{"$schema":"nativecad-dfm-pack/1","id":"standards-testing","title":"Standards & testing — tolerances, fits, surface finish, environmental and compliance tests","sector":"standards-testing","version":"2026-09-03","summary":"Cross-sector reference for what a part is measured and tested against: ISO 2768 general tolerances, ISO 286 fits, surface finish by process, and the drop/vibration/IP/salt-spray/UL flammability tests that come back as geometry requirements.","aliases":["tolerance","tolerances","gd&t","gdt","iso 2768","surface finish","fit","test","testing","drop test","ip rating","ip67","vibration","salt spray","ul 94","rohs","inspection"],"crossSector":true,"size":"standard","sources":[{"id":"iso-2768","title":"ISO 2768-1/-2:1989 General tolerances — linear/angular and geometrical","url":"https://www.iso.org/standard/7748.html","accessed":"2026-09-03"},{"id":"iso-286","title":"ISO 286-1/-2:2010 ISO code system for tolerances on linear sizes","url":"https://www.iso.org/standard/45975.html","accessed":"2026-09-03"},{"id":"asme-y14.5","title":"ASME Y14.5-2018 Dimensioning and Tolerancing (GD&T)","url":"https://www.asme.org/codes-standards/find-codes-standards/y14-5-dimensioning-tolerancing","accessed":"2026-09-03"},{"id":"iso-1101","title":"ISO 1101:2017 Geometrical tolerancing (form, orientation, location, run-out)","url":"https://www.iso.org/standard/66777.html","accessed":"2026-09-03"},{"id":"iso-4287","title":"ISO 4287:1997 Surface texture, profile method (Ra, Rz)","url":"https://www.iso.org/standard/10132.html","accessed":"2026-09-03"},{"id":"protolabs-tol","title":"Protolabs design tips — standard tolerances by process","url":"https://www.protolabs.com/resources/design-tips/","accessed":"2026-09-03"},{"id":"xometry-tol","title":"Xometry manufacturing tolerance and surface finish guides","url":"https://www.xometry.com/resources/","accessed":"2026-09-03"},{"id":"iec-60068-2-31","title":"IEC 60068-2-31:2008 Test Ec: Rough handling shocks (free fall)","url":"https://webstore.iec.ch/publication/972","accessed":"2026-09-03"},{"id":"mil-std-810","title":"MIL-STD-810H Method 516.8 Shock (transit drop)","url":"https://www.atec.army.mil/","accessed":"2026-09-03"},{"id":"iec-60068-2-32","title":"IEC 60068-2-32:1975 Test Ed: Free fall (tumble)","url":"https://webstore.iec.ch/publication/1029","accessed":"2026-09-03"},{"id":"iec-60068-2-6","title":"IEC 60068-2-6:2007 Test Fc: Vibration (sinusoidal)","url":"https://webstore.iec.ch/publication/23794","accessed":"2026-09-03"},{"id":"iec-60068-2-64","title":"IEC 60068-2-64:2019 Test Fh: Vibration, broadband random","url":"https://webstore.iec.ch/publication/61088","accessed":"2026-09-03"},{"id":"iec-60068-2-27","title":"IEC 60068-2-27:2008 Test Ea: Shock","url":"https://webstore.iec.ch/publication/2647","accessed":"2026-09-03"},{"id":"iec-60529","title":"IEC 60529:1989+A2:2013 Degrees of protection (IP Code)","url":"https://webstore.iec.ch/publication/2452","accessed":"2026-09-03"},{"id":"iec-62262","title":"IEC 62262:2002 Degrees of protection against impact (IK code)","url":"https://webstore.iec.ch/publication/6968","accessed":"2026-09-03"},{"id":"astm-b117","title":"ASTM B117-19 Operating salt spray (fog) apparatus","url":"https://www.astm.org/b0117-19.html","accessed":"2026-09-03"},{"id":"astm-g154","title":"ASTM G154-16 Fluorescent UV lamp exposure of nonmetallics","url":"https://www.astm.org/g0154-16.html","accessed":"2026-09-03"},{"id":"iso-4892","title":"ISO 4892-2:2013 Exposure to xenon-arc lamps","url":"https://www.iso.org/standard/60420.html","accessed":"2026-09-03"},{"id":"iec-60068-2-14","title":"IEC 60068-2-14:2009 Test N: Change of temperature","url":"https://webstore.iec.ch/publication/347","accessed":"2026-09-03"},{"id":"iec-60068-2-78","title":"IEC 60068-2-78:2012 Test Cab: Damp heat, steady state","url":"https://webstore.iec.ch/publication/2166","accessed":"2026-09-03"},{"id":"ul-94","title":"UL 94 Tests for flammability of plastic materials","url":"https://www.ul.com/services/ul-94-flammability-standard","accessed":"2026-09-03"},{"id":"ul-746","title":"UL 