{"$schema":"nativecad-dfm-pack/1","id":"electronics","title":"Electronics — PCBs, enclosures, connectors, heat sinks, DIN-rail devices","sector":"electronics","version":"2026-09-03","summary":"PCB mounting, form-factor hole patterns (Raspberry Pi, Arduino, Pico, ESP32, Mini-ITX, Eurocard), enclosure walls/vents/gaskets/IP ratings, connector cutouts, thermal and DIN-rail design, plus the tests and materials electronics housings are held to.","aliases":["pcb","enclosure","electronics enclosure","raspberry pi","arduino","esp32","circuit board","heatsink","din rail","project box"],"crossSector":false,"size":"core","sources":[{"id":"rpi-4-mech","title":"Raspberry Pi 4 Model B Mechanical Drawing (raspberrypi.com downloads)","url":"https://datasheets.raspberrypi.com/rpi4/raspberry-pi-4-mechanical-drawing.pdf","accessed":"2026-09-03"},{"id":"rpi-5-mech","title":"Raspberry Pi 5 Mechanical Drawing (raspberrypi.com downloads)","url":"https://datasheets.raspberrypi.com/rpi5/raspberry-pi-5-mechanical-drawing.pdf","accessed":"2026-09-03"},{"id":"rpi-pico-datasheet","title":"Raspberry Pi Pico Datasheet (board dimensions and hole pattern)","url":"https://datasheets.raspberrypi.com/pico/pico-datasheet.pdf","accessed":"2026-09-03"},{"id":"arduino-uno-mech","title":"Arduino UNO Rev3 Reference Design (mechanical drawing)","url":"https://docs.arduino.cc/resources/pcb/A000066-full-pcb.zip","accessed":"2026-09-03"},{"id":"usb-if-type-c","title":"USB Type-C Cable and Connector Specification Release 2.2 (USB-IF)","url":"https://www.usb.org/document-library/usb-type-cr-cable-and-connector-specification-release-22","accessed":"2026-09-03"},{"id":"usb-if-usb2","title":"Universal Serial Bus Specification Revision 2.0 (Type-A/B connector mechanicals, USB-IF)","url":"https://www.usb.org/document-library/usb-20-specification","accessed":"2026-09-03"},{"id":"hdmi-spec","title":"HDMI Specification 1.4b (Type A receptacle mechanical outline, HDMI Licensing Administrator)","url":"https://www.hdmi.org/spec/index","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"},{"id":"en-60715","title":"EN 60715:2017 Dimensions of low-voltage switchgear and controlgear — Standardized mounting on rails (TH35 DIN rail)","url":"https://www.din.de/en","accessed":"2026-09-03"},{"id":"ul-94","title":"UL 94 Standard for Tests for Flammability of Plastic Materials for Parts in Devices and Appliances","url":"https://www.ul.com/services/ul-94-plastic-flammability","accessed":"2026-09-03"},{"id":"ipc-2221","title":"IPC-2221 Generic Standard on Printed Board Design (board thickness, spacing)","url":"https://www.ipc.org/toc/IPC-2221.pdf","accessed":"2026-09-03"},{"id":"protolabs-thermal","title":"Protolabs design guide — heat sink fin design for die casting and CNC","url":"https://www.protolabs.com/resources/design-tips/","accessed":"2026-09-03"},{"id":"molex-rj45","title":"Molex RJ45 shielded jack panel-cutout drawing","url":"https://www.molex.com/en-us/products/connectors/rj45","accessed":"2026-09-03"}],"entries":[{"id":"pcb-mounting-hole-diameters","kind":"fastener","tier":1,"title":"PCB mounting hole diameters for M2/M2.5/M3 standoffs","summary":"PCB mounting holes for standoffs run ⌀2.2 mm (M2 close fit), ⌀2.7 mm (M2.5, the Raspberry Pi size), ⌀3.2 mm (M3 close fit) — 0.2 mm over the screw major diameter, tighter than the generic clearance-hole series so the board doesn't shift on its standoffs.","applies":["pcb","circuit board","standoff"],"value":{"table":[{"size":"M2","hole":2.2},{"size":"M2.5","hole":2.7},{"size":"M3","hole":3.2}],"unit":"mm"},"basis":"Close-fit (H12) hole 0.2mm over major diameter keeps