Solutions to curling of punching holes and warping and twisting of stamping parts

First, the curling phenomenon appearing on the punching hole has different shapes due to different reasons.
(1) Curling due to uneven die surface.
When the edge of the die edge is collapsed or notched, the above defects are often generated when stamping in a concave state after partial correction. Eliminate it by improving the accuracy of the mold surface.

(2) The curling occurs due to the improper design of the discharge plate.
Because the gap between the discharge plate and the punch is too large, curling occurs. The measure is that the discharge plate must be close to the punch. In addition, even with this design, if the power of the discharge plate is weak, the same phenomenon often occurs.

(3), when bending and punching are performed at the same time, curling caused by stretching.
When the bending process and the stamping process are performed at the same time, curling often occurs due to the hole being stretched into an oval shape. The measures are: either separate the two processes, or pay attention to the simultaneous punching and bending.

(4) When bending, the guide hole is elliptical.
When the hole guide is used for bending, the hole becomes elliptical due to stretching. The measures are to increase the pressure of the discharge plate or change the guiding method.

Second, when the stamping part has a bad shape, the stamping part often has defects such as warpage and distortion.
1. Warping (bending)
The phenomenon that the stamped part is curved is called warping (bending). Causes and solutions
(1). Due to the anisotropy of the material and the leveling of the end of the coil. Unloading plate, ejector rod, etc. can be used to press the material tightly and then press. When punching medium and thick plates, it is effective to use a shear angle beveled die with a shear stroke of 1/3 to 1/4 of the plate thickness.
(2) If the shearing angle is too large or the shearing angle is too small, the above defects will occur. It can be solved by correcting the cutting angle and appropriately increasing the width of the edge.
(3) When the die pressing pad is not designed on the die structure, it needs to be corrected after stamping.

2. distortion
The phenomenon that the stamped part is twisted is called twisting. Cause and elimination method:
(1) When cutting the strip material, the product will inevitably have a twisted shape. It can be solved by using the top material bar, and the blanking die of the discharge plate.
(2) However, even if the blanking die mentioned above is used, if the shear angle of the beveled blade is too large, twisting may occur. The measure is to replace the press with a larger tonnage while reducing the shear angle.
(3) If the gap is distorted due to uneven gaps, the cutting edge needs to be corrected.
(4) When it touches the back corner of the die and cannot be blanked uniformly, it is easy to twist. The measure is to observe the shear section and correct the back angle.

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