Thread processing have? Must see the end of the Lao shifu

1

Thread cutting

Generally refers to using forming cutting tool or grinding on the workpiece machining thread method, mainly include turning, milling, tapping sets of wire cutting grinding, grinding and cyclone, etc. Thread turning, milling and grinding workpiece every turn a turn, machine tool transmission chain to ensure that turning tool, milling cutter, or grinding wheel along the workpiece axis accurately and evenly to move a lead. When tapping or set of silk, tool (tap or die) and relative rotation motion artifacts, and formed by first thread groove guided tools make axial movement (or artifacts).

2 the thread turning

Turning on a lathe thread forming tool can be used or chaser (see thread machining tools). With the forming tool thread cutting, due to the cutting tool has simple structure, is a single piece and small batch production thread artifacts commonly used method; With a chaser thread cutting, high production efficiency, but the cutting tool structure is complex, only suitable for medium and fine turning teeth short thread workpieces in mass production. Ordinary lathe turning trapezoidal thread pitch accuracy normally only LVL 8 ~ 9 (JB2886-81, the same below); On the specialization of threading lathe processing thread, productivity or accuracy can be improved significantly.

3 thread milling

On the thread milling machine by disc cutter or comb milling cutter. Disc cutter is mainly used for milling screw, worm and other artifacts on the outside of the trapezoidal thread. Comb milling cutter for milling of internal and external common thread and taper thread, because it is with multiple milling cutter milling, the working part of the length is greater than the length of the thread processed, so the artifacts only need to rotate turn to be able to be finished processing of 1.25 ~ 1.5, the productivity is high. The pitch precision of screw thread milling generally can reach 8 to 9 magnitude, the surface roughness of R5 ~ 0.63 microns. General precision of this method is suitable for the batch production of threaded workpiece or unfinished before grinding.

4 thread grinding

On thread grinding machine is mainly used for machining of hardened workpiece precision thread, according to the different cross section shape points single grinding wheel and multi-line grinding wheel grinding two kinds. Single pitch accuracy of grinding wheel grinding can be achieved for 5 ~ 6 grade, the surface roughness is R1.25 ~ 0.08 microns, grinding wheel dressing is more convenient. This method is suitable for precision leadscrew grinding, thread gauge, worm, small batch of artifacts and shovel grinding precision gear hob. Vertical line grinding wheel grinding and more point grinding and cutting grinding two kinds. Longitudinal grinding wheel width less than be ground thread length, the grinding wheel vertical movement once or several times trip to grinding thread to the final size. Cut grinding wheel width is greater than be ground thread length, radial cut into the workpiece surface grinding wheel and workpiece about can grind good 1.25 turns, the productivity is high, but slightly lower precision, grinding wheel dressing is more complex. Cut into the grinding method is suitable for relief grinding batch larger tap and grinding some fastening screw thread.

5 thread grinding

Made from soft material such as cast iron type nut or screw thread tool and the workpiece is processing on the part of the screw pitch error exists to carry on the positive and negative to the rotating grinding, in order to improve the accuracy of pitch. Hardening of the internal thread is usually use grinding method to eliminate the deformation, improve the accuracy.

6 tapping and set of silk

Tapping is to use a certain distance to tap screwing in workpieces in the base hole of the drill (work out internal thread.

Set of silk is in bar with die cut out thread (or tube) artifacts. Tapping or set of silk processing precision depends on tap or the precision of the die. Processing method of internal and external thread though many, but the small diameter of inside thread can only rely on tap for processing. Tapping and the set of available manual operation, also can use lathe, drilling machine, tapping machine, and set of silk machine.

7 thread rolling

Use of forming roller die parts to produce plastic deformation for thread machining method of the thread rolling in thread rolling machine thread rolling machine or in the attached automatic opening and closing thread rolling on the head of the automatic lathe, suitable for mass production of standard fasteners and other outside screw thread connection. Rolling thread diameter is generally not more than 25 mm, length is not greater than 100 mm, the screw thread precision can be up to level 2 (GB197-63), the diameter of the parts is used broadly and processed pitch diameter of thread is equal. Generally can not machining internal thread rolling, but on the soft material artifacts available slotless extrusion tap cold extrusion female around can be up to 30 mm (diameter), working principle and tapping. Cold extrusion internal thread when the required torque is about 1 times larger than the tapping, the machining accuracy and surface quality is higher than tapping slightly.

The advantage of thread rolling is: (1) the surface roughness is less than the turning, milling and grinding; (2) of the surface of the screw thread after rolling by cold work hardening can improve the strength and hardness; (3) high material utilization; (4) productivity than a doubling of machining, and easy to realize automation; 5. Rolling die life is very long. But rolling thread required hardness of workpiece material is less than HRC40; Higher requirements on the blank dimensions accuracy; Precision and hardness of roll mould requirement is high also, manufacturing mould is difficult; Not suitable for rolling thread tooth shape asymmetry.

According to the rolling mould different, thread rolling can be divided into two categories, thread rolling and rolling.

Rub two pieces of silk thread rolling plate with thread profile 1/2 pitch relative stagger arrangement, static plate fixed and moving plate parallel to the static plate reciprocating linear motion. When the workpiece into two plates, plate forward rolling pressure artifacts, make its surface plastic deformation and into thread.

Thread rolling with tangential and radial thread rolling, rolling and rolling head screw rolling 3 kinds.

Radial rolling: (1) 2 (or 3) with the thread profile rolling wheel axis parallel to each other in the installation, the workpiece on the bearing between the two wheels, two rounds of synthetic constant speed rotation, also for the radial feed movement of round. Artifacts in driven rotating screw rolling wheel, the radial extrusion formation on the surface of screw thread. Screw of certain accuracy is not high, also can use similar approaches rolling.

(2) the tangential thread rolling: also called planetary rolling, rolling tool by a rotating central thread rolling wheel and three fixed arc wire panels. Thread rolling, the workpiece can be sent to continuously, so the productivity is higher than thread rolling and radial thread rolling.

(3) thread rolling head screw rolling: in automatic lathe, general used for short thread machining workpieces. Rolling head in 3 ~ 4 are actually thread rolling wheel peripheral parts. Thread rolling, the workpiece rotation and axial feed roller head, the workpiece rolled out of the thread.