What are the classifications of thread lathes?
1. Short thread lathe
The layout of the short thread lathe is basically similar to that of the ordinary lathe. The thread forming movement between the workpiece and the tool does not use a lead screw, but is completed by an end cam installed in the middle of the bed. The lift profile of the cam makes the tool post move forward and turn the thread; the descending profile makes the tool post return. It can avoid the frequent forward and reverse rotation of the main shaft and lead screw during high-speed turning of threads on a general lathe.
2. Pipe thread lathe
Pipe threading lathes generally have a large through hole on the spindle box. After the workpiece passes through the through hole, it is clamped by two chucks at both ends of the spindle for rotary motion. There are generally two ways to feed the tool: one is similar to a normal lathe by a lead screw to drive the slide and tool holder in front of the bed; the other is by the flat comb on the slide in the center of the bed. The external thread cutting head (see the automatic opening and closing thread cutting head) is cut into the workpiece and realized with the previous movement. Some machine tools for processing long tubes also have workpiece support devices. The pipe threading lathe has partially adopted digital control. For each revolution of the workpiece, the tool moves evenly by a distance equivalent to the selected pitch according to the number of feed pulses, which is very convenient for processing taper threads, changing pitches and correcting pitch errors. This type of machine can process workpieces up to 15 meters in length and up to 400 mm in diameter.
3. Tubing joint thread lathe
The tubing joint thread lathe can also adopt digital control. Because the taper threads at both ends of the pipe joint have different directions of rotation and higher concentricity requirements, the workpiece chuck on some machine tools can carry the workpiece with the workpiece after processing the thread at one end and use the hydraulic method to turn the head in order to turn the other end. Thread.
4. Lead screw lathe
The difference between a lead screw lathe and an ordinary lathe is that the female lead screw has a larger diameter and is placed between the two guide rails of the bed instead of in front of the bed. In order to improve the machining accuracy, the machine tool is equipped with a pitch error correction device, which is mainly used for turning precision lead screws. The pitch error of the workpiece generally does not exceed 7 microns per 300 mm.