746A/B/C Polymeric materials property evaluation","url":"https://www.ul.com/","accessed":"2026-09-03"},{"id":"rohs","title":"EU Directive 2011/65/EU (RoHS 2/3)","url":"https://environment.ec.europa.eu/topics/waste-and-recycling/rohs-directive_en","accessed":"2026-09-03"},{"id":"reach","title":"EC 1907/2006 (REACH)","url":"https://echa.europa.eu/regulations/reach","accessed":"2026-09-03"},{"id":"as9102","title":"AS9102 First Article Inspection requirement","url":"https://www.sae.org/standards/content/as9102/","accessed":"2026-09-03"}],"entries":[{"id":"iso2768-linear-tolerances","kind":"tolerance","tier":1,"title":"ISO 2768-1 linear tolerance classes f/m/c/v (mm by size range)","summary":"± mm by nominal size and class (f=fine, m=medium, c=coarse, v=very coarse): 3-6: 0.05/0.1/0.3/0.5; 6-30: 0.1/0.2/0.5/1.0; 30-120: 0.15/0.3/0.8/1.5; 120-400: 0.2/0.5/1.2/2.5; 400-1000: 0.3/0.8/2.0/4.0 mm. 'm' is the drawing default when unstated.","applies":["cnc machining","sheet metal","casting"],"value":{"table":[{"range":"0.5-3","f":0.05,"m":0.1,"c":0.2,"v":null},{"range":"3-6","f":0.05,"m":0.1,"c":0.3,"v":0.5},{"range":"6-30","f":0.1,"m":0.2,"c":0.5,"v":1},{"range":"30-120","f":0.15,"m":0.3,"c":0.8,"v":1.5},{"range":"120-400","f":0.2,"m":0.5,"c":1.2,"v":2.5},{"range":"400-1000","f":0.3,"m":0.8,"c":2,"v":4},{"range":"1000-2000","f":0.5,"m":1.2,"c":3,"v":6}],"unit":"mm"},"basis":"ISO 2768-1 table 1, classes f/m/c/v","sources":["iso-2768"],"tags":["iso 2768","linear","tolerance"]},{"id":"iso2768-angular","kind":"tolerance","tier":1,"title":"ISO 2768-1 angular tolerance by shorter side length","summary":"± degrees by the shorter leg, class f/m then c then v: ≤10mm 1.0/1.5/3.0; 10-50mm 0.5/1.0/2.0; 50-120mm 0.33/0.5/1.0; 120-400mm 0.17/0.25/0.5; >400mm 0.08/0.17/0.33 deg.","applies":[],"value":{"table":[{"range":"0-10","f_m":1,"c":1.5,"v":3},{"range":"10-50","f_m":0.5,"c":1,"v":2},{"range":"50-120","f_m":0.333,"c":0.5,"v":1},{"range":"120-400","f_m":0.167,"c":0.25,"v":0.5},{"range":"400-plus","f_m":0.083,"c":0.167,"v":0.333}],"unit":"deg"},"basis":"ISO 2768-1 table 2","sources":["iso-2768"],"tags":["iso 2768","angular","tolerance"]},{"id":"iso2768-radii-chamfers-m","kind":"tolerance","tier":1,"title":"ISO 2768-1 permissible deviation for radii and chamfer heights","summary":"External radii/chamfer heights, class f/m: ≤3mm ±0.2, 3-6mm ±0.5, >6mm ±1.0 mm; class c/v doubles this. Applies to an untoleranced fillet/chamfer, not a functional fit radius.","applies":[],"value":{"table":[{"range":"0-3","f_m":0.2,"c_v":0.4},{"range":"3-6","f_m":0.5,"c_v":1},{"range":"6-plus","f_m":1,"c_v":2}],"unit":"mm"},"basis":"ISO 2768-1 table 3","sources":["iso-2768"],"tags":["iso 2768","radius","chamfer"]},{"id":"iso2768-form-tolerances-k","kind":"tolerance","tier":2,"title":"ISO 2768-2 general form tolerance (straightness/flatness), class H/K/L","summary":"By longest side, class K (default): ≤10mm 0.05, 10-30mm 0.1, 30-100mm 0.2, 100-300mm 0.3, 300-1000mm 0.4 mm. Class H is ~half, class L ~2x.","applies":[],"value":{"table":[{"range":"0-10","H":0.02,"K":0.05,"L":0.1},{"range":"10-30","H":0.05,"K":0.1,"L":0.2},{"range":"30-100","H":0.1,"K":0.2,"L":0.4},{"range":"100-300","H":0.15,"K":0.3,"L":0.6},{"range":"300-1000","H":0.2,"K":0.4,"L":0.8}],"unit":"mm"},"basis":"ISO 2768-2 table 1","sources":["iso-2768"],"tags":["iso 2768","flatness","straightness","form"]},{"id":"general-tolerance-by-process","kind":"tolerance","tier":1,"title":"Achievable general tolerance by manufacturing process","summary":"±mm standard shop tolerance: CNC 0.05-0.13, injection molding 0.1-0.3 (+0.2%/mm beyond 50mm), sheet metal 0.2-0.5, laser cutting 0.1, FDM 0.3 (or 0.2% of dim), SLA 0.1, SLS/MJF 0.3, DMLS 0.1-0.2, die casting 0.1/25mm (+0.02mm/mm beyond).","applies":[],"value":{"table":[{"process":"cnc","min":0.05,"max":0.13},{"process":"injection_molding","min":0.1,"max":0.3},{"process":"sheet_metal","min":0.2,"max":0.5},{"process":"laser_cutting","typical":0.1},{"process":"fdm","typical":0.3},{"process":"sla","typical":0.1},{"process":"sls_mjf","typical":0.3},{"process":"dmls","min":0.1,"max":0.2},{"process":"die_casting","typical":0.1}],"unit":"mm"},"basis":"Protolabs/Xometry