ATS Controller Housing OEM Machining

An ATS controller housing is not a box. It is a stiff frame that keeps a PCB from flexing under vibration, a thermal path that pulls heat off the power devices, and a shield that limits how much noise reaches the analog front end. Those three jobs fight each other. A wall thick enough to damp 200 Hz vibration adds mass and slows heat transfer. A vent that fixes the thermal problem opens an EMI gap. The machining plan has to settle that argument before the first chip is cut.

Most failures we see on incoming housings are not dimensional. They are functional. A cover that bows 0.15 mm across a 300 mm span stops sealing. A connector pocket cut 0.05 mm shallow makes a panel-mount D-sub sit proud, and the gasket never compresses evenly. Thread depth on a heatsink boss runs short, and the screw bottoms out before the thermal pad touches.

So the drawing has to name the critical features, not just the general tolerance block. Flatness on the gasket face, position of the mounting holes to the PCB datum, perpendicularity of the connector bores, and Ra on any surface that meets a thermal interface. Everything else can float. When a shop knows which four or five callouts matter, the fixture design and the inspection plan follow from them.

Materials follow the same logic. Die-cast ADC12 is cheap in volume but porous at thin walls, so it needs sealed surfaces if you want IP protection. Extruded 6061-T6 gives you straight walls and good thermal conductivity with no tooling cost. Sheet metal is fastest to prototype but flexes at the panel. Pick the process before you pick the shop.

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  Flatness on gasket faces0.05 mm over 300 mm keeps a gasket in compression.
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  Hole position to PCB datum±0.05 mm avoids preloading the board.
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  Connector bore perpendicularity0.02 mm per 25 mm stops shell tilt.
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  Thermal interface finishRa 0.8–1.6 μm closes the gap to a pad.

A housing with pockets on five sides, angled connector bores and a raised gasket land cannot be made on a 3-axis mill without three or four setups. Every setup adds a fixture, a datum shift and an operator touch. Error stacks. A simultaneous 5-axis center cuts five sides in one clamping, so the datum never moves and the position tolerance between a connector bore and a PCB boss stays tight.

That matters most on small, stiff parts. A controller housing might measure 300 × 200 × 80 mm with 4 mm walls. Thin walls ring under interrupted cuts. Holding it in a vise to machine the second side distorts it, and the part springs back after unclamping. In-process probing on a 5-axis machine catches that before the next operation.

GreatLight runs 16 simultaneous 5-axis machining centers, 12 four-axis mills, 27 three-axis machines and 16 mill-turn centers across 127 high-precision CNC machines. Maximum processing size is 4,000 mm, with travel of 4,000 × 400 × 150 mm on the large frame and 750 × 1,150 × 550 mm or 600 × 600 × 600 mm on the medium frames. Controller housings sit well inside those envelopes, which means we can run them on the machine that matches the feature count rather than the one that happens to be free.

One caution. Five-axis is not automatically cheaper. If your housing is a simple two-sided plate, a 3-axis machine with a soft jaw does the job faster. Use 5-axis when the part has angled faces, contoured surfaces, or tolerances that break under multiple setups. Below 50 units, tooling and programming often dominate the price anyway.

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  Single clampingKeeps connector bores and PCB bosses in one datum.
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  In-process probingCatches wall deflection before the finish pass.
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  Right machine for the jobSimple plates run faster on 3-axis.

Machining leaves a housing that fits but does not yet survive. Anodizing adds a dielectric layer, which is fine on the outside and a problem on any surface that must ground to the chassis. If the housing is part of the EMI path, mask the gasket land or specify conductive anodizing. Hardcoat gives wear resistance on sliding covers but cannot be masked at the same fine detail.

Electroless nickel goes on uniform, including inside blind pockets, and it solders. Zinc and black oxide are cheaper but thinner. Powder coating covers tool marks on a welded frame and hides a lot of cosmetic damage, though it adds 60–100 μm and can bridge tight gaps. Bead blasting before anodizing gives a matte, uniform look and removes the cutter marks that show through a clear finish.

Laser marking is the last step. Minimum character height is 1.5 mm. Put the part number, revision and a date or lot code on a face the operator can read after the unit is installed, not on the bottom where it disappears into a rack.

Every housing we ship gets raw material verification, in-process monitoring and a final inspection before it leaves. That is 100% inspection, with reports on request. Qualification rate across the shop runs at 99.99%. For a controller housing, that final step is where flatness and hole position get confirmed on a CMM rather than trusted to the operator.

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  Conductive anodizeKeeps the gasket land grounded.
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  Electroless nickelUniform inside blind pockets, solderable.
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  Powder coatAdds 60–100 μm; check gap clearance.
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  Laser marking1.5 mm minimum character height.

Ask what the shop assumed. A quote built on a general tolerance block and a three-setup plan will drift once the gasket flatness callout shows up. Get the DFM notes back with the price. GreatLight returns a quotation and a free DFM analysis within 12 hours, and production can start within 24 hours once the drawing is frozen. Parts ship in 3–5 days.

Ask who inspects. If the machine shop sends parts out for anodizing and a different vendor measures them, nobody owns the stack-up. An integrated shop machines, finishes and inspects in the same building, so a flatness problem is caught before plating, not after.

Ask about volume range. A shop tooled for 10,000-unit runs will price a 20-piece prototype badly, and a prototype shop will not hold tolerance at volume. GreatLight has no minimum order quantity, from one prototype to 10,000+ part runs, across three wholly-owned plants covering 7,600 m² with 150 technicians. Certifications are ISO 9001:2015, IATF 16949:2016, ISO 13485:2016 and ISO 27001:2022.

The last question is confidentiality. Controller drawings carry your architecture. Uploads are secure and confidential, and a non-disclosure agreement is available on request before any file moves.

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  DFM notes with the priceReveals the assumptions behind the number.
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  One building, one ownerMachining, finishing and inspection together.
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  Volume rangeNo MOQ; prototype to 10,000+ units.