The stability of metal stamping parts production and its influencing factors

What is stability? Stability is divided into process stability and stability. Process stability refers to satisfy the production of qualified products with the stability of the process; Production stability is refers to the stability of the production process of production capacity. Because most of the domestic mold manufacturing enterprises, for small and medium enterprises and a considerable part of the enterprise, is still stay on the production management of traditional cottage stage, the stability of the mould is ignored, causing mold development cycle is long, the manufacturing cost is high, seriously restricted the development of enterprise. First let's take a look at the main factors which influence the stability of metal stamping parts, respectively: the use of the mold material; The strength of the mold structure requirements; The stability of the stamping material performance; Material thickness fluctuation characteristic; The change of the material; Tensile steel resistance; Blank-holder force range; The choice of lubricant. As is known to all, stamping die involves many kinds of metal materials used, because of the role of the various parts in the mould is different, the material selection requirements and principles are also different. Therefore, how to reasonably choose mould material, has become one of important work in the mould design. When choosing mould material, in addition to the required material must have high strength, high wear resistance and appropriate toughness, also must fully consider the characteristics of the material products processed with production requirements, so as to meet the requirements of the stability of the die forming. In practice, due to the mold designers tend to with personal experience in selecting mould material, often appear in the metal stamping for mold parts caused by the improper material selection and the problem of the die forming. Try the following examples (cases) in the material thickness is 1. 2毫米( The shear strength of 64 KGF/was) Iron plate, processing a diameter of 2. 8 mm round hole. 1) blunt shear: P = Lt tau. Among them, the blanking contour length (L: mm) ； T: the thickness of the material ( mm) ； Tau: shear strength of materials, kgf/mm2) ； D: the punch diameter ( mm) ； P = 3。 14×2. 8×1. 2 x 64 = 675 KGF (2) the stress of the punch edge: tau sigma S = 4 t/d. Namely, sigma S = 4 x 1. 2×64/2. 8 = 110 KGF/was pictured above: when sigma S for 110 KGF/was, choose punch material is SKD11, its speed of around 9000 times, punch edge could be damaged. And if the material change is SKH51, can make the speed increased to around 40000 at times. This shows, in the mold design stage, it is necessary for mold structure to make the necessary intensity checking calculation, whereas when choosing materials have the following considerations: (1) the stress of the punch under the & lt; Punch allowable compressive stress of the material (2) to improve the bending strength of punch, should choose the material of elastic coefficient of large (3) based on euler's formula, stable capability check. It is important to note that in the process of metal stamping, because each kind of pressing plate has its own chemical composition, mechanical properties and is closely related to the stamping performance characteristic value, stamping material performance is not stable, punching material thickness fluctuation, and the change of the stamping material, not only directly affect the metal stamping processing precision and quality, also may cause the damage of the mould. In the case of tensile reinforcement, its in metal stamping will occupy a very important position. In stretch forming process, products, need to have a certain size, shape and along the fixed around the appropriate distribution of tension, the pulling force from stamping device, edge part material deformation resistance, and flow resistance on the surface of the blank holder ring. And the generation of flow resistance, if only depend on the effect of blank holder force, the friction between mold and material is not enough. To this end, still must set on blank holder ring can produce larger resistance tensile reinforcement, to increase the feeding resistance, so that the material produces large plastic deformation, to meet the requirements of material of the plastic deformation and plastic flow. At the same time, by changing the size and distribution of the tensile reinforcement resistance control and material to the mold flow speed and feed rate, realize the tensile strain in the deformation area and its distribution of effective adjustment, thus preventing stretch forming product rupture, wrinkling, and deformation and other quality problems. By visible, in the process of stamping process and die design, the size of the stretching resistance must be considered, according to the range of blank-holder force will decorate tensile reinforcement and determine the form of tensile reinforcement, make each region according to the need of complete forming deformation mode and deformation extent. In order to solve the problem of stability of metal stamping mold, need to strictly control from the following aspects: (1) in the process stage, through the analysis of the product, to predict product defects may be produced in the manufacturing, so as to develop a has the stability of the manufacturing process; (2) to implement the standardization of the production process, the standardization of production technology; (3) to establish a database and a summary of the optimization continuously; With the help of CAE analysis software system, optimization solutions are obtained. A: hardware products with unique advantages of stamping process