Common problems in the use of punch molds

    (1) The punch wears out too fast

       Main reasons: ①The mold gap is too small. Generally, the total mold gap is recommended to be 20% to 25% of the material thickness. ②Poor alignment of the convex-concave mold, including the lack of precision of the mold base, mold guide components, and turret inserts, etc., resulting in poor mold alignment. ③The temperature of the punch is too high, mainly due to the overheating of the punch caused by the same mold for a long time. ④Improper mold sharpening method will cause mold annealing and increase wear. ⑤Partial unilateral punching, such as nibbling, angle of attack or shearing, the lateral force will deflect the punch to one side, and the gap on this side will decrease, causing serious mold wear. If the machine tool mold installation accuracy is not high, it will be serious This will cause the punch to deflect over the lower die, causing damage to the punch and die.

       (2) Die material problem

       Die with material will cause the scrap to rebound. The related factors: ①The sharpness of the die edge, the larger the rounded corner of the edge, the easier it is to cause the scrap to rebound. ②The entry modulus of the mold, the entry modulus of each station of the machine tool is fixed, and the mold entry modulus is small, which is easy to cause the scrap to rebound. ③Whether the mold gap is reasonable, if the mold gap is inappropriate, it is easy to cause the scrap to rebound. ④Whether there is much oil on the surface of the processed plate. ⑤The spring is damaged due to fatigue.

       The method to prevent the mold from stripping: ① Use a special anti- stripping die. ②The mold is often sharpened to keep it sharp and demagnetized. ③ Increase the gap of the cavity. ④The oblique blade mold is used instead of the flat blade mold. ⑤The mold is equipped with a stripper. ⑥ Reasonably increase the modulus of the mold. ⑦Check the fatigue strength of the mold spring or discharge sleeve.

       (3) Mold alignment problem

       When the mold is in use, the amount of wear on each side of the punch is prone to be different, and some parts have larger scratches and wear faster. This situation is particularly obvious on narrow rectangular molds. The main reason for this problem: ①The machine tool turret design or machining accuracy is insufficient, mainly due to the poor alignment of the mold mounting seat of the upper and lower turntables. ②The design or machining accuracy of the mold cannot meet the requirements. ③The precision of the guide sleeve of the mold punch is not enough. ④The mold gap selection is inappropriate. ⑤The mold mounting seat or mold guide sleeve is not neutral due to long-term wear and tear.

       In order to prevent inconsistent mold wear, you should: ①Regularly use centering mandrels to check and adjust the neutrality of the machine tool turret and mounting seat. ②Replace the mold guide sleeve in time and choose a convex-concave mold with appropriate clearance. ③Using full-lead mold. ④Strengthen the sense of responsibility of the operators, find out the cause in time after discovery, and avoid greater losses.

       (4) Use of special forming dies

       In order to meet the production needs, it is often necessary to use forming molds or special molds, mainly bridge molds, shutter molds, counterbore molds, turning and tapping molds, boss molds, stretching molds, combined molds, etc., using special or Forming molds can greatly improve production efficiency, but the price of forming molds is higher, usually 4 to 5 times that of ordinary molds. In order to avoid mistakes, the following principles should be noted and followed:

       ① Check the direction during mold installation to ensure that the mold male and female molds are installed in the same direction.

       ②According to the requirements, adjust the punching depth of the mold correctly, and each adjustment should not exceed 0.15mm.

       ③Use a lower punching speed.

       ④The plate should be flat without deformation or warping.

       ⑤The forming processing position should be as far away as possible from the clamp.

       ⑥ The downward forming operation should be avoided when using the forming mold.

       ⑦When stamping, press the ordinary mold first, and finally use the forming mold.