board registration on standoffs tighter than ISO 273 medium clearance","sources":["ipc-2221"],"tags":["pcb","hole","standoff","m2","m2.5","m3"],"see":["hardware/clearance-holes-metric"]},{"id":"pcb-standoff-height","kind":"dimension","tier":1,"title":"PCB standoff height (component clearance underside)","summary":"Standoffs raise a board 3–6 mm off the enclosure floor: 3 mm minimum clears solder tails and 0402/0603 passives, 5–6 mm is typical when a connector or electrolytic cap overhangs the underside.","applies":["pcb","standoff","enclosure"],"value":{"min":3,"max":6,"typical":5,"unit":"mm"},"basis":"Solder-side component height plus solder tail length on a wave- or hand-soldered THT board","sources":["ipc-2221"],"tags":["standoff","pcb","clearance"]},{"id":"pcb-edge-clearance","kind":"rule","tier":1,"title":"PCB mounting-hole edge clearance","summary":"Keep every mounting-hole centre ≥ 3 mm from the board edge (annular ring plus fab tolerance) and ≥ 1.5x the hole diameter from any plane-layer cutout, so the pad and via ring survive routing and depaneling.","applies":["pcb"],"value":{"min":3,"unit":"mm"},"basis":"IPC-2221 minimum land-to-edge spacing after routing/depanel tolerance","sources":["ipc-2221"],"tags":["pcb","edge","clearance","hole"]},{"id":"pcb-thickness-standard","kind":"dimension","tier":1,"title":"Standard PCB (FR4) thicknesses","summary":"Standard rigid PCB thicknesses are 1.6 mm (most full-size boards, the Pi and Arduino default), 1.0 mm, and 0.8 mm (compact/flex-adjacent boards like Pico); card-edge and mechanical fit must be checked against the actual thickness, not assumed 1.6 mm.","applies":["pcb","fr4"],"value":{"options":[0.8,1,1.6],"unit":"mm"},"basis":"JEDEC/IPC common panel thickness offerings from PCB fabricators","sources":["ipc-2221"],"tags":["pcb","thickness","fr4"]},{"id":"pcb-component-keepout","kind":"rule","tier":1,"title":"Component keep-out around mounting holes and board edge","summary":"Leave a ≥ 3 mm keep-out disc around every mounting hole and a ≥ 2 mm keep-out strip along the board edge, clear of tall components and copper pours, so a standoff or enclosure rib can land without shorting or crushing a part.","applies":["pcb","enclosure"],"value":{"min":2,"typical":3,"unit":"mm"},"basis":"Standoff head/rib footprint plus assembly tolerance around a plated hole","sources":["ipc-2221"],"tags":["keepout","pcb","standoff"]},{"id":"raspberry-pi-4-5-mounting","kind":"dimension","tier":1,"title":"Raspberry Pi 4/5 board outline and mounting-hole pattern","summary":"Raspberry Pi 4B and 5 share an 85 × 56 mm outline with four ⌀2.7 mm mounting holes on a 58 × 49 mm rectangle, each hole centre inset 3.5 mm from the nearest board edge (so the pattern origin sits at x=3.5, y=3.5 from the corner).","applies":["raspberry pi 4","raspberry pi 5","pcb","enclosure"],"value":{"table":[{"param":"board","x":85,"y":56},{"param":"holes","x":58,"y":49},{"param":"hole-diameter","value":2.7},{"param":"inset","value":3.5}],"unit":"mm"},"basis":"Official Raspberry Pi 4/5 mechanical drawings, mounting-hole table","sources":["rpi-4-mech","rpi-5-mech"],"tags":["raspberry pi","rpi4","rpi5","mounting","pattern"]},{"id":"arduino-uno-mounting","kind":"dimension","tier":1,"title":"Arduino Uno board outline and mounting holes","summary":"Arduino Uno Rev3 is 68.6 × 53.4 mm with four mounting holes of ⌀3.2 mm; hole positions are irregular (not a clean rectangle) — model from the four absolute coordinates in the reference drawing rather than assuming symmetric spacing.","applies":["arduino