Application CNC Machining Services: Choosing the Right Process for Your Part

Most parts do not need five axes. A flat bracket with holes on one face runs faster on a 3-axis mill, and the setup is simpler to inspect. Save the rotary tables for geometry that cannot be reached from one direction.

Parts with features on multiple faces fit 4-axis work well. The rotary table indexes the part between operations, so holes on four sides stay aligned to one datum. It is a good middle option for housings, manifolds and shaft-mounted plates where the tolerance band is ±0.02 mm or looser.

Simultaneous 5-axis centers cut angled faces, deep pockets and undercuts in one setup. On a camshaft lobe or a humanoid robot joint, that removes the re-fixturing steps that stack error. We run 16 simultaneous 5-axis machining centers, plus 12 four-axis mills and 27 three-axis machines, so the route is matched to the drawing rather than to whatever is free.

The trade-off is cost per hour and programming time. If a part only has one angled face, a 3-axis job with an angle plate is often the cheaper call. This is the kind of choice we flag during the free DFM review.

We hold ±0.005 mm (±0.0002 in) on features that need it. That number belongs on a bearing bore, a spigot fit or a mating face, not on every dimension on the sheet. Tightening a non-critical dimension adds inspection time and can push a part into a slower machine.

Surface finish matters as much as size. As-machined faces land at Ra 1.6–3.2 μm, high-finish work at Ra 0.8–1.6 μm, and fine finishing reaches Ra 0.2–0.8 μm. Sealing faces and sliding surfaces usually need the finer bands. Cosmetic faces can stay rough if they are painted later.

Material changes the answer. Aluminium 6061 and 7075 cut cleanly and hold tight limits with less heat. Stainless 316L and 17-4PH work-harden, so light passes and sharp tools matter. Titanium TC4 and Inconel move more during cutting, which means the tolerance call has to account for stress relief.

If a feature sits far from the main datums, error accumulates. Tell us which dimensions carry the function. We can then concentrate inspection where it counts instead of measuring everything to the same limit.

Aluminium covers most prototype and light-production work. Grades 6061, 6061-T6, 7075 and 6082 are common, and ADC12 shows up on die-cast parts that need later machining. These cut fast and finish well, so a prototype can ship in 3–5 days.

Stainless and steel take longer. Grades 303, 304, 316L, 17-4PH and 440C appear in medical and food-contact parts; 1018, 1045, 4130 and 4140 show up in structural work. Tool wear and chip control set the cycle time here, not the machine.

Titanium, Inconel and magnesium need a different approach. TC4 and Inconel hold strength at heat but resist cutting, so passes are light and coolant flow matters. Magnesium AZ31B and AZ91D cut easily but require chip handling care.

Plastics are their own case. POM and PEEK hold tight dimensions; ABS and PP move with temperature. Carbon fibre eats tools and needs dust control. Tell us the service environment and we will match the grade.

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  Prototype firstNo minimum order quantity, from one part to 10,000+ runs.
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  Finish optionsAnodizing, plating, powder coating, bead blasting, laser marking.
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  InspectionRaw material check, in-process monitoring, final inspection. Reports on request.

Different sectors ask for different paperwork. Aerospace and medical buyers usually want full dimensional reports and material certs. Automotive buyers care about process control and traceability. We hold ISO 9001:2015, IATF 16949:2016, ISO 13485:2016 and ISO 27001:2022, which cover these common requests.

Inspection runs at three points: incoming material, in-process checks, and final review. Every part gets a final check before it ships. If a drawing calls out a critical feature, that feature is measured and recorded.

For medical and food-contact parts, we deburr and clean before packing. For robot and automotive parts, we check fit interfaces against the mating drawing. The goal is to catch a problem at the machine, not at the customer's assembly line.

Confidentiality is part of the job. Uploads are secure, and we can sign an NDA before files move. Many customers send step files for a DFM review before any purchase order exists.

Send a 3D model in STEP or IGES plus a 2D drawing with tolerances, datums and finish callouts. If the drawing is missing, we can work from the model but will flag assumptions. Include the material grade and any surface treatment.

Say how many parts you need and when you need them. Volume changes the route: one prototype may be 3-axis with hand finishing, while a 500-piece run may move to a mill-turn center or a fixture that cuts setup time.

We return a quote and free DFM analysis within 12 hours. Production can start within 24 hours of approval, and parts ship in 3–5 days. Our historical late-delivery rate is below 2%.

If a feature is hard to machine, tell us early. Changing a corner radius or opening a pocket floor is cheaper at the quote stage than after the first article is cut.