Attention to the use of the cutter die for the four column cutting machine
First, the form and cause of tool wear
The four column cutting machine cuts metal chips on the one hand while cutting metal. On the other hand, the cutter itself is also damaged. The form of tool damage mainly includes two categories: wear and breakage. The former is progressive wear, and the latter includes brittle failure (such as collapse, breaking, spalling, crack damage, etc.) and plastic damage two. After the tool wear, the machining precision of the workpiece is reduced and the surface roughness is increased, and the cutting force is increased, the cutting temperature is raised, even the vibration is produced, and it can not continue to be cut normally. Therefore, tool wear directly affects machining efficiency, quality and cost. There are several forms of tool wear:
Front knife surface wear
Knife surface wear
From the dependence of temperature, the main causes of tool wear are mechanical wear, thermal and chemical wear. The wear of four column cutting machinery is caused by the carving of hard points in the workpiece material. The thermal and chemical wear is caused by the bonding (the bonding between the tool and the workpiece material to the distance between the atoms) and the diffusion (the chemical elements of the two friction surfaces of the tool and the workpiece are mutually opposite to the opposite side and corrosion, etc.).
Two, tool wear process, blunting standard and tool life.
With the prolongation of cutting time, tool wear is increased. According to the cutting experiment, the typical wear curves of the tool during normal wear process can be obtained. The cutting time and the worn surface of the rake face VB (or the depth of the front face crescent depression KT) are taken as abscissa and ordinate. The tool wear process can be divided into three stages:
Initial stage of wear
Normal wear stage
Sharp wear stage
Tool wear can not continue to use at a certain limit. The wear limit is called the blunt standard. The actual cutting time that a new knives (or re sharpened tools) experienced from beginning to grinding to blunting standards is called tool life.