Often you will encounter customers saying that your mold has problems, but are all about the quality of your mold, and never reflect on the use of the process is not a problem, the following common problems in the maintenance of the mold can be solved.
1. Attention should be paid to the punch before it is used.
Clean the punch with a clean cloth.
(2) Check whether there are scratches or dents on the surface. If yes, remove with oil stone.
3. Oil and rust prevention in time.
(4) Be careful not to tilt the punch when installing it. Use soft material tools such as nylon hammer to tap it gently. Only after the punch is positioned correctly can the bolt be tightened.
2. Installation and debugging of die
Special care must be taken to install and adjust the die. Because the stamping die, especially large and medium-sized ones, is not only expensive, but also difficult to move with large weight and trace amount, so personal safety should always be put in the first place. The blanking die with infinite position device should have a mattress board between the upper and lower dies. After the punch table is cleaned up, the test die in the closing state should be placed in a suitable position on the table.
According to the process documents and die design requirements, the selected press slider stroke is adjusted to the position of the lower dead point before the die is moved to the stage, which is 10-15 mm higher than the closed height of the die. The slider connecting rod is adjusted and the die is moved to ensure that the die handle aligns with the hole of the die handle and reaches the appropriate height of the die. Generally, the blanking die first fixes the lower die (not tightening) and then fixes the upper die (tightening). The suitable torque wrench should be used to tighten the T-type bolts of the pressing plate to ensure that the same bolt has a consistent and ideal pre-tightening force. It can effectively prevent manual tightening of threads due to physical force, gender, feel errors caused by the pre-tightening force is too large or too small, the same thread pre-tightening force is not equal, thus causing the stamping process of upper and lower die offset, gap change, chewing edge and other faults.
Before the die test, lubricate the die completely and prepare the normal material for production. Start the die 3-5 times in empty stroke to confirm the normal operation of the die and then try again. Adjust and control the depth of the punch into the die, check and verify the performance and operation flexibility of the mechanism and device such as die guide, feeding, pushing, side pressure and elastic pressure, and then adjust properly to achieve the best technical state. Three, five and ten large and medium-sized stamping dies were tested respectively for initial inspection after shutdown, and 10, 15 and 30 for re-inspection after passing the test. Only after marking, punching and burr inspection, all dimensions and shape and position accuracy meet the requirements of the drawings, can the production be delivered.
3. stamping burrs
(1) Mould clearance is too large or uneven, and the mould clearance is readjusted.
(2) If the material and heat treatment of the die are improper, the upside-down cone of the die or the edge of the die is not sharp, the material should be selected reasonably and the working part of the die should be made of cemented carbide, and the heat treatment method should be reasonable. Mould Daren Weixin: mujudaren
(3) Stamping wear, grinding punch or insert.
(4) Punch into the die too deep, adjust the depth of the punch into the die.
_. The guide structure is not precise or the operation is inappropriate. The guide sleeve of the guide pillar and the guide precision of the punch are overhauled, and the operation of the punch is standardized.
4. hop waste
Large die clearance, short punch, material effect (hard, brittle), high stamping speed, sticky stamping oil or oil droplets caused by too fast adhesion, stamping vibration to produce chip divergence, vacuum adsorption and inadequate core demagnetization can cause waste chips to be brought to the surface of the die.
The sharpness of the edge. The bigger the roundness of the edge, the easier it is to cause the scrap rebound. For stainless steel with thinner material, inclined edge can be used.
(2) For the more regular waste, the complexity of the waste can be increased or the polyurethane ejector can be added to the punch to prevent the waste from jumping, and scratches can be added to the edge of the concave die.
(3) Whether the clearance of the die is reasonable. The unreasonable die clearance can easily cause scrap rebound. For small diameter holes, the clearance can be reduced by 10%, and the diameter is greater than 50.00mm. The clearance can be enlarged.
(4) Increase the depth of injection. The requirement of input modulus is certain when stamping the die at each working station. The input modulus is small, which can easily cause scrap rebound.
(5) Whether there is oil stain on the surface of the material being processed.
_. Adjust the stamping speed and the concentration of stamping oil.
_. Vacuum adsorption.
