The selection of the hand model cutter is one of the important contents in the NC machining process, which not only affects the machining efficiency of the machine tool, but also directly affects the machining quality of the parts. NC tool is one of the prerequisites to improve the processing efficiency. Its selection depends on the geometric shape of the part to be processed, the material state, and the rigidity of the tool selected by the fixture and machine tool.
Different tools have different uses in the NC machining process, so what tools are commonly used in the NC machining process?
1 Milling cutter
Milling cutter is a kind of multi – edge rotary cutter, which is widely used. It can be divided into: 1) for machining plane, such as cylindrical plane milling cutter, end milling cutter, etc; 2) For groove processing, such as end milling cutter, T-shaped cutter and angle milling cutter; 3) For machining formed surfaces, such as convex and concave semicircle milling cutters and milling cutters for machining other complex formed surfaces. The productivity of milling is generally high, and the machined surface roughness value is large.
2 Turning tool
Turning tool is the most widely used tool in metal cutting. It can be used for machining excircles, end planes, threads, and internal holes on lathes, as well as for grooving and cutting. In structure, turning tools can be divided into integral turning tools, welding assembling turning tools and turning tools with mechanically clamped inserts. Turning tools with mechanically clamped inserts can also be divided into machine tool turning tools and indexable turning tools. Mechanical clamping turning tool has stable cutting performance, and workers do not need to sharpen the tool, so it is used more and more in modern production.
3 Hole machining tool
Hole cutting tools can generally be divided into two categories: one is the tools for machining holes from solid materials, commonly used fried dough twist drills, center drills and deep hole drills; The other is the tool for reprocessing the existing hole on the workpiece, commonly used are reamer, reamer and boring cutter. For example, the following figure shows the structure of the standard high-speed steel fried dough twist drill. The front end of the working part (tool body) is the cutting part, which undertakes the main cutting work. The rear end is the guide part, which guides the drill bit and is also the backup part of the cutting part.
4 Broach
Broach is a multi tooth tool with high machining accuracy and cutting efficiency, which is widely used in mass production and can process various internal and external surfaces. Broaches can be divided into various internal broaches and external broaches according to the different surface of the workpiece being machined. When using broach for machining, in addition to selecting the rake angle and rake angle of the cutter teeth according to the workpiece material, and determining the broach size according to the size of the workpiece processing surface (such as the diameter of the circular hole), two parameters need to be determined: (1) tooth rise angle af [i.e. the difference between the radius or height of the front and rear two cutter teeth (or gear sets)]; (2) Pitch p [i.e. the axial distance between two adjacent cutter teeth].
5 Gear cutter
The gear cutter is used to process the gear tooth profile. According to the working principle of the cutter, gears are divided into forming gear cutter and generating gear cutter. Commonly used forming gear cutters include disc gear milling cutter and finger gear cutter. Commonly used generating gear cutters include gear shaper cutter, gear hob, gear shaving cutter, etc. When selecting gear hob and gear shaper cutter, the following points should be noted: (1) The basic parameters of the cutter (module, tooth shape angle, addendum height coefficient, etc.) should be the same as those of the gear being machined. (2) The tool accuracy level shall be equivalent to the accuracy level required for the gear being machined. (3) The rotation direction of the cutter shall be the same as that of the gear to be machined as far as possible. When hobbing spur gears, the left rotary gear cutter is generally used.