Common defects and causes of carbon steel stamping process

Carbon steel stamping die is a special process equipment for processing materials into parts (or semi-finished products) in stamping processing.

According to the nature of the process classification: punching die, bending die, drawing die, forming die, etc.

Classification according to the degree of process combination: single process die, compound die, progressive die.

Three elements of carbon steel stamping production: reasonable stamping process, advanced mold, efficient stamping equipment.

1. Blanking, punching, trimming

Defects: burr too large, deformation, surface scratches, size discrepancy, less holes, etc

1) Burr is too large: the gap between the mold is too large or too small; Cutting edge wear; Poor guidance accuracy; The position of the die is different.

2) Deformation: the hole distance is too small; The press plate and concave model surface are not well matched; The gap is too large.

3) Surface scratches: dragging, pulling and other phenomena during operation; The sheet material is scratched during shearing.

4) The size does not match: the material is not in place; Positioning device damaged or loose, position shifting, etc.

5) Less hole: punch broken; Punch length is not enough.

2. Stretch

1) The mouth is easy to crack

2) Straight side easy to pull, pull the line

3) The bottom R line is easy to wrinkle

3. Flanging

Defects: flanging is not vertical, flanging height is inconsistent, flanging hair, flanging cracks, etc.

1) flanging is not vertical: the gap between the convex and concave dies is too large.

2) flanging height is inconsistent: the gap between the convex and concave dies is uneven; Inaccurate positioning; The size of the falling parts is not correct.

3) flanging and drawing: the cutting edge has scars; There are impurities on the surface of parts; The edge hardness is too low.

4) flanging cracks: large burrs when trimming edges; The die gap is too small; There's a change in the shape of the flanging.

4. Bend

Defects: the bending Angle is not qualified, the bending edge is broken, and there are steps at the bending Angle R.

1) The bending Angle is not qualified: the gap between the convex and concave die is too large, and the Angle of the convex and concave die does not match the thickness of the plate material.

2) The bending edge is broken: the gap between the convex and concave dies is too small; The bending Angle is too small; Blanking force is too high speed; The plate material is hard.

3) There are steps in the bending R Angle: the bending Angle of the convex and concave die is too large; The outer R Angle is too large; The bending force is too small.

5. Waste jumping hole

1) The length of the punch is not enough, press the cutting edge of the punch to cut the die and add 1mm to replace the punch;

2) The gap of the concave die is too large, and the gap is reduced by cutting the hole or using the coating machine;

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

6. Waste plugging holes

1) The blanking hole is small or the blanking hole is offset to increase the blanking hole, so that the blanking is smooth;

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

3) The cutting edge is not taper, the line 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 opposite side is drilled to shorten the straight wall position of the knife edge;

5) The edge is broken, resulting in a large tip, and the material is blocked to re-grind the edge.

7. Bad headwear

1) The cutting edge is broken, resulting in too large a tip to re-grind the cutting edge;

2) The gap between the punch and the die is too large, the line is cut into the block, and the gap is re-matched;

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

4) The gap between the punch and the die is too small, re-save the die and match the gap;

5) The topping force is too large, reverse pull out the cap to change the spring, reduce the topping force.

8. Uneven cutting edges

1) Positioning offset adjustment positioning;

2) There is unilateral forming, pull material to increase the pressure, adjust the positioning;

3) Design error, resulting in uneven reline cutting edge inserts;

4) Feed is not allowed to adjust the feeder;

5) The feeding step calculation is wrong. Recalculate the step and reset the cutter position.

9. The punch is easy to break

1) The closing height is too low, and the cutting edge part of the punch is too long to adjust the closing height;

2) Improper material positioning, resulting in unilateral cutting of punching punch, adjustment positioning or feeding device due to uneven force fracture;

3) The lower die waste blocks the knife edge, causing the punch to break and drill a large blanking hole again, so that the blanking is smooth;

4) The fixed part of the punch (splint) and the guide part of the repair or re-line cutting block to make the punch up and down smoothly (plate) offset;

5) Poor plate guidance, resulting in the unilateral force of the punch to repair the plate gap;

6) the cutting edge of the punch is too short, and the punching plate interferes with re-changing the punch to increase the length of the cutting edge part;

7) The punch is not fixed well, moving up and down to re-fix the punch so that it can not move up and down;

8) The cutting edge of the punch is not sharp and re-grind the cutting edge;

9) The surface of the punch is strained, and the force is uneven when the material is removed.

10) The punch is too thin, too long, and the strength is not enough to change the punch type again;

11) Punch hardness is too high, punch material is not replaced punch material, adjust the hardness of heat treatment.

10. Iron filings

1) The position or bending position of the reinforcement is recalculated.

2) The bending gap is too small, extrude iron scraps to readjust the gap, or grind the forming block, or grind the forming punch;

3) Bending punch is too sharp to repair R Angle;

4) Too little knife-edge material to reconnect the knife-edge;

5) The squeezer is too narrow and re-grind the squeezer.

11. Poor budding

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

2) The gap between the die is not uniform, resulting in low or even broken gap between the bud - edge high - edge repair;

3) The bottom hole of the bud extraction does not meet the requirements, resulting in the height of the bud extraction and recalculation of the bottom hole aperture, pre-punching to increase or reduce the diameter deviation, or even rupture.

