Machine tap: description and function

In the class of metal-cutting tools, a special place is occupied by devices that perform the functions of attachments on machine tools. These include taps, which allow the formation of internal threads in metal workpieces.

Despite the simple appearance, this device is a very responsible tool. Suffice it to say that the machine tap is made of special alloys based on high-speed metal or tool steel. As a result, the structure of the material and gives the design a high cutting ability with minor wear processes, which, however, are also inevitable.

Purpose of the tool

Any tap is oriented to forming threads in the internal surfaces of various parts. Usually this tool is considered as an element of the working tooling of machine tools. Thus, a typical machine tap is used in processing plants, allowing you to quickly and effectively implement the task of cutting the desired edge.

At the same time, it is worth emphasizing the variety of thread configurations that this tool implements. Most often distinguish the techniques of cutting grooves in through and blind holes.

In the first case, a groove is formed along the entire length of the profile channel, and in the second case, partially, up to a certain point in the length. It is noteworthy that the tapping machine for blind holes, as a rule, differs by a special facet on the working rod. However, the design of the instrument should be considered separately.

Tap device

The tool consists of two main parts, which can have different parameters and in general the shape of the structure. The working part is a cylindrical rod, which is both a calibrator and a carver. The second part - the shank, which performs the task of the lock to the place of installation in the machine.

By the way, fastening is realized both through the collet chuck and with the help of special clamping elements - they are also provided in the machine tool system. For example, machine taps elongated by their approach part are suitable for installation in axial compensation mechanisms. But there are also manual models that do not integrate into the cartridges of machine tools, but interact with lever devices having grooves of a certain format.

It is important to note that the cutting edge itself can have different accuracy. As a rule, the first processing session is performed by draft models, and then more accurate, final surface finishing is carried out.

Types of tap

Typically, tile models are classified into three categories:

• Spotted;
• Uterine;
• Special devices.

The first option is used to create a thread, provided that the pass is processed in one working session. The uterine instrument has a different task - the work of stripping in the holes that previously served a roughing or a spot tap.

There are also special nonchannel models. This is a special category, which differs in the principle of thread formation. As a rule, a machine tap without grooves is used in working with soft metals. The processing is carried out by deformation by rolling, not by cutting. Thus, for example, the formation of threads with the help of taps-rollers, eliminating the formation of metal shavings.

Main characteristics

There are several parameters by which experts select the right tool for forming threads:

1. The main characteristic is the nominal thread diameter, which can be, for example, 10 mm.
2. The thread pitch will depend on the groove configuration . This amount of indentation between the edges can be several millimeters.
3. It should be noted that the machine tap, whose dimensions in diameter are of the order of 10 mm or less, has a harder alloy at its core. More large models are often made of high-speed metals - modifications, the diameter of which can exceed 25 mm. But this does not mean that a large-scale tap is losing reliability and accuracy of cutting small analogs. The fact is that the increase in the area of the cutting edges compensates for the less high rigidity of the metal structure.

Tips for tap operation

First of all, you need to choose a suitable tap. Further, the design of its shank is considered, which should approach the place of installation in the cartridge.

If you plan to use a CNC machine, the optimal speed mode is also pre-calculated. In the case of a threaded chuck, for example, the machine tap should rotate with the expectation that the feed rate per revolution will have an average value of 95% with respect to the step size. This parameter must be set in the machine program. Compliance with this condition will prevent self-tightening of the tool.

Also, whenever possible, it is recommended to use high-quality ammunition with compensation, which will limit the torque. Thanks to such equipment, more accurate axial movement of the taps is provided, not to mention their tight control during the work operations.

Conclusion

The quality of groove formation is determined by several parameters. This can be the correspondence of the target and processing materials, the correctness of the choice of the dimensional values of the tool design, etc. Often the characteristics of the result obtained are influenced by the method of the effort.

There are taps hand, machine and universal, which are successfully used in both machine tools and in the collar of the clamping device. The most risky method of forming threads in terms of obtaining poor quality is the hand tap. This technique entirely depends on how accurately and uniformly apply the effort in cutting grooves. Experienced specialists recommend that such operations be carried out slowly, but at the same pace throughout the entire passage.