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Key points for maintaining stamping dies Key points for maintaining stamping dies The purpose of die maintenance is to quickly identify and resolve problems, restoring the die to its original state so that it can continue to produce products that meet standards. Products manufactured using the same mold have identical dimensions and shapes; that is, after each processing step, part or all of the dimensions and shapes are finalized. Therefore, when variations occur in the products, it is possible to identify the specific processing station responsible for those variations and make corrections to restore them to their original state. If it is determined that the issue stems from a design error, then the design must be modified. Mold maintenance is based on this principle. The following points can serve as a reference for maintenance: Measure the final finished product, check against the standards to identify areas of variation; verify the dimensions of the part according to the layout drawings to see if they match those specified in the mold drawings and to detect any dimensional variations. If necessary, measure related components before and after to accurately determine the locations and causes of the variations, and then take appropriate actions to resolve them. When it is impossible to make a decision or come up with a solution on one’s own, one should seek advice from others and avoid acting arbitrarily. Excessively large hair length: (1) Blade wear: Re-grind it. (2) Excessive gap: Most of the side surface is a polished area resulting in lower brightness; reduce the gap. (3) Gap too small: Increase the gap at the secondary shear plane. (4) Matching notch: Change the degree of jointing, create a step, or reduce the gap. (5) Excessively sharp: If the sharpness of the product is less than 75 degrees, the design or clearance needs to be adjusted. (6) The material is too hard: Replace the material or increase the gap. (7) Mold chipping: Re-grind. (8) Abnormal die surface: local hairiness or scoring occurs. Recalibrate or modify the mold. Mold bite (1): Loose mold: The movement of the punch or die exceeds the one-sided clearance. Adjust the assembly clearance. (2) Die inclination: The straightness of the die is incorrect, or there are foreign objects between the die plates, preventing them from lying flat against each other. Reassemble or grind for correction. (3) Formwork deformation: The formwork has inconsistent hardness or thickness, or it deforms due to external force impacts. Replace with a new template or correct the disassembly method. (4) Mold base deformation: Inconsistent thickness of the mold base or uneven stress distribution, resulting in variations in the straightness of the guide posts and guides. Grind and correct, or refill the plastic steel, or replace the mold base, or distribute the forces evenly. (5) Die interference: Whether the dimensions and position of the die are correct, if there are any deviations in the positioning of the upper and lower dies, whether it will become loose after assembly, if the precision of the punching machine is insufficient, and if the die holder is not properly aligned. (6) Shearing deviation: The punch is not strong enough, the large and small punches are too close to each other, the lateral forces are unbalanced, resulting in skewed shearing. Enhance the guiding and protective role of the stripping inclined plate, or increase the size of the punch; shorten the small punch to increase the heel length for earlier support and guidance, and pay attention to the feeding length. Dimensional variation (1) Blade wear: Excessive burrs or increased size (when cutting shapes) ； Shrink (punching) ； The flatness is poor. Re-grind or replace the die. (2) No guidance: The guide pin or other positioning devices are not functional; the feed mechanism does not release, or the diameter of the guide pin is insufficient, preventing proper guidance. The positioning block is worn, and the feed distance is too long. (3) The die is too short: the bending degree increases, the reverse bending is insufficient, and the forming is incomplete. (4) Hole escape failure: Caused by compression, crushing, or deformation. Clean the escape hole or increase its size and depth. (5) Poor ejection: poor feeding, bent material strips, inadequate material release, the upper die pulling the material, and extended ejection distance. (6) Improper ejection: The ejector pin is improperly configured, the spring force is inadequate, or the ejection distance is too long. Adjust elasticity or change position or number of pins ； Wear down the short fit. (7) Poor material guidance: The length of the guide plate is insufficient, or the gap for guiding the material is too large; either the mold and the unloading device are misaligned, or the distance between the mold and the feeding device is too great. (8) Material dropping deformation: In some bent parts, material overlap is not allowed; the material must be dropped one at a time, or the discoidal strain can be overcome using pressure pads or diagonal cutting. (9) Bending deformation: Material extrusion at the upward bend ； The proximity hole deforms under tensile force; the uneven stress causes bending and tilting, as the punch is not long enough. (10) Shear deformation: The material becomes distorted and uneven, with increased dimensions or eccentric asymmetry. (11) Impact deformation: Deformation caused by excessive blowing pressure of the product or impact due to gravity. (12) Floating debris compression: Variation caused by waste floating or fine debris remaining on the mold surface, as well as foreign objects. (13) Improper material: An inappropriate width or thickness of the material, as well as an unsuitable material type or hardness, can also lead to problems. (14) Poor design: Poor engineering planning and inadequate gap settings; it is difficult to overcome this unless the design is changed. Mold damage: (1) Heat treatment issues: too high or inappropriate quenching temperature, improper number of tempering cycles along with incorrect temperature and time settings, as well as inadequate control over the quenching process and its duration ； The problem only appeared after using it for some time. (2) Stamping of stacked materials: Stamping continues with the sheets overlapping, usually resulting in the breakage of the stripping plate. (3) Waste blockage: The material dropping holes are not drilled or are of incorrect size, or the debris on the bed surface is not cleared in time, resulting in significant damage to the punch and the lower die plate. (4) Punch drop: Inadequate fixation or suspension, or screws that are too thin and lack strength, or a broken punch. (5) Missing escape hole: The size or depth of the escape hole in the punch pressure plate is insufficient; the failure of the escape parts of the punch and the stripping plate is usually due to damage to the stripping plate. (6) Foreign object intrusion: The product being blown out and rebounding, the mold components breaking off and falling, screws protruding from the mold surface, or other objects entering the mold can all damage the lower mold, the stripper plate, the punch, or the guide posts. (7) Assembly error: Damage caused by incorrect placement or orientation of parts. (8) Spring factor: Inadequate spring force, spring breakage, or uneven height of the sleeves causing the stripping plate to tilt, as well as improper spring settings, can lead to overlapping impacts that damage the parts. (9) Improper stamping: Damage caused by setting the working height too low, loss of lubrication in the guide posts, incorrect feeding of the material or stamping of only half of it, damage to surrounding equipment such as feeding, unloading, and loading machines, missing or inactive air pipes, and abnormalities in the stamping machine. (10) Improper maintenance: The above issues occur due to components that should have been replaced not being replaced, screws not being tightened properly, or the system not being restored to its original state.