After selecting a cutter, many people do not clear on setting the cutting speed ,rotate speed and the cutting depth. This is very dangerous, it will cause the cutter breaks, the material melts or scorches. Is there any calculation way? The answer is yes!
1.The cutting speed：
The cutting speed refers to the instantaneous speed of the selected point on the tool relative to the corresponding point on the workpiece.
Vc=πDN/1000
Vc- cutting speed，Unit: m/min
N- rotate speed，Unit: r/min
D- Cutter diameter，Unit: mm
Cutting speed is affected by factors such as tool material, workpiece material, rigidity of machine tool components, and cutting fluid. Usually lower cutting speeds are often used to machine hard or ductile metals, which is powerful cutting but can reduce tool wear and extend tool life. Higher cutting speeds are often used to machine soft materials in order to obtain a better surface finish. Higher cutting speeds can also be used at small-diameter cutter that is used to perform micro-cutting on brittle material workpieces or precision components. For example, the milling speed of high-speed steel cutter is 91~244m/min for aluminum, and 20~40m/min for bronze.
2.The cutting feed speed:
The feed speed is another equally important factor that determines the safe and efficient machining work. It refers to the relative travel speed between the workpiece material and the tool. For multi-tooth milling cutters, since each tooth participates in the cutting work, the thickness of the workpiece to be cut depends on the feed rate. The thickness of the cut can affect the life of the milling cutter.So the excessive feed rates can cause the cutting edge or tool broken.
Vf = Fz * Z * N
Vf-feed speed,Unit mm/min
Fz-feed engagement，Unit mm/r
Z-Cutter teeth
N-Cutter rotate speed，Unit r/min
From the above formula, we only need to know the feed engagement (cutting amount) of each tooth and the rotate speed that can derivate the feed speed. In other words, knowing the feed engagement and feed speed per tooth, the rotate speed can be calculated easily.
For example, the high-speed steel milling cutter, when the cutter diameter is 6 mm, the feed per tooth:
Aluminum 0.051; Bronze 0.051; Cast Iron 0.025; Stainless Steel 0.025
3.The cutting depth:
The third factor is the depth of cutting. It is limited by the cutting amount of the workpiece material, the rotate power of the CNC, the cutter and the rigidity of the machine tool. Generally, the depth of steel end mill cutting should not exceed half of the cutter diameter. For cutting soft metals, the depth of cutting can be larger. The end mill must be sharp and work concentrically with the end mill chuck ,and with as little overhang as possible when the tool is installed.
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Post time: Jul-04-2022