In the design and manufacture of the mold, the designer's experience and skills play a key role. If the design is reasonable or not, it can be confirmed by the test model, and the die needs to be finished by repeated test and repeated modification. In production practice, when some dies are put into production line, they will often produce various problems, which can not meet the production requirements or technical requirements of the products, cause the production line's abnormal shutdown, and bring many unstable factors. Therefore, how to improve the stability of the die has become a practical problem facing the mould manufacturing enterprise.
A comprehensive balance of factors affecting stability
It is worth noting that, in the stamping process, because each kind of stamping sheet has its chemical composition, mechanical properties and stamping performance is closely related with the characteristics of value, stamping materials performance is not stable, stamping material thickness fluctuation, and stamping the material changes, not only directly affect the stamping precision and quality, but also may lead to mold damage.
Taking tensile steel as an example, it occupies a very important position in the stamping forming. During stretch forming, the forming of the product needs a certain size and tensile force that is properly distributed along the fixed periphery. The pulling force comes from the force acting on the stamping device, the deformation resistance of the edge material, and the flow resistance on the blank holder surface. The friction between the mold and the material is not enough if the flow resistance is produced only by the action of the pressing force.
Stability and influencing factors of die and stamping forming
What is stability? The stability is divided into process stability and production stability. Process stability refers to the process plan that meets the stability of the qualified product, and the stability of production refers to the production capacity that has stability in the production process.
Because the domestic mold manufacturing enterprises are mostly small and medium enterprises, and of which a considerable part of the business, still remain in the traditional workshop style production management stage, often overlooked the stability of mold, causing mold development cycle is long, the high cost of manufacturing, seriously restricting the pace of the development of enterprises.
The main factors, let's take a look at the effect of die stamping and stability respectively: use the method of mold material requirements; mold structure strength; stability performance of stamping materials; the fluctuation characteristics of the material thickness range; materials; drawbead resistance; pressure range; selection of lubricants.
For this reason, it is also necessary to set up tension bars that can produce larger resistance on the blank holder ring to increase the resistance of feeding, resulting in larger plastic deformation of materials, so as to meet the requirements of plastic deformation and plastic flow of materials. At the same time, through changing the size and distribution of drawbead resistance, and control the material flow into the die speed and feed rate, effectively regulate the implementation of force and its distribution on the deformation in the area stretching, thus preventing drawing rupture, wrinkling and deformation of the product, such as quality problems. It can be seen from above that when drawing up the stamping process and die design process, we must consider the size of the tensile resistance, arrange the drawing bar according to the change range of blank holder force and determine the form of the drawing bar, so that the deformation area can be completed according to the required deformation mode and deformation degree.