{"$schema":"nativecad-dfm-pack/1","id":"automotive","title":"Automotive — brackets, sheet-metal body/structure, die-cast and trim, EV and underhood","sector":"automotive","version":"2026-09-03","summary":"Bracket and mount fastener conventions, body/structure sheet-metal gauges, die-cast aluminium and injection-moulded trim rules, underhood thermal and vibration environment, EV battery enclosure and busbar basics, exhaust tube sizing, tolerancing and the salt-spray/thermal/vibration/flammability tests a vehicle part is held to.","aliases":["car","automotive bracket","vehicle","ev","battery enclosure","underhood","trim","body panel","exhaust","engine mount","engine","v12","crankcase ventilation","pcv","breather","oil drain"],"crossSector":false,"size":"core","sources":[{"id":"iso-16750-3","title":"ISO 16750-3:2023 Road vehicles — Environmental conditions — Part 3: Mechanical loads","url":"https://www.iso.org/standard/78026.html","accessed":"2026-09-03"},{"id":"iso-16750-4","title":"ISO 16750-4:2023 Road vehicles — Environmental conditions — Part 4: Climatic loads","url":"https://www.iso.org/standard/81219.html","accessed":"2026-09-03"},{"id":"sae-j1455","title":"SAE J1455 Recommended Environmental Practices for Electronic Equipment Design (heavy-duty vehicle)","url":"https://www.sae.org/standards/content/j1455_202307/","accessed":"2026-09-03"},{"id":"gmw3172","title":"GMW3172 General Specification for Environmental/Durability Validation (GM worldwide standard)","accessed":"2026-09-03"},{"id":"nadca-403","title":"NADCA Product Specification Standards for Die Castings (draft, wall, tolerance)","url":"https://www.diecasting.org/","accessed":"2026-09-03"},{"id":"astm-a1011","title":"ASTM A1011/A1011M Standard Specification for Steel, Sheet and Strip, HSLA","url":"https://www.astm.org/a1011_a1011m-18a.html","accessed":"2026-09-03"},{"id":"sae-j2340","title":"SAE J2340 Categorization and Properties of Dent Resistant, High Strength, and Ultra-High Strength Automotive Sheet Steel","url":"https://www.sae.org/standards/content/j2340_202007/","accessed":"2026-09-03"},{"id":"iso-20653","title":"ISO 20653:2013 Road vehicles — Degrees of protection (IP code) — Protection of electrical equipment","url":"https://www.iso.org/standard/71681.html","accessed":"2026-09-03"},{"id":"iec-60529","title":"IEC 60529:1989+AMD2:2013 Degrees of protection provided by enclosures (IP Code)","url":"https://webstore.iec.ch/publication/2452","accessed":"2026-09-03"}],"entries":[{"id":"bolt-class-usage-8-8-10-9","kind":"fastener","tier":1,"title":"Bracket and mount bolt class: M6/M8/M10, 8.8 vs 10.9","summary":"Chassis and bracket bolts run M6, M8 and M10 mostly in property class 8.8; 10.9 is used where the joint is fatigue- or shear-critical (engine mounts, suspension brackets) — never mix a 10.9 bolt with an 8.8 nut.","applies":["bracket","mount","chassis fastener"],"value":{"options":["M6 class 8.8","M8 class 8.8","M10 class 8.8","M8 class 10.9","M10 class 10.9"]},"basis":"ISO 898-1 property classes; 10.9 reserved for fatigue-critical joints per common OEM fastener standards","sources":["sae-j2340"],"see":["hardware/bolt-torque-and-preload-classes","hardware/torque-table-class-8-8"],"tags":["bolt","class","bracket","mount","8.8","10.9"]},{"id":"weld-nut-sizing","kind":"fastener","tier":1,"title":"Weld nut sizes for body-in-white attachment","summary":"Square and hex weld nuts for body brackets run M5–M10, projection-welded to 0.7–2.0 mm panel; pilot hole is the nut's tapped size plus 0.5–1.0 mm to seat the weld projections without arc blow.","applies":["weld nut","body-in-white","bracket