How Do You Finish-Mill Aluminum Alloys?

Machining Characteristics of Aluminum Alloys

Aluminum alloys have relatively low strength and hardness and good thermal conductivity, producing light milling loads and low cutting temperatures. High cutting speeds can be used with carbide cutters; a typical milling speed is v = 300-600 m/min. However, aluminum is ductile and has a low melting point, so it tends to adhere to the cutter and impede chip evacuation. Aluminum milling cutters should have fewer teeth and a large rake angle, γ_n = 20°-30°. The surface roughness Ra of the rake and flank faces should be below 0.16 μm. YG-series carbide inserts should be used to reduce chemical affinity between aluminum and the tool material.

Finish Milling Aluminum Alloys

Water-soluble cutting fluids should not be used for finish milling aluminum because they can produce fine pinholes on the machined surface. Kerosene or diesel fuel can be used instead.

A large-rake-angle face mill for aluminum finish milling clamps each insert to a round cutter bar with a small clamp plate. The round bar fits in a square sleeve, which is installed in a cutter-body slot and secured with a set screw. Because the cutter bar is cylindrical, the cutting-edge inclination λ_s can be adjusted as needed. One tooth is a finishing tooth and the other three are semifinishing teeth. During setup, the finishing tooth should have a slightly smaller radial dimension than the semifinishing teeth but project approximately 0.05 mm farther axially.

Finish-Mill Geometry

Finish-Milling Parameters