at 0.45 MPa. Specimens were printed at 70 C ambient and the HDT is likely for annealed/standard test bars. Tg 97.8 C; HDT 100.2 C @1.8 MPa link
ASA heat resistance (second brand) Bambu ASA V3.0: Vicat 106 C, HDT 92 C at 1.8 MPa and 100 C at 0.45 MPa, tensile strength 37 MPa XY and 31 MPa Z. The datasheet PDF no longer opened, so the values come from a search summary. Brand variation is therefore about 92-100 C at 1.8 MPa. HDT 92 C @1.8 MPa link
ASA injection-moulded reference (cold toughness) Luran S 757R (ASA, injection moulded): notched Charpy 3 kJ/m2 at -30 C, Vicat 98 C, HDT 97 C at 1.8 MPa (annealed). Low notch toughness at -30 C means ASA is notch-sensitive in cold weather, so avoid sharp corners in the latch. From a search snippet; the datasheet page would not open. 3 kJ/m2 notched Charpy at -30 C link
ASA anisotropy Printed PolyLite ASA: tensile strength 43.8 MPa (XY) versus 32 MPa (Z); elongation at break 6.7% (XY) versus 1.65% (Z); modulus 2379 MPa (XY) versus 1965 MPa (Z). Print the main load path along the layers (XY). Ratio Z/XY strength = 0.73 (my calculation). 43.8 MPa XY, 32 MPa Z link
PETG / PETG-CF heat resistance Bambu PETG-CF datasheet: Tg 68 C, Vicat 85 C, HDT 68 C at 1.8 MPa and 74 C at 0.45 MPa; water absorption 0.30%; tensile strength 59 MPa XY and 38 MPa Z (this is the V2-type sheet; a newer V3 sheet reportedly lists lower tensile values of 35 and 29 MPa). Carbon fibre does not raise heat resistance. A sun-heated latch at 60-70 C sits at or above this HDT. Tg 68 C; HDT 68 C @1.8 MPa link
PETG heat resistance (Prusament) Prusament PETG V0 (flame-retardant variant, so the standard grade may differ slightly): HDT 74 C at 0.45 MPa and 68 C at 1.8 MPa, tensile yield 39.4 MPa. A generic PETG datasheet gives Tg about 80 C and HDT 73 C at 0.45 MPa. Values come from search summaries. HDT 68 C @1.8 MPa; Tg about 80 C (generic) link
PETG behaviour near 60 C An academic study of additively manufactured PETG found its time-temperature superposition creep method was limited by the 60 C test temperature, above which the material stopped behaving in a simply predictable way. In practice 60 C is already close to the PETG creep cliff. From a search summary; I did not read the paper. limit of predictable behaviour about 60 C link
PC filament heat resistance PolyMax PC (Polymaker): Tg 113 C, Vicat 116.9 C, HDT 99.3 C at 1.8 MPa and 114.1 C at 0.45 MPa (V5.1). The V5.4 sheet also lists 114 C at 0.45 MPa. Bulk injection-moulded Makrolon 2405 PC has Tg 144 C, so filament PC is typically a modified or blended grade with lower heat resistance. From search summaries. Tg 113 C; HDT 99.3 C @1.8 MPa link
PA6-CF heat resistance (dry) PolyMide PA6-CF (Polymaker): Tg 74.2 C, melting 218.5 C, HDT 173 C at 1.8 MPa and 215 C at 0.45 MPa. Specimens were annealed at 80 C for 6 h and dried for 48 h before testing, so the HDT is for dry material. The Tg of 74 C is within reach of a hot enclosure, and moisture lowers stiffness (see moisture entries). HDT 173 C @1.8 MPa dry; Tg 74.2 C link
PAHT-CF (PA12-type) heat and moisture Bambu PAHT-CF: Tg 70 C, melting 225 C, Vicat 220 C, HDT 170 C at 1.8 MPa and 194 C at 0.45 MPa, saturated water absorption 0.88% (25 C, 55% RH), tensile strength 92 MPa XY and 47 MPa Z (dry, annealed). Composition is PA12 and other long-chain PA plus carbon fibre. Z/XY strength ratio 0.51 (my calculation), so interlayer loading is a weak point. HDT 170 C @1.8 MPa; 0.88% water link
ASA UV weathering, lamp exposure Sedlak et al. 2023 exposed printed samples to a 125 W mercury lamp for 20 h and 100 h. After 100 h ASA tensile strength changed 0.0%, -1.6% and -2.9% (three brands, 44-46 MPa reference); ABS changed -0.9% to -2.3%; PETG rose +8.6% to +9.7% (49.5-49.9 MPa reference); PLA ranged -0.5% to +16.6%. Mild, short test, so useful for ranking only. Percent values were calculated from the paper's tables. ASA -2.9% to 0%; PETG +8.6% to +9.7% (100 h) link
ASA UV weathering, 1000 h QUV Stratasys ASTM G154 QUV test, 1000 h (8 h UV at 60 C plus 4 h condensation at 50 C), upright ZX coupons: ASA yield strength 30.5 to 30.3 MPa (-0.7%), stress at break 30.5 to 29.5 MPa (-3%), modulus 1.82 to 1.95 GPa, elongation 2.8 to 2.3%; colour change minor (delta-E 0.9 on one plaque, 9.2 on the other, mainly lightening). Best option among the polymers tested for outdoor load-bearing. ASA -0.7% yield, -3% break after 1000 h QUV link
