In the daily production practice, once the Stool Mould is put into use on the production line, various problems often occur, which cannot meet the production requirements or technical requirements of the product, resulting in abnormal shutdown of the production line and many unstable factors. Therefore, how to improve the stability of stool mould has become a practical problem faced by mould manufacturing enterprises.
What is stability is divided into process stability and production stability. Process stability refers to a process scheme that meets the requirements of producing qualified products with stability; Production stability refers to the stable production capacity in the production process.
First, let's look at the main factors that affect the stability of stool mould and stamping. Respectively: the use method of mould materials; The strength requirements of the mould structure; Stability of stamping material performance; Fluctuation characteristics of material thickness; The range of material changes; The resistance of that stretch rib; Change range of blank holder force; Selection of lubricants.
It is worth noting that in the stamping process, because each stamping plate has its own chemical composition, mechanical properties and characteristic values closely related to stamping properties, the unstable performance of stamping materials, the fluctuation of thickness of stamping materials and the change of stamping materials not only directly affect the precision and quality of stamping process, but also may lead to the damage of stool moulds.
Take stretch rib as an example, it occupies a very important position in stamping forming. In the process of stretch forming, the forming of the product needs to have a certain size and a proper distribution of pulling force along the fixed periphery. This pulling force comes from the acting force of the stamping equipment, the deformation resistance of the edge material and the flow resistance on the blank holder ring surface. However, the friction between the mould and the material is not enough if the flow resistance is generated only by the action of the blank holder force.
For this reason, it is also necessary to set tensile ribs that can generate greater resistance on the blank holder ring to increase the resistance of feeding, thus causing greater plastic deformation of the material to meet the requirements of plastic deformation and plastic flow of the material. At the same time, by changing the size and distribution of the tensile bar resistance and controlling the flow speed and feed rate of the material into the mould, the effective adjustment of the tensile force and its distribution in each deformation region of the tensile member is realized, thus preventing the quality problems such as cracking, wrinkling, deformation and the like of the product during stretching and forming.
From the above, it can be seen that in the process of drawing up the stamping process and die design, the tensile resistance must be considered, the tensile ribs should be arranged according to the variation range of the blank holder force and the form of the tensile ribs should be determined, so that each deformation area can be formed according to the required deformation mode and degree.