published standard-tolerance tables per process","sources":["protolabs-tol","xometry-tol"],"tags":["tolerance","process","cnc","injection molding","sheet metal","fdm","sla","sls","dmls","die casting"]},{"id":"iso286-common-fits","kind":"tolerance","tier":1,"title":"ISO 286 common fits H7/g6, H7/k6, H7/p6 at ⌀10 and ⌀20","summary":"H7/g6 sliding: ⌀10 hole 10.000-10.015/shaft 9.995-10.000 (gap 0-0.02); ⌀20 hole 20.000-20.021/shaft 19.980-19.993 (gap 0.007-0.041). H7/k6 transition: ⌀10 shaft 10.001-10.010; ⌀20 shaft 20.002-20.015. H7/p6 press: ⌀10 shaft 10.024-10.033; ⌀20 shaft 20.035-20.048 mm.","applies":["shaft","bushing","dowel","bearing"],"value":{"table":[{"fit":"H7/g6","size":10,"holeMin":10,"holeMax":10.015,"shaftMin":9.995,"shaftMax":10},{"fit":"H7/g6","size":20,"holeMin":20,"holeMax":20.021,"shaftMin":19.98,"shaftMax":19.993},{"fit":"H7/k6","size":10,"holeMin":10,"holeMax":10.015,"shaftMin":10.001,"shaftMax":10.01},{"fit":"H7/k6","size":20,"holeMin":20,"holeMax":20.021,"shaftMin":20.002,"shaftMax":20.015},{"fit":"H7/p6","size":10,"holeMin":10,"holeMax":10.015,"shaftMin":10.024,"shaftMax":10.033},{"fit":"H7/p6","size":20,"holeMin":20,"holeMax":20.021,"shaftMin":20.035,"shaftMax":20.048}],"unit":"mm"},"basis":"ISO 286-2 hole H7 and shaft g6/k6/p6 deviation tables","sources":["iso-286"],"tags":["iso 286","fit","h7g6","h7k6","h7p6","sliding","transition","press"]},{"id":"surface-finish-by-process","kind":"tolerance","tier":1,"title":"Achievable surface roughness Ra (μm) by process","summary":"Ra μm: turning 0.8-3.2, milling 1.6-3.2, grinding 0.2-0.8, injection molding 0.4-1.6 (as-moulded; texture VDI 3400 for matte grain), FDM 10-20, SLA 1-3, SLS/MJF 5-15, DMLS 5-15. Layer/tool-mark direction is not captured by Ra alone.","applies":[],"value":{"table":[{"process":"turning","min":0.8,"max":3.2},{"process":"milling","min":1.6,"max":3.2},{"process":"grinding","min":0.2,"max":0.8},{"process":"injection_molding","min":0.4,"max":1.6},{"process":"fdm","min":10,"max":20},{"process":"sla","min":1,"max":3},{"process":"sls_mjf","min":5,"max":15},{"process":"dmls","min":5,"max":15}],"unit":"um"},"basis":"ISO 4287 Ra convention; Protolabs/Xometry finish tables by process","sources":["iso-4287","protolabs-tol","xometry-tol"],"tags":["surface finish","ra","turning","milling","grinding","injection molding","fdm","sla","sls","dmls"]},{"id":"flatness-position-typical","kind":"tolerance","tier":2,"title":"Typical GD&T flatness and position callouts by feature role","summary":"Sealing/mounting face flatness: 0.05-0.1mm over ≤100mm span; bolt-pattern position (MMC): ⌀0.25-0.5mm for clearance holes, ⌀0.1mm for dowelled locating holes. Tighter needs grinding or wire EDM, not 3-axis milling.","applies":["mounting face","bolt pattern","sealing face"],"value":{"min":0.05,"max":0.5,"unit":"mm"},"basis":"Common practice for machined mounting interfaces","sources":["xometry-tol"],"tags":["flatness","position","gd&t","bolt pattern"]},{"id":"press-fit-pin-interference","kind":"tolerance","tier":2,"title":"Press-fit interference for steel pins in aluminium and steel","summary":"Light press (H7/m6, H7/n6): 0.005-0.02mm interference on a 3-10mm pin. In plastic use 0.05-0.1mm plus a lead-in chamfer. Model the hole at nominal, carry the fit as a callout.","applies":[],"value":{"min":0.005,"max":0.02,"unit":"mm"},"basis":"ISO 286 transition/interference fits for locating pins","sources":["iso-286"],"tags":["press fit","interference","pin"]},{"id":"standard-iso-2768","kind":"standard","tier":1,"title":"ISO 2768 — general tolerances for linear and angular dimensions","summary":"Two parts: -1 (linear/angular size, classes f/m/c/v) and -2 (form/position, classes H/K/L). One title-block callout ('ISO 2768-mK') sets every un-toleranced dimension on the sheet.","applies":[],"basis":"Reduces drawing clutter by giving default tolerances a single callout","sources":["iso-2768"],"tags":["iso 2768","standard","general tolerance"]},{"id":"standard-iso-286","kind":"standard","tier":1,"title":"ISO 