The tool is hard, and the tool will have some wear and tear with the delay of the use time. What are the reasons for the tool wear? There are several reasons for this by summarizing.
1, tool material
Tool material is the fundamental factor determining the cutting performance of the tool, and has a great influence on machining efficiency, machining quality, machining cost and tool durability. The harder the tool material is, the better its wear resistance is. The higher the hardness, the lower the impact toughness and the brittle material. Hardness and toughness are a pair of contradictions and a key to the tool material. For graphite tools, ordinary TiAlN coatings can be selected with a relatively good toughness in the selection of materials, that is, the cobalt content is slightly higher; for diamond-coated graphite tools, the hardness can be appropriately selected on the material selection. , that is, the cobalt content is slightly lower;
2, the geometric angle of the tool
The choice of the appropriate geometric angle of the graphite tool helps to reduce the vibration of the tool, and in turn, the graphite workpiece is not easily broken;
(1) The rake angle, when the graphite is processed by the negative rake angle, the cutting edge strength is good, and the impact resistance and friction performance are good. As the absolute value of the negative rake angle decreases, the flank wear area does not change much, but The overall trend is decreasing. When the positive rake angle is used, the tool edge strength is weakened as the rake angle increases, which in turn leads to increased wear on the flank. When the negative rake angle is processed, the cutting resistance is large, and the cutting vibration is increased. When the large positive rake angle is used, the tool wear is severe and the cutting vibration is large.
(2) Back angle, if the back angle increases, the tool edge strength decreases, and the flank wear area gradually increases. When the back angle of the tool is too large, the cutting vibration is strengthened.
(3) When the helix angle is small, the blade length of the graphite workpiece is the longest at the same cutting edge, the cutting resistance is the largest, and the cutting impact force of the tool is the largest, so the tool wear, milling force and cutting vibration are the largest. . When the helix angle is large, the direction of the milling force is larger than the surface of the workpiece, and the cutting impact caused by the collapse of the graphite material is intensified, so that the tool wear, the milling force and the cutting vibration are also increased. Therefore, the influence of tool angle change on tool wear, milling force and cutting vibration is the combination of front angle, back angle and spiral angle, so we must pay more attention to the selection.
Through a large number of scientific tests on the processing characteristics of graphite materials, PARA tools optimize the geometric angle of the relevant tools, so that the overall cutting performance of the tool is greatly improved.
3, the coating of the tool
Diamond coated tools have the advantages of high hardness, good wear resistance and low friction coefficient. At present, diamond coating is the best choice for graphite processing tools, and it also best reflects the superior performance of graphite tools; hard coating of diamond coating The advantages of alloy cutters are the combination of the hardness of natural diamonds and the strength and fracture toughness of cemented carbides. However, in domestic diamond coating technology is still in its infancy, and the cost investment is very large, so diamond coatings in the near future There won't be much development, but we can optimize the angle of the tool, select materials and improve the structure of the ordinary coating on the basis of ordinary tools, and it can be applied to graphite processing to some extent.
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