Name and function of each part of turning tool
Turning tool belongs to single blade tool. There are many types due to different shapes of turning objects, but the names and functions of its parts are the same. A good turning tool must have two parts: a rigid handle and a sharp blade. The cutting edge angle of turning tool directly affects the turning effect. Different turning tool materials, workpiece materials and cutting edge angles are also different. Lathe tools have four important angles: front clearance angle, side clearance angle, back bevel angle and side bevel angle.
1 front clearance angle
The angle of inclination from the nose down to the inside of the tool is the front clearance angle. Due to the front clearance angle, a space is formed under the working face and the tool tip, so that the cutting effect is concentrated on the nose. If the angle is too small, the tool will rub on the surface and produce rough surface. If the angle is too large, the tool is easy to vibrate, so that the nose is broken and cannot be polished. When installing the clearance angle before grinding of turning tool with inclined middle handle, the inclination angle of handle shall be considered. The angle of high-speed steel turning tool is about 8 ~ 10 degrees, while that of carbide turning tool is 6 ~ 8 degrees.
2 side clearance angle
The inclination angle of the tool side from the cutting edge to the inside of the tool is the edge clearance angle. The edge clearance angle forms a space between the working surface and the tool side, so that the cutting effect is concentrated on the cutting edge and improves the cutting efficiency. The angle of high-speed steel turning tool is about 10 ~ 12 degrees.
3 rear bevel
The angle of inclination from the nose to the handle from the top of the knife is the back inclined angle. This angle is mainly used to guide chip removal and reduce chip removal resistance. Cutting general metal, high-speed steel turning tool is generally 8 ~ 16 degrees, while carbide turning tool is negative inclination or zero degrees.
4 side bevel
It is inclined from the cutting edge to the other side from the top surface of the cutter. The angle between the inclined plane and the horizontal plane is the bevel angle. This angle is the angle to make the chip separate from the working object, so that chip removal is easy and effective turning can be obtained. For cutting general metal, the angle of high-speed steel turning tool is about 10 ~ 14 degrees, while carbide turning tool can be positive or negative.
5 cutter end angle
The vertical angle between the front end of the blade and the handle. The function of this angle is to keep a gap between the front end of the blade and the workpiece, so as to avoid the friction or scratch of the machined surface between the blade and the workpiece.
6 trimming angle
The vertical angle between the front end of the blade and the handle is used to change the thickness of the cutting layer. At the same time, the trimming angle can also change the force direction of the turning tool, reduce the feed resistance and increase the tool life. Therefore, in general, the turning tool with large trimming angle should be used in rough turning to reduce the feed resistance and increase the cutting speed.
7 nose radius
The arc radius of the cutting edge at the highest point of the blade. The nose has large radius and strength, which is used for large cutting depth, but it is easy to produce high-frequency vibration.
The improvement and development of tool materials is one of the important topics in the development of metal processing today, because good tool materials can effectively and quickly complete the cutting work and maintain good tool life.