In metal cutting, the surface load at the tool/workpiece interface and the energy and friction generated by the high-speed slip of the chip along the rake face of the tool are converted into heat, and usually 80% of this heat is taken away by the chip (this The change in proportion depends mainly on the cutting speed. The remaining 20% of the heat is transferred into the tool. Heat and temperature are fundamental to tool wear.
First, the method of judging the wear of the tool:
1. Tool life table (based on the number of workpieces), some high-end equipment manufacturing or single-product mass production enterprises use it to guide production. This method is suitable for processing expensive aerospace, steam turbine, automotive key components such as engines. enterprise.
2, look at the processing, if the processing process, the intermittent random Mars, indicating that the tool has worn, can be changed according to the average life of the tool.
3, look at the color of iron filings, iron color changes, indicating that the processing temperature has changed, may be the tool wear.
4, look at the shape of iron filings, sawing teeth on both sides of the iron filings, iron filings are not normally curled, iron filings become more fine, these phenomena are the basis for the judgment of tool wear.
5, look at the surface of the workpiece, there are bright traces, but the roughness and size have not changed a lot, this is actually the tool has worn.
6. Listening to the sound, the processing vibration is intensified, and abnormal noise will occur when the tool is not fast. At this time, pay attention to avoid "slashing the knife" and cause the workpiece to be scrapped.
7. Observe the machine load. If there is a significant incremental change, the tool has worn out.
In addition, when the tool is cut out, the workpiece has severe burrs, roughness is reduced, and the workpiece size changes are also the criteria for determining the tool wear.
Second, the type of tool wear and common methods to prevent damage when using mechanical tools:
1. The cutting edge is worn. Improved method: increase feed rate; reduce cutting speed; use more wear-resistant blade material; use coated blade.
2, broken. Improved method: use a material with better toughness; use a blade that is edged to strengthen; check the rigidity of the process system; increase the lead angle.
3. Thermal deformation. Improvements: reduce cutting speed; reduce feed; reduce depth of cut; use a more thermodynamic material.
4, the depth of the cut is broken. Improvement method: change the lead angle; edge reinforcement; replace the blade material.
5. Hot cracks. Improved method: use coolant properly; reduce cutting speed; reduce feed; use coated blades.
6, accumulated debris. Improved method: increase cutting speed; increase feed; use coated blades or cermet blades; use coolant; make the cutting edge sharper.
7, the crescent is worn. Improved method: reduce cutting speed; reduce feed; use coated blades or cermet blades; use coolant.
8, broken. Improved method: use a material or groove with better toughness; reduce feed; reduce depth of cut; check the rigidity of the process system.
The evolving best tool base, coating and cutting edge preparation techniques are critical to limiting tool wear and resisting cutting temperatures. Lathe machining recognizes Titanium, and these elements, combined with the chipbreaker and corner radius used on indexable inserts, determine the suitability of each tool for different workpieces and machining operations. The est combination of all these elements extends tool life and makes machining more economical and reliable.