The Main Features Of Deep Hole Drilling
Jun 28, 2018

The main features of deep hole drilling

Deep hole processing: deep hole drilling (the ratio of Kong Shen and aperture > 5) occupies a very important position in the field of mechanical processing, accounting for more than 40% of the amount of hole processing. With the progress of science and technology, the new type of deep hole parts with high strength, high hardness and high value are constantly appearing, and the requirements of machining depth, machining precision and processing efficiency are constantly improved, which makes the deep hole machining become the key process and difficult point of machining. The traditional machining method is due to the rigidity of the process system, the problem of cutting discharge and cooling and lubrication. It is more and more difficult to meet or even fail to meet the requirements of accuracy, efficiency and material in deep hole machining. Therefore, deep hole machining requires support from a specific drilling technology.


The deep hole drilling method can adopt a variety of machine tool installation methods: the workpiece rotates, the tool is feed movement, the workpiece is not moving, the tool rotates as the feed movement, the workpiece rotates and the tool rotates in reverse. The specific way is determined according to the characteristics of the workpiece and the hole in which it is processed.

There are usually two kinds of deep hole drilling tools: gun drill and BTA single pipe drill.

The main features of deep hole drilling in numerical control deep hole drilling are:

High material removal rate; in normal processing conditions, drilling deep holes run through, without halfway back knife; excellent aperture size accuracy, straightness, surface roughness can be obtained, and various forms of deep holes, such as cross holes, blind holes and oblique holes, can be processed, and the high consistency of processing quality. When drilling deep holes, the whole drilling process has very high requirements for cutting tools, machine tools and related equipment.

Deep hole machining is in closed or semi closed state, so the cutting condition of the tool can not be observed directly. At present, only by experience, can we judge whether the cutting process is normal by listening to sounds, looking at cutting, observing the appearance of machine tools load, pressure gauge, touch vibration and so on.

The cutting heat is not easy to spread. In the general cutting process, 80% of the cutting heat is taken away by the chip, while the deep hole drilling is only 40%. The cutting tool takes up a large proportion of the cutting heat, the diffusion is late, the heat is easy to overheat, and the blade temperature is up to 600 degrees. The numerical control deep hole drill must take a compulsory and effective cooling method.

The chip is not easy to expelled. Because of the deep hole, the cutting path is long, so it is easy to cause blockage and cause bit breakage. Therefore, the length and shape of chips should be controlled and mandatory chip removal should be carried out.

The numerical control deep hole drilling technology system has poor rigidity. Due to the limitation of the size of the hole, the length of the hole is larger, the drill pipe is thin and long, and the rigidity is poor. It is easy to cause vibration and the drilling is easy to deviate. Therefore, the support orientation is very important. This is more prominent in the machine tool.

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