When we perform thread processing on a CNC lathe, we usually use a tool for cutting. When machining large-pitch threads, the tool wears too fast, which will cause large changes in thread size and low thread accuracy after cutting. After years of exploration, we have found out a method for cutting threads on a CNC lathe, which is divided into rough and fine turning tools. In the machining process, when the rough turning blade wears to the limit, the finishing turning blade is changed to the rough turning tool, and the finishing turning tool is replaced with a new blade. This can not only ensure the accuracy of thread cutting, but also reduce tool costs. The key to this method depends on the tool setting accuracy of coarse and fine thread tools.
1. Operation method
Cut both the end face and the outer circle of the workpiece (the end face is flat, the outer circle is turned), and then the outer circle diameter D is measured; the thread is cut by a rough turning tool. The specific method is as follows:
Turn the roughing tool (T0X00) by hand with the pulse generator to the outer circle D after cutting. Shake the workpiece in the positive direction of the Z axis by hand cranking the pulse generator, and input the D value (this tool has been set on the X axis). Note down the specific data displayed on the X axis. Feed the pulse generator by hand to 1～2mm in the negative direction on the data displayed and recorded on the X axis. Similarly, feed the pulse generator by hand in the negative direction of the Z axis, and the tool can cut to the workpiece. Enter Z0 (Z-axis tool setting completed). At this time, the roughing thread tool setting ends.
According to this method, the thread is finished again, and the operation steps are exactly the same as the rough turning tool setting method. In this way, random buckles will not occur during the cutting process. Even if there are more tools for cutting, there will be no random snapping.
2. Matters needing attention
(1) When each tool is aligned to the X axis, the numbers displayed on the machine tool are different. Be sure to record the actual data of each tool. After exiting the X axis, the X axis feed data of multiple thread cutting tools must be the same, and there can be no differences.
(2) In the process of tool setting, when approaching the X axis and Z axis of the workpiece, it is recommended that the manual pulse generator choose the feed range of 0.001mm.