What are the characteristics of drilling and what are the factors that affect hole accuracy?

Characteristics of drilling

Drill usually has two main cutting edges, when processing, the drill rotates while cutting.

The front angle of the drill is getting bigger and bigger from the center axis to the outer edge, and the cutting speed of the drill is higher and higher the closer it is to the outer circle, and the cutting speed decreases to the center, and the cutting speed of the center of rotation of the drill is zero.

The transverse edge of the drill is located near the axis of the rotary center, the vice front angle of the transverse edge is larger, there is no space for chips, and the cutting speed is low, thus generating a larger axial resistance.

Depending on the shape of the workpiece, material, structure, function, etc., drills can be divided into many types, such as high-speed steel drills (twist drills, group drills, flat drills), integral cemented carbide drills, indexable shallow-hole drills, deep-hole drills, nesting drills, and interchangeable head drills.

Drilling accuracy

Hole accuracy is mainly composed of hole size, positional accuracy, coaxiality, roundness, surface roughness and hole burrs.

Factors affecting the accuracy of the hole being processed during drilling processing:

① Clamping accuracy of the drill and cutting conditions, such as tool clamp, cutting speed, feed, cutting fluid, etc..

② drill size and shape, such as the length of the drill, the shape of the edge, the shape of the drill core.

③ Workpiece shape, such as hole side shape, hole shape, thickness, mounting condition, etc.