Polycarbonate UV weathering Same Stratasys 1000 h QUV test: natural PC yield strength 6370 psi (43.9 MPa) to 4230 psi (29.2 MPa), about -34% (my conversion); stress at break 5940 to 4200 psi (-29%); elongation 3.0 to 1.6%; colour change delta-E about 33 (strong yellowing). PC-ABS lost about 4% in strength but delta-E was about 31. Unstabilised PC can lose a third of its Z strength in one season-equivalent of UV; use a UV-stabilised grade or paint/overmould. PC -34% yield, -29% break, delta-E 33 link
Nylon-CF UV weathering Stratasys FDM Nylon 12CF (carbon-filled nylon 12) had the smallest colour change of all materials in the 1000 h QUV test (delta-E about 0.7-0.8) and its tensile strength rose from 4760 to 6500 psi (about 33 to 45 MPa). ABS-CF10 lost about 4% in yield strength with delta-E about 5.3-5.8. TPU 92A lost about 15% in tensile strength (2730 to 2330 psi). Why nylon 12CF gained strength is not explained in the paper. Nylon 12CF delta-E about 0.8; UTS +37% link
PETG UV weathering (mixed evidence) A 2026 QUV study of FFF-printed ASA, PETG and PLA found ASA kept ductility and showed improved strength, while PETG showed a moderate strength decrease with negligible change in elongation. A 2021 UV-B study (secondary summary) reported PETG tensile strength -36% and compression strength -38.3% after a 24 h cycle, against PLA -5.3% and -6.3%. A 1000 h UV study summary reported a modest increase for PETG. Results depend strongly on UV type and dose, so PETG outdoors is uncertain but ASA is consistently stable. PETG -36% (UV-B, 24 h) vs +9% (mild lamp, 100 h) link
PETG UV and creep In a flexural creep study of pellet-printed PETG, UV exposure (100 to 200 h) was the only stressor (compared with temperature and humidity) that increased creep compliance. Exact compliance values were not retrievable (paywall). UV increased creep compliance link
Polypropylene outdoors A peer-reviewed study of unstabilised polypropylene films in Saudi Arabia found they degraded within 2.5 months of exposure. Unstabilised PP photo-oxidises (yellowing, chalking, embrittlement). Vendor claims of 40-60% tensile loss in 12 months are unverified. PP is not recommended for a load-bearing outdoor latch unless UV-stabilised or carbon-black filled. unstabilised PP film degraded in 2.5 months link
Creep at 60 C, multi-material FDM test Dogan 2022 (ASTM D2990, 3 h tests, CNC-machined specimens, Ultimaker filaments, 25/40/60 C and 10/20 MPa): no rupture at 25 or 40 C for any material. At 60 C, ABS ruptured in about 3 min at 20 MPa, PLA and tough PLA broke at 60 C even at 10 MPa, and CPE broke at 60 C/20 MPa after a longer time. PC showed the lowest creep in every condition and never failed. Nylon crept most (the test was stopped when the micrometer ran out of range) but did not rupture. Load affected creep more than temperature. ABS rupture about 3 min @ 60 C/20 MPa; PC no failure link
Creep ranking, carbon-fibre FDM Dimitrellou et al. 2024 (FDM, PLA vs PC vs PAHT-CF) found the highest stage-II creep resistance for PAHT-CF, followed by PC, then PLA. A separate 2024 Open Engineering study concluded that fibre reinforcement generally improves creep stability, with GreenTEC Pro Carbon and add:north PC Blend HT LCF performing best, and noted that most filament datasheets give no creep data. Numeric creep rates were not retrievable (paywall). PAHT-CF > PC > PLA link
Creep data gap for open-source materials Open Engineering 2024 notes that most FDM filament datasheets include no creep behaviour and proposes a simple reproducible creep test. No source gave 100+ h creep data for printed ASA or PETG at 60 C. A vendor-style claim that PETG shows creep strain of 5% of its elastic strain within 5 h and 10% after 20 h at 50% of ultimate strength has no stated temperature or standard and is unverified. no ASA/PETG 60 C long-term creep data found link
Polycarbonate creep modulus (injection-moulded reference) Makrolon 2405 PC: tensile creep modulus 2200 MPa at 1 h and 1900 MPa at 1000 h (ISO 899-1, 23 C), a retention of 0.86 (my ratio). Applied to a displacement-controlled printed flexure this implies about a 14% force loss in 1000 h at room temperature only. Much more loss is expected at 60 C. Bulk PC has Tg 144 C, higher than filament PC. 2200 to 1900 MPa (1 h to 1000 h, 23 C) link
