Flat thread, also known as face thread, has the same tooth profile as a rectangular thread, but a flat thread is usually a thread machined on the end face of a cylinder or disc. When machining plane threads, the trajectory of the turning tool relative to the workpiece is an Archimedes spiral, which is different from the usual cylindrical threads. This requires one revolution of the workpiece, and the intermediate carriage can move the pitch on the workpiece laterally. Below we will describe in detail how to process it.
1.The basic characteristics of the thread
Threaded joints are widely used in the machining process and have both internal and internal threads. Depending on the shape of the thread profile, there are mainly four types: triangular thread, trapezoidal thread, serrated thread and rectangular thread. The number of threads according to the thread: single thread and multi thread. In various machines, the functions of the threaded part mainly include the following: one is used for fastening and connection; the other is used for fastening and connection. The other is to transmit power and change the form of movement. Triangular threads are often used for connection and robustness. Trapezoidal and rectangular threads are often used to transmit power and change the form of motion. Their technical requirements and processing methods have a certain gap due to different uses.
2.Surface threading method
In addition to using ordinary machine tools, in order to effectively reduce the processing difficulty of thread processing, improve work efficiency and ensure the quality of thread processing, CNC processing is often used.
The three commands of G32, G92 and G76 are usually used for CNC machine tools.
G32 instruction: can handle single-stroke thread, single programming task is heavy, and the program is more complex;
Command G92: A simple thread cutting cycle can be implemented, which helps simplify program editing, but requires rough machining of the workpiece blank in advance.
Command G76: Overcoming the shortcomings of command G92, it can process workpieces from blank to finished thread at one time. Saving programming time goes a long way to simplifying the program.
G32 and G92 are straight-line cutting methods, and the two cutting edges are easily worn. This is mainly due to the large cutting force and the difficulty of cutting due to the simultaneous work of both sides of the blade. When cutting a thread with a large pitch, the cutting edge wears faster due to the large depth of cut, which causes an error in the thread diameter. However, the precision of the processed tooth shape is high, so it is usually used for small pitch threading. Since the tool movement cutting is done by programming, the machining program is longer but more flexible.
G76 belongs to the bevel method. Since this is a single-sided cutting process, the right cutting edge is prone to damage and wear, resulting in a non-straight thread surface. Also, once the cutting edge angle is changed, the accuracy of the tooth shape is poor. However, the advantages of this machining method are reduced depth of cut, low tool load and easy chip removal. Therefore, this processing method is suitable for the processing of large pitch threads.