The effect of different design of holes on actual CNC machining

Compared with the surface processing of the outer circle, the conditions of precision CNC machining holes are much harder, and the processing of holes is more difficult than the processing of the outer circle. Let’s view different design of holes.

Why Holes Affect CNC Machining？

The size of the tool used in precision CNC machining hole is limited by the size of the drilled hole, and the rigidity is poor, which is easy to produce bending deformation and vibration;

With fixed size tool processing hole, precision CNC machining hole size often directly depends on the corresponding size of the tool, tool manufacturing error and wear will directly affect the machining accuracy of the hole;

When CNC machining holes, the cutting area is inside the workpiece, the chip removal and heat dissipation condition is poor, the machining accuracy and surface quality are not easy to control.

Drilling and reaming

(1) Drilling

Drilling is the first process of CNC machining holes on solid materials, and the diameter of drilling holes is generally less than 80mm. There are two ways of drilling: one is the rotation of the drill bit; The other is workpiece rotation.

(2) Hole reaming

Reaming is to use the reaming drill to drill out, cast or forged holes for further processing, in order to expand the aperture and improve the processing quality of the hole, reaming can be used as pre-processing before finishing the hole, also can be used as the final processing of the hole with low requirements.

Boring

Boring is a precision CNC machining method in which the precast hole is enlarged with a cutting tool. The boring work can be carried out either on a boring machine or on a lathe.

Honing hole

Honing is a way to finish holes by using honing heads with grinding strips (whetstones). When honing, the workpiece is fixed, and the honing head is driven by the spindle of the machine tool to rotate and make reciprocating linear motion. In honing, the grinding strip acts on the workpiece surface with a certain pressure to cut off a thin layer of material from the workpiece surface, and its cutting track is a cross mesh. In order to keep the movement track of sand bar abrasive particles from repeating, the number of revolutions per minute of honing head rotation and the number of reciprocating strokes per minute of honing head should be prime numbers.

Perforation

Perforation is a high productivity finishing method, which is carried out on a broaching machine with a special broach. Broaching machine is divided into horizontal broaching machine and vertical broaching machine, horizontal broaching machine Z is common.