Polycarbonate thermal expansion (mismatch with steel) Makrolon 2405 coefficient of linear thermal expansion 0.65e-4 per K (65e-6/K), 23-55 C. Own calculation with an assumed steel value of about 12e-6/K (handbook value, unsourced): over 60 K, a 30 mm plastic stack growing against a steel screw changes length by about 0.095 mm, about 13% of a 0.75 mm gasket deflection (3 mm gasket at 25%). ASA and PETG expansion values were not sourced here. about 0.095 mm per 30 mm stack per 60 K (own calculation) link
Nylon moisture and stiffness (PA6-CF) PolyMide PA6-CF: equilibrium water absorption 3.33%. Dry, annealed XY specimens: modulus 7453 MPa and tensile strength 105 MPa. After conditioning at 70% RH and ambient temperature for 15 days: modulus 5666 MPa (-24%) and strength 81.7 MPa (-22%) (my percentages). Z-direction values changed little: modulus 4354 to 4713 MPa, strength 67.7 to 64.4 MPa (-5%). Charpy impact in XY rose from 13.3 to 32.8 kJ/m2. XY strength 105 to 81.7 MPa; modulus 7453 to 5666 MPa link
Unfilled nylon 6 moisture stiffness loss A Unitika PA6 datasheet lists tensile modulus 2700 MPa dry-as-moulded versus 840 MPa conditioned at 23 C/50% RH (ISO 527), a drop of about 69% (my calculation), and tensile yield 68 to 42 MPa. Datasheet values from a search summary (the page text did not load). 2700 to 840 MPa; 68 to 42 MPa link
Nylon creep modulus and reinforcement BASF Ultramid B3K (unreinforced PA6) 1000 h tensile creep modulus (strain up to 0.5%, 23 C) is 700 MPa (conditioned figure only). Glass-filled PA6-GF30 grade B3WG6 GPX lists 4100 MPa. Reinforcement raises 1000 h creep modulus about 6 times. From search summaries of BASF datasheets; conditioning of the GF30 figure was not stated. PA6 700 MPa vs PA6-GF30 4100 MPa at 1000 h link
Polycarbonate humidity and UV A study of unstabilised bisphenol-A polycarbonate found molecular weight falls during UV exposure (embrittlement and surface erosion) and that humidity accelerates photo-yellowing. Many filaments are not UV-stabilised. From a search summary. not quantified link
TPU 85A compression set at 70 C Elastollan C85A55 (Shore 85A polyester TPU): compression set (ASTM D395B, 25% deflection, 22 h) is 25% at 23 C and 35% at 70 C. Tensile modulus 20.7 MPa, 100% modulus 6.89 MPa, hydrolytically stable. Other 85A grades at 70 C/22 h: 40% (ColorRx 85A0RX) and 43% (Elastane 4725-85A), and 75% for Estane 2355-85ABR. Ultrafuse TPU 85A (a printed-filament grade) lists 52% at 70 C/24 h and 26% at 23 C/72 h (ISO 815). Grade selection matters. Extruded or printed parts can be worse because of voids and weak layer bonding. 35% (70 C/22 h, Elastollan) to 52% (Ultrafuse); 75% worst link
TPU 85A filament compression set BASF Ultrafuse TPU 85A TDS: compression set 26% at 23 C/72 h and 52% at 70 C/24 h (ISO 815). The 70 C value is about double the room-temperature value and is the one that matters for a sun-heated gasket. Taken from a search summary of the datasheet. 52% at 70 C/24 h link
Preload loss from TPU set with a rigid latch (own calculation) Own calculation from the datasheets above. Compression set is the unrecovered fraction of the applied deflection. If a creep-free rigid latch holds a linear gasket at a fixed gap and the gasket sets 35-52% (70 C datasheet range), the gasket force falls by roughly the same fraction, about 35-52%. This is a proxy: constant-strain stress relaxation of printed TPU was not found in any source and may be larger. about 35-52% force loss (own calculation, upper-bound style proxy) link
Preload loss with a series spring (own calculation) Own calculation. For a gasket of stiffness kg in series with a latch spring of stiffness ks, and a gasket set of S (fraction of its compression), the force loss fraction is S x ks/(kg+ks). With ks = kg/4 the loss is 0.2 x S: 7% for S = 35% and 10% for S = 52%. The spring needs about 4x the gasket compression travel (3 mm for a 0.75 mm gasket compression). With ks much larger than kg (rigid latch) the loss equals S. ks = kg/4 gives 7-10% loss instead of 35-52% link
Plastic joint clamp-load loss mechanism Creep or stress relaxation of plastic well below its elastic limit makes it lose its ability to maintain load, and the threaded connection loosens. Any thickness lost reduces screw clamp load, and the screw spring rate is so low that very little thickness change gives a loose joint. Metal threaded inserts are not susceptible to creep. No numeric percentage preload retention for printed or moulded polyamide joints was found. qualitative link
