Formed carbide milling cutter is widely used because of its small shape tolerance. Because the cutter cannot be directly replaced, most of the milling cutter is scrapped after the cutter is broken, which greatly increases the processing cost.
1. Processing material properties
When cutting titanium alloy, due to the poor thermal conductivity of titanium alloy, the chips are easy to adhere to the vicinity of the tool tip and the blade edge or form chip accumulations, and high-temperature zones are formed on the front and rear surfaces near the tool tip, resulting in the loss of the red hardness of the tool and the aggravation of wear. In the continuous cutting under high temperature, the adhesive and fusion material will be impacted by subsequent processing, and part of the tool material will be taken away in the process of forced punching, resulting in the defect and damage of the tool. In addition, when the cutting temperature reaches above 600 ℃, a hardened hard layer will be formed on the surface of the part, which will have a strong wear effect on the tool. Titanium alloy has low elastic modulus, large elastic deformation, and large springback on the workpiece surface near the flank, so the contact area between the machined surface and the flank is large and the wear is serious.
2. Normal wear
In normal production and processing, when the allowance of continuous milling titanium alloy parts reaches 15mm-20mm, serious blade wear will occur. The efficiency of continuous milling is extremely low, and the surface finish of machined parts is poor, which cannot meet the production and quality requirements.
3. Improper operation
During the production and processing of titanium alloy casting box and box cover, improper clamping, inappropriate cutting depth, too fast spindle rotation speed, insufficient cooling and other improper operations will lead to blade collapse, damage and fracture of the tool. In addition to being unable to perform effective milling, this kind of defective milling cutter will also cause surface defects such as concave machining surface due to "gnawing" during milling, which will not only affect the machining quality of the milling surface, but also cause the workpiece to be scrapped in serious cases.
