Cyclone milling is a high-speed thread milling device matched with precision lathe. The invention relates to a thread processing method, which uses a cemented carbide forming knife mounted on a high-speed rotating cutter head to mill threads from a workpiece. Because of its high milling speed (up to 400m/min) and high machining efficiency, and the use of compressed air for chip removal and cooling, the cutting splash in the machining process is like a whirlwind, so it is named cyclone milling.
Turn left | turn right
Cyclone milling can realize dry cutting, heavy-duty cutting, difficult-to-machine materials and ultra-high-speed cutting, and the power consumption is very small. The surface roughness can reach ra 0.8 μ m, and the spindle speed of the lathe is slow, so the machine tool has high motion accuracy and good dynamic stability, which is an advanced thread processing method.
First of all, the cutting forms of cyclone milling are divided into:
1, ? Internal incision
2, ? External cutting type
2. Types of parts that can be processed by cyclone milling:
1, bone screw, spinal screw
2. Threads
3. Lead screw
4. bugs
5, screw parts
……
Third, the advantages of cyclone milling thread cutting:
1, high processing efficiency, several times or even ten times higher than the traditional processing efficiency;
2, the product is formed by one knife, and the eccentric cutting does not need to retract, so the machining accuracy is high;
3, the lathe structure is not changed, the spiral angle is adjustable, the installation is convenient, and the cost of investing in special equipment is saved;
4, the surface roughness can reach Ra0.8 micron, and the machining accuracy is improved by 2 levels;
5, the lathe axial feed is slow, easy to operate, and the professional skills of workers can be reduced.
Four, parts processing requirements:
The parts are adjustable wrench screw wheels with adjustable opening width, and the material is 20 round steel. There is a certain roughness requirement on the tooth side. Cut off part of the spiral teeth need to be chamfered, and the middle pin hole and the outer cylindrical surface must have good coaxiality, otherwise the adjustment will be inflexible or even stuck. In order to facilitate thumb grasping and poking, the surface should have straight knurling parallel to the axis.
V. Analysis and comparison of processing technology
The lead screw was originally machined by turning, and the process route is: cold drawing → knurling → tapping → correction → drilling → cutting → chamfering, which not only has low efficiency and high cost, but also leads to the deformation of small round steel when turning and knurling, and it is impossible to produce small spiral wheels. Therefore, we designed the cyclone milling screw equipment, which not only increased the rotational speed from the empirically recognized 1000 r/min to 20000 r/min. The process route is changed to: cold drawing → knurling, wire milling → correction → drilling, cutting → chamfering. Although cyclone milling causes large deformation of small-diameter workpiece (small deformation of large-diameter workpiece), it is easy to correct. The improved process has the following characteristics:
Surface roughness value decreases:
The vibration caused by cutting force is reduced;
The pitch cumulative error of small diameter workpiece has increased.
Structural design of intransitive verbs
The equipment is modified by lathe, the workpiece rotates, and the cutter head and knurled tool rest move. Put down the tool rest part of the lathe, install the milling head and the self-made tool rest on the slide rail, install the knurling knife on the tool rest, and put the tool rest in front of the milling head. The left end of the workpiece is clamped by chuck, and the right end falls off the tailstock. Installing a bracket with a long hollow tube can clamp a long raw material at one time (equivalent to more than twice the length of one milling) and cut off the milling part, which can reduce the waste of end materials.
Specially designed, the polished rod drives the screw to rotate in the nut, the left end of the screw is equipped with a spring chuck, and the workpiece rotates to the left to feed. Both the polished rod and the lead screw are hollow tubes (reducing the waste of end materials). Because of the long suspension time in the middle, you can consider using an auxiliary bracket to lift it.
Clamping device of knurling knife. The knurling cutter devices of the two designs are the same, but the connection parts between the support frame and the machine tool are different. Machining a hole on the support frame, and milling a groove and a through hole on the center line of the transverse through hole opposite to the machining position, wherein the width of the groove is the same as that of the knurled handle, and the depth is the same as that of the handle; A narrow groove is vertically milled at the groove root near the lower edge of the groove connecting hole, so as to facilitate the outflow of fine iron filings extruded by knurling and prevent Hua Lun from being stuck. The knurling knife is pressed by the quick-change cover plate, and the knurling handle is pressed by the plum-blossom handle screw. After the round steel passes through the guide sleeve, it is knurled and then milled at high speed, so that the two processes can be completed at one time. The guide sleeve is made of quenched and tempered tool steel, and an opening is milled on it, and the length of the opening is parallel to the end face of the bracket. The locating pin hole and mounting screw of the guide sleeve are matched with the bracket, and the opening should be ensured to face the center line of the groove.