Aluminum Cutting

Many engineers and technicians think about aluminum milling as a easy task, until when faced with their first aluminum parts process. The same properties that allow higher speed in process and a good mechanical performance, making the cutting process difficult and demanding special measures.

An endmill is a type of milling cutter, a cutting tool used in industrial milling applications. It is distinguished from the drill bit in its application, geometry, and manufacture. While a drill bit can only cut in the axial direction, a milling bit can generally cut in all directions, though some cannot cut axially.

The recommendations on this article has been written considering the milling, turning, drilling andboring operations, but it also serves like a guide for resolving the most common problems in aluminum cutting.

Usual Problems

One of the biggest problems in aluminum cutting is the Built Up Edge. The built up edge is a welding of workpiece material to the tool edge that commonly occurs on soft, gummy workpiece materials and the loss of effective geometry causes increases in cutting forces and quality problems.

Top view of a 3 knifes drill with built up edge

Top view of a square insert with built up edge

The quality problems caused by the built up edge are scratchesin the surface and cloudy finish, both increasing the rugosity dramatically and compromising the finish visual. Eventually a small piece of the built up edge unties and it takes a bit of the tool, leading to the tool breakage.

A few simple (but effective) actions can be taken to minimize the built up edge:

• Higher cutting speed;
• PVD (Phisical Vapor Deposition) coatings;
• Polished edges;
• Abundant coolant (reducing the temperature in the tool edge, preventing the workpiece welding);
• Non-honed tool edges (keen edges preferable).

Another problem decurrent of the aluminum ductility is the formation of long chips. The ideal format of the chip is short fragmented pieces or commas, because long chips harm the surface finishing and can cause unsafe situations for the operator.

Comma chips