1. Influence of stamping process selection on manufacturing cost
The rationality of stamping process has a direct impact on the manufacturing cost of stamping parts. The quality of stamping process reflects the advantages and disadvantages of stamping process plan. In terms of reasonable selection of stamping process, domestic mold enterprises have accumulated a lot of experience, and many measures can be used to achieve cost control.
1. reasonable design of stamping process
Reasonable design of stamping process to achieve the best structure and the least process, for example: the right circumference die for a car in our company is 5 processes (excluding the blanking die), a total of 10 pairs of moulds, and the newly developed two models, left and right peri mold only 4 processes (excluding the blanking die), a total of 8 moulds. After a reasonable split of the stamping process, the development cost of the two dies is reduced. In terms of production, the reduction of two pairs of moulds has greatly improved production efficiency and achieved twice the result with half the effort.
2. joint installation method
The operation mode of the joint installation is to complete two or more than two working procedure contents in the same mold, for example, the most representative type of car type refueling box in our company is realized by joint installation. There are 5 pairs of moulds in the fuel tank of a vehicle. If it is connected to the production line, it needs 5 machine tools to meet its requirements. In order to improve the production efficiency and reduce the occupancy of the machine tools, the latter 3 pairs of dies are assembled in a combined installation, which is assembled on the same mold, as shown in Figure 1. In this way, there are only 3 pairs of moulds in the model.
After the combined 1 pairs of dies, each completion of one stroke is equivalent to the original 3 pairs of die, effectively improving the production efficiency, the machine tool occupancy pressure is also reduced. At the same time, 3 pairs of molds are combined on 1 pairs of molds, and the dies are reduced correspondingly, so that the quality is reduced and the cost is reduced.
The way of joint installation is usually used in small and medium-sized stamping parts, and the parts with large surface quality requirements such as large parts and outer panels are not recommended.
How to effectively control the cost of mold development and manufacture in automobile stamping?
Fig. 2 drawing die for scrap cutter of right front outer door of a vehicle
Process plan for installing waste cutting tool on 3. drawing die
Reducing stamping process is an important way to control stamping cost. There are many ways to reduce the process, and one of them is to install scrap cutter on drawing die. Some workpiece faces are complex, with large gap and difficult forming. It may be more difficult to directly use whole sheet metal forming. If the blanking die is developed, not only increase the mold input, but also increase the process, which is considered inappropriate from the economic point of view. In process design, we can consider cutting corners on drawing waste materials, which can ensure drawing forming, reduce one mould and improve economy. This method is often used in the drawing die of the inner and outer panels of automobile stamping parts. The drawing die of the waste front cutter for the front right door of a vehicle is shown in Figure 2.
4. to achieve the common mode production of left and right parts as far as possible
The common mode production of left and right parts is not only more conducive to the forming of materials, but also more important than single piece production. The left and right wingplate of the first car of our company is only selected from the formability but not fully considering the factors of cost control. The left and right parts are drawn, the material utilization ratio is 26.8%, the left and right common mode tension is adopted, the material utilization ratio reaches 33.5%, compared with 6.7% higher, each production one (left or right) needs to be produced. Less consumption of materials 2.8kg, less development of 5 sets of mold, reducing the number of processes, reducing equipment and personnel occupation and resource consumption. From the point of view of cost control, the advantages and disadvantages of the two schemes are obvious. When we develop the CE project, we use the common mode production of the left and right parts of the fender and car door outer panel.
Through the comparison and analysis, it is known that the common mode production of left and right parts should be used as far as possible. In actual production, many parts can be produced by common mode production of left and right parts.