刀具和刀夹CUTTING TOOLS AND TOOLHOLDERS
刀具和刀夹CUTTING TOOLS AND TOOLHOLDERS(中文6500字,英文4300字)
CUTTING TOOLS AND TOOLHOLDERS
To machine a workpiece successfully you must have :
1. the correct kind of cutting tool or tool bit
2. the right type of toolholder
3. a tool with a sharp cutting-edge
4. the cutting tool set or adjusted to the correct height and position.
Tool bits used on the lathe are made form one of six basic materials: water-hardening steels,high-speed steels,hard-cast,nonferrous alloys,sintered (cemented) carbides,ceramics,and diamonds. The selection of the material used depends upon many factors including:tool cost,size and design of tool ,metal-removal rate ,length of run ,finish and tolerance of part,and condition and capability of the machine tool . Because of these factors ,material selection is more often based on general experience than on precise evaluation . There are, however ,certain general characteristics of the different cutting-tool materials you should understand.
Water-hardening Steels.These include the high-carbon tool steels (either plain carbon or those with minor additions of chromium , vanadium,or tungsten) .The different grades of water-hardening tool steels are classed as W steels in American Iron and Steel Institute’s system of classification . Tools made from these materials have very sharp ,smooth cutting-edges when properly heat-treated. They are adequate for limited turning at a relatively low cutting speed or when old ,low-speed equipment ,such as a flat-belt lathe , is used .