The most direct and effective way to reduce machining costs is to effectively apply turning and machining different parts of CNC tools. Therefore, in order to select the most suitable CNC tool, in addition to selecting the appropriate tool material, it is also necessary to understand the geometric angle characteristics of the CNC tool. However, due to the wide range of cutting geometry, the focus is now on the application of the rake angle, the most commonly used cutting angle for the rake angle, and the effect of the two on cutting.
Rake angle of CNC tool
Generally speaking, the rake angle has a great influence on cutting force, chip discharge, and tool durability.
The influence of the rake angle of the CNC tool
1) Large positive rake angle and sharp cutting edge;
2) When the rake angle increases by 1 degree, the cutting power decreases by 1%;
3) If the positive rake angle is too large, the cutting edge strength will decrease; if the negative rake angle is too large, the cutting force will increase.
The large negative rake angle of CNC tools is used for
1) Cutting hard materials;
2) The cutting edge needs to be strong to meet the cutting conditions of interrupted cutting and cutting the surface layer with black skin.
The positive rake angle is used
1) Cutting soft materials;
2) Free cutting materials;
3) When the rigidity of the processed material and the machine tool is poor.
The advantages of cutting rake angles with CNC tools
1) Since the use of the rake angle can reduce the resistance encountered during cutting, it can improve the cutting efficiency;
2) It can reduce the temperature and vibration generated during cutting and improve the cutting accuracy;
3) Reduce tool loss and extend tool life;
4) When choosing the right tool material and cutting angle, using the rake angle can reduce tool wear and enhance the reliability of the blade.
Bad outside with too big front angle
1) Since the increase of the rake angle will reduce the angle of the tool cutting into the workpiece and the cutting efficiency, when cutting the workpiece with higher hardness, if the rake angle is too large, the tool is prone to wear and even chipping;
2) When the material of the tool is weak, the reliability of the cutting edge is difficult to maintain.
Back angle of CNC tool
The relief angle reduces the friction between the back of the tool and the workpiece, so that the knife can cut into the workpiece freely.
The influence of the clearance angle of the CNC tool
1) Large clearance angle, less positive wear of the rear knife
2) The clearance angle is large, and the strength of the tool tip decreases.
Small rear angle is used
1) Cutting hardness materials;
2) When high cutting strength is required.
Large relief angle is used
1) Cutting soft materials
2) Cutting materials that are easy to work hardening.
The benefits of back corner cutting
1) Large clearance angle cutting can reduce the wear of the flank surface, so if the rake angle loss does not increase sharply, using a large clearance angle and a smaller clearance angle can extend the life of the tool;
2) Generally speaking, it is easier to melt when cutting ductile and softer materials. Melting will increase the clearance angle and the contact surface of the workpiece, increase cutting resistance, and reduce cutting accuracy. Therefore, this situation can be avoided if cutting with a larger clearance angle when cutting such materials.
Restriction of the cutting of the back corner of the CNC tool
1) When cutting materials with low heat transfer, such as titanium alloy and stainless steel, cutting with a large relief angle will make the rake face easy to wear, and even tool damage may occur. Therefore, the large relief angle is not suitable for cutting this type of material;
2) Although the use of a large relief angle can reduce the wear of the flank surface, it will accelerate the decline of the blade. Therefore, the cutting depth of cut will be reduced accordingly, affecting the cutting accuracy. To this end, technicians need to adjust the angle of the tool regularly to maintain cutting accuracy;
3) When cutting high-hardness materials, if the large clearance angle is too large, the resistance encountered during cutting will cause the rake angle to be chipped or damaged due to strong compression force.