Aluminium turned parts: fast to cut, easy to get wrong

Aluminium machines two or three times faster than steel and weighs a third as much. It also builds up on the tool, throws long chips and moves with temperature. Knowing that is the whole difference.

Aluminium looks like the easy material. Cutting speeds are high, forces are low, the machine barely notices the part. Then the first batch comes back with smeared surfaces, oversize bores and burrs that will not brush off, and it becomes clear the material has its own rules.

What actually goes wrong

• Built-up edge. Aluminium welds itself to the cutting edge, then tears away and takes a piece of the surface with it. Sharp, polished, high-rake tooling and enough speed keep it off.
• Chips that do not break. A ductile alloy produces long spirals that wrap around the part. On an unattended night shift that ends the run, not the part.
• Burrs. Aluminium pushes rather than shears at the exit of a hole. Deburring is not an afterthought on an aluminium part; it belongs in the process.
• Thermal movement. Aluminium expands roughly twice as much as steel. A part measured warm off the machine and a part measured next morning are not the same part.

Alloys and blanks

We machine aluminium both as bar and from castings. The free-machining alloys behave predictably; the softer, more ductile grades ask for more attention to chip control. If a drawing specifies an alloy for its strength or its anodising behaviour rather than for machining, that is worth saying at enquiry stage — it changes the cycle time and therefore the price.

Where aluminium earns its place

Anywhere weight matters and load does not exceed what the alloy can carry: pneumatics, electrical enclosures, lighting, optics, and increasingly e-bike and light vehicle components. The machining is faster than steel, which offsets a higher material price sooner than most people expect.

We turn aluminium, brass, stainless, carbon steel, titanium and nickel alloys from Ø 2 to Ø 52 mm. See the parts we make.