The causes and countermeasures of common mold failures, Mr. Li Xiaosha Mould share for free
In the stamping production of progressive dies, specific analysis must be done for the stamping defects, and effective countermeasures must be taken to fundamentally solve the problems that occur, so as to reduce production costs and achieve smooth production. The following is the analysis of the causes and countermeasures of the common stamping defects in production as follows for the reference of mold maintenance personnel.
1. Punching parts with raw edges.
(1) Reasons: A. The blade is worn; B. The effect is not obvious after the clearance is too large; C. The blade is chipped; D. The clearance is unreasonable up and down or loose; E. The mold is up and down.
(2) Countermeasures: A. Research the knife edge; B. Control the processing accuracy of the convex and concave die or modify the design gap; C. Research the knife edge; D. Adjust the blanking gap to confirm the wear of the template hole or the processing accuracy of the molded part; E. Replace the guide Pieces or re-molding.
2. Jumping chip crush
(1) Reasons: A. The gap is too large; B. Improper feeding; C. The stamping oil drops too fast and the oil is sticky; D. The mold is not demagnetized; E. The punch is worn and the chips are pressed on the punch; F. The punch is too short, and the length of the insert is insufficient; G. The material is hard and the punching shape is simple; H. Emergency measures.
(2) Countermeasures: A. Control the processing accuracy of the convex and concave molds or modify the design gap; B. Trim the material belt and clean the molds in time when sent to the appropriate position; C. Control the amount of stamping oil drops, or change the oil type to reduce the viscosity; D. After training, it must be demagnetized (more attention should be paid to the punching material); E. Research the punch edge; F. Adjust the length of the punch blade into the die; G. Change the material and modify the design. The punch inserts into the end face to push out or trim out the bevel or arc (pay attention to the direction). Reduce the bonding area between the end face of the punch edge and the chip; H. Reduce the sharpness of the die edge, reduce the amount of training on the die edge, and increase the surface roughness (coating) of the straight edge of the die. Use a vacuum cleaner to suck up waste. Reduce the impulse speed and slow down the chipping.
3. Chip blocking
(1) Reasons: A. The leakage hole is too small; B. The leakage hole is too large, and the scrap material rolls; C. The knife edge is worn and the burr is large; D. The punching oil drops too fast and the oil is sticky; E. The die is straight The surface of the blade is rough, and the powder sintering adheres to the blade; F. The material is soft; G. Emergency measures.
(2) Countermeasures: A, modify the leaking hole; B, modify the leaking hole; C, trim the knife edge; D, control the amount of dripping, change the oil type; E, surface treatment, polishing, pay attention to reducing the surface roughness during processing ; Change the material, F, modify the blanking gap; G, trim the slope or arc on the end of the punch blade (pay attention to the direction), use a vacuum cleaner, and add air to the blanking hole of the backing plate.
4. Size variation
(1) Reasons: A. The cutting edge of the convex and concave die is worn, resulting in burrs (the shape is too large, the inner hole is too small); B. The design size and clearance are improper, and the processing accuracy is poor; C. The blanking position of the punch and the concave mold insert Equal misalignment, uneven clearance; D, guide pin wear and insufficient pin diameter; E, guide wear; F, improper adjustment of feeder distance, pressure, and relaxation; G, improper adjustment of mold closing height; H, The pressure level of the stripping insert is worn, and there is no pressure (strong pressure) function (the material pulling and turning over causes the punching to be small); I. The unloading insert is too deep and the punching is too large; J. The mechanical properties of the stamping material vary ( The strength elongation is unstable); K. When punching, the punching force pulls the material and causes dimensional variation.
(2) Countermeasures: A. Research the knife edge; B. Modify the design to control the machining accuracy; C. Adjust its position accuracy and blanking gap; D. Replace the guide pin; E. Replace the guide post and sleeve; F. Re-adjust Feeder; G, readjust the height of the closed mold; H, grind or replace the stripper insert, increase the pressure function, adjust the pressure; I, reduce the depth of the pressure; J, replace the material, control the quality of the feed; K, the punch The end face of the blade is trimmed with a slope or arc (pay attention to the direction) to improve the stress condition during punching. When permitted, the unloading part is located on the unloading block, and a guide function is added.
5. Jam
(1) Reasons: A. Improper adjustment of feeding distance, pressing and loosening of the feeder; B. Variation in the feeding distance during production; C. Feeder failure; D. The material is curved, the width is out of tolerance, and the burrs are large; E. Die stamping is abnormal, caused by sickle bend; F. Insufficient hole diameter of guide material, upper die pulls material; G. Bending or tearing position is not smoothly stripping up and down; H. The stripping function of the guide plate is set improperly, and the strip is taped ; I. The material is thin and warps during feeding; J. The mold is improperly erected and the vertical deviation from the feeder is large.
(2) Countermeasures: A. Re-adjustment; B. Re-adjustment; C. Adjustment and maintenance; D. Replace material to control the quality of the feed; E. Eliminate the sickle bend of the material belt; F. Research the punching and guide hole convex and concave die ; G. Adjust the force of the stripping spring, etc.; H. Modify the guide material to prevent the material from being taped; I. Add up and down pressure between the feeder and the mold, and install the upper and lower extrusion safety switches; J. Re-erect the mold.
