The use of the matters needing attention

Broaching machine is a kind of machine tool that uses broach to process various internal and external forming surfaces, with high production efficiency and good processing quality. It is widely used in automobile, motorcycle, agricultural machinery, aviation and construction machinery industries. In recent years, due to the strategic significance of the machine tool industry to the development of manufacturing industry and the promotion of the real economy, all countries attach great importance to the research of equipment and broaching technology.

The upper and lower workbenches of the broaching machine are fixed together by four columns to form the bed, the oil cylinder is installed under the bed, and the broach is pushed up and down by the piston rod for broaching. In order to shorten the height of the broaching machine, the oil cylinder and cooling oil tank are installed in the pit, and the hydraulic console and oil pump device are installed on the right side of the broaching machine.

The following is to introduce the matters needing attention in the use of the pulling machine:

1. The shape of the workpiece should be as simple as possible, and the wall thickness of the hole should be as thin as possible to avoid deformation of the hole surface after broaching and affect the accuracy.

2, if the processing surface oxide layer or other dirt, should be used before broaching sandblasting or pickling and other methods to remove.

3. The base surface of broaching must be flat and smooth, and should be the drilling base surface of the previous process, otherwise the spherical support fixture should be used.

4, for a shorter workpiece, its length is less than the broach two tooth pitch, the available fixture to several workpieces fastened together broaching, but must pay attention to the workpiece clamping, not loose, otherwise it will damage the broach teeth.

5. The chilled layer on the blank surface should avoid direct contact with the cutting edge of the broach, otherwise the cutter teeth will be blunt quickly. Therefore, other cutting is generally required before broaching. However, if the wheel-bar broach or the comprehensive wheel-cutting broach is used, the cutting edge of the cutter tooth can cut into the surface of the chilled layer due to the large tooth lift, so it is possible to broach directly on the surface of the bad surface.

6, the workpiece hardness between HB180-210, after broaching can get better surface quality, such as lower than HB170 or higher than HB240JF, must be pre-heat treatment, change the hardness, improve cutting performance.

7. Both ends of the hole before broaching should be chamfered to avoid burrs from affecting the passage of the broach and the positioning of the workpiece.

8, broaching before the aperture must ensure a certain degree of geometric accuracy. The leading part of the broach should be able to penetrate completely into the hole. Broaching cannot be carried out when it does not penetrate or only passes through half, otherwise the broach will be bent or broken. Generally, the accuracy of the hole is required to reach H11-H13, and the surface roughness of the workpiece before broaching should not be too small, generally in Ra1.6-6.4 microns.