attachment"],"value":{"options":["M5","M6","M8","M10"]},"basis":"Common OEM weld-nut standards (e.g. GM/Ford weld-fastener specs) size the pilot to the projection ring, not the thread","sources":["gmw3172"],"tags":["weld-nut","projection-weld","body-in-white"]},{"id":"clip-christmas-tree-holes","kind":"fastener","tier":1,"title":"Clip and christmas-tree fastener hole sizes","summary":"Christmas-tree (arrowhead) push clips take a ⌀6.3 mm or ⌀8 mm panel hole in 0.7–3 mm sheet or trim; ⌀6.3 mm is the common 2-leg clip, ⌀8 mm the heavier 4-leg / high-retention clip.","applies":["trim clip","christmas tree clip","panel fastener"],"value":{"options":["6.3 mm hole","8 mm hole"]},"basis":"Trim-clip vendor catalogs (ITW, Nifco, Bollhoff) standardise on these two panel-hole sizes across 0.7–3 mm stock","sources":["gmw3172"],"tags":["clip","christmas-tree","trim","hole"]},{"id":"push-pin-hole-sizes","kind":"fastener","tier":1,"title":"Push-pin (nylon dowel) fastener hole sizes","summary":"Nylon push-pin fasteners take ⌀6.5, ⌀7 or ⌀8 mm mating panel holes depending on pin family; the pin's flared shank interferes 0.2–0.5 mm past the hole to lock, so undersizing 0.1 mm below spec loses retention.","applies":["push pin","trim fastener","panel fastener"],"value":{"options":["6.5 mm hole","7 mm hole","8 mm hole"]},"basis":"Common trim push-pin catalog hole callouts (e.g. Ford/GM interior trim fastener specs)","sources":["gmw3172"],"tags":["push-pin","trim","hole","nylon"]},{"id":"u-nut-j-nut-panel-thickness","kind":"fastener","tier":1,"title":"U-nut / J-nut spring clip panel thickness range","summary":"U-nuts and J-nuts (spring steel push-on nuts) clamp onto 0.6–2.5 mm flange panels; select by flange thickness first, then by the screw's major diameter (commonly M5–M6 for trim, M6–M8 for structural clips).","applies":["u-nut","j-nut","spring clip nut"],"value":{"min":0.6,"max":2.5,"unit":"mm"},"basis":"Spring-clip nut catalogs size the leg spread to a flange-thickness range, independent of thread size","sources":["gmw3172"],"tags":["u-nut","j-nut","clip-nut","flange"]},{"id":"body-panel-gauge-outer","kind":"dimension","tier":1,"title":"Outer body panel gauge (skin panels)","summary":"Exterior skin panels (doors, fenders, hood, roof) run 0.7–0.8 mm cold-rolled or HSLA steel, or 0.8–1.0 mm for aluminium skins, to hold class-A surface with minimum mass.","applies":["body panel","skin panel","outer panel"],"value":{"min":0.7,"max":0.8,"unit":"mm"},"basis":"Dent-resistance vs. mass trade-off standardised across OEM body-panel gauge tables","sources":["sae-j2340","astm-a1011"],"tags":["body-panel","gauge","skin","outer"]},{"id":"bracket-sheet-gauge","kind":"dimension","tier":1,"title":"Bracket sheet-metal gauge","summary":"Formed steel brackets (mounting brackets, reinforcements, small load-carrying stampings) run 1.0–2.0 mm, chosen by the fastener class and the bracket's span rather than by panel-class rules.","applies":["bracket","reinforcement","stamped bracket"],"value":{"min":1,"max":2,"unit":"mm"},"basis":"Typical OEM bracket-gauge tables for M6–M10 fastener classes on cantilevered brackets","sources":["astm-a1011"],"tags":["bracket","gauge","sheet-metal"]},{"id":"structural-sheet-gauge","kind":"dimension","tier":1,"title":"Structural sheet-metal gauge (rails, crossmembers, load paths)","summary":"Structural stampings that carry crash or chassis load (rails, crossmembers, pillar reinforcements) run 2.0–3.0 mm HSLA/DP steel, thicker where a hot-stamped boron grade is not used.","applies":["structural member","rail","crossmember","pillar reinforcement"],"value":{"min":2,"max":3,"unit":"mm"},"basis":"Load-path stampings need section