How to improve mold life?
Ways to improve the mold life
The manufacturability of the fine blanking parts (especially the radius of the fillet) has a certain impact on the life of the fine blanking die.
The relationship between the radius of the fillet and the life of the mold, generally r/t≥0.8 is better, if it is less than 0.25, the life of the mold will be low
The main working parts of the fine blanking die are generally made of Cr12MoV, and when the thickness of the workpiece is greater than 4mm, W6Mo5Cr4V2 high-speed steel can be used for punch.
For punches with high working intensity and serious stress, powder metallurgy steel (V4, ASP23, ASP30) or cemented carbide GT30 are used. The heat treatment hardness of convex and concave die is generally 58~62HRC.
For molds with simple shape and wear as the main failure form, 60~64HRC can be taken; For molds with complex shapes and blade collapse as the main failure form, 56~60HRC or even 54~58HRC can be taken.
For the heat treatment of Cr12MoV molds, when the shape of the cutting edge is simple and the thickness of the blanking material is thin (t≤3mm), the one-time quenching process (1020°C quenching and 220°C tempering) can obtain high strength and wear resistance.
When the cutting edge shape is complex and the blanking material is thick (t>3mm), the double quenching process (1080°C quenching and 520°C tempering) can obtain high impact toughness and stability.
For the heat treatment of W6Mo5Cr4V2 mold, the low-temperature quenching process must be used to obtain high strength and good toughness.
The stress state of the mold should be good to prevent eccentric load, cantilple, unidirectional stress, etc.; Reliable guidance is effective in reducing wear and tear on working parts, ensuring uniformity of clearances, avoiding gnawing on molds, avoiding misalignment of pressure centers, etc.
In the design of the punch of the fine punching deep long hole, the punch sleeve structure should be reasonably adopted, and when designing some large molds, the internal structure should consider the use of small guide pillars to increase the guiding accuracy. The guidance of the pressing plate and punch is also better. When the thickness of the material is ≥4mm, it is best to add a prestressed sleeve to the die.
Due to the precise coordination between the parts of the fine blanking die, coupled with the thicker lubricating oil used, the precise matching, the closed space is easy to form between the bottom surface of the die and the punching punch, and between the punch base and the base.
In the process of mold movement, the air in the closed area is not easy to be discharged quickly, so that the heat generated by friction between mold parts is not easy to be carried away with the air, which affects the movement of push plate and ejector rod, reduces the production speed, and even causes the phenomenon of uneven force on the workpiece, which affects the normal life of the precision stamping die.
Therefore, an exhaust groove should be set up on the punch, the bottom surface of the die, the punch fixing plate, and the base
In addition to paying attention to the uniformity of the gap between the upper and lower die blades, the coaxiality and the matching relationship between the parts, the assembly of the fine blanking die should also pay special attention to the phase of the working parts, so as to ensure the correct position of the die in the closed state and the open state, so as to ensure the reliability of its work.
When installing the mold to adjust the pressure, under the premise of ensuring the quality of the fine blanking parts, the pressing force and back pressure should be as small as possible. When using fine blanking continuous die, special attention should be paid to the force balance of the die at the beginning and end of the strip, otherwise the punch is easy to break due to lateral force.
When feeding, attention should be paid to the setting of the bar height limit and other devices to prevent the waste from being overpressurized. When it is found that the burr of the workpiece exceeds the standard, it should be re-sharpened in time, and the amount of re-grinding is generally 0.1~0.2mm, and attention should be paid to eliminating internal stress.
Categories
injection moldin
mold life
Featured Article
For more details, please visit our other website：Injection Mold