How to extend the life of stamping die
The purpose of all stamping is: high productivity, high quality and low cost. The design and construction of the bed, top structure, and fuselage frame all play a decisive role in this goal. If you want to increase the life of the mold and improve the quality of the product, considering the movement of the slider, the impact of the equipment is very important.
basic structure
The sturdy frame structure of the bed and the foundation isolation belt can resolve the impact force during the stamping process. Setting a high-humidity isolation belt around the foundation of the press can greatly extend the life of the equipment compared to directly fixing the press on the ground. The use of foundation can maintain the levelness of the press, and the levelness affects the life of the press and the mold. The whole press is composed of long bolts connecting the upper beam, bed and column together. The new press machine body and column are now designed to be taller and thicker, which is more difficult to deform than the small bed and thin frame of the previous press.
Slider movement
Another key to extending the life of the mold and improving the quality of the workpiece is to minimize the eccentricity of the slider. In general, the press should be designed to control the stamping action by controlling the movement of the slider.
Most presses only rely on the guide rail to control the vertical movement of the slider. The guide rail not only controls the movement of the drive wheel but also the force generated by the bearing mechanism. The slide rail must be replaced regularly, but if a
Guide Sleeve is installed, the life of the slide and the guide rail will be extended.
This slider with guide sleeve absorbs the lateral force generated by the eccentric and decomposes it. In the double-guided stroke, the role of the guide rail is to guide the slider that bears the reaction force of the mold, so it is necessary to make full use of the entire length of the guide rail to make the slider fully guided during the entire stroke. The combined guide of the guide sleeve and the guide rail is more than double the guide area guided by the guide rail alone.
The use of guide bushings plus lubricating oil (instead of grease lubrication) can make the guide rail clearance (0.0015 inches) smaller than those without guide bushes (0.008-0.015 inches). The use of a small gap guide can control the movement of the slider. Although this structure is more expensive than the initial period without a guide sleeve, it can extend the life of the mold by 30%.
Connecting rod movement
Another factor that affects the life of the mold is the impact force during blanking or when the punching force is large. When the cutting edge is sheared to 20% -30% of the thickness of the sheet, the sheet begins to break and release energy, which causes the slider to descend at high speed. The sudden increase in the speed of the slider at the end of the stroke will have a huge impact on the press and the mold. The speed of the slider at the point of material breakage is directly related to the generated reaction force.
To reduce this impact, a drive link was used to reduce the speed of the slider at the end of the stroke to 40% of the crank press at the same production cycle. The contact speed and impact force of the slider to the mold will also be reduced to 60% of the crank press. This reduction in speed means that the impact of the upper and lower dies is reduced, thereby extending the life of the dies.
Because the speed of the slider is reduced, the stamping working time will be extended. Longer pressing time is beneficial, especially in forming, the low speed pressing time can ensure the accuracy of stamping and improve the quality of the workpiece.
May 26, 2020