286 — ISO code system for tolerances on linear sizes (fits)","summary":"Defines the letter+number fit code (H7, g6, k6, p6...), written 'hole/shaft' e.g. ⌀20H7/g6. Part -1 is the tolerance classes, part -2 the tables of limits and fits.","applies":[],"basis":"Standardises fit callouts across CAD/drawing systems worldwide","sources":["iso-286"],"tags":["iso 286","standard","fit"]},{"id":"standard-asme-y145","kind":"standard","tier":1,"title":"ASME Y14.5 — dimensioning and tolerancing (GD&T)","summary":"The US GD&T standard: datum reference frames, feature control frames, MMC/LMC modifiers, position/profile/runout. A drawing needs ≥3 mutually perpendicular datums (3-2-1 scheme) to fully constrain a part for inspection.","applies":[],"basis":"Datum scheme and feature-control-frame syntax an inspector reads against","sources":["asme-y14.5"],"tags":["gd&t","asme y14.5","datum","standard"]},{"id":"standard-iso-1101","kind":"standard","tier":2,"title":"ISO 1101 — geometrical tolerancing (form, orientation, location, run-out)","summary":"ISO's GD&T counterpart to ASME Y14.5 — symbols mostly match, but datum and envelope rules differ (ISO defaults envelope off; ASME rule #1 is on). Mixing both on one drawing causes inspection disputes.","applies":[],"basis":"ISO's GD&T symbol and interpretation standard","sources":["iso-1101"],"tags":["gd&t","iso 1101","standard"]},{"id":"standard-iso-4287","kind":"standard","tier":2,"title":"ISO 4287 — surface texture, profile method (Ra, Rz and friends)","summary":"ISO 4287 defines Ra (arithmetic mean roughness), Rz (mean peak-to-valley, ~4–7× Ra) and Rq, with a 0.8 mm sampling length for Ra 0.1–2 µm and 2.5 mm for Ra 2–10 µm. Ra is the default unless the drawing states otherwise.","applies":[],"basis":"Common surface-roughness parameter definitions","sources":["iso-4287"],"tags":["surface finish","ra","iso 4287","standard"]},{"id":"test-drop-iec-60068-2-31","kind":"test","tier":1,"title":"Free-fall drop test, IEC 60068-2-31 / MIL-STD-810 Method 516","summary":"Handheld devices: 1000/1200/1500 mm drop onto concrete, one face/edge/corner per orientation. Geometry response: corner radii ≥ 2 mm at impact corners, internal ribs behind the impact zone, no unsupported span > 40 mm near a corner.","applies":["handheld device","enclosure","consumer electronics"],"value":{"options":[1000,1200,1500],"unit":"mm"},"basis":"IEC 60068-2-31 Test Ec free-fall / MIL-STD-810H Method 516.8 transit drop","sources":["iec-60068-2-31","mil-std-810"],"tags":["drop test","corner radius","impact","rugged"]},{"id":"test-tumble-iec-60068-2-32","kind":"test","tier":2,"title":"Tumble (repeated free-fall) test, IEC 60068-2-32","summary":"Product tumbled in a 1m rotating drum through 50-1000 falls, simulating random handling impacts rather than one worst-case face. Geometry response: recess or rib-support any protruding feature (connector, boss) beyond the enclosure's own corner radius.","applies":["shipped product","portable device"],"value":{"min":50,"max":1000,"unit":"count"},"basis":"IEC 60068-2-32 Test Ed free fall (tumbling barrel)","sources":["iec-60068-2-32"],"tags":["tumble test","drop test","transport"]},{"id":"test-vibration-sinusoidal-iec-60068-2-6","kind":"test","tier":2,"title":"Sinusoidal vibration test, IEC 60068-2-6","summary":"Sweep 10-500 Hz at 0.5-5g (transport) or 10-20g (vehicle-mounted), swept log per axis, 1-2h/axis. Geometry response: keep any cantilevered PCB/bracket's natural frequency above 2x the top test frequency; lock every fastener in the path.","applies":["automotive","industrial equipment","shipped electronics"],"value":{"min":10,"max":500,"unit":"Hz"},"basis":"IEC 60068-2-6 Test Fc sinusoidal vibration","sources":["iec-60068-2-6"],"tags":["vibration","resonance","cantilever","fastener locking"]},{"id":"test-vibration-random-iec-60068-2-64","kind":"test","tier":2,"title":"Broadband random vibration test, IEC 60068-2-64","summary":"PSD ~0.01-0.1 g2/Hz over 10-2000 Hz, 3 axes, tens of minutes to hours/axis — closer to real road/flight vibration than a