What should be paid attention to in the use of four-column cutting machine tool die?
I. The form and reason of tool wear
In the process of cutting metal, on the one hand, the cutter will cut off the chip, and on the other hand, the cutter itself will be damaged. The main forms of tool damage are wear and tear. The former is a continuous gradual wear and tear; The latter includes two kinds of brittle damage (such as breaking edge, breaking, spalling, crack damage, etc.) and plastic damage. After tool wear, the workpiece machining precision decreases, the surface roughness increases, and leads to the increase of cutting force, cutting temperature, and even vibration, unable to continue the normal cutting. Therefore, tool wear directly affects machining efficiency, quality and cost. Tool wear can take the following forms:
The front knife face is worn
The back knife face is worn
In terms of the degree of temperature dependence, the main causes of tool normal wear are mechanical wear, thermal wear and chemical wear. The mechanical wear of four-column cutting is caused by the characterization of hard points in the workpiece material, while the thermal and chemical wear is caused by bonding (the phenomenon of bonding when the distance between the tool and the workpiece material comes into contact with atoms) and diffusion (the chemical elements of the two friction surfaces of the tool and the workpiece are mutually opposite each other and corroding, etc.).
2. tool wear process, blunt standard and tool life
Tool wear increases with cutting time. The tool wear process can be divided into three stages:
Initial wear stage
Normal wear stage
Rapid wear stage
When a tool wears down to a certain extent, it cannot be used any longer. This degree of wear is called the abrasiveness standard. The actual cutting time experienced by a new (or re-sharpened) knife from the beginning of use until it has reached the grinding standard is called tool life.