Application of the hottest thread milling technolo

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Application of thread milling technology in mechanical manufacturing industry

with the popularity of numerical control machine tools, thread milling technology is more and more used in mechanical manufacturing industry. Thread milling is to use the three-axis linkage of CNC machine tools to form threads by spiral interpolation milling with a thread milling cutter. Each cycle of circular motion of the cutter on the horizontal plane moves a pitch in a straight line in the vertical plane

thread milling has many advantages, such as high machining efficiency, high thread quality, good tool versatility, good machining safety and so on. At present, there are many kinds of thread milling tools used. This paper will analyze and introduce several common thread milling tools from the perspective of application characteristics, tool structure, processing technology and so on

1 ordinary machine clamp thread milling cutter

machine clamp thread milling cutter is the most commonly used and inexpensive tool in thread milling. Its structure is similar to that of ordinary machine clamp milling cutter, which is composed of reusable arbor and easily replaceable blade. If it is necessary to process conical threads, the special tool bar and blade for processing conical threads can also be used. This blade is equipped with multiple thread cutting teeth, and the tool can process multiple thread teeth at one time by processing along the spiral line. For example, if a milling cutter with five 2mm thread cutting teeth is used, five thread teeth with a thread depth of 10mm can be processed along the spiral line for one week. In order to further improve the processing efficiency, multi blade machine clamp thread milling cutter can be selected. By increasing the number of cutting edges, the feed rate can be significantly improved, but the radial and axial positioning errors of the elderly housing reverse mortgage endowment insurance (i.e. "housing endowment") pilot launched on July 1 will affect the accuracy of thread machining. For example, if you are not satisfied with the accuracy of the thread processed by the multi blade machine clamp thread milling cutter, which is why Solvay's materials are popular with customers, you can also try to install only one blade for processing. When selecting the machine clamp thread milling cutter, you should try to select the cutter rod with larger diameter (to improve the rigidity of the cutter) according to the diameter, depth and workpiece material of the processed thread And appropriate blade material. The thread processing depth of the clamp thread milling cutter is determined by the effective cutting depth of the cutter bar. Because the length of the blade is less than the effective cutting depth of the tool bar, when the depth of the processed thread is greater than the length of the blade, it needs to be processed in layers

2 ordinary integral thread milling cutter

integral thread milling cutters are mostly made of integral cemented carbide materials, and some are also coated. The integral thread milling cutter has a compact structure, which is more suitable for processing medium and small diameter threads; There are also integral thread milling cutters for machining taper threads. This kind of cutter has good rigidity, especially the integral thread milling cutter with spiral groove, which can effectively reduce the cutting load and improve the machining efficiency when machining high hardness materials. The cutting edge of the integral thread milling cutter is full of thread processing teeth, and the whole thread processing can be completed by processing along the spiral line for one week. There is no need for layered processing like the clamp type cutter, so the processing efficiency is higher, but the price is also relatively expensive

3 integral thread milling cutter with chamfer function

the structure of integral thread milling cutter with chamfer function is similar to that of ordinary integral thread milling cutter, but there is a special chamfer edge at the root (or end) of the cutting edge, which can process the chamfer of the thread end while processing the thread. There are three ways to process the chamfer. When the tool diameter is large enough, the chamfer can be directly countersunk with the chamfer edge. This method is only limited to processing the chamfer of the internal thread orifice. When the tool diameter is small, the chamfer edge can be used to process the chamfer through circular motion. However, when chamfering with the chamfer edge at the root of the cutting edge, it should be noted that there should be a certain gap between the thread cutting part of the tool and the thread to avoid interference. If the processed thread depth is less than the effective cutting length of the tool, the tool will not be able to achieve the chamfer function. Therefore, it is understood that when selecting the tool, it should ensure that its effective cutting length matches the thread depth

4 thread drilling and milling cutter

the thread drilling and milling cutter is made of integral cemented carbide, which is an efficient tool for machining small and medium-sized internal threads

the thread drilling and milling cutter can complete the processing of thread bottom hole drilling, hole chamfering and internal thread at one time, reducing the number of tools used. But the disadvantage of this kind of cutting tool is poor versatility and relatively expensive price. The tool consists of three parts: the drilling part of the head, the thread milling part in the middle and the chamfer edge at the root of the cutting edge. The diameter of the drilling part is the bottom diameter of the thread that the tool can process. Limited by the diameter of the drilling part, a thread drill and milling cutter can only process internal threads of one specification. When selecting the thread drill and milling cutter, we should not only consider the specification of the processed thread hole, but also pay attention to the matching between the effective machining length of the cutter and the automatic switching depth between the control rings of the processed hole, otherwise the chamfer function cannot be realized

5 thread auger milling cutter

thread auger milling cutter is also an integral cemented carbide tool for efficient machining of internal threads, which can also process bottom holes and threads at one time. The end of the tool has a cutting edge like an end mill. Because the spiral rise angle of the thread is not large, when the tool processes the thread in spiral motion, the end cutting edge first cuts off the workpiece material to process the bottom hole, and then processes the thread from the back of the tool. Some thread auger milling cutters also have chamfering edges, which can process the chamfer of the orifice at the same time. The machining efficiency of the tool is very high, and its versatility is better than that of the thread drill and milling cutter. The diameter range of the internal thread that the tool can process is d ~ 2D (D is the tool body diameter)

6 deep thread milling cutter

deep thread milling cutter is a single tooth thread milling cutter. Generally, there are multiple thread processing teeth on the blade of thread milling cutter, the contact area between the cutter and the workpiece is large, and the cutting force is also large, and the diameter of the cutter must be smaller than the thread aperture when machining internal threads. Because the cutter body diameter is limited, which affects the rigidity of the cutter, and the cutter is forced on one side when milling threads, it is easy to yield the cutter when milling deeper threads, which affects the machining accuracy of threads. Therefore, the effective cutting depth of general thread milling cutters is about 2 times of their cutter body diameter. The use of single tooth deep thread milling tools can better overcome the above shortcomings. Because the cutting force is reduced, the thread processing depth can be greatly improved, and the effective cutting depth of the tool can reach 3 ~ 4 times of the tool body diameter

7 thread milling tool system

versatility and efficiency are a prominent contradiction of thread milling tools. Some tools with composite functions (such as thread drilling and milling cutters) have high processing efficiency but poor versatility, while the efficiency of tools with good versatility is often not high. To solve this problem, many tool manufacturers have developed modular thread milling tool systems. The tool system is generally composed of tool shanks, countersink and chamfer edges and general thread milling cutters. Different types of countersink and chamfer edges and thread milling cutters can be selected according to processing requirements. This tool system has good versatility and high processing efficiency, but the tool cost is high

the above briefly introduces the functions and characteristics of several common thread milling tools. When milling threads, cooling is also very important. It is recommended to use machine tools and tools with internal cooling function. Because when the tool rotates at high speed, the external coolant is not easy to enter under the action of centrifugal force. In addition to the internal cooling method, which can cool the tool well, it is more important that the high-pressure coolant is conducive to chip removal when machining blind hole threads. In particular, a higher internal cooling pressure is required when machining small-diameter internal thread holes to ensure smooth chip removal. In addition, when selecting thread milling tools, we should also comprehensively consider the specific processing requirements, such as production batch, number of screw holes, workpiece materials, thread accuracy, size specifications and many other factors, and reasonably select tools

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