uno","pcb","enclosure"],"value":{"table":[{"param":"board","x":68.6,"y":53.4},{"param":"hole-diameter","value":3.2}],"unit":"mm"},"basis":"Arduino UNO Rev3 reference design mechanical drawing","sources":["arduino-uno-mech"],"tags":["arduino","uno","mounting","pattern"]},{"id":"pi-pico-mounting","kind":"dimension","tier":1,"title":"Raspberry Pi Pico board outline and mounting holes","summary":"Raspberry Pi Pico is 51 × 21 mm with two ⌀2.1 mm mounting holes (fits an M2 self-tapper) on a 47 × 11.4 mm rectangle centred on the board, castellated edges along the 21 mm sides for direct soldering.","applies":["raspberry pi pico","pico","pcb"],"value":{"table":[{"param":"board","x":51,"y":21},{"param":"holes","x":47,"y":11.4},{"param":"hole-diameter","value":2.1}],"unit":"mm"},"basis":"Raspberry Pi Pico datasheet mechanical drawing","sources":["rpi-pico-datasheet"],"tags":["pico","mounting","pattern"]},{"id":"enclosure-wall-thickness-im","kind":"rule","tier":1,"title":"Injection-moulded enclosure wall thickness","summary":"Injection-moulded electronics enclosures run a 1.5–2.5 mm nominal wall (2 mm typical for ABS/PC), held constant to avoid sink marks; bosses and ribs branch off this wall per the hardware pack's boss/rib rules, not thicker.","applies":["enclosure","injection molding"],"value":{"min":1.5,"max":2.5,"typical":2,"unit":"mm"},"basis":"Uniform-wall moulding guidance for ABS/PC housings","sources":["ul-94"],"tags":["wall","enclosure","injection-molding"],"see":["hardware/screw-boss-plastic"]},{"id":"enclosure-wall-thickness-fdm","kind":"rule","tier":1,"title":"FDM-printed enclosure wall thickness","summary":"FDM-printed enclosures need a 2–3 mm wall (a multiple of nozzle width x wall-loop count, commonly 3 loops at 0.4 mm) to be self-supporting and to hold a heat-set insert without cracking — thinner than 2 mm risks layer splitting under screw preload.","applies":["enclosure","fdm","3d printing"],"value":{"min":2,"max":3,"unit":"mm"},"basis":"Wall-loop multiples of common 0.4mm nozzle width; heat-set insert boss needs enough shell","sources":["ul-94"],"tags":["wall","enclosure","fdm"]},{"id":"usb-c-cutout","kind":"dimension","tier":1,"title":"USB-C panel cutout","summary":"A USB-C receptacle body is about 9.0 × 3.3 mm; cut the panel opening to ~ 10 × 4 mm (0.5 mm clearance per side) so the shell floats past a moulded panel and doesn't bind on tolerance stack-up.","applies":["usb-c","connector cutout","enclosure"],"value":{"table":[{"param":"receptacle","x":9,"y":3.3},{"param":"cutout","x":10,"y":4},{"param":"clearance","value":0.5}],"unit":"mm"},"basis":"USB Type-C connector mechanical envelope plus panel clearance","sources":["usb-if-type-c"],"tags":["usb-c","cutout","connector"]},{"id":"usb-a-cutout","kind":"dimension","tier":1,"title":"USB-A panel cutout","summary":"A standard USB Type-A receptacle body measures about 13 × 5.8 mm; cut the panel to that envelope plus 0.3–0.5 mm clearance per side (≈13.6–14 × 6.4–6.8 mm) for a stacked or single-port opening.","applies":["usb-a","connector cutout","enclosure"],"value":{"table":[{"param":"receptacle","x":13,"y":5.8}],"unit":"mm"},"basis":"USB 2.0 Type-A receptacle mechanical outline","sources":["usb-if-usb2"],"tags":["usb-a","cutout","connector"]},{"id":"hdmi-cutout","kind":"dimension","tier":1,"title":"HDMI Type-A panel cutout","summary":"An HDMI Type-A receptacle body is about 15 × 6 mm; cut the panel opening to that size plus 0.3–0.5 mm clearance per side so a moulded or die-cast panel doesn't interfere with the connector shell.","applies":["hdmi","connector cutout","enclosure"],"value":{"table":[{"param":"receptacle","x":15,"y":6}],"unit":"mm"},"basis":"HDMI 1.4b Type