How to choose CNC machining cutting volume?

How to correctly select the cutting amount for CNC machining is a specific content of the basic principles of CNC machining parts. There are three basic principles for metal material processing:

1. CNC lathe machining feed (tool feed)

F critically depends on the roughness of the workpiece. During finishing, the surface layer is set to be high, and the cutting amount is small: 0.06~0.12mm/spindle rotation. When roughing, it is better to be larger. The key decision is the compressive strength of the tool, which is generally better than 0.3. For high-precision CNC machining in Dongguan, the tool compressive strength is poor when the main clearance angle of the tool is large, and the feed amount cannot be large. In addition, the output power of the machine tool, the rigidity of the workpiece and the tool should also be considered. The CNC machine tool program uses two kinds of company's feed rate: mm/min, mm/spindle per revolution, the above companies are all mm/spindle per revolution, if you apply mm/min, you can use the formula to calculate the transformation: feed per minute Quantity = amount of feed per revolution * spindle speed per minute.

2. Cutting rate of CNC lathe (linear velocity, circular velocity) V (m/min)

To select the spindle speed per minute, you must first understand the cutting linear velocity V. The choice of V: depends on the tool material, workpiece material, processing standard, etc.

Tool material:

For cemented carbide cutting tools, V can be higher, generally above 100 m/min. Generally, the performance parameters are shown when buying the cutting head:

How many linear speeds can be selected when processing which materials. Spring steel: V is only low, generally not more than 70 m/min. In most cases, it is below 20-30 m/min.

Workpiece material:

High strength, low V; pig iron, low V, 70~80 m/min when the tool is made of cemented carbide; high carbon steel, V can be higher than 100 m/min, for rare metals, V can be higher Some (100~200m/min). For hardened steel and stainless steel plates, V should be lower.

Processing standard:

For rough machining, V should be lower; for finishing, V should be higher. The rigidity system of the machine tool, workpiece, and tool is poor, and V is taken as low. If S used by the CNC machine tool program is the spindle speed per minute, then S should be calculated based on the workpiece diameter and the cutting linear speed V: S (spindle speed per minute)=V (cutting linear speed)*1000/(3.1416*workpiece diameter ) If the CNC machine tool program uses constant linear speed, CNC precision metal processing, then S can immediately apply the cutting linear speed V (m/min)

3. CNC lathe processing deep cutting (cutting deep)

When finishing, generally take 0.5 (semi-longitude value) or less. When roughing, make decisions based on the workpiece, tool, and machine tool conditions. Generally, small lathes (larger processing diameters below 400mm) mill 45# steel under quenching conditions. The depth of the semi-longitudinal cutter is generally no more than 5 mm. In addition, it should be noted that if the spindle speed of the CNC lathe adopts a general DC variable frequency variable speed, then when the spindle speed per minute ratio is very low (less than 100~200 rpm), the motor power will be significantly reduced. For parts processing, the depth of the knife and the amount of feed can only be obtained at this time.