Twin screw threaded component processing method
In the processing of whirlwind milling screw, the process of thread and knurling is high, the cost is low, and the processing precision is not high. The structure planning idea and plan have better promotion and application value.
Cyclone milling is a highly efficient threading method for large-volume thread roughing. The process uses high-speed milling of the thread with a carbide knives. It has the advantages of good tool cooling and high productivity. For threads with low precision requirements, this method can be used to complete the cutting process at one time. The reversal axis of the cyclone milling cutter is spatially oriented with the workpiece axis, and the cross-point of view is the angle β (equal to the helix angle). The machining process includes the rotary motion of the workpiece, the helical axial feed motion of the workpiece (or tool feed), and the rotary motion of the cutting edge on the milling cutter.
1. Parts processing requirements: The parts are adjustable wrenches with adjustable span width. The data is No. 20 round steel. There is a certain roughness requirement on the flank. The chamfering part of the thread is required to be chamfered. The middle pin hole and the outer cylindrical surface are necessary. There is better coaxiality, otherwise it will not be sensitive and even stuck when adjusting. In order to facilitate the grip of the thumb, the appearance should have a straight knurl parallel to the axis.
2. Analysis and comparison of the processing technology: the screw processing originally used turning processing, the process road is: cold drawing → knurling → thread thread → proofreading → drilling → blocking → chamfering, not only low efficiency, high cost, and small The round steel has low rigidity, and it is easy to be deformed when turning and knurling. The small screw can not be produced. For this reason, we have planned the cyclone milling screw equipment, which not only raises the speed from 1000r/min determined by the experience to above 2000r/min and will The milling knurling is completed once. The craft road becomes: cold drawing → knurling, milling, → proofreading → drilling, blocking → chamfering. Although cyclone milling causes large deformation of small-diameter workpieces (large deformation of large-diameter members), proofreading is simple. The improved process has the following characteristics: the roughness of the appearance is reduced: the oscillation reduction caused by the cutting force: the cumulative error of the pitch of the small-diameter workpiece is necessarily added.
3. Thread component structure planning: The equipment is modified by lathe, workpiece rolling, cutter head and knurling tool holder move. Remove the lathe tool holder part, install the milling head and the self-contained tool holder on the slide plate, and place the knurling knife on the tool holder, and place it on the front of the milling cutter. The left end of the workpiece is clamped by the chuck, the right end is removed from the tailstock, and the device has a bracket with a long hollow tube, so that the long material can be clamped at one time (equivalent to more than twice the length of one milling), and the milling part can be cut and processed. Cut the waste. In the special planning, the light rod drives the lead screw to roll in the nut, the left end of the screw rod is equipped with a tension spring chuck, the workpiece is rolled to the left, and the polished rod and the screw rod are processed by a hollow tube (cutting the end material waste). Since the middle suspension is long, it can be considered to be lifted with the auxiliary bracket. Knurling knife clamping equipment. The two planned knurling device methods are the same, only the joint between the support frame and the machine tool is different. A hole is machined on the support frame, and the groove and the through hole are formed in the center line of the transverse through hole at the opposite side of the processing part: the groove width is equal to the width of the knurling handle, and the depth is the same as the height of the shank, and the bottom of the groove is straight at the lower side of the groove. Milling a narrow groove makes it easy for the squeezing and extruding fine iron chips to flow out, avoiding the knurling wheel from being stuck and jammed. The knurling knife is pressed with the quick change cover, and the knurled shank is tightened by a screw with a plum handle. The round steel is knurled after passing through the guide sleeve, followed by high-speed milling, and the two processes are completed at one end. The guide sleeve is made of tool steel quenched and tempered, and the upper sleeve is milled and the length is flat with the end surface of the bracket. The guide sleeve positioning pin hole, the mounting screw and the bracket are matched to ensure that the opening is facing the groove center line.
4. Precautions for processing of threaded components : The data needs to be a regular trademark round steel. Otherwise, the workpiece surface is easy to form scales, etc. The milling cutter is easy to break and crack, and the knurling knife is costly: it is necessary to make the knurling knife in processing and installation. The movement in the tank is relatively easy, and the gap is not too large. If the gap is too large, the hob wheel is skewed during operation, the unevenness of the roll is uneven, and it is easy to damage itself: the platen should be closed as much as possible to prevent chipping and miscellaneous Splashing into the material: Do not smooth the knurling knife during operation to prevent damage to the carbide insert that is close to it: first turn the lathe, let the workpiece roll, then tighten the screw to avoid excessive static friction, the workpiece slips: Make a good knurling knife to reduce the number of tool changes: Temporarily disassemble the quick change cover and align the sipe.
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