Summary of common problems and solutions of stamping dies

This paper summarizes some problems of stamping die and lists some corresponding solutions for your reference.

1. Scrap jumping

1) The length of the punch is not enough, and the punch shall be replaced according to the thickness of one material cut into the female die by the cutting edge of the punch plus 1mm

2) If the clearance of the female die is too large, cut in the die to reduce the clearance or use a draper to reduce the clearance

3) If the punch or template is not demagnetized, demagnetize the punch or template with a demagnetizer

2. Waste plugging

1) The blanking hole is small or deviated, and the blanking hole is enlarged to ensure smooth blanking

2) The blanking hole has chamfer, increase the blanking hole to remove the chamfer

3) The tool edge is not tapered, the linear cutting taper or the reverse expansion hole reduces the length of the straight wall position

4) The straight wall position of the knife edge is too long, and the reverse side is drilled to shorten the straight wall position of the knife edge

5) The cutting edge collapses, resulting in a large flaring edge, and the material is blocked and the cutting edge is reground

3. Poor tip

1) The edge is broken, causing excessive flaring and regrinding the edge

2) The clearance between the punch and the die is too large, the line is cut into the block, and the clearance is reset

3) Poor finish of concave die edge, polishing edge straight wall position

4) The clearance between the punch and the female die is too small, and the die shall be saved again

5) If the ejecting force is too large, pull out the flaring edge reversely to replace the spring, reducing the ejecting force

4. Uneven trimming

1) Positioning offset adjusting positioning

2) Unilateral forming, pulling, increasing pressing force, adjusting positioning

3) Design error, causing unevenness of the cutter, and cutting the edge insert with new lines

4) Feeding is not allowed to adjust the feeder

5) Recalculate the feeding step if the calculation is wrong, and reset the tool position

5. The punch is easy to break

1) The closing height is too low, and the cutting edge of the punch is too long. Adjust the closing height

2) Improper material positioning causes the punching punch to cut one side, and the positioning adjustment or feeding device is broken due to uneven stress

3) The cutting edge is blocked by the waste of the lower die, causing the punch to break, and the blanking hole is drilled again to make the blanking smooth

4) Fix the fixed part (clamp plate) and the guide part of the punch or re thread the cutting block to make the punch move smoothly up and down (punching plate)

5) The punching plate is poorly guided, which causes the punch to be forced on one side and the punching plate clearance is repaired

6) The punch knife edge is too short, which interferes with the punching plate. Replace the punch, and increase the length of the knife edge

7) The punch is not fixed well, and it moves up and down. Fix the punch again to prevent it from moving up and down

8) The punch edge is not sharp, regrind the edge

9) The punch surface is strained, and the punch is replaced when the force is uneven during stripping

10) Punch is too thin, too long, and the strength is not enough. Change the punch type again

11) The hardness of the punch is too high. The punch material is not correct. Replace the punch material and adjust the heat treatment hardness

6. Iron filings

1) Rebar dislocation Recalculate the rebar position or bending position

2) If the bending clearance is too small, extrude iron filings to readjust the clearance, or grind the molding block, or grind the molding punch

3) The bending punch is too sharp to trim the R angle

4) There is too little material to connect the knife edge

5) The pressing rib is too narrow, regrind the pressing rib

7. Poor sprouting

1) The center of the bud bottom hole does not coincide with the center of the bud punch to determine the correct center position, or move the position of the bud punch, or move it to the position of the bud – high side – low side, or even break the dynamic pre punching hole, or adjust the positioning

2) Uneven clearance of concave die, resulting in low or even broken budding edge high edge repair budding clearance

3) The sprouting bottom hole does not meet the requirements, resulting in sprouting height and recalculation of the bottom hole diameter, increase or decrease the diameter deviation of the pre punched hole, or even crack

8. Poor molding

1) The punch of the forming die is too sharp, which causes the material to crack. The forming punch shall be trimmed with an R angle, and the knife edge shall be properly trimmed with an R angle

2) The length of the forming punch is not enough, resulting in the failure to calculate the correct length of the punch. Adjust the actual length of the punch to meet the forming requirements

3) The forming punch is too long, and the material at the forming part is deformed. The correct length of the punch is determined. Adjust the actual length of the punch to meet the requirements until the punch breaks

4) The material at the forming part is not enough to cause tension crack. Calculate the material to expand, or trim the R angle, or reduce the forming height

5) Poor positioning, resulting in poor molding Adjust the positioning or feeding device

6) The forming gap is too small, causing tension crack or deformation, and the gap is adjusted

9. Bending size

1) The mold is not adjusted in place, resulting in angle error, which causes dimension deviation, poor closing height or poor angle difference

