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 life and thus improve production efficiency. Next, we will mainly understand the four major maintenance precautions for progressive metal stamping dies.
I. Maintenance of punches and dies.
1. When disassembling punches and dies, 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 punches, test whether the stripper insert fits smoothly into the die and whether the gap between the insert and the die is uniform. When replacing dies, also test whether the gap between the insert and the punch is uniform.
3. Considering that punches become shorter after grinding, shims need to be added to achieve the required length. Check whether the effective length of the punch is sufficient. When replacing damaged punches, it is necessary to find out the cause and at the same time check whether the corresponding die has chipped edges and whether the edges need to be ground.
4. When assembling punches, check whether there is sufficient clearance between the punch and the fixing block or fixing plate. If there is a pressure block, check whether there is any moving allowance. 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 level with the mold 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 and lock crosswise from the inside to the outside. 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.
II. Maintenance and care 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. When encountering difficulty in disassembly, 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, 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 posts and guide bushes are aligned properly, whether any parts are damaged, whether the new punch can pass through the stripper plate smoothly, and whether the position is correct), then take appropriate action.
3. If there are clamping blocks on the retainer plate, check that there is sufficient space on the stripper backing plate. During prolonged stamping, the contact surface between the stripper plate and the material will develop indentations. Severe indentations can affect material pressing accuracy, causing unstable product dimensions. The stripper insert and stripper plate need to be inspected and repaired or reground as necessary.
4. The accuracy of the height-equalizing sleeves should be checked. If the heights are not equal, the stripper plate will tilt, compromising its precise guidance and smooth downward pressure function. This must be corrected through maintenance.
III. Die Clearance Adjustment.
1. The die core locating holes may wear due to frequent die core assembly, resulting in excessive clearance after assembly (looseness) or uneven clearance (positioning deviation), which can cause changes in the cross-sectional shape after stamping. If poor, the punch can easily break and produce burrs. You can inspect the cross-section after punching and make appropriate clearance adjustments.
2. When the clearance is small, there will be fewer burnish zones. When the clearance is large, there will be more burnish zones and larger burrs. A reasonable clearance can be achieved through adjustment. After adjustment, make proper records and mark the side of the die for future maintenance reference.
3. In daily production, pay attention to collecting and preserving the best condition of the original die strips. If subsequent production encounters issues or the die undergoes changes, 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 bushes are worn.
IV. Guide Component Inspection.
1. Check the fit clearance between guide posts and guide bushes for any signs of burning or wear, and verify that the lubrication supply to the die guides is functioning properly.
2. Wear of guide components and damage to precision 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 accuracy of the guide components. If the guide pins are worn and have lost proper strip guiding precision and function, they must be replaced. Inspect the stripping springs and ejector springs to see if they are broken, or if they have not broken after long-term use 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 difficulties.
The above are the four major maintenance precautions for progressive metal stamping dies. I hope that in addition to following operating procedures, all metal stamping die operators can correctly perform routine maintenance on metal stamping dies, which can help die manufacturers save costs.