The reasonable cutting parameters selection principle is: rough, generally to improve productivity,but also should consider the economic and the processing cost; semi finish machining and finish machining, should be on the premise of ensuring the processing quality, efficiency and economy ofboth cutting and processing cost. Should be based on the specific numerical machine instructions,cutting manual, combined with the experience and. Specific should consider the following factors:

The cutting depth of ap. In the machine tool, workpiece and cutting tool rigidity allow circumstances,AP is equal to the machining allowance, which is an effective measure to improve productivity. In order to guarantee the machining precision and the surface roughness, the general should leave some margin for finishing. Precision machining allowance of CNC machine tools is slightly less thanthe general machine tools.

The cutting width of L. General L and tool diameter is proportional to D, and inversely proportional to the depth of cut. Economic type CNC machine tools machining process in the range of L, the general is: l= (0.6 ~ 0.9) d.

The cutting speed v. V is a measure to improve to improve productivity, but the relationship between V and the tool life is close. With the increase of V, the tool endurance decreased rapidly,so the choice of V mainly depends on the tool durability. In addition, the cutting speed and machining of materials have great relations, such as alloy steel for end milling 30crni2mova, V can use 8m/min or so; and with the same end milling of aluminum alloy, V optional 200m/min above.