6. Tape sickle bend
(1) Reasons: A, punching burrs (especially on the carrier); B, material burrs, no trimming of the mold; C, improper punch depth (too deep or too shallow); D, stamping parts crush, there are chips in the mold Material; E. The local pressing material is too deep or the pressing part is locally damaged; F. Mold design.
(2) Countermeasures: A, study the cutting edge; B, change the material, add a trimming device to the mold; C, reset the punch depth; D, clean the mold, solve the problem of chip jumping and crushing; E, check and adjust everyone The height of the stripping and die inserts is correct, and the damage position is studied; F. The adjustment of the whole bending mechanism is adopted.
7. Punch fracture and chipping
(1) Reasons: A, chip jumping, chip blockage, jamming, etc.; B, improper feeding, cutting half of the material; C, insufficient punch strength; D, large and small punches are too close together, and the material is pulled during punching, Causes the small punch to break; E. The punch and the die are partially too sharp; F. The punching gap is too small; G. There is no punching oil or the used punching oil is volatile; H, the punching gap is uneven, Offset, the convex and concave molds interfere; I. The precision of the stripping insert is poor or worn, and the precision guiding function is lost; J. The mold is not guided and worn; K. The convex and concave mold materials are improperly selected and the hardness is improper; I. The guide material (pin) is worn; m. Improper installation of gaskets.
(2) Countermeasures: A. Solve the problems of chip jumping, chip blockage, jamming, etc.;
B. Pay attention to feeding, trim the material belt in time, and clean the mold in time; C. Modify the design to increase the overall strength of the punch, reduce the size of the straight edge of the die, and pay attention to the slope or arc of the edge of the punch. Back-cutting; D. The length of the small punch is shorter than that of the large punch by more than one material thickness; E. Modify the design; F. Control the processing accuracy of the punch and concave mold or modify the design gap, and the small punching gap should be increased appropriately; G. Adjust stamping Oil drop volume or oil type; H. Check the accuracy of each forming part, and adjust or replace it to control the machining accuracy; I. Research or replace; J. Replace the guide post and guide sleeve, pay attention to daily maintenance; K, replace Use the material and use the appropriate hardness; I. Replace the guide parts; m. Correct. The number of shims should be as few as possible, and the steel pad should be used.
8. Bending deformation size variation
(1) Reasons: A. The guide pin is worn and the pin diameter is insufficient; B. The bending guide position is poor in accuracy and wear; C. Bending convexity and die wear (pressure loss); D. Insufficient mold clearance; E. Material slippage, bending convex and concave molds have no positioning function, and no pre-compression is applied during bending; F. The mold structure and design dimensions are poor; G. The punching parts are burrs, causing poor bending; H. Bending There are more gaskets in the punch and concave molds, resulting in unstable dimensions; I. Material thickness and size variation; J. Material mechanical shape energy variation.
(1) Countermeasures: A, replace the guide pin; B, re-grind or replace; C, re-grind or replace; D, check, modify; E, modify the design, add guiding and pre-compression functions; F, modify the design size , Decompose the bending, increase bending shaping, etc.; G, study the cutting edge of the material position; H, adjust, use the overall steel pad; I, replace the material, control the quality of the feed; J, replace the material, control the quality of the feed.
9. The height of the punching parts (when one mold has multiple parts)
(2) Reasons: A, burrs of the punching parts; B. The punching parts are crushed, and there are chips in the mold; C, the convex and concave molds (bending positions) are compressed or damaged; D, the material is turned during punching and shearing; E , Wear and pressure loss of relevant pressing parts; F. Inconsistent tearing dimensions of relevant tearing and cutting positions, and abrasion of the knife edge; G. Inconsistent pre-cutting depths of relevant fragile positions, and wear or chipping of convex and concave molds; H. Convex and concave of relevant convex parts Die chipping or wear is more serious; I. Die design defects.
(2) Countermeasures: A. Study the cutting edge of the material; B. Clean the mold to solve the problem of floating debris; C. Re-train or replace with new parts; D. Study the punching edge, adjust or add a strong pressure function; E. Check, Perform maintenance or replacement; F. Repair or replace to ensure consistent tearing and cutting conditions; G. Check the condition of pre-cut convex and concave molds, implement maintenance or replacement; H. Check convex and concave mold conditions, and implement maintenance or replacement; I. Modify Design, add height adjustment or add plastic station.
10. Improper maintenance
(1) Reasons: A. The mold has no fool-proof function, and negligence in the assembly of the mold leads to the reverse direction and misalignment (referring to different stations), etc.; B. The inserts that have shifted through the gap are not restored as they are.
(2) Countermeasures: A. Modify the mold to increase the foolproof function; B. Use methods such as marking on the mold, and make necessary inspections and confirmations against the material belt after the mold is assembled, and make a written record for inquiries.
In the stamping production, the daily maintenance of the mold is very important, that is, daily attention to check whether the stamping machine and the mold are in a normal state, such as the refueling of the stamping oil supply guide. The inspection before the mold is put on the machine, the inspection of the blade, the confirmation of the locking of each part, etc., can avoid many unexpected accidents. When repairing a model, you must first think before doing it, and earnestly record and accumulate experience.