Gasket stress relaxation in flange joints (analogue) In an industry article on bolted flange gaskets, ePTFE lost 12.6% of bolt stress in 20 h without retorquing, and a retorque 15 min after installation cut loss in spiral wound gaskets nearly in half, to 7.5%. This is a steel flange context, not TPU, but it shows loss is front-loaded. Taken from a search summary. 12.6% loss in 20 h (ePTFE); 7.5% after early retorque link
Corrosion of zinc-plated vs stainless hardware Fastener guide salt-spray ratings: electroplated zinc 12-72 h, yellow zinc (chromate) 96-120 h, hot-dip galvanised 500+ h, zinc-nickel 500-1000 h, Dacromet/Geomet 500-1000+ h. 18-8 (304/A2) stainless is general-purpose and 316 (A4) is recommended for marine, salt and chemical exposure; stainless needs no coating (passivated). Salt-spray hours are only a ranking aid, not outdoor life. For latch pins and screws outdoors use A2 (inland) or A4 (coastal/de-icing salt), not zinc-plated steel. zinc plated 12-72 h; yellow zinc 96-120 h link
Spring materials outdoors Lee Spring: music wire may lose strength above 250 F (121 C), rusts in humid or wet conditions and often needs zinc/phosphate/powder coating. 302/304 stainless suits moisture, chemicals, wash-down and outdoor use and is rated about 550-600 F (288-316 C). Tensile strength: music wire above 400,000 psi in small sizes; 302/304 about 275,000-300,000 psi (so a stainless spring is about 25-30% weaker per wire size). No relaxation data for either material were found. The 316-grade statement (better in salt water) comes from a second spring vendor's page. music wire 121 C max; 302/304 about 288-316 C max link
Belleville / disc springs vs creep A vendor white paper claims a Belleville washer can cut preload loss in a steel bolted joint to under 1% by adding elasticity. A flange-engineering source argues Belleville washers are not effective against high-temperature creep and that thermal cycling is the main failure mechanism there. A 2008 ASME paper found Belleville washers or longer bolts with spacer tubes can reduce load loss in flange joints. None of these is a plastic-joint test, so treat disc springs as helpful but unproven for printed hosts. under 1% (vendor claim, steel joint) link
Freeze / thermal cycling evidence Little quantified data was found for freeze-thaw or thermal cycling of printed latches. Known points: ASA (injection moulded Luran S 757R) has notched Charpy 3 kJ/m2 at -30 C, and PC Makrolon 2405 shows a puncture energy of 65 J at -30 C. ASA is therefore notch-sensitive in cold weather, and PC stays tough. Differential expansion over a 60 K swing is about 0.095 mm per 30 mm stack for PC vs steel (own calculation). No source gave PETG or nylon low-temperature impact data. ASA 3 kJ/m2 notched at -30 C; PC puncture 65 J at -30 C link
Real-world outdoor test status A long-term outdoor filament test (eight common filaments including Polymaker ASA and Snapmaker PETG) was started in August 2025 by Finnish operator Ari Sovijarvi. No results were published as of my search. Vendor claims that PETG yellows after 3-6 months in sun and that ASA retains 85-90% property after 12 months are unverified. no results yet link
Material recommendation summary (own judgement) Own judgement from the data above: ASA is the best default printed latch body (stable under UV, Tg about 98 C, HDT 92-103 C) but keep sustained printed-part stress low because ABS-class printed material ruptured at 60 C/20 MPa in minutes. PETG and PETG-CF (Tg about 68-80 C) should not carry sustained load in hot sun. PC is the best for creep and heat but needs a UV-stabilised grade. PAHT-CF (PA12-type, 0.88% water) is better than PA6-CF (3.33% water, -22 to -24% when wet). Avoid PP. Put the clamp preload in a stainless steel spring or screw regardless of the plastic. ASA first choice; steel carries the preload link
Research limitations The web-search budget was used up before the cold-impact, thermal-expansion, corrosion-detail and insert-pull-out searches could be run. Several datasheet values (Bambu ASA, PolyMax PC, Prusament PETG V0, Unitika PA6, BASF Ultramid, Luran S 757R) come from search summaries because the PDFs or pages could not be opened. No source gave measured sustained clamp force or preload decay for a printed latch on a TPU gasket. n/a link