How Precision Milling Machines Operate
Unlike standard drilling machines that are limited to a single axis of motion, precision milling machines move along multiple axes (X, Y and Z). This allows milling machines to contour 2D and 3D shapes efficiently and precisely in a wide variety of metals such as 300 and 400 series stainless steels, aluminum, brass, titanium, L605 and other specialty alloys.
When a part is milled, it is held in place on a moving table (or bed) with tools such as vices, V blocks (to hold cylindrical seamless tubing) or step clamps. A rotating cutting tool, housed in the machine head, is brought down onto the part while chips are removed via a cooling lubricant.
The cutting head of a milling machine typically has saw shaped teeth. Straight teeth are more effective when cutting dense materials, while helical teeth are more effective when working with softer materials. It is important to note that because the milling process applies significant pressure to machined parts, weak or thin shapes are more difficult to mill, as are shapes with irregular edges.
CNC milling machines are usually grouped together by the number of axes on which they operate. Most machines operate within three to five axes. In general, the X and Y axis of a milling machine moves the part back and forth within the horizontal axis while the cutting tool moves vertically within the Z axis.