(1) Demagnetization of punches, inserts and materials.
5. crush and scratch.
(1) Oil stains and scraps on material belts or moulds lead to crushing. It is necessary to wipe oil stains and install automatic air guns to remove scraps.
(2) The surface of the die is not smooth, so the smoothness of the die surface should be improved.
(3) The surface hardness of the parts is not enough, and the surface needs chromium plating, carburizing, boronizing and other treatments.
(4) material strain and instability, reduce lubrication, increase compressive stress, adjust spring force.
9633 Mould Daren Weixin: mujudaren
(7) When the product scratches to the mold positioning or other places to cause scratches, it is necessary to modify or reduce the mold positioning, and educate the operators to take it lightly while working.
6. Scratch on the outer surface of workpiece after bending
The surface of raw materials is not smooth, clean and plain material.
(2) There are scraps in the moulding block to remove the scraps between the blocks.
(3) The moulding block is not smooth. The moulding block is electroplated and polished to improve the smoothness of the punch and concave die.
(4) The bending radius R of the punch is too small to increase the bending radius of the punch.
(5) The bending clearance of the die is too small to adjust the bending fit clearance of the upper and lower dies.
_. Roller forming with die forming block.
7. hole piercing
Leakage punching is usually caused by factors such as punch breakage not found, missing punch after die repair, and punch sinking. After die repair, the first piece should be confirmed, and compared with the sample to check whether there is any leakage. For the sinking of punch, the hardness of the upper die cushion plate should be improved.
8. abnormal stripping.
(1) If the stripper and punch are too tight, the stripper is inclined, the screw height is not uniform or other stripping device is not appropriate, the stripper should be repaired, and the stripping screw should be in the form of casing and inner hexagonal screw.
(2) The die clearance is too small, the punch needs a large demoulding force when it is separated from the material, which causes the punch to be bitten by the material and needs to increase the lower die clearance.
(3) The die has an inverted cone to trim the die.
(4) The blanking hole of the concave die is not aligned with the leaking hole of the lower die base, and the leaking hole is repaired.
(5) Check the state of the processed materials. Material fouling adheres to the die, making the punch bitten by the material and unable to process. After punching, the warped material will clamp the punch, and the warped material needs to be smoothed and processed.
(5) Blade passivation of punch and lower die should be grinded in time. The sharp cutting edge of the die can produce a beautiful cutting surface. If the cutting edge is blunt, additional stamping force is needed. Moreover, the rough section of the workpiece produces a great resistance, which causes the punch to be bitten by the material.
_. Appropriate use of oblique edge punch.
_. Minimize wear and tear, improve lubrication conditions, lubricate plates and punches.
_, spring or rubber elasticity is insufficient or fatigue loss, timely replacement of spring.
_The gap between the guide pillar and the guide sleeve is too large, and the guide pillar sleeve should be repaired or replaced.
Accumulation of parallelism and parallelism error, re-grinding and assembly.
The holes on the pusher block are not vertical, so that the small punch is offset, and the pusher block is repaired or replaced.
Installation of punch, punch or guide post is not vertical, reassemble to ensure verticality.
9. The bending edge is not straight and the dimension is unstable.
(1) Increasing line pressing or pre-bending process
(2) Material pressing force is insufficient to increase material pressing force
(3) Asymmetrical wear or non-uniform bending force of punch and concave die fillet, adjusting the gap between punch and concave die to make it uniform, polishing punch and concave die fillet
(4) Height size should not be less than the minimum limit size.
10. Thinning of extruded materials on curved surfaces
Increasing the radius of the fillet of the die because the fillet of the die is too small
(2) The gap between the punch and the concave die is too small to correct the gap between the punch and the concave die.
11. Uneven bottom of concave parts
The material itself is not uniform and needs to be leveled.
(2) The contact area between roof and material is small or the ejection force is insufficient, so the ejection device should be adjusted to increase the ejection force.
(3) There is no ejector in the die, so the ejector should be added or corrected.
4. Shaping process.
12. Flanging Deformation of Stainless Steel
Applying high quality forming lubricant to the material before flanging can make the material separate from the die better and move smoothly on the surface of the lower die during flanging. This gives the material a better chance to distribute the stress produced by bending and stretching, and to prevent deformation on the edge of the flanging hole and wear on the bottom of the flanging hole.