modulus that 2.0 mm and below cannot give without a hot-stamped grade","sources":["astm-a1011","sae-j2340"],"tags":["structural","gauge","hsla","dp-steel"]},{"id":"hole-to-edge-bend-automotive","kind":"rule","tier":1,"title":"Hole-to-edge and hole-to-bend distance on automotive stampings","summary":"Keep a hole centre >= 2x its diameter from a cut edge and >= 2.5x the material thickness plus the bend radius from a bend line, or the flange tears or the hole distorts during forming.","applies":["bracket","body panel","stamped part"],"basis":"General sheet-metal tearing/distortion limits near a bend, tighter than the generic edge-distance rule because of springback","sources":["astm-a1011"],"see":["hardware/edge-distance-holes"],"check":{"process":"sheet-metal","rule":"hole-to-bend-distance"},"tags":["hole","edge-distance","bend","stamping"]},{"id":"diecast-a380-wall-thickness","kind":"process","tier":1,"title":"Die-cast aluminium (A380) nominal wall thickness","summary":"A380 high-pressure die-cast walls run 2–4 mm nominal; below 2 mm the die fills unreliably, above 4 mm the section develops shrink porosity and extends cycle time.","applies":["die-cast bracket","housing","A380 casting"],"value":{"min":2,"max":4,"unit":"mm"},"basis":"NADCA process-capability wall-thickness guidance for A380 HPDC","sources":["nadca-403"],"check":{"process":"die-casting","rule":"min-wall"},"tags":["die-cast","a380","wall-thickness"]},{"id":"diecast-draft-angle","kind":"rule","tier":1,"title":"Die-cast draft angle","summary":"A380 die-cast exterior walls need 1-2 deg of draft per side to release from the die without galling; textured or deep-cavity walls want the higher end.","applies":["die-cast bracket","housing","A380 casting"],"value":{"min":1,"max":2,"unit":"deg"},"basis":"NADCA draft-angle recommendation for aluminium HPDC","sources":["nadca-403"],"check":{"process":"die-casting","rule":"min-draft"},"tags":["die-cast","draft","a380"]},{"id":"diecast-rib-thickness-ratio","kind":"rule","tier":1,"title":"Die-cast rib thickness vs. wall","summary":"Ribs on an A380 casting should stay at or below 60% of the adjacent wall thickness to avoid sink marks on the show surface opposite the rib.","applies":["die-cast bracket","housing","A380 casting"],"value":{"typical":60,"unit":"%"},"basis":"Cooling-rate mismatch at a rib-to-wall junction thicker than 60% pulls the opposite face in as it solidifies","sources":["nadca-403"],"check":{"process":"die-casting","rule":"rib-to-wall-ratio"},"tags":["die-cast","rib","sink-mark"]},{"id":"trim-wall-thickness-pp-tpo","kind":"dimension","tier":1,"title":"Injection-moulded trim wall thickness (PP/TPO)","summary":"Interior and exterior trim panels in PP or TPO mould at 2.5–3.5 mm nominal wall; thinner sections risk short shots across a large flow length, thicker sections add sink and cycle time.","applies":["trim panel","interior trim","PP trim","TPO trim"],"value":{"min":2.5,"max":3.5,"unit":"mm"},"basis":"PP/TPO flow-length-to-wall ratio at typical trim-panel flow lengths (300-800 mm)","sources":["sae-j1455"],"check":{"process":"injection-molding","rule":"min-wall"},"tags":["trim","pp","tpo","wall-thickness"]},{"id":"trim-draft-angle","kind":"rule","tier":1,"title":"Trim panel draft angle, plus grain allowance","summary":"PP/TPO trim walls need >= 1 deg draft per side to eject cleanly; add roughly +1 deg of draft per 0.025 mm of texture/grain depth so a grained panel with 0.075 mm texture wants about 4 deg.","applies":["trim panel","grained trim","textured trim"],"value":{"min":1,"unit":"deg"},"basis":"Standard injection-mould grain-draft allowance (mold-tech style guidance): +1 