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With the continuous development of the economy, the scientific and technological level is also improved a lot especially in deep hole drilling industry. When drilling deep hole, deep hole drilling machine plays a very important role in it. And following is the main character of deep hole drilling machine:
1) Because of the small hole diameter but long drill shank, which will lead to a poor rigidity and intensity, and when drilling, it’s easy to cause vibration, ripple and taper, and it will effects the straightness and roughness of the hole.
2) When drilling and expanding the hole, without special device, it’s difficult to input the lubrication oil to the cutting area, and thus, reduce the life service of the tool and difficult to remove the chip.
3) During the processing of deep hole, the only way to check the cutting condition of drilling tool is through sound of cutting, observe the iron chip, working environment ,oil pressure gauge and electricity meter.
4) It’s difficult to remove the iron chip. And it’s very necessary to apply for some technical means to make the iron chip shorter, thus it won’t block the drill shank.
5) In order to ensure the smooth processing condition and high processing quality, there should be equipped with tool chip removing device, tool guide and support device and high pressure coolant smooth equipment.
Usually when the hole depth is 3 to 5 times bigger than the hole diameter, it’s called deep hole. When drilling the small hole diameter, use to the twist drill to solve the difficulty of small chip and cooling. For the grinding of drill bit can apply for the simple grinding method.
1. When the drill point angle increase to 130 to 140 degree, change the chip removing direction.
2. Grinding the chisel edge to decrease the axial direction, and there is a break angle which is propitious to remove the chip.
3. If the drilling diameter is large, grind a chip dividing groove in one side of the cutting edge, grinding more wider to balance the cutting force of the two cutting edges.
4. Chamfer a 1mm,45 degree angle to reduce the wearing volume, and improve the roughness.
5. Reduce the rotary speed of the drilling hole, increase the feed volume, thus the chip will be bigger and easy to remove.
6. The mouth of the cooling oil should towards the drilling hole, so that the cooling oil can reach to the cutting area.
There are two kinds of chip removing method: internal chip removing and external chip removing.
When the hole diameter is small, we chose the external chip removing, cause the drill shank is too small to remove the chip. For the big hole diameter hole, there is more space for the chip removing, the high pressure oil enter into the hole wall and drill shank and press the chip and heat from the drill shank. The drill bit is usually made of carbide, consists of guide and cutting edge. For the cutting edge, it’s ladder-shape to remove the chip. The width and height of the chip breaker groove is ascribed to the material of the workpiece and feed volume.