13. material distortion
A large number of holes are punched on the material, resulting in poor flatness of the material, which may be caused by the accumulation of stamping stress. When punching a hole, the material around the hole is stretched downward, which increases the tensile stress on the upper surface of the sheet and the compressive stress on the lower surface of the sheet. For a small number of holes punched, the results are not obvious, but with the increase of the number of holes punched, the tensile stress and compressive stress increase exponentially until the material is deformed. Mould Daren Weixin: mujudaren
One way to eliminate this deformation is to punch every other hole and then return to the remaining hole. Although this produces the same stresses on the sheet, it disintegrates the accumulation of tension/compression stresses caused by continuous in-situ punching in the same direction. In this way, the first group of holes share the deformation effect of the second group of holes.
14. Serious wear of dies
Replacement of worn die guide components and punches in time.
(2) Check whether the clearance of the die is unreasonable (on the small side), and increase the clearance of the lower die.
(3) Minimizing wear and tear, improving lubrication conditions, lubricating sheets and punches. The amount of oil and the number of times of oil injection depend on the material conditions. Cold-rolled steel plate, corrosion-resistant steel plate and other rustless materials, to the mold oil injection, oil injection point for the guide bush, oil injection mouth, lower die, etc. Light oil for oil. When processing rusty materials, rust powder will inhale between the punch and the guide sleeve, resulting in dirt, which prevents the punch from sliding freely in the guide sleeve. In this case, if oil is applied, the rust dirt will be more easily stained. Therefore, when flushing this material, instead, clean the oil, decompose it once a month, and use steam (wood) oil to make the punch. Remove the dirt from the lower die and wipe it before reassembly. In this way, good lubricity of the die can be guaranteed.
(4) The improper grinding method results in annealing of the die and worsening wear. Soft abrasive grinding wheels should be used, with small cutter feed, sufficient coolant and regular cleaning of the grinding wheels.
15. Prevent punching noise
Punch press is the most essential equipment in sheet metal processing industry. Punch press produces mechanical transmission noise, stamping noise and aerodynamic noise when it works. The maximum value of this noise can reach 125 dB(A) which is much higher than that of 85 dB(A) stipulated by the national standard and the noise index below it, thus causing extremely serious damage to the operating workers and the surrounding environment (such as offices, residential areas, conference rooms, etc.). Injury and pollution. Effective control of this noise has become an urgent problem to be solved. Especially with the implementation of the first "Noise Law" in China, the scale of environmental protection industrialization is increasing, which accelerates the urgency of noise control.
Starting with the noise source of punch press and the structure of die, the following points should be paid attention to in order to reduce noise:
(1) Pay attention to the maintenance and cleaning of the mould and keep the edge sharp.
(2) The shape, quantity, material and cutting line of the die edge are long, the contact surface between the die edge and the parts is not too large, and the punch is punched by step with inclined edge, so that the penetration depth of the die is different at different positions, and the whole process realizes real cutting, rather than synchronous extrusion.
(3) The cutting edge of the die must be perpendicular to the installation surface, and the clearance of the punch and concave die should be reasonable. When discharging is difficult, the clearance of the lower die can be increased, and the discharging force can be increased. The discharging plate with soft surface is adopted.
(4) Coordination accuracy among working templates, and processing some exhaust grooves.
(5) The stop plate is changed into small pieces, the stripper and the lower template are changed into insert type to reduce the attack area.
_. The spring is mounted on the upper die base, and the equal height sleeve is used with the ejector. The ejector still has a certain amount of free movement under the open die condition.
_Maintain good lubrication, no interference in the die, smooth.
_. Aluminum plate on the surface of upper and lower die base is used as impact buffer.
_After the die is debugged, the sound insulation cover or sponge plate is added to the punch.
_Improve the accuracy of punch press and reduce structural noise. Buffer, vibration and noise reduction cylinders are installed on the workbench, helical gears are used to enhance lubrication and gear cover, and mufflers are installed in the pneumatic system.
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