sine sweep. Geometry response: same as sinusoidal, but random hits every mode at once; add margin on the lowest structural mode.","applies":["automotive","aerospace","industrial equipment"],"value":{"min":10,"max":2000,"unit":"Hz"},"basis":"IEC 60068-2-64 Test Fh random vibration, broadband","sources":["iec-60068-2-64"],"tags":["vibration","random","resonance"]},{"id":"test-shock-iec-60068-2-27","kind":"test","tier":2,"title":"Mechanical shock test, IEC 60068-2-27","summary":"Half-sine shock pulse, commonly 15g/11ms or 30g/18ms, 3 shocks per direction per axis (18 total). Geometry response: check the fastener/boss taking the load isn't the weakest section (thin boss root, sharp internal corner).","applies":["industrial equipment","automotive","shipped electronics"],"value":{"options":[15,30],"unit":"g"},"basis":"IEC 60068-2-27 Test Ea shock, half-sine pulse","sources":["iec-60068-2-27"],"tags":["shock","impulse","boss"]},{"id":"test-ip-ratings-iec-60529","kind":"test","tier":1,"title":"IP ingress protection rating, IEC 60529","summary":"IP54 dust-protected/splash; IP65 dust-tight/jets; IP67 immersion 1m/30min; IP68 beyond 1m per spec. Geometry response: continuous gasket groove at every seam, a gland or vent membrane boss at cable/vent ports, no through-hole from a sealed screw boss.","applies":["enclosure","outdoor equipment","wearable"],"value":{"options":["IP54","IP65","IP67","IP68"]},"basis":"IEC 60529 IP code, first digit dust / second digit water","sources":["iec-60529"],"tags":["ip rating","ip67","ip68","gasket","sealing","vent"]},{"id":"test-ik-impact-iec-62262","kind":"test","tier":2,"title":"IK mechanical impact rating, IEC 62262","summary":"IK07 (2J, common minimum) to IK10 (20J, vandal-resistant); a steel hammer dropped from a set height onto the enclosure face. Geometry response: thicker wall or internal ribbing behind the impact face — IK10 often needs ≥3mm polycarbonate.","applies":["outdoor enclosure","public-space equipment"],"value":{"min":2,"max":20,"unit":"Nm"},"basis":"IEC 62262 IK code, impact energy by rating","sources":["iec-62262"],"tags":["ik rating","impact","vandal resistant","wall thickness"]},{"id":"test-salt-spray-astm-b117","kind":"test","tier":2,"title":"Salt spray (fog) corrosion test, ASTM B117","summary":"5% NaCl fog at 35C; consumer spec 48-96h to first red rust, automotive/marine spec 250-1000+h. Geometry response: a material/coating test — pick stainless, anodised aluminium, or ≥60um powder coat; avoid crevices that trap salt film.","applies":["outdoor equipment","marine","automotive"],"value":{"min":48,"max":1000,"unit":"h"},"basis":"ASTM B117 standard salt-fog exposure practice","sources":["astm-b117"],"tags":["salt spray","corrosion","coating","material"]},{"id":"test-uv-astm-g154-iso-4892","kind":"test","tier":2,"title":"UV / weathering exposure test, ASTM G154 / ISO 4892","summary":"Fluorescent-UV or xenon-arc exposure, 500-2000h to simulate 1-5 years outdoors; failure is fade, chalking or embrittlement. Geometry response: none directly — use a UV-stabilised resin (PC-UV, ASA) for outdoor parts and avoid thin ribs in a UV-brittle resin.","applies":["outdoor enclosure","automotive exterior"],"value":{"min":500,"max":2000,"unit":"h"},"basis":"ASTM G154 fluorescent-UV / ISO 4892-2 xenon-arc weathering practice","sources":["astm-g154","iso-4892"],"tags":["uv","weathering","material","outdoor"]},{"id":"test-thermal-cycling-iec-60068-2-14","kind":"test","tier":2,"title":"Thermal cycling / thermal shock test, IEC 60068-2-14","summary":"Cycle -40C to +85C (consumer) or -55C to +125C (auto/mil), 10-100 cycles, dwell 30min-2h. Geometry response: dissimilar-material joints need CTE clearance — a heat-set insert boss should keep ≥0.5mm surrounding wall to avoid cracking on cool-down.","applies":["automotive","outdoor electronics","sealed assembly"],"value":{"min":-55,"max":125,"unit":"C"},"basis":"IEC 60068-2-14 Test N change of temperature","sources":["iec-60068-2-14"],"tags":["thermal cycling","thermal shock","cte","insert"]},{"id":"test-humidity-iec-60068-2-78","kind":"test","tier":2,"title":"Damp