Analysis and summary of 9 major problems of tap fracture

1. Poor quality of taps:

Main materials, CNC tool design, heat treatment, machining accuracy, coating quality and so on. For example, too big size difference at the transition of tap section or no design of transition fillet leads to stress concentration, which is easy to fracture at the stress concentration. The section transition at the junction of handle and blade is too close to the welding joint, resulting in the superposition of complex welding stress and stress concentration at the section transition, resulting in large stress concentration, resulting in the fracture of taps in use. Metal processing wechat, good content, worth paying attention to. For example, improper heat treatment. During the heat treatment of taps, cracks may occur if the taps are not preheated, overheated or overburned, tempered or cleaned prematurely before quenching. To a large extent, this is an important reason why the overall performance of domestic taps is not as good as that of imported taps.

2. Improper tap selection:

The hardness is too large tapping parts should choose high-quality taps, such as cobalt high speed steel taps, carbide taps, coating taps and so on. In addition, different tap designs are used in different workplaces. For example, tap chip slot number, size, Angle and so on have an impact on chip removal performance

3. The taps do not match the processed materials:

This problem is taken seriously more and more in last few years, before domestic manufacturer always feels what import is good, expensive is good, it is suitable actually good. With the increase of new materials and difficult to process, in order to adapt to this need, the variety of tool materials is also increasing. This requires a good selection of suitable tap products before tapping.

4. Small bottom hole:

For example, when machining the M5×0.5 thread of ferrous metal material, the cutting tap should be used to select the diameter of 4.5mm drill hole, if the 4.2mm drill hole is misused, the cutting part of the tap is bound to increase when tapping, and then the tap is broken. It is recommended to choose the right bottom hole diameter according to the types of taps and different tapping materials. If there is no drill that completely matches, you can choose a larger one.

5. Material problems of attacking parts:

Tapping material is not pure, local hard points or pores, resulting in the tap instantly lost balance and broken.

6. The machine tool does not meet the precision requirements of taps:

Machine tools and clamps are also very important, especially for high-quality taps, as long as a certain precision of machine tools and clamps can play the performance of taps. What's common is not enough concentricity. At the beginning of tapping, tap starting positioning is not correct, that is, the spindle axis is different from the center line of the bottom hole, too much torque in the process of tapping, which is the main reason for tap fracture.

7. Poor quality of cutting fluid and lubricating oil:

This domestic many enterprises began to pay attention to, many of the procurement of foreign tools and machine tools of the company has a very deep experience, cutting fluid, lubricating oil quality problems, processed product quality is easy to appear burr and other adverse conditions, at the same time, the life will also have a great reduction.

8. Unreasonable cutting speed and feed:

When processing problems, most of the domestic users is to reduce cutting speed and reduce feeding, such tap propulsion strength is reduced, the production of thread accuracy was greatly reduced, it increased the roughness on the surface of the screw thread, thread aperture and cannot control precision, burr problem, of course, such as more inevitable. However, too fast feed speed, resulting in too much torque will easily lead to tap fracture. Machine tapping cutting speed, general steel 6-15m/min; Tempered and tempered steel or hard steel material is 5-10m/min; Stainless steel, 2-7m/min; Cast iron is 8-10m/min. In the same material, the tap diameter is small and the tap diameter is large, the tap diameter is low.

9. The operator's technology and skills do not meet the requirements:

These problems above, all need operators to make a judgment or feedback to the technical staff, but at present the vast majority of domestic operators do not pay enough attention to. For example, when processing blind hole thread, when the tap is about to contact the bottom of the hole moment, the operator did not realize that the tap speed is still not to the bottom of the hole, or when the chip discharge is not free, forced into the tap resulting in tap fracture. It is suggested that operators strengthen their sense of responsibility.

It can be seen from the above that the causes of tap fracture are various, such as machine tools, fixtures, workpieces, processes, collets and tools, etc., and the real reason may never be found only by armchair armchair soldiers. As a qualified and responsible tool application engineer, the most important thing is to go into the field, not just by imagination.