Custom Aluminum Heatsink Enclosures — CNC Machined Around Your Board

Looking for someone to machine a heatsink enclosure to your design — or to design one around your board? Send the STEP file, or just the PCB and the component powers. Drawing for approval before machining, from one piece, quote in 12 hours.

Why the housing and the heatsink should be one part

A separate heatsink bolted to a box adds two thermal joints, a stack of tolerances and an assembly step. Machining the fins into the enclosure wall removes all three: heat crosses one interface — the thermal pad between processor and pedestal — and then it is already in the fin field. The same block gives you EMI shielding, structural mounting and, with an O-ring groove in the cover joint, IP65/IP67 sealing with zero vents.

That is why fanless edge computers, robot controllers and outdoor AI boxes are built this way. The catch is that the fin field, pedestal and cut-outs are specific to your board — which is exactly the part a catalogue enclosure cannot give you, and the part we machine.

CNC billet or extrusion — the honest decision table

	CNC from 6061-T6 billet	Extruded 6063-T5 profile + CNC
Fin geometry	Any — pin fins, radial, variable pitch, fins over the hot spot only	Straight fins fixed by the die, one direction
Tooling cost	None — prototype = production	Profile die required
Sensible quantity	1 – ~500 pcs	From a few hundred pcs
Thermal conductivity	≈167 W/m·K	≈200 W/m·K
Strength (bosses, threads)	Higher — T6 billet	Softer alloy
Wall / cavity freedom	Full 3D — pockets, pedestals, variable walls	Constant cross-section, then machined

The practical rule: prototypes and volumes up to a few hundred are billet CNC; sustained volumes justify a die and move to extrusion with CNC finishing. We quote both when the quantity is near the boundary, so you see the crossover price instead of guessing. Where strength matters more than heat — a bracket, not a heatsink — 7075-T6 is available; where corrosion or washdown dominates, a 304 stainless enclosure without fins is the honest answer and we will say so.

Where these enclosures go

What we machine into the enclosure

• Thermal pedestal — raised contact pad over the processor, height set to your component stack with the thermal pad gap you specify
• Fin field — straight, pin or radial; pitch and height sized to the power and the mounting orientation, not copied from a catalogue
• Connector cut-outs — machined to your I/O panel, not punched approximations; countersunk and deburred
• Standoffs and bosses — tapped in the housing itself, positioned from your board data
• O-ring groove — in the cover joint for IP65/IP67, with the gasket specified for the temperature range
• Finish — anodize clear or black (black helps passive dissipation), bead blast, laser-engraved markings

Where a catalogue enclosure profile runs out

Fischer Elektronik and Alutronic stock extruded profiles deep, in fixed cross sections you cut to length. That covers a lot of jobs. It stops where your board stops fitting somebody else's cross section.

What your board needs	In the catalogue?	What we do about it
Cavity to your board outline — 120 × 120 mm with a clipped corner, wall thick where the mounting feet load it	Only if the board fits between the profile's fixed inner walls. The cross-section is the die's; you choose the length, nothing else	Cavity milled to the outline, wall thickness set where you need it instead of where the die left it
Connector cut-outs on your I/O face — your stack, M12 glands, an odd-height header	Not from the profile. The die makes the cross section; every opening on the I/O face is a second operation on top of the extrusion	Openings cut from your DXF or Gerber panel data in the same setup as the cavity, so panel and board share one datum
Standoffs at your board's hole pattern, tapped into the enclosure floor	No — a constant section has no floor features. Standoffs are separate parts you screw, press or bond in	Bosses milled and tapped from the same board file as the cavity — one part to inspect instead of six
Fin field only over the 25 W SoC, shell flat elsewhere for the label and the DIN-rail clip	No — one constant cross-section, so the fins run the full length in one direction whether the heat is there or not	Fins cut where the heat is; the rest of the shell stays flat, and the removed metal comes off the shipping weight
Copper under a concentrated hot spot — spreading before the heat reaches the fins	No — a profile is one aluminum alloy end to end	C11000 pedestal insert (about 388 W/m·K) into a machined pocket in the 6061-T6 wall. It costs weight: 8.96 g/cm³ against 2.70
Fins 0.6 mm thick, 20 mm tall (33:1) directly over the processor	No — extruded profiles reach about 12:1, from about 1.20 mm, with 1–2° draft per side	Not millable into the wall either: milled fins run out near 8:1, from about 1.00 mm. Below 8:1 the fins are cut into the wall and there is no joint at all. Above it the fin field stops being part of the housing: machined base, 0.30–1.00 mm rolled fins bonded in, up to 50:1, no tooling, from 1 piece. That buys aspect ratio and costs you one bonded joint — worth it only when 8:1 is not enough
A plain finned box — 100 × 160 mm, straight fins, no sealing, openings only on the end plates, 300 pcs	Yes. Stocked profile, cut to length, end plates drilled	Buy it off the shelf. At that spec we would machine what is already on a shelf, charge more for it, and ship later than the distributor
A 5 W board that needs sealing, not cooling — IP65, no fin field	Yes — a stock sealed box in a standard size	Buy it, and bolt a catalogue heatsink to the lid if it runs warm. Two shelf parts and four screws beat one machined part until the seal and the fin field have to be the same piece of metal

Send what you have — CAD or not

You have	What happens
STEP / STP / SolidWorks	Straight to CAM — quote and lead time in 12 h
DXF + Gerber / PCB data	We build the enclosure model around the board outline and component map
PDF drawing	Redrawn as a 3D model, submitted for your approval
The physical board or a sample enclosure	Measured and reverse engineered — how that works
Only the requirement	Tell us the board size, component powers and environment — we design it, you approve the drawing before machining

Frequently asked questions