Agtoelectronics Agent Agtoletronique CNC Machining

A connector assembly is mechanical and electrical at once. The electrical side is wire, crimp contacts and insert bodies. The mechanical side is what we machine: the connector shell, the backshell, the coupling nut, the strain relief, the panel mounting plate and the keying hardware. On a machine tool these parts hold contacts in alignment, carry shield continuity to the chassis, and survive vibration and coolant for years.

When an engineer says agtoelectronics agent agtoletronique cnc in a sourcing conversation, the request is usually for these metal components rather than the cable bundle. The cable house crimps and overmolds. We cut metal. Splitting the work that way keeps the interfaces clean, because the shell dimensions and the insert dimensions are both inspectable before final assembly.

The reason to machine these parts rather than cast or print them is simple. A shell needs a true bore, a real thread and a flat sealing face. Those three features decide whether the connector mates without galling and whether the seal holds at pressure. CNC turning gives all three in one setup on a mill-turn center, which is why most small and medium shell families start there.

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  Turned partsShells, coupling nuts, backshells, contact pins, threaded adapters
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  Milled partsPanel plates, brackets, keying inserts, mounting flanges
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  Typical batchOne prototype through 10,000+ piece runs

Most connector shells are bodies of revolution with a few side features. A mill-turn center cuts the bore, the external thread and the O-ring groove in one operation, then cross-drills the set screw hole without a second fixture. That single-setup route is what holds concentricity between the bore and the thread, which is the dimension that decides whether the contact sits centered in the insert.

Backshells with angled cable exits are different. Once the exit is at 45° or 90°, the part has features on three or four faces and the angles have to intersect correctly. Simultaneous 5-axis machining handles this by tilting the tool rather than re-fixturing the part, so the angled bore and the mating face stay in the same coordinate frame.

Panel plates and brackets are milled. They are flat, they carry a hole pattern, and the critical thing is position tolerance across the plate rather than roundness. On a 750 × 1,150 × 550 mm travel machine we can cut a plate with a full connector array in one pass, which removes the stack-up error that comes from moving a part between machines.

Small pins and contacts are a turning job, often from brass or beryllium copper. At Ø1–3 mm the challenge is not the profile but the handling. We run these in bar feeders and inspect them optically, because a burr on a pin end will not show up on a caliper but will show up in a crimp pull test.

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  Mill-turnRound parts with side holes or cross features, one setup
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  5-axisAngled backshell exits, compound-angle faces
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  3-axis millingFlat plates, brackets, hole arrays
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  Bar-fed turningSmall pins and contacts, Ø1–3 mm

Aluminum 6061-T6 is the default for shells and backshells. It machines fast, anodizes cleanly and takes a thread without tearing. For shells that see salt spray or repeated mating cycles, 7075 gives higher strength but is harder to anodize evenly, so we usually suggest hardcoat anodizing on 6061 instead.

Stainless 303 and 316L cover the corrosive end of the range. 303 turns with a clean chip and is the practical choice for shells and nuts in food or marine equipment. 316L is the one to specify when the part touches washdown chemicals or a medical cleaning cycle, though it work-hardens and needs slower feeds.

For pins and contacts, brass C36000 is the standard because it crimps predictably and plates well. Beryllium copper is worth the extra cost when the contact needs spring temper, such as a split pin or a retention finger. Titanium TC4 and 17-4PH appear in aerospace shells where weight or fatigue life drives the design.

Plastics have a narrower window. PEEK and POM work for insulators and small housings, and carbon fibre suits lightweight brackets. But a plastic shell will not carry shield continuity to the chassis, so if grounding matters the shell stays metal.

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  Aluminum6061-T6, 7075, 6082 for shells and plates
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  Stainless303, 316L, 17-4PH for corrosive and high-strength shells
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  Copper alloysC36000 brass, beryllium copper for pins and contacts
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  PlasticsPEEK, POM, carbon fibre for insulators and light brackets

We hold ±0.005 mm (±0.0002 in) on critical diameters, which is tighter than most connector interfaces need. The bore and the thread are the two features worth controlling that closely, because they set contact alignment. Faces and mounting holes usually live at ±0.05 mm and pushing them tighter only adds cost.

Surface finish follows the same logic. A sealing face wants Ra 0.8–1.6 μm to let the O-ring seat. An as-machined Ra 1.6–3.2 μm is fine for brackets and plates. Where a bore has to slide against another part, Ra 0.2–0.8 μm reduces friction and wear, but it also adds a finishing pass, so specify it only where the part actually moves.

Plating choices are driven by conductivity and corrosion, not appearance. Electroless nickel gives uniform coverage inside a bore, which electroplated finishes struggle to match on a deep shell. Silver and gold plating go on contacts where contact resistance matters. Conductive anodizing keeps the shell insulating but still grounded.

Inspection is 100% before shipment, and it covers three stages: incoming material check, in-process monitoring during the run, and final inspection. For a connector program the useful report is the CMM record on bore diameter, thread gauge results and a plating thickness reading. We supply those on request rather than as a default, so tell us on the PO if you need them.

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  CriticalBore and thread at ±0.005 mm
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  GeneralFaces and holes at ±0.05 mm
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  Sealing faceRa 0.8–1.6 μm
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  Sliding boreRa 0.2–0.8 μm