A receptacle mechanical outline","sources":["hdmi-spec"],"tags":["hdmi","cutout","connector"]},{"id":"rj45-cutout","kind":"dimension","tier":1,"title":"RJ45 panel cutout","summary":"A shielded RJ45 jack body is about 16 × 13.5 mm; size the panel window to the jack's own shield flange (per the connector's drawing) rather than the plug, since the jack shell — not the cable — sits in the panel.","applies":["rj45","ethernet","connector cutout","enclosure"],"value":{"table":[{"param":"receptacle","x":16,"y":13.5}],"unit":"mm"},"basis":"Shielded RJ45 jack panel-cutout drawing (Molex)","sources":["molex-rj45"],"tags":["rj45","ethernet","cutout","connector"]},{"id":"dc-jack-cutout","kind":"dimension","tier":1,"title":"DC barrel jack panel hole","summary":"A common 5.5 × 2.1 mm DC barrel jack needs a ⌀8 mm round panel hole for the barrel body (a 5.5 mm OD barrel with a threaded bezel); use a bigger ⌀9–9.5 mm hole if the jack has a locking nut bezel.","applies":["dc jack","barrel jack","connector cutout","enclosure"],"value":{"value":8,"unit":"mm"},"basis":"5.5x2.1mm barrel jack body diameter plus bezel clearance","sources":["usb-if-usb2"],"tags":["dc-jack","barrel","cutout","connector"]},{"id":"vent-slot-ip2x","kind":"rule","tier":1,"title":"Vent-slot width for IP2X finger-safe venting","summary":"Ventilation slots must be ≤ 3 mm wide (or ≤ 2.5 mm round holes) to keep the standard IP2X test finger (⌀12 mm articulated probe) out while still passing convective air; grille ribs between slots should be ≥ 1.5 mm thick.","applies":["enclosure","vent","ip rating"],"value":{"max":3,"unit":"mm"},"basis":"IEC 60529 IP2X test finger diameter (12.5mm) cannot enter an opening this narrow","sources":["iec-60529"],"tags":["vent","ip2x","finger-safe","slot"]},{"id":"din-rail-profile","kind":"dimension","tier":1,"title":"TH35 DIN rail cross-section (EN 60715)","summary":"The standard EN 60715 top-hat rail is 35 mm wide, 7.5 mm or 15 mm deep, formed from ~1 mm steel with the top edges curled ~1 mm inward; a clip must grip the 35 mm width and the curled top lips, not just sit on the flat.","applies":["din rail","th35","enclosure"],"value":{"table":[{"param":"width","value":35},{"param":"depth-shallow","value":7.5},{"param":"depth-deep","value":15},{"param":"material-thickness","value":1}],"unit":"mm"},"basis":"EN 60715 standardized rail dimensions","sources":["en-60715"],"tags":["din-rail","th35","en60715"]},{"id":"fin-spacing-natural-convection","kind":"dimension","tier":1,"title":"Heat-sink fin spacing for natural convection","summary":"Fins cooled by natural convection (no fan) need 5–8 mm centre-to-centre spacing; tighter spacing chokes the boundary-layer airflow and increases junction temperature despite the extra surface area.","applies":["heat sink","thermal","enclosure"],"value":{"min":5,"max":8,"unit":"mm"},"basis":"Natural-convection boundary-layer thickness between vertical fins","sources":["protolabs-thermal"],"tags":["heatsink","fin","thermal","convection"]},{"id":"material-fr4","kind":"material","tier":1,"title":"FR4 as the PCB substrate","summary":"FR4 (glass-fibre/epoxy laminate) is the default rigid PCB substrate: ~1.85 g/cm3 density, glass-transition temperature Tg 130–170°C depending on grade, and UL 94 V-0 rated — treat the board itself as a UL94 V-0 part when the enclosure's flammability rating is being assessed.","applies":["pcb","fr4"],"value":{"table":[{"property":"density","value":1.85,"unit":"g/cm3"},{"property":"Tg","min":130,"max":170,"unit":"C"}]},"basis":"Standard FR4 laminate datasheet properties","sources":["ipc-2221"],"tags":["material","fr4","pcb"]}]}