1, Thread cutting

Generally refers to the use of shaped tools or abrasives in the workpiece thread processing methods, mainly turning, milling, tapping sleeve grinding, grinding and cyclone cutting. Turning, milling and grinding threads, the workpiece every turn, the machine tool transmission chain to ensure that the turning tool, milling cutter or grinding wheel along the axial direction of the workpiece accurately and uniformly move a lead. In tapping or threading, the tool (tap or thread) and the workpiece make relative rotary movement, and the first formed thread groove guides the tool (or workpiece) for axial movement.

2, Thread turning

Turning threads on a lathe can be done with either a form turning tool or a thread combing tool (see Threading Tools). Turning threads with forming cutter, due to the simple tool structure, is a single piece and small batch production of threaded workpieces commonly used methods; thread comb turning threads, high productivity, but the tool structure is complex, only suitable for medium and large-scale production of turning fine threaded workpieces of short threads. Ordinary lathe turning trapezoidal thread pitch accuracy generally can only reach 8 ~ 9 level (JB2886-81, the same below); in the specialised thread lathe processing thread, productivity or accuracy can be significantly improved.

3, Thread milling

Mainly used in thread grinding machine processing hardened workpiece precision thread, according to the wheel cross-section shape of the different sub-single line grinding wheel and multi-line grinding wheel grinding two kinds. Single line grinding wheel can achieve pitch accuracy of 5 ~ 6, surface roughness of R1.25 ~ 0.08 microns, wheel dressing is more convenient. This method is suitable for grinding precision screws, thread gauges, worm gears, small batches of threaded workpieces and grinding precision hobs. Multi-line grinding wheel grinding is divided into longitudinal grinding method and plunge-cut grinding method. The width of the grinding wheel of the longitudinal grinding method is less than the length of the thread to be ground, and the grinding wheel can be moved longitudinally for one or several strokes to grind the thread to the final size. The width of the grinding wheel of the plunge-cut grinding method is greater than the length of the thread to be ground, the grinding wheel radially cuts into the surface of the workpiece, and the workpiece can be ground by turning about 1.25 revolutions, which has higher productivity, but with slightly lower precision and more complicated dressing of the grinding wheel. The plunge-cut grinding method is suitable for grinding a larger batch of taps and grinding certain threads for fastening.