Comparison between the hottest thread milling tech

Comparison between thread milling technology and tapping

in general production and processing, the traditional process of tapping is often used in the processing of threads. With the development of numerical control technology, the innovation of software, the improvement of control accuracy, the emergence of three-axis linkage or multi axis linkage numerical control system and its wide application in the production field, the corresponding advanced processing technology - thread milling is gradually realized, and its processing accuracy The smoothness and flexibility of tapping are incomparable. In addition, its economy is better than traditional technology in some cases

thread milling is to process threads by rotating the spindle at high speed and doing arc interpolation. As long as the program is changed, the processing of threads with different diameters, left and right threads and internal and external threads can be realized, and its flexibility is very ideal, as shown in Figure 1. In addition, thread milling also has the advantages of high wire speed, small stress, good chip removal, high machining accuracy, good finish and so on

Figure 1

advantages of thread milling over tapping

through the comparison of various aspects, it can be found that thread milling has many advantages:

1) a thread milling cutter can process threads with different diameters and the same tooth shape. As shown in Figure 2, m15x1.0, m18x1.0 and m20x1.0 threads are processed by changing the interpolation radius with a thread milling cutter, which can reduce the number of tools, save the tool change time, improve efficiency and facilitate tool management

figure 2

2) thread accuracy and finish are improved. Because thread milling is completed by means of high-speed tool rotation and spindle interpolation. Its cutting method is milling, with high cutting speed and beautiful processed threads; The cutting speed of tap is low, and the chip is long, which is easy to damage the inner hole surface

3) the internal thread is convenient for chip removal. Milling thread belongs to chip breaking cutting, and the chip is short. In addition, the diameter of the machining tool is smaller than that of the machining thread hole, so the chip removal is smooth; The tap belongs to forming continuous cutting, the chip is very long, and the tap diameter is as large as the machining hole, so it is difficult to remove the chip

4) it can avoid that the rotary mineral products formed by the reversal of the tap will be affected by many factors such as logistics conditions when they are transported to the domestic market (it is not allowed under the condition of high sealing requirements). Because of different processing principles, there is no rotation line for thread milling cutter, and tap cannot be avoided

5) it is not easy to form sticky chips. For relatively soft materials, chip sticking is easy to occur in the machining process, but thread milling rotates at high speed and chip breaking cutting; The cutting speed of tap is low, and the full thread acts on the machined surface, which is easy to cause chip sticking

6) low machine power is required. Because thread milling is chip breaking cutting, the cutting tool is in local contact, and the cutting force is small, while the tap is in full thread contact, and the force is large, which requires a lot of power of the machine tool

7) tool breakage is easy to handle. First of all, the force of the thread milling cutter is small, and breakage rarely occurs. If it happens, because the machining aperture is larger than the tool, the broken part is easy to take out; However, the tap is subject to large force and poor chip removal, which is easy to break. After breaking, it is slightly easier to deal with the large hole. If it is a small hole, it is very troublesome, as shown in Figure 3

figure 3

8) the reserved depth of bottom hole is small. Because of the design of the cutter itself, the thread milling cutter can process flat bottom threads, as shown in Figure 4; The reserved depth of the bottom hole of the tap is relatively large

figure 4

9) materials with high hardness can be processed. The cutting principle determines that the thread milling cutter is chip breaking cutting, with local stress, low tool wear and long service life; Generally, for materials with hardness greater than 50HRC, tap processing is quite difficult and its service life is very short

10) reduce the process and the number of tool changes. Thread milling cutter can be designed to drill, chamfer, countersink, ream and thread in one

· one knife can process left and right-hand threads. Whether the thread milling cutter processes the left-hand or right-hand thread completely depends on the processing program

· one knife can process internal and external threads. At present, VARGUS thread milling cutter series blades and arbors can be used for processing internal and external threads, as shown in Figure 5

figure 5

11) high efficiency. For the processing of large aperture, it is more obvious. In 2014, firstly, the linear speed is high, and secondly, the multi blade cutter head can be used. The efficiency can be doubled when abnormal conditions are found in the power line and power plug, as shown in Figure 6

Figure 6

disadvantages of thread milling

of course, thread milling also has certain disadvantages, such as:

1) when processing ordinary threads, it is not cost-effective to use thread milling simply from the perspective of single piece cost. Ordinary thread is classified as general hardness of 38mm), which is suitable for thread milling, because thread milling is local contact, and the force is small, and the general machine power is sufficient. The tap is in full thread contact, which requires high-power equipment. In addition, in terms of the price of cutting tools, the price of a large-diameter tap is not lower or even higher than that of a set of thread milling cutters. Moreover, the thread milling cutter can choose the blade type. As long as the blade is replaced, its economy is self-evident. Considering all aspects, thread milling cutter is more suitable

small batch thread processing is also suitable for thread milling. Firstly, the thread milling cutter can process various workpieces with different diameters and the same threads, so the number of cutters can be reduced. Even in the case of different threads, the use of blade type thread milling cutter can process a variety of threads as long as the blade model is changed. Whether it is the initial cost investment or the flexibility of use, it is incomparable to tap

mold or large parts, suitable for thread milling. What should I do if the tool is broken during machining? If you use a tap, of course, you can use an electric spark to break the broken branch, but the process will be very complex. In addition, if you damage the parts, it will be penny wise and pound foolish. If a thread milling cutter is used, it is not easy to break because of the small force; Even if it is broken, because the machining aperture is larger than the tool diameter, the broken branch can be easily taken out. In terms of product qualification rate, thread milling is much higher than tap

the machining of high hard materials (hardness>50hrc) is suitable for thread milling, because milling is chip breaking cutting, the local contact tool is less stressed, and the blades are coated with cemented carbide, so the wear is small and the service life is long; However, the general high-speed steel wire taps cannot be processed at all. For example, the price of solid carbide taps is not cheap, which is similar to that of thread milling cutters. According to our existing processing experience, the efficiency and economy of thread milling are absolutely higher than tap

the machining of composite holes (with chamfer) is also suitable for thread milling. The thread milling cutter has multiple functions and can integrate thread and chamfer machining

thin wall processing, suitable for thread milling, thread milling cutter processing stress is small, so the deformation is small. In addition, the bottom hole can be made into a flat bottom, and the thread can be close to the bottom, so the required space is small

for processing with high thread accuracy requirements, nearly all quality laboratories in rubber related industries will be equipped with one or more rubber tensile testing machines because of the thread milling line, which is more suitable for thread milling because of its high speed, good chip removal, high thread accuracy and finish

the use of thread milling is conducive to achieving high-efficiency machining. Now the thread milling cutter has developed into a multi process of drilling, chamfering, countersinking and thread; In addition, internal and external threads, left and right threads can be processed with a knife; Multi blade cutter head can be used; The knife retracts quickly

processing of soft materials and titanium alloys is suitable for thread milling, because the thread milling cutter is not easy to produce sticking debris

for unstable cutting, the thread milling cutter can fully adapt to this condition because its cutting principle is intermittent milling

of course, users can choose their own processing methods according to production equipment, process requirements, accuracy requirements and cost requirements. It is believed that thread milling will gradually be understood by people and go deep into production practice. (end)