Process characteristics and chip removal method of deep hole processing
The so-called deep hole processing is a hole with a ratio of the length of the hole to the diameter of the hole greater than 5. Deep hole processing Generally, the depth-diameter ratio L / d≥100 in most cases of deep holes. Such as cylinder hole, shaft axial oil hole, hollow spindle hole and hydraulic valve hole, etc. Some of these holes require high machining accuracy and surface quality, and some of the processed materials have poor machinability, which often becomes a major problem in production.
Deep hole processing occupies a very important position in the field of mechanical processing, accounting for about 40% of the volume of hole processing. With the advancement of science and technology, new types of high-strength, high-hardness, and high-value difficult-to-machine deep-hole parts continue to appear. The continuous increase in processing depth, processing accuracy, and processing efficiency of machining workpieces has made deep-hole machining a mechanical Key procedures and processing difficulties.
How to solve the problem of deep hole machining lies in chip removal, but in addition to the big problem of chip removal in deep hole processing, there are other difficulties, such as the inability to directly observe the cutting situation, only sound, chip, observation of machine tool load, oil pressure, etc. Parameters to judge chip removal and drill bit wear; chip heat is not easy to spread; due to the length, poor rigidity and easy vibration of the drill pipe, it will cause the hole axis to deflect easily, affecting price accuracy and production efficiency.
Process characteristics of deep hole processing
1. The shank is limited by the hole diameter, small diameter, large length, resulting in poor rigidity and low strength. It is easy to produce vibration, ripple and taper during cutting, which affects the straightness and surface roughness of deep holes.
2. When drilling and reaming, it is difficult to input the cooling lubricant into the cutting area without using special devices, which reduces the durability of the tool and makes chip removal difficult.
3. In the process of deep hole machining, you cannot directly observe the cutting status of the tool. You can only judge by cutting sound, cutting chips, hand vibration and workpiece temperature, and measuring instruments (oil pressure gauge and electricity meter) based on work experience. Whether the cutting process is normal.
4. The chip removal is difficult, and reliable means must be used to break the chip and control the length and shape of the chip to facilitate smooth removal and prevent chip blocking.
5. In order to ensure the smooth progress of the deep hole during the processing and achieve the required processing quality, the chip (or outside) chip removal device, tool guidance and support device and high-pressure cooling lubrication device should be added.
6. Poor heat dissipation conditions of the tool and increased cutting temperature reduce the durability of the tool.
During the deep hole machining operation, pay attention to the coaxiality of the center line of the main shaft and the tool guide sleeve, the tool rod support sleeve, the workpiece support sleeve, etc .; the cutting fluid system should be smooth; And avoid drilling holes and so on.