2) Insufficient elasticity leads to poor angle, resulting in dimensional deviation Replace the spring

3) The material does not meet the requirements, resulting in poor angle, which leads to size change or re adjustment of gap deviation

4) Poor angle caused by material thickness deviation determines the material thickness due to size deviation. Replace the material or readjust the gap difference

5) Size deviation caused by improper positioning Adjust the positioning to make the size OK

6) Design or processing errors cause repair welding and grinding between the bending male blocks, eliminate the gap between the blocks, resulting in small bending size

7) There is no R angle for forming, and the bending height is too small under the angle and other normal conditions for forming the common R angle

8) The bending size on both sides is too large

9) Unstable size caused by unilateral bending and drawing, increase spring force, and adjust positioning

10) Unreasonable clearance, resulting in poor angle and dimension deviation

11) The height of the folding knife is not enough. The bending punch is too short to close the folding knife. The height of the folding knife is increased to make the bending punch close to the folding knife position as much as possible, causing more bad angles

12) When bending, the speed is too fast, causing deformation at the bending root. Adjust the speed ratio and select a reasonable speed

13) The structure is unreasonable, the folding knife is not inserted into the fixed template, and the groove is milled again. When the folding knife is inserted into the template for stamping, the gap becomes larger

14) The hardness of the forming male during heat treatment is not enough, resulting in the collapse of the pressing line or the flattening of the reshaping male pressing line

10. No unloading

1) Improper positioning or feeding Adjust the positioning or feeding device

2) Refuge position is not enough, repair and grind the avoidance position

3) The inner guide pillar is strained, which causes the blocking movement to be impeded. Replace the inner guide pillar

4) The punch is strained or the surface is not smooth Replace the punch

5) Unreasonable layout of ejector pin Relocate the position of ejector pin

6) The ejection force is not enough or the stripping force is not enough. Replace the ejection spring or stripping spring

7) The punch and the splint don’t fit smoothly. Repair the punch and the splint to make the punch fit smoothly

8) The formed slider does not fit smoothly. Trim the slider and the guide groove to make them fit smoothly

9) The stamping heat treatment is not suitable, and the deformation occurs after stamping for a period of time. Grind the stamping again, and correct the deformation

10) The punch is too long or the length of the ejector pin is not enough. Increase the length of the ejector pin or replace it with a punch with a suitable length

11) Punch break Replace the punch

12) The template is not magnetized, and the workpiece is demagnetized upward to the template

11. Unsmooth feeding

1) The mold is not upright, resulting in the material belt not in the same line with the feeder and the mold to re frame the mold or adjust the feeder

2) Uneven belt leveling machine or material replacement

3) If the feeding is not smooth due to non unloading, refer to the non unloading solution

4) Positioning is too tight Adjust positioning

5) The guide pin is too tight or the straight wall position is too long Adjust the guide pin

6) The punch is not fixed well or is too long to interfere with the strip. Replace the punch with a suitable length and fix it again

7) The ejector pin is too short, and the strip interferes with the forming block. Adjust the length of the ejector pin to avoid interference

8) Improper arrangement of floating block position Adjust floating block position

12. Poor riveting

1) The closing height of the die is improper. The riveting is not in place. Adjust the closing height

2) The workpiece is not put in place, and the positioning deviation is adjusted for positioning

3) Before riveting, confirm whether the riveting hole is chamfered by referring to the countermeasures for solving the defective workpiece. If there is no chamfer, increase the chamfer

4) The riveting punch is not long enough. Replace it with a punch with proper length

5) Confirm that the riveting punch does not meet the requirements and use the riveting punch that meets the requirements

13. Missing or missing installation

1) Careful and wrong punches during careless assembly

2) Punches have no direction marks. Punches with direction shall be marked

14. Install the wrong screws

1) Do not know the thickness of the formwork. Know that the thickness of the formwork is too long or too short

2) Inadequate care and inexperience in selecting appropriate screws

15. Disassembly and assembly of mould

1) The pin hole and the pin are not wiped clean. When removing the mold, the locating pin should be removed first. When installing the mold, it is easy to damage the locating pin. When installing the mold, it is necessary to use a screw to guide and then drill the locating pin hole

2) Do not damage the pin hole when dropping the pin due to incorrect mold assembly and disassembly procedures

16. Locating pin

1) When the hole wall is roughened and the die assembly is too tight due to scratches, carefully check whether the pin hole is roughened, or re ream the pin hole that cannot be drilled

2) The pin hole is offset or there is no escape hole below it. The locating pin escape hole is added

17. The spring is too long

1) It was not noted that the depth of the spring hole was measured well, the compression amount of the spring was calculated, and it could not be pressed down to

2) Not careful and inexperienced; suitable lower dead center of spring