What is stability? Stability is divided into process stability and production stability. Process stability refers to meet the production of qualified products with stability of the process plan; production stability refers to the production process with stability of production capacity.
As most of the domestic mold manufacturing enterprises are small and medium-sized enterprises, and a considerable part of them are still in the traditional workshop production management stage, often ignoring the stability of the mold, resulting in long mold development cycle, high manufacturing costs, which seriously restricts the pace of development of enterprises.
First, let's look at the main factors affecting the stability of hardware stamping parts, which are: the method of using the die material; the strength requirements of the structural parts of the die; the stability of the performance of the stamping material; the fluctuation characteristics of the material thickness; the range of change of the material; the size of the resistance of the tensile bar; the range of change of the crimping force; and the choice of lubricant.
As we all know, the metal materials used in stamping dies involve many kinds, and because of the different roles played by various parts in the dies, the requirements and selection principles for their materials are not the same. Therefore, how to reasonably choose the mold material becomes one of the very important work in the mold design.
When choosing the mold material, in addition to the requirement that the material must have high strength, high wear resistance and appropriate toughness, but also must take into account the characteristics of the processed product material and yield requirements, so as to achieve the stability of the mold forming requirements.
In practice, due to the tendency of mold designers to select mold materials based on personal experience, the problem of unstable mold forming due to improper selection of materials for mold parts often occurs in hardware stamping.
It is worth noting that in the process of hardware stamping, as each stamping plate has its own chemical composition, mechanical properties and characteristics closely related to the stamping performance, the unstable performance of stamping materials, fluctuations in the thickness of stamping materials and changes in stamping materials not only directly affect the accuracy and quality of hardware stamping processing, but also may lead to damage of the die.
Take stretching bar for example, it occupies a very important position in hardware stamping. In the stretch forming process, the product needs to be formed with a certain size and properly distributed tension along the fixed perimeter, which comes from the force of the stamping equipment, the deformation resistance of the edge part of the material, and the flow resistance on the surface of the crimped circle. If the flow resistance is generated by the crimping force alone, the friction between the die and the material is not sufficient.
For this reason, it is also necessary to set up the stretching tendons on the crimp ring that can produce larger resistance to increase the resistance of the feeding material, so as to produce larger 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 resistance of the stretching tendons and controlling the speed of material flow into the die and the amount of feed, effective regulation of the tension and its distribution in each deformation area of the stretched part is realized, so as to prevent the rupture, wrinkling, and quality problems such as deformation of the product during stretching and forming. As can be seen from the above, in the process of developing stamping process and die design, it is necessary to consider the size of tensile resistance, arrange the tensile tendons and determine the form of tensile tendons according to the change range of crimping force, so that each deformation area can complete forming according to the required deformation mode and degree of deformation.
In order to solve the problem of hardware stamping die stability, strict control is needed from the following aspects.
① In the process formulation stage, by analyzing the product, anticipating the defects that may arise in the manufacturing of the product, so as to develop a manufacturing process plan with stability.
② Implementing the standardization of the production process and the standardization of the production process.
③Establish a database and continuously summarize and optimize it; with the help of CAE analysis software system, come up with the most optimal solution.