deg per 0.025 mm texture depth","sources":["sae-j1455"],"check":{"process":"injection-molding","rule":"min-draft"},"tags":["trim","draft","grain","texture"]},{"id":"underhood-temp-zones","kind":"dimension","tier":1,"title":"Underhood ambient temperature by mounting zone","summary":"Underhood component ambient runs 105 C for engine-bay-general locations, up to 125 C near the exhaust manifold shield, and up to 150 C for parts clamped directly to the engine block or turbo heat shield.","applies":["underhood component","bracket","connector","sensor housing"],"value":{"min":105,"max":150,"unit":"C"},"basis":"ISO 16750-4 climatic-load temperature classes by mounting location","sources":["iso-16750-4"],"tags":["underhood","temperature","thermal-zone"]},{"id":"bracket-first-mode-rule","kind":"rule","tier":1,"title":"Bracket first natural frequency > 200 Hz","summary":"A vehicle bracket should keep its first bending mode above 200 Hz so it does not resonate with the engine's firing-order excitation band or road-induced random vibration below that frequency.","applies":["bracket","mount","sensor bracket"],"value":{"min":200,"unit":"Hz"},"basis":"Keeps the bracket's fundamental clear of typical 4-cylinder firing-order and chassis random-vibration content (10-200 Hz band)","sources":["iso-16750-3"],"tags":["vibration","natural-frequency","bracket","nvh"]},{"id":"biw-tolerance-rps","kind":"tolerance","tier":1,"title":"Body-in-white tolerance under an RPS / 3-2-1 datum scheme","summary":"Body-in-white sheet-metal assemblies hold approximately +/-0.5 mm at the reference point system (RPS) locators; feature-to-feature tolerance on a single stamping is typically +/-0.3-0.5 mm.","applies":["body-in-white","stamping","assembly"],"value":{"typical":0.5,"unit":"mm"},"basis":"Standard OEM RPS tolerance stack-up target for BIW sub-assembly build","sources":["gmw3172"],"tags":["tolerance","rps","biw","3-2-1"]},{"id":"machined-tolerance-automotive","kind":"tolerance","tier":1,"title":"Machined automotive component tolerance","summary":"Machined automotive features (bearing bores, mount faces, bolt patterns) hold +/-0.1 to +/-0.2 mm general tolerance, tightening to +/-0.02-0.05 mm on bearing fits and sealing faces.","applies":["machined bracket","housing","mount face"],"value":{"min":0.1,"max":0.2,"unit":"mm"},"basis":"Typical OEM machining general-tolerance class for cast/machined automotive components","sources":["nadca-403"],"tags":["tolerance","machining","bore","mount-face"]},{"id":"battery-enclosure-ip67","kind":"rule","tier":1,"title":"EV battery enclosure sealing target: IP67","summary":"An EV battery pack enclosure seals to IP67 (dust-tight, 1 m submersion for 30 min) at minimum, using a compressed EPDM or silicone gasket at the lid-to-tray joint with continuous bolt-and-groove compression.","applies":["battery enclosure","battery tray","ev pack"],"value":{"value":"IP67","unit":"text"},"basis":"ISO 20653 / IEC 60529 IP67 is the common minimum EV pack sealing target across OEM specs","sources":["iso-20653","iec-60529"],"tags":["ev","battery-enclosure","ip67","sealing"]},{"id":"mechanical-shock-20g","kind":"rule","tier":1,"title":"Mechanical shock pulse: 20 g automotive component","summary":"Automotive brackets and enclosures should survive a 20 g, 6-11 ms half-sine mechanical shock pulse without fracture or fastener loosening, applied in each of 3 axes.","applies":["bracket","ecu housing","connector"],"value":{"typical":20,"unit":"g"},"basis":"ISO 16750-3 mechanical shock test severity for chassis- and body-mounted components","sources":["iso-16750-3"],"tags":["shock","20g","mechanical-load"]}]}