Alloy CNC Machining Services for Demanding Metal Parts

Pure aluminum is soft and gummy. Add 4.5% copper and a little magnesium, as in 2024, and you get a strong alloy that machines into a clean chip but corrodes easily without coating. Add zinc instead, as in 7075, and the strength climbs toward steel territory while the chip gets shorter and the cutting forces go up. The base metal tells you little about the final part.

That matters because tooling, spindle speed and feed rate all key off the alloy, not the family name. 6061-T6 cuts at high surface speed with generous feed. 17-4PH stainless in the H900 condition needs lower speed, more coolant and a rigid setup, or you burn the insert and scrap the part.

Magnesium sits at the other end. AZ31B and AZ91D cut fast and leave a fine finish, but the chips are flammable, so the shop needs dedicated extraction and a strict no-water rule at the spindle. Not every supplier will run it. We do.

A part with five faces of work and tight datums belongs on a 5-axis center. One setup holds the datums, and you avoid re-fixturing an expensive billet of Inconel or Ti-6Al-4V. We run 16 simultaneous 5-axis centers, plus 12 four-axis mills and 27 three-axis machines for simpler geometry.

Size decides as much as shape. Our largest travel is 4,000 × 400 × 150 mm, which suits long extrusion profiles and rail-type parts. Mid-size work runs on 750 × 1,150 × 550 mm and 600 × 600 × 600 mm platforms. Compact housings and connectors fit the 500 × 500 × 450 mm and 500 × 310 × 200 mm machines, and a Ø400 mm rotary table handles round alloy parts in one pass.

Thin walls are the usual trouble spot. Aluminum alloy at 0.8 mm wall thickness is routine. The same wall in 316L stainless will deflect under cutting pressure unless we take light finishing passes and support the back side. If a wall is thinner than 0.5 mm in steel or titanium, casting or sheet metal usually beats machining on cost.

Mill-turn centers cover parts that need both turning and milling without losing concentricity. Shafts, bushings and valve bodies with cross-drilled holes are typical. We have 16 of them.

We hold ±0.005 mm (±0.0002 in) on alloy parts when the geometry allows it. That number assumes a rigid setup, a controlled temperature, and a feature you can actually reach with a probe. A deep bore at 8× diameter is a different problem than a flat face, and we will say so before quoting.

Surface finish is functional on most alloy parts, not cosmetic. As-machined surfaces land at Ra 1.6–3.2 μm. A fine finishing pass gets Ra 0.8–1.6 μm. Mirror-level Ra 0.2–0.8 μm is possible on aluminum and brass, and it usually needs a separate finishing operation rather than a single pass.

Alloy parts often move after machining. 7075 and 17-4PH relieve internal stress when you remove material, so a thin flange can bow overnight. For tight parts we rough, stress-relieve, then finish. It adds a day and it saves the part.

Every batch gets a raw material check, in-process monitoring and a final inspection before it ships. Reports are available on request. Our historical qualification rate is 99.99%.

Anodizing adds thickness. Clear anodize builds roughly 5–10 μm per surface, so a ±0.005 mm feature can drift out of tolerance if the finish is applied after final machining. We mask critical bores or machine them undersize to compensate. Hardcoat builds more and is worth a conversation on any mating surface.

Electroless nickel, zinc, silver and gold plating all go through our finishing line. Copper and beryllium copper parts usually get a nickel or gold layer for solderability and corrosion. Powder coating and black oxide suit steel and cast housings where appearance and rust protection matter more than micron-level fit.

Bead blasting, tumbling, brushing and polishing cover the mechanical finishes. Laser marking handles part numbers and traceability codes, with a minimum character height of 1.5 mm so the mark stays readable after coating.

If a finish would push your part out of tolerance, we flag it during the DFM review rather than after the parts come back from the coater.

Send the 3D model and 2D drawing. We return a quotation and a free DFM analysis within 12 hours. The DFM note lists any feature we think will be hard to hold, plus material and finish suggestions if the alloy you picked is fighting the geometry.

Production can start within 24 hours of approval. Parts ship in 3–5 days for most alloy work. Historical late-delivery probability is below 2%, and we track that number rather than quote a promise.

There is no minimum order quantity. One prototype and a 10,000-part run go through the same inspection process. We are ISO 9001:2015, IATF 16949:2016, ISO 13485:2016 and ISO 27001:2022 certified, so automotive and medical programs can be handled without a second supplier for the paperwork.

Uploads stay confidential. An NDA is available on request. Our three plants cover 7,600 m² in Dongguan and Singapore, with 150 technicians and 127 high-precision CNC machines.