heat (humidity) test, IEC 60068-2-78","summary":"Steady-state 40C/93%RH (or 85C/85%RH accelerated), 48-1000h; checks corrosion, delamination and moisture ingress. Geometry response: same sealing as the IP test plus drainage — any pocket that traps condensate needs a weep hole at its low point.","applies":["outdoor electronics","sealed enclosure"],"value":{"min":48,"max":1000,"unit":"h"},"basis":"IEC 60068-2-78 Test Cab damp heat, steady state","sources":["iec-60068-2-78"],"tags":["humidity","damp heat","sealing","drainage"]},{"id":"test-ul94-flammability","kind":"test","tier":1,"title":"UL 94 plastics flammability rating (HB, V-2, V-0)","summary":"HB: horizontal slow-burn, min 1.5mm. V-2/V-1: vertical, self-extinguishes, drips allowed(V-2)/not(V-1). V-0: extinguishes <=10s, no flaming drips, down to 0.8-1.5mm. Geometry response: the rating only holds at or above the resin's UL-tested min thickness.","applies":["injection moulded housing","electrical enclosure"],"value":{"options":["HB","V-2","V-1","V-0"]},"basis":"UL 94 vertical/horizontal burn test, rating tied to tested minimum thickness","sources":["ul-94"],"tags":["ul 94","flammability","v-0","minimum wall","plastic"]},{"id":"test-ul746-material-properties","kind":"test","tier":2,"title":"UL 746A/B/C polymeric material property evaluation","summary":"746A: short-term electrical (dielectric, tracking). 746B: long-term thermal aging (RTI, e.g. 105C/130C resins). 746C: use in specific enclosures. Geometry response: none — pick a resin whose RTI covers the part's operating temperature near any heat source.","applies":["electrical enclosure","appliance housing"],"value":{"options":["105C","130C","155C"],"unit":"C"},"basis":"UL 746 series polymeric material evaluation","sources":["ul-746"],"tags":["ul 746","rti","thermal aging","material"]},{"id":"test-rohs-reach-compliance","kind":"material","tier":2,"title":"RoHS / REACH restricted-substance compliance","summary":"RoHS caps Pb/Hg/Cd/Cr(VI)/PBB/PBDE/4 phthalates each <=0.1% by weight (Cd <=0.01%) per homogeneous material; REACH flags SVHCs >0.1%. Geometry response: none — constrains material/plating choice, verified by supplier certificate.","applies":["electronics","consumer product","eu market"],"value":{"typical":0.1,"unit":"%","note":"per restricted substance, per homogeneous material (Cd 0.01%)"},"basis":"EU RoHS 2011/65/EU and REACH 1907/2006","sources":["rohs","reach"],"tags":["rohs","reach","compliance","material","plating"]},{"id":"test-fatigue-cycle","kind":"test","tier":2,"title":"Fatigue / cycle life test","summary":"Consumer snap-fit/hinge: 5,000-20,000 actuation cycles; structural metal fatigue design commonly targets 1e6 cycles (steel endurance limit). Geometry response: radius the flex root >= 0.5x wall thickness — cracks start at stress concentrations.","applies":["snap fit","living hinge","structural bracket"],"value":{"min":5000,"max":1000000,"unit":"cycles"},"basis":"Typical consumer actuation spec vs. steel endurance-limit design cycle count","sources":["protolabs-tol"],"tags":["fatigue","cycle life","snap fit","stress concentration"]},{"id":"test-static-proof-load","kind":"test","tier":2,"title":"Static load / proof load test","summary":"Proof load is 1.5-2x rated working load, held 60s, no permanent deformation; a destructive ultimate test runs separately at 3-4x rated load. Geometry response: keep the load path's min cross-section below yield at proof load with the safety factor applied.","applies":["bracket","lifting point","structural part"],"value":{"min":1.5,"max":2,"unit":"ratio","note":"x rated working load"},"basis":"Standard proof-load practice for structural/lifting hardware","sources":["xometry-tol"],"tags":["static load","proof load","safety factor","structural"]},{"id":"test-hardness","kind":"test","tier":2,"title":"Hardness testing (Rockwell / Shore)","summary":"Metals: Rockwell C for hardened steel (HRC 20-65), Rockwell B for softer alloys. Plastics/elastomers: Shore A (20-90A, gaskets) or Shore D (50-90D, rigid). Geometry response: none directly, but heat-treat