Processing characteristics of deep hole drilling machine tools
The continuous development of science and technology has driven the advancement of all walks of life. In terms of machinery, the use of deep hole drills is quite extensive. In deep hole machining, deep hole drilling machine tools are indispensable mechanical products, so the processing of deep hole drilling machine tools has its own characteristics? If you still don't know, just follow it.
1. The arbor is constrained by the aperture. The diameter is small, the length is large, the rigidity is poor, the strength is low, and the oscillation, corrugation and taper are easy to occur during cutting, which affects the straightness and appearance roughness of the deep hole.
2. When drilling and reaming, the cooling smooth liquid is difficult to input into the cutting area without special equipment, which makes the tool durability decrease and the chip removal is difficult.
3. In the process of deep hole processing, it is not possible to directly investigate the cutting condition of the tool. It can only be judged by the working experience, listening to the sound during cutting, looking at the chip, the hand oscillation and the workpiece temperature, and the appearance (oil pressure gauge and electricity meter). The cutting process is not normal.
4, Chip removal difficult, it is necessary to use a firm method to break the chip and control the length and shape of the chip, in order to facilitate smooth cleaning, to avoid chip blocking.
5, in order to ensure that the deep hole smoothly in the processing process and reach the required processing quality, the tool inside (outer) chip removal equipment, tool guiding and supporting equipment and high pressure cooling smoothing equipment should be added.
Generally, the hole depth is more than 3-5 times of the hole diameter. It is called a deep hole. It is difficult to use a twist drill in the hole with a small depth in the chip evacuation and cooling hole. In order to smooth the chip, the iron chip becomes a thin strip straight. Pull out and bring out smaller pieces, and the coolant is simply entered. The grinding method of the drill bit can be done with a simpler grinding method.
1. Increase the angle of the cutting edge to 130-140 degrees to add the chip thickness and change the direction in which the chips are discharged (the direction of chip discharge is straight with the cutting edge)
2. Grinding the chisel edge to reduce the axial cutting edge together with the cutting edge of the cutting core.
3. If the drill diameter is large, the chip flute can be ground on one side edge to be wider to balance the cutting force of the two cutting edges.
4. Pour 1 mm and 45 degrees from the outer edge of the cutting edge to reduce wear and improve the finish.
5. The rotation speed of the drill hole is slightly lower, and the feed amount should be larger, so that the chips are thickened and discharged in strips.
6. The nozzle of the coolant should face the hole inward to facilitate the coolant to enter the cutting area.
When the hole ratio is more than 8 times larger than the batch size, it is best to drill holes in the special deep hole drilling machine. The efficiency is very high. The diameter of the main shaft of the lathe is 32, which is about 850 mm and the material of the 45th steel is only 13 minutes.
Deep hole drilling is divided into two types: external chip removal and internal chip removal:
The outer diameter of the smaller diameter is selected because the drill pipe is too small to remove chips. The inner hole of the larger diameter drill pipe has a space for chip evacuation, and the high pressure oil is pressed between the hole wall and the drill pipe to discharge the chips and heat from the rod. The drill bit is specially made of hard alloy, which is divided into two parts: the guide and the cutting edge. The chip is sharpened into a trapezoidal shape to divide the chip. The height and width of the chip breaker depend on the material and feed of the workpiece to ensure the shape of the chip. A tight C shape or a tile shape is preferred.