With the continuous improvement of China's oil exploration level, the number of deep wells, ultra deep wells, thermal recovery wells and high temperature and high pressure gas wells is increasing year by year, and the requirements for the performance and quality control of special threaded joints are getting higher and higher. At present, most domestic manufacturers of special threaded joints use imported high-precision CNC lathes to better control the product quality of special threaded joints. When machining the thread on the thin wall pipe body with poor rigidity, in order to avoid the occurrence of machining chatter marks, the reasonable overhang length of the pipe body can be determined according to the design length of the thread, the processing characteristics of the lathe and the clamping method of the cutter, so as to avoid the occurrence of machining chatter marks caused by the excessive overhang of the pipe body and the swing of the pipe head. Similarly, the design of the jaw shall also be specially designed according to the size and steel grade of the sample to be processed and the characteristics of the lathe. At present, there are plane jaws and arc wrap jaws. The clamping form of the flat jaw is point line contact. This clamping mode has a small contact area, which can effectively increase the clamping force between the jaw and the sample surface and prevent the movement of the processed sample. However, it will lead to uneven force on the sample and make the size or ovality of the sample after processing out of tolerance.
In recent years, with the rapid development of electronic technology and numerical control technology, the booming manufacturing industry in China has brought about the popularization of numerical control applications. Numerical control processing is no longer a unique patent of a few scientific research institutes and large military enterprises. Numerical control equipment has entered ordinary enterprises. Moreover, the scale of the application of numerical control in these enterprises is no longer dependent on one or two numerical control machines to process key parts or support enterprises. They have more than ten, even dozens There are hundreds of enterprises with CNC equipment everywhere, forming a CNC workshop with a considerable scale. The development of CNC system today is no longer a proprietary and closed NC unit in the early years. The modern CNC device is actually a computer, even a high-performance general-purpose computer. Of course, the work undertaken is far beyond the CNC function itself.