can add distortion — hold critical dims after treat.","applies":["heat-treated part","elastomer seal","grip"],"value":{"options":["HRC","HRB","Shore A","Shore D"]},"basis":"Standard hardness scales by material class","sources":["xometry-tol"],"tags":["hardness","rockwell","shore","heat treat"]},{"id":"test-dimensional-inspection-cmm","kind":"test","tier":2,"title":"Dimensional inspection — CMM, gauges, first-article (AS9102)","summary":"CMM measures position/profile to ~0.001-0.005mm repeatability; go/no-go gauges check fits fast on production. AS9102 first-article requires every drawing dimension balloon-numbered and measured. Geometry response: leave probe clearance on toleranced features.","applies":["aerospace part","production run","critical dimension"],"value":{"min":0.001,"max":0.005,"unit":"mm","note":"typical CMM repeatability"},"basis":"CMM metrology practice; AS9102 first-article requirement","sources":["as9102","xometry-tol"],"tags":["cmm","inspection","first article","as9102","gauge"]},{"id":"test-leak-pressure","kind":"test","tier":2,"title":"Leak / pressure test","summary":"Pressure-decay or bubble-immersion at 1.5-2x working pressure, hold 30-60s, decay limit ~1-2% of applied pressure. Geometry response: every sealed joint needs a defined seal land (O-ring groove per AS568, or a flat gasket face).","applies":["pressure vessel","sealed housing","fluid fitting"],"value":{"min":1.5,"max":2,"unit":"ratio","note":"test pressure / rated working pressure"},"basis":"Standard pressure-decay/proof-pressure test practice","sources":["xometry-tol"],"tags":["leak test","pressure test","o-ring","seal"]},{"id":"rule-datum-scheme-321","kind":"rule","tier":1,"title":"3-2-1 datum scheme for fixturing and inspection","summary":"Primary datum: 3 points on the largest stable face (removes 3 DOF). Secondary: 2 points on a perpendicular face (2 DOF). Tertiary: 1 point on a third perpendicular face (last DOF). Pick datums matching how the part is fixtured and measured.","applies":[],"basis":"ASME Y14.5 datum reference frame construction","sources":["asme-y14.5"],"tags":["datum","3-2-1","fixturing","gd&t"]},{"id":"rule-tolerance-stack-basics","kind":"rule","tier":2,"title":"Tolerance stack-up: worst-case vs. RSS","summary":"Worst-case stack sums each dimension's tolerance in the chain (always safe). RSS combines them as sqrt(sum t^2), ~40-60% tighter for the same confidence, valid only for independent normal dims. Use worst-case for short/safety-critical chains, RSS for long runs.","applies":[],"value":{"typical":0.5,"unit":"ratio","note":"RSS stack / worst-case stack, rule of thumb for >3 links"},"basis":"Standard tolerance-stack methodology","sources":["asme-y14.5"],"tags":["tolerance stack","rss","worst case"]},{"id":"rule-when-gdt-vs-plusminus","kind":"rule","tier":1,"title":"When to call out GD&T vs. plain ± dimensions","summary":"Use plain +/- for non-functional, non-mating sizes (default ISO 2768). Switch to GD&T (position/profile/runout with a datum frame) when a feature mates, rotates, or must pass a functional gauge — GD&T defines a usable zone that coordinates cannot.","applies":[],"basis":"GD&T defines a functional tolerance zone; coordinate tolerancing often over-constrains at the corners","sources":["asme-y14.5"],"tags":["gd&t","tolerancing","mating","position"]},{"id":"note-stating-tolerance-on-drawing","kind":"note","tier":1,"title":"How to state a tolerance on a drawing or in PMI","summary":"Title block default: 'UNLESS OTHERWISE SPECIFIED, TOLERANCES PER ISO 2768-mK'. Per-feature override: an explicit +/- or feature control frame. In NativeCAD use cad_pmi_author to attach PMI to a face/edge so it round-trips in the STEP AP242 export.","applies":[],"basis":"PMI (product manufacturing information) authoring practice for model-based definition","sources":["asme-y14.5"],"tags":["pmi","drawing","title block","cad_pmi_author"]},{"id":"note-fit-selection-guidance","kind":"note","tier":2,"title":"Choosing an ISO 286 fit class for a design intent","summary":"Parts that rotate/slide -> clearance fit (H7/g6, H7/f7). Parts