How to set CNC milling conditions?

1. Milling speed

Milling cutting speed refers to the instantaneous speed of the selected point on the tool relative to the corresponding point of the workpiece. Vc= DN/1000Vc cutting speed, unit m/minN tool speed, unit r/minD milling cutter diameter, unit mm cutting speed by tool materials, workpiece materials, machine tool parts rigidity and cutting fluid and other factors. Usually lower cutting speed is used to process hard or ductile metal, belong to the strong cutting, the purpose is to reduce tool wear and prolong tool life. Higher cutting speed is often used to process soft materials in order to obtain better surface machining quality. When choosing to use small diameter tool to make micro cutting on brittle material workpiece or precision parts, higher cutting speed can also be used. For example, with high speed steel milling speed, aluminum is 91~244m/min, bronze is 20~40m/min.

2. Feed speed

Feed speed is another equally important factor that determines the safe and efficient machining of machine tools. It refers to the relative cutting speed between the workpiece material and the tool. For multi-tooth milling cutters, because each tooth is involved in the cutting work, the cutting thickness of the workpiece to be processed depends on the feed speed. Cutting thickness will affect the life of the milling cutter, and excessive feed speed will lead to cutting edge damage or tool fracture. Vf = Fz * Z * NVf feed speed, unit mm/minFz feed per tooth, unit mm/rZ tool teeth N tool speed, unit r/min from the above formula, we only need to know the feed per tooth (cutting), spindle speed, can know the feed speed. In other words, knowing the amount of feed per tooth and the speed of feed, you can figure out the spindle speed. For example, feed of high speed steel milling cutter, when the tool diameter is 6 mm, feed per tooth: aluminum 0.051; Bronze 0.051; Cast iron is 0.025; Stainless steel 0.025

3. Cutting depth

The third factor to be considered in machining is cutting depth. It is subject to the workpiece material cutting amount, machine tool spindle power, tool and machine tool rigidity and other factors. Generally, the cutting depth of steel end mills should not exceed half of the tool diameter. Cutting soft metal, cutting depth can be greater. End milling cutters must be sharp and work in a concentric manner with the end milling chuck and minimize overhang during tool installation.