In the design and manufacture of graphite molds, the designer's experience and technology play a key role in the design of reasonable or not, and can be confirmed by trial mode; while graphite molds need to be tried and modified repeatedly to complete the production practice. Some graphite molds, once put into the production line, often have various problems, which cannot meet the production requirements or technical requirements of the products, and bring many unstable factors. Therefore, how to improve the stability of graphite molds has become a practical problem faced by graphite mold manufacturers.
Stability is divided into process stability and production stability. Process stability refers to a process plan that satisfies the stability of a qualified product; production stability refers to a production capacity with stability during the production process. Since most of the domestic graphite mold manufacturing enterprises are small and medium-sized enterprises, and a considerable number of them are still in the traditional production management stage, the stability of graphite molds is often neglected, resulting in long development cycle of graphite molds and high manufacturing costs. The problem is that companies are severely constrained by the development of these problems.
Let us first look at the main factors affecting the stability of graphite molds and stamping, the use of graphite mold materials, the strength requirements of graphite mold structural parts, the stability of stamping material properties, the fluctuation characteristics of material thickness, the range of material variation. , the resistance of the tensile ribs, the range of the blanking force, the choice of lubricant.
The comprehensive trade-off affects the stability. It is worth noting that in the stamping process, since each stamping sheet has its own chemical composition, mechanical properties and characteristic values closely related to the stamping properties, the properties of the stamping material are unstable, and the thickness of the stamping material is The fluctuations, as well as the changes in the stamping material, not only directly affect the accuracy and quality of the stamping process, but also may cause damage to the graphite mold.
Taking stretch ribs as an example, it occupies a very important position in stamping. However, if the flow resistance is generated only by the action of the blank holder force, the friction between the graphite mold and the material cannot be obtained. In the stretch forming process, the forming of the product needs to have a certain size and a proper pulling force along the fixed periphery. The pulling force comes from the force of the punching device, the deformation resistance of the material at the edge portion, and the flow resistance on the crimping ring surface. .