The structure characteristics of twist drill and influence on machining

Aperture diameter restrictions 1 drill, spiral groove to drill more fine, low stiffness of aiguille; only two edges of the belt guide, hole axis deviation easily; chisel edge that the centring difficulties, axial force increases, the drill bit is easy to swing. Therefore, the shape and position error of drilled holes.

2 Serratula drill before the knife and the knife surface are surface, along the main cutting edge of the anterior horn, posterior horn of each are not identical, the chisel edge of the anterior horn of -55 degree. The cutting conditions are very poor; cutting speed along the cutting edge of the unreasonable distribution, maximum strength is the lowest of the cutting tool tip speed, so serious wear and tear. Therefore, the machining accuracy of the hole is low.

3 drill main cutting edge of the blade of the cutting part, edge on the cutting speed is not equal, easy to form spiral chip, chip removal difficult. Therefore, the friction between the chip and the hole wall is often scratched, and the surface roughness is very low.

Maintenance and maintenance twist drill

(1) in drilling steel, please ensure adequate cooling capacity and the use of metal cutting fluid.

(2) good and drill pipe steel rail gap can improve the life precision and the drill bit

(3) please ensure smooth and clean between magnet and workpiece.

(4) when drilling the sheet to the workpiece, reinforcement, drilling a large workpiece, please ensure that the workpiece is stable.

(5) at the beginning and end of drilling, feed rate should be reduced 1/3.

(6) of drilling appeared a large number of fine powder materials, such as cast iron, cast copper can without the use of cooling liquid, and compressed air is used to help chip.

(7) please promptly removed the wound on the drill body iron, to ensure smooth chip.