Common methods of thread processing

The common methods of thread processing are: thread cutting, CNC lathe machining thread, milling thread, grinding thread and rolling thread. Small batch of non-standard thread, the standard thread is often CNC lathe turning, CNC lathe processing thread is simple and quick, more and more widely used.

In the workpiece on the processing of internal and external thread method, mainly cutting and rolling processing two categories.

1) thread cutting: generally refers to the use of forming tools or grinding tools in the workpiece processing thread, mainly turning, milling, tapping, sets of silk, grinding, grinding and cyclone cutting. Turning, Milling and Grinding Threads Each time the workpiece is rotated, the drive chain of the machine ensures that the tool, milling cutter, or grinding wheel moves accurately and evenly along the workpiece axis. When tapping or threading, the tool (tap or die) rotates relative to the workpiece and guides the tool (or workpiece) axially by the first threaded groove.

2) Thread turning: turning the thread on the lathe can be used to form a turning tool or a thread comb. It is a common method of producing threaded parts by single piece and small batch. The thread is cut with thread combs, and the production efficiency is high, but the tool structure is complex and only suitable for medium and high-volume production. Turning the short thread of the workpiece. General lathe turning trapezoidal thread pitch accuracy can only reach 8 ~ 9; in the specialized thread lathe processing thread, productivity or accuracy can be significantly improved.

3) Thread milling: milling with a disc cutter or a comb cutter on a thread milling machine. Disk cutter is mainly used for milling screw, worm and other parts on the trapezoidal external thread. Comb-type milling cutter for milling inside and outside the ordinary thread and taper thread, because it is multi-blade milling cutter milling, the length of its working part is greater than the length of the thread being processed, so the workpiece only need to spin 1.25 ~ 1.5 turn can be processed Finished, high productivity. Thread milling pitch accuracy can generally reach 8 to 9, the surface roughness of R 5 ~ 0.63 microns. This method is suitable for batch production of general precision thread workpiece or rough before grinding.

4) thread grinding: mainly used in the thread grinding machine on the processing of hardened parts of the precision thread, according to the different shape of the wheel section of single-wheel grinding wheel and multi-line grinding wheel two. Single-line grinding wheel grinding can achieve the pitch accuracy of 5 to 6, the surface roughness of R 1.25 ~ 0.08 microns, grinding wheel dressing more convenient. This method is suitable for grinding precision screw, thread gauge, worm, small batch of threaded workpiece and shovel grinding precision hob. Multi-line grinding wheel grinding and sub-grinding method and cut into two kinds of grinding method. The grinding wheel width of the longitudinal grinding method is less than the length of the grinding thread, and the grinding wheel can be moved to the final size by one or several strokes. Cut into the grinding method of the wheel width is greater than the length of the grinding thread, grinding wheel radial cut into the workpiece surface, the workpiece about 1.25 turn can be polished, high productivity, but the accuracy is slightly lower, wheel dressing more complex. Cut the grinding method for grinding a large batch of tap and grinding some of the threads used for fastening.

5) Thread grinding: with cast iron and other soft materials made of nut type or screw type of threading tool, the workpiece has been processed on the thread pitch error of the parts of the positive and negative rotation grinding to improve the pitch accuracy. Hardened internal threads are usually also used to eliminate the deformation of the grinding method to improve accuracy.