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problem and solving

Product Description

 

Problemreasons
Hole degree of deviation is very bad.

Workpiece not positioned or fixed well.

Drill guide is not suitable, big space between the drill guide and gun drill、

No good support for the gun drill shank.

Workpiece structure is not good, such as workpiece wall thickness is too big, and material issue such as not even.

Hole roughness too bad

Main spindle rotating speed, feeding rate is too slow.

Cutting oil not suitable;Pressure low, fow low, oil temperature is too high; 

Cutting oil filtering result is not good;

Cutting tool is over worn. 

Machine vibrating; workpiece is not fixing steadlily.

Hole diameter is larger.

Drill guide not used well, workpiece positioning and holding not correct.

big space between the drill guide and gun drill.

Drill tool tip grinding angle not correct.

trumpet hole

big space between the drill guide and gun drill.

Drill guide rigidity is not enough.

Gun drill life is short or tip is chipping.

Main spindle rotating speed & feeding rate is too low or too high. Have to choose suitable parameters.

Drill tool tip grinding angle not correct.

Gun drill type is not correct. 

Cutting oil is not suitable;Pressure low, fow low, oil temperature control is not good;

Chip removal is not good, or not continuous

Cutting oil pressure and flow is too low.

Workpiece chip removal is difficult, we should grind a chip breaker groove. 

Feeding rate is too big, spindle rotating is too small. 




Control of drill guide and deviation in deep hole drilling.

The deviation of the hole is an important index in deep hole processing. In our projects, we have higher requirement for processing, and deviation. Especially for deeper hole, it is more important to control the hole deviation.

1.First we have to consider the rotating ways in drilling. The best way to control the deviation is by the relative rotation, which is workpiece rotating, while cutting tool rotates in the opposite and feeds; second is workpiece rotates which cutting tool only feeds; the worst way is workpiece fixed, cutting tool rotates and feeds.
2、 The installation accuracy of drill guide is very important and sensitive to the deviation of the hole. You must keep the concentrity of the drill guide, workpiece spindle and drilling box spindle. It is linear relation between deviation and drilling length. For example: Drill guide length is 50mm, and if the deviation is 0.05mm between the guide axis and the drilling depth, then it would be 1mm when the drilling depth is 1000mm.
3、 The grinding angle will affect the deviation as well. We suggest you referring to our company catalog and website, to grind the angle according to the material being drilled and hole diameter, in order to get better hole deviation.
4、The evenness of the material being drilled will affect the deviation as well. The gun drill will deviate to the direction which the material is soft. So the heat treatment of the material is very important. You need to try your best to make the material even.  
5、The cutting parameter will affect the deviation as well. It is better not to take big feed rate when it doesn’t affect your production progress. Big feeding rate will have bad result for the deviation.


Drill guide production and user manual

The characteristic of the deep hole drilling is that : bad rigidity, be confined to the hole diameter, and drilling depth is very long, gun drill is very long, gun drill rigidity is bad, and easy for vibrating therefore will cause the deviation. So the drill guide is quite important.

Drill guide is usually made by high alloy tool steel or carbide, and the hardness is 63~65HRC. The diameter of drill guide should be the same with the gun drill nominal diameter, tolerance is ISOH6, internal hole roughness is Ra0.8μm, inside hole and outside of workpiece concentricity is 0.015mm, drill guide and drilling box concentricity is 0.02mm.

Note: New drill guide diameter should be 0.005~0.01mm bigger than the gun drill tip diameter. You need to change drill guide when then space between the gun drill tip and the drill guide. Bigger space will bring bad hole surface and straightness, and shorten the gun drill life. 


+86 138 6920 6100 jennifer.pang.china jennifer.pang@drillstar.cn 2960757986