Chinese machine - [classic review] stamping cost control, starting from process design

Table 1 Comparison of material usage of three layout methods on reinforcing board / driver / passenger seat belts

To improve process stability, reduce scrap rate. In actual production, due to poor process stability and high reject rate, the utilization ratio of actual material and theoretical material utilization will be greatly different. Therefore, the process design phase of the process of poor stability of the parts, should be based on quality characteristics of process improvement, to ensure stable, high utilization of production.
Control the stamping process
The number of stamping parts is one of the important markers to measure the stamping process. The number of stamping parts has a direct impact on the number of press, the number of tooling, the number of transmission devices, floor space, personnel and kinetic energy consumption. Therefore, the number of stamping parts is the key to the investment scale and the cost of stamping parts.
In China, because of the importance of vehicle performance and effect in product development and design, the process and economy are not considered enough, so the stamping process is more. The major automotive manufacturers all attach great importance to the design of automobile body, and take the number of stamping processes as an important way to reduce the cost of automobile manufacturing. When the product structure requirements and manufacturing processes conflict, the requirements of optimizing product design, so that it can meet both the structural requirements and meet the process requirements. At present, the number of stamping processes in the most advanced design of truck body and popular car body panel is not more than 4, and the number of car covers in general is slightly higher than that of truck.
Adopt a reasonable mode of production
In the stamping process, the impact of production batch size on cost is immediate. Therefore, it is necessary to adopt different production methods for different production batches to reduce the cost of stamping. From the current development of stamping technology all over the world, along with the stamping production batch is different, can be considered roughly: in mass production, mainly to improve die life and productivity of unit of time to reduce the cost of stamping parts; in small batch production, the current main toward simplified mold tooling, in general universal direction.
Lower die cost
The relation between part processing cost and die depreciation charge and output is shown in figure 2. Q1 said a small amount of production, mass production mold depreciation expenses than the much higher mold depreciation increases with the decrease in production, Q2 said that a large number of production conditions, low processing cost a small amount of production, and lower mold depreciation. In other words, a small amount of production to reduce the cost of manufacturing parts, you must reduce the cost of tooling and shorten the mold manufacturing cycle.
In general, from the following aspects to reduce the cost of the cost of stamping die, including: reduce the number of stamping process; to reduce the dimension of blank, simplify the transition piece shape, especially the shape of drawing piece, each process parts for the size and complexity of the structure, have a great relationship; optimization of stamping process the content of this design, die design, manufacturing, commissioning, maintenance and repair have direct effect; reasonable choice of stamping direction, optimizing die structure; improve die standardization, seriation, parameterization, in order to reduce the mold design and manufacturing cycle and maintenance cycle, and to realize the quick change in the mold; meet the strength requirements of die and stamping operation requirements, reduce the size of die; die design should be practical and reliable, convenient maintenance, in order to reduce the use of dimension Repair cost and time; in order to meet the production life, try to use cheaper materials, reduce the mold materials; design and production program to meet the requirements of die life, without too much or not enough life reserves, with the lowest life cycle cost to achieve reliable necessary function of mold insert structure is adopted; in the damageable parts, reduce mold materials and maintenance costs; simple mould is widely used in small batch production, the following introduces several methods.
The increase of incision in the drawing die, saving blanking die. In order to improve the stiffness of the outer panel and the inner plate structure, the drawing depth of the parts is deeper. In the deep drawing process, the parts with deep drawing or window reverse drawing are easy to be split. In order to meet the requirements of forming, many parts need blanking die to provide irregular shape or material with technological hole. But only a small gap or a small technological hole is applied to a large sheet material, which increases the cost of the mould and wastes manpower, equipment, energy and economy. For this reason, a blanking die can be reduced by increasing the process opening in the drawing die, as shown in figure 3.
Figure 3 is used in the form of drawing production of left / right side beam, the ratio of intermediate junction depth and width is larger, the difficulty of forming parts, R anti cracking forming by AUTOFORM simulation, in the middle part of waste two extra process holes, the material flowing outwards. If a blanking die is added, it is obviously uneconomical to solve the problem by adding a cutting edge in the drawing die. At this point, note that the process hole in the middle of the drawing die, not waste, should use the form of cutting tongue, that is not completely cut off waste materials, and should pay attention to after positioning.
The multi slot die, reduce the number of molds and equipment occupation. D310 models of beam - Passenger / driver seat 5101073/74-C0100, parts of the symmetry, the duplex process, completed by three steps: blanking, forming, punching cut, according to the conventional design of manufacturing three sets of small mold, completed in 2 400t press, the operator needs at least 6, equipment required belt conveyor. Taking into account the small size of the parts, materials, light weight, will be three processes integrated into a set of molds (Figure 4) for multi groove stamping, just take 1 400t press, 4 people can enter