Industry News

How to set CNC milling processing conditions-Feed rate,Depth of cut


Feed speed

Feed speed is another equally important factor that determines the safe and efficient processing of machine tools. It refers to the relative travel speed between the work piece material and the tool. 

For multi-tooth milling cutters, since each tooth is involved in the cutting work, the thickness of the work piece to be processed depends on the feed speed. The cutting thickness will affect the service life of the milling cutter, and an excessive feed rate will cause the cutting edge to break or the tool to break.

Vf = Fz * Z * N

Vf feed speed, unit mm/min Fz feed per tooth, unit mm/rZ number of tool teeth N tool speed, unit r/min

It can be seen from the above formula that we only need to know the feed amount (cutting amount) of each tooth and the spindle speed to know the feed speed. In other words, knowing the feed amount and feed speed of each tooth, the spindle speed can be calculated.

For example, the feed rate of a high-speed steel milling cutter, when the tool diameter is 6 mm, the feed rate per tooth: aluminum 0.051; bronze 0.051; cast iron 0.025; stainless steel 0.025

Depth of cut 
The third factor that needs to be considered when machining is the depth of cut. It is limited by factors such as the amount of workpiece material cut, the spindle power of the machine tool, the cutting tool and the rigidity of the machine tool. 

Generally, the cutting depth of steel-cutting end mills should not exceed half of the tool diameter. For cutting soft metals, the depth of cut can be greater. The end mill must be sharp, and must be kept concentric with the end mill chuck when working, and minimize the amount of extension when the tool is installed.