located once and fastened -> transition fit (H7/k6, H7/js6). Parts meant to stay together without fasteners -> interference fit (H7/p6, H7/s6). Hold the hole at H7, vary the shaft grade.","applies":[],"basis":"ISO 286 'hole basis' system convention","sources":["iso-286"],"tags":["fit","iso 286","hole basis","selection"]},{"id":"note-tolerance-vs-process-capability","kind":"note","tier":2,"title":"A drawing tolerance is a promise the process must be able to keep","summary":"Specifying ISO 2768-f on a die-cast part or +/-0.05mm on an FDM print doesn't make the process more accurate — it makes every part a rework/scrap risk. Match the tolerance class to this pack's achievable-tolerance entries for the chosen process.","applies":[],"basis":"Tolerance should follow process capability, not wish","sources":["protolabs-tol"],"tags":["tolerance","process capability","design intent"]},{"id":"gasket-groove-for-ip-sealing","kind":"feature","tier":1,"title":"Gasket groove for IP-rated enclosure seams","summary":"Rectangular groove: width = gasket cord dia x 1.3-1.5, depth = cord dia x 0.75-0.8 for 20-25% compression, continuous with rounded corners (r >= 2x groove width) so the gasket doesn't kink. Undersized compression is the top cause of an IP67 fail.","applies":["enclosure","outdoor equipment","sealed housing"],"value":{"min":0.2,"max":0.25,"unit":"ratio","note":"compression fraction of gasket cord diameter"},"basis":"Standard elastomer gasket groove design for a continuous seam seal","sources":["iec-60529"],"tags":["gasket","groove","ip rating","sealing"]},{"id":"oring-gland-as568","kind":"feature","tier":2,"title":"O-ring gland dimensions (AS568 static face seal)","summary":"Static face-seal gland: groove width = 1.4-1.5x O-ring cross-section, groove depth = 0.75-0.8x cross-section for 20-25% squeeze, corner radius 0.25-0.4mm to avoid nicking the O-ring on assembly. Undersized groove volume causes extrusion; oversized causes leak.","applies":["pressure vessel","fluid fitting","sealed housing"],"value":{"min":0.2,"max":0.25,"unit":"ratio","note":"squeeze fraction of O-ring cross-section"},"basis":"AS568 O-ring standard and Parker O-ring handbook gland design","sources":["xometry-tol"],"tags":["o-ring","gland","seal","leak test"]},{"id":"vent-membrane-boss","kind":"feature","tier":2,"title":"Pressure-equalizing vent membrane boss","summary":"A Gore-style vent membrane (⌀6-13mm typical) needs a boss with a through-hole to atmosphere on one face and an O-ring or gasket seal against the membrane's flange on the other; boss wall >= 1.5x nominal wall so the membrane retention doesn't crack the boss under thermal cycling.","applies":["ip67 enclosure","ip68 enclosure","sealed housing"],"value":{"min":6,"max":13,"unit":"mm"},"basis":"Vent-membrane supplier mounting-boss guidance","sources":["iec-60529"],"tags":["vent","membrane","ip rating","boss"]},{"id":"vibration-isolator-mounting","kind":"feature","tier":2,"title":"Vibration isolator (grommet) mounting boss","summary":"Rubber grommet isolators sit in a boss sized to the grommet OD + 0.2-0.3mm clearance, with a shoulder to control compression (10-20%) rather than bottoming the fastener metal-to-metal, which would bypass the isolation entirely.","applies":["automotive","industrial equipment"],"value":{"min":0.1,"max":0.2,"unit":"ratio","note":"grommet compression fraction"},"basis":"Standard vibration-isolator mounting practice","sources":["iec-60068-2-6"],"tags":["vibration","isolator","grommet","mounting"]},{"id":"standard-as9102","kind":"standard","tier":2,"title":"AS9102 — First Article Inspection Requirement (aerospace)","summary":"Requires every drawing dimension balloon-numbered and measured on the first production part (Form 3) before a production run proceeds, with material and process certs (Forms 1/2). Design for measurement access on every toleranced feature before submitting for FAI.","applies":["aerospace part"],"basis":"Aerospace supply-chain first-article inspection requirement","sources":["as9102"],"tags":["as9102","first article","standard","aerospace"]}]}