Briefly describe several common surface defects of non-standard tools and their solutions

Non-standard tools are a general term for all non-standard tools, including non-standard turning tools, boring tools, milling cutters, reamers, broaches, etc. These non-standard designs can meet a wider range of production needs. Processing characteristics, we can also customize non-standard tools. In the process of customization of non-standard tools, the problem of surface roughness can be achieved by changing the geometric angle of the blade. For example, increasing the degree of front and rear angles will significantly improve the surface roughness of the workpiece. Non-standard tools can meet the production needs of different workpieces, which is of great significance to mechanical production. Common surface defects in design and production are as follows:

1. Ring corrugation

Reason: The cutting force changes greatly during the broaching process, and the broaching tool does not work smoothly, which causes the teeth to cut unevenly in the circumferential direction.

Solution: Check whether the width of the margin is uniform and small, and especially focus on checking the machining accuracy of the first seven or eight teeth of the calibration section. From the perspective of use, the broaching speed should not be too high; the precision and rigidity of the broaching machine should be good, and no chattering phenomenon will occur; whether the bending and radial runout of the broaching tool are out of tolerance, etc.

2. Sharpening

Reason: When the general wear amount vb exceeds 0.3mm, it needs to be reground.

Solution: When regrinding, it is generally carried out on a special grinding machine. For a relatively short broach, it can also be sharpened along the rake face with a disc grinding wheel on a universal tool grinding machine.

3. Scratches

Reason: omitted.

Solution: Check whether there is a bruised notch on the cutting edge of the blade; whether there is any attached chip on the blade (especially the fine-cutting tooth) that has not been cleaned; Smooth step shape, so that the chip curling is not smooth and squashed. Teeth and scratched machined surfaces, etc.

4. Squeeze the highlights

Reason: It is caused by the severe extrusion friction between the flank of the cutter tooth and the machined surface.

Solution: Use cutting fluid with good performance, and need to pour enough, and take appropriate heat treatment of workpiece with high hardness to reduce its hardness to eliminate this defect.