With the development of CNC machine tools in China, thread milling as a method of using CNC machine tools to process threads has gradually been accepted and loved by the majority of customers in China. Thread milling is accomplished by using the three-axis linkage function of NC machining center machine tool. The thread milling process itself has certain advantages. Because the manufacturing material of thread milling cutter is carbide, the machining line speed can reach 80 ~ 200m/min, and the machining line speed of high-speed steel tap is only 10 ~ 30m/min, so the thread milling cutter is suitable for high-speed cutting, and the surface finish of the processing thread is also greatly improved.
In this paper, by summarizing the common thread machining methods in the actual processing, the selection of thread machining tool, CNC programming method and matters for attention are analyzed and explained, to help the staff quickly grasp the thread machining method, and can improve the efficiency of the machining center. Thread machining is one of the very important applications of machining center. The machining quality and efficiency of thread will directly affect the machining quality of parts and the production efficiency of machining center. With the improvement of machining center performance and cutting tools, the method of thread processing is also improving, and the precision and efficiency of thread processing are gradually improving. In order to enable staff to reasonably choose thread processing methods in processing, improve production efficiency and avoid quality accidents, several thread processing methods commonly used in the actual cnc machining center are summarized as follows:
Thread Milling Method:
Thread milling is the use of thread milling tool, for large hole thread processing, and more difficult to process material thread hole processing, has the following characteristics, carbide tool with fast speed, high precision milling thread characteristics, processing efficiency is also high. The same pitch, whether left – or right-handed, can use a tool, reducing the cost of the tool. Thread milling method is especially suitable for the thread processing of stainless steel, copper and other difficult materials, easy to remove chips and cooling, can ensure the quality and safety of processing. Without the guide of the front end of the tool, it is more convenient to process the blind hole with short thread bottom hole or the hole without the back slot. Thread milling tool is divided into two kinds: machine clip-type carbide blade milling cutter and integral carbide milling cutter. Machine clip-type cutting tool can not only process the thread depth is less than the length of the blade hole, but also can process the thread depth is greater than the length of the blade hole; The integral carbide milling cutter is used for machining holes where the thread depth is less than the tool length.
Center Tap Processing Method:
It is suitable for threaded holes with small diameter or low requirement of hole position accuracy. In general, the diameter of threaded bottom hole bit is close to the upper limit of the diameter tolerance of threaded bottom hole, which can reduce the machining allowance of the tap, reduce the load of the tap, and improve the service life of the tap. We should choose the right tap according to the material processed, tap relative to the milling cutter, boring cutter. Very sensitive to the material being processed; Tap is divided into through hole tap and blind hole tap, through hole tap front-end guide long, for the front row chip, in the processing of blind hole can not ensure the depth of thread processing, and blind hole front-end guide is short, for the back row chip, so pay attention to the difference between the two; Using flexible tapping chuck, it should be noted that the diameter of the tap handle and the width of the square should be the same as the tapping chuck; The diameter of the tap shank for rigid tapping should be the same as that of the spring jacket. Tap machining method programming is relatively simple, are fixed mode, add parameter value can, should pay attention to one point, numerical control system is different, the format of the subroutine is different, the parameter value represents the meaning is different.
Pick And Buckle Processing Method:
The pick processing method is suitable for the processing of large thread holes on the box parts, or without taps and thread milling cutter using this method, the boring tool bar is installed on the thread turning tool, boring thread. CNC machining center pick processing method is only a temporary emergency method, it is recommended that we thread processing method processing tool, in order to effectively improve the efficiency and quality of thread processing, reduce the processing cost and improve the efficiency of the use of processing center.