Analysis and summary of 9 major problems of tap fracture

1. The quality of the tap is not good:

Main materials, CNC tool design, heat treatment, processing accuracy, coating quality and more. For example, the size of the tap section transition is too different or not

There are design transition fillets that cause stress concentration and breakage at stress concentrations during use. The cross-section transition at the intersection of the shank and the blade is too far from the weld.

Recently, the complex welding stress is superimposed on the stress concentration at the cross-section transition, resulting in a large stress concentration, causing the tap to break during use.

Metal processing WeChat, the content is good, it is worthy of attention. For example, the heat treatment process is improper. When the tap is heat treated, if it is not preheated before quenching,

Quenching overheating or overheating, failure to temper in time, and premature cleaning may cause cracks in the tap. To a large extent, this is also the overall performance of domestic taps.

Not as important as the import of taps.

2. The tap is not properly selected:

For high-strength tapping parts, high-quality taps, such as cobalt-containing high-speed steel taps, hard alloy taps, coated taps, etc., should be used. In addition, different wires

The cone design is used in different workplaces. For example, the number of taps, the size, the angle, etc. of the tap have an effect on the chip removal performance.

3. The tap does not match the processed material:

This problem has received more and more attention in recent years. In the past, domestic manufacturers always felt that the import was good and the price was good. In fact, it was suitable. With new materials

Increasingly and difficult to machine, in order to meet this need, the variety of tool materials is constantly increasing. This requires a good choice before tapping.

Tap products.

4. The bottom hole diameter is too small:

For example, when machining a black metal material M5×0.5 thread, the cutting tap should be drilled with a 4.5 mm diameter drill bit. If the misuse is 4.2 mm.

The drill bit is used to make the bottom hole, and the portion to be cut of the tap is inevitably increased when tapping, and the tap is broken. It is recommended according to the type of tap and the material of the tapping material.

With the correct bottom hole diameter, if the drill bit is not fully matched, you can choose a larger one.

5. Attack material problem:

The material of the attack piece is not pure, and there are too hard points or stomata in the part, which causes the tap to lose balance and break.

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

Machine tools and clamping bodies are also very important, especially for high-quality taps, as long as the precision of the machine and the clamping body can play the tap.

can. It is common that the concentricity is not enough. At the beginning of tapping, the tap is not positioned correctly, that is, the spindle axis is not concentric with the center line of the bottom hole.

Excessive torque during the wire process is the main cause of the breakage of the tap.

7. Cutting fluid, the quality of lubricating oil is not good:

At this point, many companies in China have begun to pay attention. Many companies that have purchased foreign tools and machine tools have a deep understanding of cutting fluids and lubrication.

There is a problem with the quality of the oil, and the quality of the processed product is prone to glitch and other undesirable conditions, and the life expectancy will be greatly reduced.

8. Cutting speed and feed rate are unreasonable:

When there is a problem in processing, most domestic users are reducing the cutting speed and reducing the feed rate, so that the pushing force of the tap is reduced, and the snail produced by it

Therefore, the precision of the grain is greatly reduced, which increases the roughness of the thread surface, the thread pitch and the thread precision are uncontrollable, and the problem of burr is

It is even more inevitable. However, if the feed speed is too fast, the resulting excessive torque will easily cause the tap to break. Cutting speed during machine attack, general steel

It is 6-15m/min; the quenched and tempered steel or harder steel is 5-10m/min; the stainless steel is 2-7m/min; the cast iron is 8-10m/min. In the same material,

The diameter of the tap is smaller and the diameter of the tap is larger.

9. Operator skills and skills do not meet the requirements:

All of the above problems require the operator to make judgments or feedback to the technical staff, but at present most of the operators in China do not pay enough attention.

For example, when machining a blind hole thread, when the tap is about to contact the bottom of the hole, the operator does not realize that it is still fed at the tapping speed when it is not at the bottom of the hole.

Forced feeding when the chip removal is not smooth causes the tap to break. It is recommended that operators strengthen their sense of responsibility.