Four Key Maintenance Considerations for Progressive Stamping Dies

Many people know that in the production of metal stamping dies, the machine needs to be maintained and carefully inspected to increase the die's lifespan and thus improve production efficiency. Next, we will mainly understand the four major maintenance precautions for progressive metal stamping dies.
1. Maintenance of punch and die.
1. When disassembling the punch and die, care should be taken to maintain the original state of the die so that it can be easily restored during subsequent die installation. If there are shims or shifts, the thickness of the shims must be engraved on the parts and recorded.
2. When replacing the punch, test whether the stripper insert fits smoothly into the die and whether the gap between the insert and the die is uniform. When replacing the die, also test whether the gap between the insert and the punch is uniform.
3. Considering that the punch becomes shorter after grinding, shims need to be added to achieve the required length, and check whether the effective length of the punch is sufficient. When replacing a damaged punch, the cause must be identified, and the corresponding die should be inspected to see if there is edge chipping and whether the edge needs to be sharpened.
4. When assembling the punch, check whether there is sufficient clearance between the punch and the fixed block or fixed plate. If there is a pressure block, check whether there is room for movement. The assembled die should be placed horizontally, then a flat iron block should be placed on the die surface and lightly tapped into place with a copper rod. Do not place it at an angle and force it. The bottom of the die should be chamfered. After installation, check whether the die surface is flush with the die surface.
5. After assembling the punch, die, and die core, necessary checks should be carried out on the protective strip to see whether any parts are installed incorrectly or reversed. Check whether the die and die pad are installed backwards, whether the blanking holes are blocked, and replace with new ones if necessary. Check whether parts need to be stolen, whether there is enough material to be stolen, and whether the parts that need to be locked are locked.
6. Pay attention to confirming the locking of the stripper plate screws. When tightening, balance the force from the inside to the outside and lock crosswise. Do not lock one screw first and then another, to avoid causing the stripper plate to tilt, which may lead to punch breakage or reduced die precision.
2. Maintenance of the stripper plate.
1. When disassembling the stripper plate, first use two screwdrivers to pry it up evenly, then use both hands to remove it with even force. If it is difficult to disassemble, check whether the inside of the die is clean, whether all locking screws have been removed, and whether the die is damaged due to material jamming. Find out the cause and then handle it accordingly. Do not handle it blindly.
2. When installing the stripper plate, first clean the punch and stripper plate thoroughly, apply lubricating oil to the guide posts and punch entry points, place them level, then press into position with both hands, repeating several times. If it is too tight, investigate the cause (whether the guide post and guide bushing alignment is normal, whether any components are damaged, whether the new punch can pass through the stripper plate smoothly, and whether the position is correct), then take appropriate corrective action.
3. If there are pressure blocks on the retainer plate, check whether there is sufficient space on the stripper backing plate. During prolonged stamping operations, pressure marks will develop on the contact surface between the stripper plate and the material. When pressure marks become severe, they can affect material pressing accuracy, causing abnormal and unstable product dimensions. The stripper plate and backing plate need to be inspected, repaired, or reground as necessary.
4. The precision of the equal-height sleeves should be checked. If the heights are not equal, it will cause the stripper plate to tilt, compromising its precise guiding and smooth downward pressing functions. This must be corrected through maintenance.
3. Die clearance adjustment.
1. The die core locating holes may wear out due to frequent die core assembly/disassembly, resulting in excessive clearance after assembly (loose fit) or uneven clearance (positioning deviation), which can cause changes in cross-sectional shape after stamping. In severe cases, the punch may break easily and burrs may form. You can inspect the cross-sectional condition after stamping and make appropriate clearance adjustments.
2. When the clearance is small, there will be fewer burnished sections. When the clearance is large, more sections and larger burrs will appear. A reasonable clearance can be achieved through adjustment. After adjustment, proper records should be kept, and markings can also be made on the side of the die for convenient reference during future maintenance operations.
3. In daily production, attention should be paid to collecting and preserving the optimal condition of the original die strips. If subsequent production encounters difficulties or the die undergoes variation, these can serve as references for die maintenance.
4. Additionally, auxiliary systems should be inspected and maintained, such as checking whether ejector pins are worn and can eject properly, and whether guide pins and bushings show signs of wear.
4. Inspection of guide components.
1. Check the fit clearance between guide posts and guide bushings for any signs of burning or wear marks, and verify that the lubrication supply to the die guide system is functioning properly.
2. Wear and precision loss of guide components will reduce the accuracy of the die, and problems can arise in various parts of the die, requiring proper maintenance and periodic replacement. Check the precision of the guide components. If the guide pins are worn and have lost their correct strip guiding accuracy and function, they must be replaced. Inspect the condition of the stripper springs and ejector springs to see if they are broken, or if, after prolonged use, they have not broken but have become fatigued and lost their original strength. They must be maintained and replaced on a regular basis. Otherwise, this can cause die damage or result in production interruptions.