Thread milling cutter has many advantages. It has great advantages over tapping. Thread milling cutter is more than ten times faster than tapping and has high accuracy,
The surface roughness is good. The same pitch can be used to obtain large and small holes. The drilling and milling thread chamfer can be formed at one time. After breaking, it will not be taken out like a tap, and the resistance of the machine tool is also small.
Introduction to thread milling cutter:
The traditional thread processing methods mainly include turning thread with thread turning tool or manual tapping and threading with tap and die. With the development of NC machining technology, especially the emergence of the three-axis linkage NC machining system, the more advanced thread processing method - NC milling of thread has been realized. Compared with traditional thread processing, thread milling has great advantages in processing accuracy and efficiency, and is not limited by thread structure and thread direction. For example, a thread milling cutter can process multiple internal and external threads with different directions. For the thread that does not allow transition thread or undercut structure, it is difficult to use traditional turning method or tap and die, but it is very easy to use NC milling. In addition, the durability of the thread milling cutter is more than ten times or even tens of times that of the tap, and in the process of NC thread milling, it is very convenient to adjust the thread diameter size, which is difficult to achieve with the tap and die.
Classification of milling thread processing
Clamp type:
Single-tooth machine clamp: the mechanical structure is similar to the thread turning tool. The blade is connected with the turning tool, and there is only one thread processing tooth. The tool can only process one tooth per spiral movement, and the corresponding thread pitch in the Z-axis direction is decreased by one thread pitch. The efficiency is lower than that of the multi-tooth machine clamp thread milling cutter
Multi-tooth machine clamp: there are multiple threaded teeth on the cutting edge. When the tool rotates for one cycle, it can machine multiple threaded teeth by lowering the pitch of the corresponding number of teeth on the Z axis, and the machining effect is high
Integral type: there are many thread processing teeth on the cutting edge, which is a fixed pitch thread milling cutter. The cutter is made of integral cemented carbide, with good rigidity, high cutting speed and feed speed, wide processing range, compact structure, and can process internal threads of small and medium diameters. But its price is more expensive
Features of thread milling
1 Stability
When machining difficult-to-machine materials such as titanium alloy, superalloy and high-hardness materials, the tap will often be twisted or even broken in the parts due to too much cutting force. In the process of processing long chip materials, once the chip removal is not smooth, the chip will wrap around the tap or block the orifice, often causing the tap to break or break in the part. Taking out the broken tap is not only time-consuming and laborious, but also may damage the parts. To solve this problem, we can use thread milling cutter. Because the thread milling cutter is gradually cutting into the material, it produces less cutting force and rarely breaks the cutter. Even in case of a broken cutter, because the diameter of the milling cutter is much smaller than that of the threaded hole, the broken part can be easily removed from the part without damaging the part;

2 High precision
Because thread milling is convenient for chip removal of internal thread through high-speed rotation of the tool and spindle interpolation. Milling thread belongs to chip cutting, and the chip is short. In addition, the diameter of the processing tool is smaller than that of the processing thread, which can avoid the rotation line formed by the reversal of the tap (it is not allowed when the sealing requirements are high). Because there is no rotation line in the original milling cutter, and the tap cannot be avoided. It is not easy to form chips. For soft materials, chip sticking is easy to occur during processing, but the thread requires low machine power. Because thread milling is chip breaking cutting, the tool is in local contact, and the cutting force is small, and the tap tool is easy to be broken;

3 High efficiency
Processing efficiency We know that it is very difficult to improve the processing efficiency in mass thread processing due to the relatively low cutting speed limit of the tap and the reverse tool withdrawal after the thread is processed. However, if we use thread milling cutter, it not only has a high milling speed, but also its multi-groove design increases the number of cutting edges, which can easily improve the feed speed, which can greatly improve the processing efficiency. In the processing of long thread, we can also select the blade with longer blade to reduce the axial feed distance (equivalent to making the thread shorter) to further improve the processing efficiency;
4 Good finish
When machining with tap, it is very difficult to obtain good surface finish and thread accuracy due to the influence of low cutting speed and difficult chip breaking. However, everything is not a problem for thread milling! High cutting speed and small cutting force make the cutting surface very smooth; Fine chips can be easily washed out of the workpiece by the coolant without scratching the machined surface. For the workpiece with high requirements for thread accuracy, the thread milling cutter can easily obtain the required high-precision thread by adjusting the program, because the accuracy is guaranteed by screw interpolation. This feature has absolute advantages in precision thread processing.

5 Low cost
The thread milling cutter is flexible and can be applied to various working conditions. For example, we can use the same thread milling cutter to process left-handed threads and right-handed threads; Both external and internal threads can be processed. All this just needs to adjust the interpolation procedure. Use a tap for machining. If there are multiple threaded holes with different diameters but the same pitch on the part, a tap with different diameters is required. This not only requires a large number of taps, but also a large tool change time. If a thread milling cutter is used, because it is processed by using spiral interpolation, the thread of all diameters can be processed by changing the processing program, which greatly saves the tool cost and tool change time. In order to ensure the thread accuracy, different types of taps are required when machining different materials with taps. However, there is no such limitation when using thread milling cutters. The same thread milling cutter can process most materials and obtain high-precision threads. This can also greatly reduce tool costs. When the processing thread is required to be close to the bottom of the blind hole, it will be difficult to obtain a complete thread at the bottom if tapping is used. It is also possible that the tool will continue to move forward a little distance (floating tapping) during the time when the tap stops at the bottom and is ready to reverse and retreat, which is easy to cause the tap to break. This problem can be avoided by using the thread milling cutter - the thread milling cutter is smaller than the hole, and it is not necessary to reverse the tool retraction, and it is still a complete thread shape at the tool tip. In this way, we can obtain complete and accurate thread depth! In some machining, thread milling can help us solve many problems. For example, in the thread processing of large, non-circular parts, if it is processed on a lathe, it requires complex clamping and balancing to avoid vibration. At this time, it can be processed on the machining center, the parts are not moving, and the thread milling cutter rotates to avoid the balance problem. For example, when machining intermittent threads, vibration and impact have a great impact on the blade and are prone to crack. The use of thread milling cutter can avoid large impact and prolong the tool life because the tool gradually cuts into the material discontinuity.