Alloy CNC Machining Services

An alloy is a base metal modified with other elements to reach properties the pure metal cannot deliver. Add chromium to steel and it resists corrosion. Add zinc and magnesium to aluminium and it age-hardens to high strength. Those additions change how the material shears, how heat leaves the cut, and how the chip breaks.

Pure aluminium cuts soft and fast but galls on the tool. A 7075 plate cuts cleaner and holds a thread, yet it work-hardens quickly if the feed is too light. The same logic runs across families. What the alloy gains in service, the shop pays for at the spindle.

This is why the grade matters more than the geometry in early quoting. Two parts with identical drawings can differ by hours of cycle time once one is 6061-T6 and the other is 17-4PH in condition H900.

The practical question is never whether an alloy can be cut. The practical questions are: at what tool life, at what surface finish, and whether the part moves after unclamping.

Heat is the first problem. Titanium and Inconel conduct heat poorly, so the cutting edge keeps most of it. Tool temperature climbs, edge wear accelerates, and a tool that lasts an hour in 4140 may last ten minutes in Ti-6Al-4V.

Work hardening is the second. Austenitic stainless such as 304 and 316L hardens under the tool if the cutter rubs instead of bites. A light pass with a dull insert leaves a skin harder than the parent metal, and the next pass fights it.

Built-up edge is the third. Soft, gummy alloys like 5052 and pure copper smear onto the rake face. The chip stops breaking cleanly, the finish turns torn, and the dimension drifts as the built-up edge grows and sheds.

Residual stress is the fourth, and it is the quiet one. Heavy roughing locks stress into the workpiece. After unclamping or after heat treatment, the part bows. A bore that measured true on the machine may be out of round the next morning.

We start by reading the drawing for function, not just dimensions. Which faces are datums? Which bore has to hold a fit? A bearing seat and a clearance hole are not the same problem, so they do not get the same process.

From there we set the stock allowance, the roughing strategy and the number of stress-relief steps. For a thin-walled part in 7075 or 17-4PH, we may rough, stress-relieve, then finish in a separate setup. That costs a setup but saves a scrapped part.

Tool selection follows the alloy, not the other way round. Aluminium runs on polished, high-rake carbide with coolant through the spindle. Titanium runs slower, with more cobalt in the substrate and a sharper edge. Stainless wants a heavier feed to stay under the work-hardened layer.

Finally we fix the inspection plan. For a ±0.005 mm callout we hold the part in a controlled state and measure the features that carry the tolerance. On request we send dimensional reports with the shipment.

Machining wins when the part needs tight tolerance, a good surface, or low volume. It loses when the geometry is a thin shell with no functional surfaces, or when the annual volume runs into tens of thousands and the design has not changed in years.

Some alloys are simply better cast or forged near net shape, with machining left for the critical faces. Inconel turbine housings and large aluminium chassis frames often follow that route. We machine the interfaces and leave the bulk to the casting.

There is also a size ceiling worth knowing before you design. Our largest travel reaches 4,000 × 400 × 150 mm, with medium platforms at 750 × 1,150 × 550 mm and compact cells at 500 × 500 × 450 mm. A part that exceeds the envelope may need splitting into bolted sections.

If you are unsure which route fits, send the model and the projected quantity. We will tell you where machining makes sense and where it does not.