The most direct and effective way to reduce the cost of machining is to effectively use different parts of CNC turning tools. Therefore, in order to select the most suitable CNC tool, we must not only select the appropriate tool material, but also understand the geometric angle characteristics of CNC tool. However, due to the wide range of cutting geometry rate, now we mainly focus on the application of cutting angle which is the most commonly used in front angle and back angle and the influence of both on cutting.
Front angle of CNC tool
Generally speaking, the front angle has a great influence on cutting force, chip discharge and tool durability.
The influence of the front angle of CNC tool
1) Large front angle, sharp cutting edge;
2) The cutting power decreases by 1% for every 1 degree increase of rake angle;
3) If the positive rake angle is too large, the blade strength will decrease; if the negative rake angle is too large, the cutting force will increase.
The large negative rake angle of CNC tool is used for
1) Cutting hard materials;
2) In order to adapt to the intermittent cutting and the machining conditions of the surface layer with black skin, it is necessary to have a strong cutting edge.
Large front angle for
1) Cutting soft materials;
2) Free cutting materials;
3) When the rigidity of the processed material and machine tool is poor.
The advantage of using CNC tool in front angle cutting
1) The use of rake angle can reduce the resistance encountered in cutting, so it can improve the cutting efficiency;
2) It can reduce the temperature and vibration during cutting and improve the cutting accuracy;
3) Reduce tool loss and prolong tool life;
4) When choosing the right tool material and cutting angle, using the front angle can reduce the tool wear and enhance the reliability of the blade.
The front corner is too big
1） Because the increase of the rake angle will reduce the cutting angle and cutting efficiency of the cutting tool when cutting the workpiece with high hardness, if the rake angle is too large, the cutting tool will be easily worn, or even break;
2) When the tool material is weak, the reliability of cutting edge is difficult to maintain.
Back angle of CNC tool
The back angle reduces the friction between the back of the tool and the workpiece, and enables the tool to cut into the workpiece freely.
The influence of back angle of CNC tool
1) Large rear angle, small positive wear of rear knife
2) When the back angle is large, the strength of the tip decreases.
Small back angle for
1) Cutting hard materials;
2) When cutting strength is high.
Large back angle for
1) Cutting soft materials
2) Cutting materials that are easy to work and harden.
Benefits of rear corner cutting
1) The cutting with large back angle can reduce the wear of the back cutting face, so when the front angle loss does not increase sharply, the use of large back angle and small back angle can prolong the service life of the tool;CNC machining
2) Generally speaking, when cutting ductile and softer materials, it is easier to dissolve. Melting will increase the back angle and the contact surface of the workpiece, increase the cutting resistance and reduce the cutting accuracy. Therefore, if the material is cut with a large back angle, this situation can be avoided.
The limitation of back angle cutting of CNC tool
1) When cutting materials with low heat transfer, such as titanium alloy and stainless steel, the use of large back angle cutting will make the front cutter face easy to wear, and even the cutter will be damaged. Therefore, large back angle is not suitable for cutting this type of material;
2) Although the use of large back angle can reduce the wear of the back face, it will accelerate the decline of the blade. Therefore, the cutting depth will be reduced, which will affect the cutting accuracy. For this reason, technicians need to adjust the angle of cutting tools regularly to maintain the cutting accuracy;
3) When cutting high hardness materials, such as large back angle, the resistance encountered in cutting will cause the front angle to be damaged or damaged due to strong compression force.