The thread turning processing

1. Transmission principle of thread cutting, in order to obtain accurate thread, must use screw drive head feed, parts per week, cutting tool moving distance is equal to the pitch. 2. Threading tool and installation of the tooth type Angle alpha, depends on the threading tool grinding and installation. Threading tool grinding requirements: 1) Turning the Angle is equal to the screw axial section of tooth type Angle alpha; 2) Before the Angle between 0 = 0 °, coarse thread in order to improve the cutting condition, can have a positive rake Angle of cutting tool ( γ0 = 5°~ 15°) 。 Threading tool installation requirements: 1) Point must be center of rotation and workpiece contour. 2) Knife Angle bisector must match the workpiece axis vertical. Therefore, to use the model of cutter knife. 3. Machine tool adjustment and installation tool installed, dealing with machine tool adjustment, according to the size of the workpiece pitch, find the lathe sign, selected feed box handle position, release polished rod feeding mechanism, instead lead screw transmission. Select low spindle speed, in order to cutting smoothly, and there is sufficient time to return. To make the tool move even and smooth, you must adjust the horizontal slip board guide clearance and little rest the clearance between the nut and screw. In turning process, the workpiece axis of tiny loose, if any, which can lead to inaccurate thread shape or pitch, so must the clamping workpiece firmly. 4. Operation thread pitch diameter is depends on the total amount of cutting depth of multiple feed to guarantee. Every time when threading cutting depth volume is smaller, and the total amount of cutting depth can work according to the calculation of the thread tooth height ( High working tooth = 0. 54 x artifact of pitch, the unit is mm) , controlled by skateboard dial in roughly, and with the aid of the thread gauge to measure. Car triangular thread there are three ways, namely the straight entered, about cutting and oblique cutting method. ( 1) Straight entered with skateboarding in the feed, two blade and blade cutting at the same time. This method is easy to operate, the car out of the tooth type is clear, the tooth profile error is small, but turning force is big, poor heat dissipation and chip removal difficult, the tip is easy to wear. Suitable for processing thread pitch is less than 2 mm, and the finish turning high-precision thread. ( 2) About the characteristics of the cutting method about cutting method is to make only a blade for cutting tool, cutting deep feed at the same time, every time the left with a small head, move a short distance to the right. Repeat this several times, cutting car to last 1 ~ 2 knives, still use straight entered, to get accurate tooth shape, tooth root is clear. This method is suitable for processing large pitch of the thread. ( 3) Oblique cutting method to transfer small head pull a point of view, makes the tool along the direction parallel to the threading on the right side of feed, makes the tool two blade, basically only one cutting edge. Cutting force is small, this method has good heat dissipation and chip removal conditions, cutting dosage can be larger, higher productivity. But not easy car out clear tooth shape, tooth profile error is bigger. Generally applicable to larger pitch screw coarse car. 5. Avoid the 'button' threading, the movement of the lathe tool is driven by opening and closing nut and screw meshing, one thread slot to go after a lot of knives to complete. When the car through a car another knife, must ensure that the tool is on of the thread slot cut out, or call 'button', the workpiece scrapped. Is the main reason of the 'button', lathe screw pitch P wire and workpiece pitch P work is not the integer times. When the wire P/P = integer workers, after every feeding, can open the 'half nuts,' tool transverse, longitudinal wave back to rest, 'the disorderly buckle' will not occur. If P/P work indicates a integer, cannot open the 'half nuts,' shake head back, but only after turning away once, don't open the 'half nuts', just out of turning tool, workpiece clamping down turn, make the tool back to the starting position. Then adjust the cut depth of cutting tool, and continue to drive ahead running, spindle rotation, the next feeding. Because do not open the 'half nuts,' clip nut and screw meshing, turning point can be accurately in a fixed spiral groove cutting, 'button' will not occur. 6. Triangular thread measurement inspection triangular thread of common measuring tool is the thread gauge. Screw thread gauge is comprehensive inspection measuring tool, divided into two kinds of ring gauge and plug gauge. Plug gauge inspection internal thread, ring gauge inspection external thread, and by the rules and check gauge of two pieces of a deputy. Thread workpiece only in general rules can be through, check gauge pass for qualified and otherwise for the nonconforming parts.