What Are The Key Points Of Deep Hole Processing Technology?

The so-called deep hole machining is a hole whose length to hole diameter ratio is greater than 6. In deep hole machining, the depth ratio L/d Greater than or equal to 100 in most cases of deep hole processing. Such as the cylinder hole, the axial oil hole of the shaft, the hollow spindle hole and the hydraulic valve hole and so on.

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.

(1) Orientation and centering problem

① Pre-drill the tapered centering hole, that is, first drill a tapered pit with a small apex angle (2=90 degree -100 degree ), a large diameter short twist drill or a center drill, and then drill a hole with a drill of the required size.

② Sharpen the drill bit, make the two main cutting edges as symmetrical as possible, so that the radial cutting forces cancel each other and reduce the radial deviation.

③ Regarding large-diameter holes (>30mm), the method of drilling twice on the drilling machine is often used, that is, the second drilling is performed according to the required size. Since the chisel blade is used for the work, the drill bit will not appear to be twisted. . Regarding small holes and deep holes, in order to prevent the axis of the holes from deviating, drill them on a lathe as much as possible.

(2) Cooling problem

In actual production, large flow cooling or pressure cooling can be used according to detailed processing conditions to ensure the cooling effect. In ordinary drilling processing, segmented drilling is often used, and the method of punctual introduction is used to cool the drill bit and the drilling area. In addition, the cooling effect can be improved from the structure of the drill bit.

(3) Chip removal problem

Ordinary drilling processing often adopts the punctual retreat method to remove the chips; in deep hole processing, the structure of the drill bit and the cooling measures are combined, and the chips are forced out by the pressure coolant. Opening chip grooves on the main cutting edge, reducing the cutting width, making the chips easy to curl, is also a way to improve the effect of chip removal.