The Quality of the Slitting and Cutting Determines the Quality of the Iron Core!
The quality of the core is critical when making a shearing line. One of the key steps in the manufacture of high-quality iron cores is the slitting and cross-cutting process. The quality of slitting and cross-cutting determines the quality of the iron core, which in turn affects the performance of the shear line. In this article, we'll explore the slitting and why it's essential, and how it affects core quality.
The quality of the iron core is mainly affected by the following two points:
Tip1: The Burr of the Iron Core
The size of the iron core burr is an important indicator to measure the quality of iron core punching. Large burrs will not only cause a short circuit and increase eddy current loss but also seriously affect the size and quality of the stack and increase iron loss. Therefore, punching and shearing workers are required to do everything possible to operate carefully, minimize burrs or take some measures to remove the generated burrs.
The mechanism of punching and shearing is: 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); as the upper die continues to descend, the workpiece begins to deform The plastic deformation gradually expands until all the material reaches the yield strength from the cutting edge and starts to crack (the third stage); the upper mold continues to descend, and cuts cracks in the direction of the force on the edge section (at a certain angle to the centerline of the upper and lower molds).
If the clearance of the lower die is reasonable, the two cracks originating from the edge of the punch and die will be connected in a straight line. The minimum size of the obtained blanking workpiece is equal to the size of the punch, the maximum size is equal to the size of the die, and the quality of the workpiece is good. If the mold gap is too small, the upper and lower cracks cannot be connected, but parallel to each other at a certain distance. When the material is optimally separated, the section between the two seams can be burred, cracked, or delaminated due to extrusion. The upper part of the workpiece forms a secondary light band, with burrs or tooth edges, in an inverted cone shape, and is easy to bite the mold. Shorten the service life of the mold.
When the die opening is too large, there are obvious burrs on the cross-section of the workpiece, which breaks after stretching, which proves that the fracture of the cross-section is due to the excessive die opening, not normal shearing. Whether the blade is sharp and whether the mold (knife) is correct. For example, when the edge of the punch is blunt, burrs will appear on the punching parts; if the edge of the die is blunt, burrs will appear around the punching hole.
Tip2: Straightness of the Core
Silicon steel coils always have internal stress. These internal stresses are generally caused by rolling shear, and the length of the shear edge deviation of the shear coil is determined. The trimming deviation is a response to the magnitude of the internal stress, which cannot be eliminated by rolling shears or cross-cutting production lines. The elimination of internal stress should start with the material itself. During roller shearing, the deviation of the trimmed edge determines the straightness of the material.
This bias is usually measured in two ways:
1) Take the determined straight edge of the rolling shear as the standard, and use its trimmed edge for comparison.
2) Take the straight edge of the measuring table as the standard and compare the measured edge with it.
When comparing, small edge and arc deviations can be measured with measuring instruments or optical instruments. Obviously, due to the different methods used, the angle error and length measurement of the finished product will also be different. no the same.
The above are the two factors that affect the quality of the core. If you want to know more or want to buy cutting wire, please contact us.
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