12. Poor molding

1) The molding die punch is too sharp, causing the material to crack the molding punch repair R Angle, the knife edge is appropriate to repair R Angle;

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

3) The forming punch is too long, the forming material is compressed and deformed, even to determine the correct length of the punch, adjust the actual length of the punch to meet the requirements until the punch breaks;

4) The material at the molding is not enough to cause the strain to calculate the expansion material, or repair the R Angle, or reduce the molding height;

5) Poor positioning, resulting in poor molding adjustment positioning or feeding device;

6) The forming gap is too small to cause tension or deformation.

13. Bend size

1) The mold is not adjusted in place resulting in Angle error resulting in poor size adjustment closing height or poor Angle difference;

2) Insufficient elasticity resulting in poor Angle resulting in dimensional deviation to change the spring;

3) Material does not meet the requirements resulting in poor Angle resulting in dimensional material change or readjust gap deviation;

4) Material thickness deviation caused by poor Angle resulting in size deviation to determine the material thickness, change the material or readjust the gap difference;

5) Improper positioning leads to size deviation Adjust positioning so that the size is OK;

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

7) There is no R Angle in the molding, and the bending height under the R Angle of the molding repair is small in the Angle and other normal conditions;

8) The bending size of both sides is too large pressure reinforcement;

9) unilateral bending and pulling material cause dimensional instability increase spring force, adjust positioning;

10) Unreasonable clearance, resulting in poor Angle and size deviation repair clearance;

11) The height of the folding knife is not enough, and the folding punch is too short to increase the height of the folding knife, so that the bending punch is as close as possible to the position of the folding knife, resulting in more bad angles;

12) The bending speed is too fast, resulting in bending root deformation adjust the speed ratio control, select a reasonable speed;

13) The structure is not reasonable, the folding knife is not inserted into the fixed template, re-milling slot, the folding knife inserted into the template stamping, resulting in a larger gap;

14) The hardness of the molding heat treatment is not enough, resulting in the collapse of the pressure line or the remade type of the pressure line.

14. No unloading

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

2) The avoiding position is not enough to trim the avoiding position;

3) The inner guide column is strained, resulting in poor plate movement, replace the inner guide column;

4) The punch is strained or the surface is not smooth to replace the punch;

5) the arrangement of the top material pin is unreasonable to re-arrange the position of the top material pin;

6) the charging force is not enough, or the stripping force is not enough to replace the charging spring or stripping spring;

7) The punch and splint play plate is not smooth repair plate and splint make the punch work smoothly;

8) The forming slider is not smooth with the dressing slider and the guide groove to make it smooth;

9) The plate heat treatment is not comfortable, after stamping for a period of time, re-grind the plate to correct the deformation;

10) The punch is too long or the length of the ejector pin is not enough to increase the length of the ejector pin or change the length of the appropriate punch;

11) The punch is broken and replaced;

12) The template is not cloud magnetic, the workpiece goes up to the template demagnetization.

15. Bad delivery

1) The mold is not upright, resulting in the material belt and the feeder and the mold heavy frame mold or adjust the feeder is not in the same straight line;

2) Uneven adjustment levelling machine or material replacement;

3) Non-discharge caused by non-discharge of materials refer to the solution of non-discharge;

4) Positioning is too tight to adjust positioning;

5) The guide pin is too tight or the straight wall position is too long to adjust the guide pin;

6) The punch is not fixed well or is too long and the punch with the appropriate length of the material belt interference is fixed again;

7) The top pin is too short, and the material belt interferes with the forming block to adjust the length of the top pin to avoid interference;

8) Improper placement of floating block position Adjust the floating block position.

16. Bad riveting

1) The closing height of the mold is not properly riveted and not in place to adjust the closing height;

2) The workpiece is not put in place, positioning deviation adjustment positioning;

3) Before riveting the workpiece is bad to confirm the bud hole, refer to the solution of bad bud hole to confirm whether the rivet hole is chamfered, if there is no chamfering, increase the chamfering;

4) riveting punch length is not enough to replace the length of the appropriate punch;

5) The riveting punch does not meet the requirements to confirm and meet the requirements of the riveting punch.

17. Missing or packing

1) Accidentally group immediately carefully wrong punch;

2) No direction of the punch mark the directional punch.

18. Install the wrong screws

1) Do not know the thickness of the template to understand the thickness of the template is too long or too short;

2) Not careful enough, lack of experience to choose the appropriate screws.

19. Disassemble mold

1) The pin hole is not wiped clean the pin hole, the pin is wiped clean, the mold should be removed first when the positioning pin is easy to damage when installing the mold, the screw should be guided first, and then the positioning pin hole;

2) Do not hurt the pin hole when the installation and dismantling mold procedure is not correct.

20. Dowel pins

1) Hole wall hair, scratch caused by too tight mold, carefully check whether the pin hole hair, otherwise the pin hole should not be played out rereaming;

2) The pin hole is offset or there is no escape hole under the pin escape hole.

21. The spring is too long

1) Do not pay attention to the depth of the spring hole measure the depth of the spring hole, calculate the compression amount of the spring, and re-select can not be pressed down to;

2) not careful enough, lack of experience suitable spring dead center.