The influence of longitudinal shearing and transverse shearing on the quality of the core

The main factors affecting the quality of the core are the following two points:

1. Core burrs

1. The burr size of the core is an important indicator for measuring the quality of iron chip stamping and shearing. Large burrs will not only cause short circuits and increase eddy current losses, but also seriously affect the stacking size and quality and increase iron loss. Therefore, stamping and shearing workers need to do everything possible to operate carefully, or use some method to remove the burrs that have been generated.

2. The mechanism of stamping and shearing is that when the upper die: falls on the workpiece, the workpiece begins to deform elastically (the first stage); as the upper die continues to descend, the workpiece begins to deform plastically (the second stage); the upper die continues to descend, and the plastic deformation of the workpiece gradually expands until all the materials from the cutting edge part reach the yield strength and begin to break (the third stage); the upper die continues to descend, and the cracks are sheared in the stress direction of the cutting edge part (at a certain angle with the upper and lower die center lines).

3. If the gap between the dies is too small, the upper and lower cracks cannot be connected, but are parallel to each other at a certain distance. When the material is best separated, due to extrusion, burrs, cracks or flakes will appear in the cross section between the two cracks, and the upper part of the workpiece will form a second shiny narrow strip with burrs or toothed edges, which is inverted conical and easy to bite on the mold. The service life of the mold will be shortened.

2. Transformer cross-cutting line

To solve the burr problem, in addition to requiring the mold designer to correctly select the mold material, structure and gap; the manufacturing personnel should strictly master the key points such as processing and fine grinding to make the finished mold qualified. In addition, the following requirements must be put forward to the operating workers:

1. Carefully install, repeatedly adjust and carefully check the mold so that the mold is in normal condition from the beginning of use. Try to avoid a large number of scraps caused by improper adjustment, and the mold will be disposed of after being bitten.

2. After stamping or shearing a small amount of finished products, insist on self-inspection and random inspection. If the burr exceeds the standard, take corresponding measures in time to solve it, and conduct regular random inspections in the future.

3. When checking the burr. Generally speaking, the burr height can be measured with a micrometer or touched by hand (do not touch it when the machine is running).

4. In contrast, measuring instruments or optical instruments can be used, which have very small edge deflection and arc deviation values, as well as micro-platform silicon steel transverse shear lines. Obviously, due to the different methods used, the angle error and length measurement values of the finished product are also different.