Molds are the basic process equipment of the automobile industry. More than 90% of the parts in automobile production need to be formed by molds. The 3D design of the mold is an important part of the digital mold technology, and it is the basis for the integration of mold design, manufacturing and inspection. Some foreign practices in mold 3D design are worth learning from. In addition to being conducive to the realization of integrated manufacturing, the 3D mold design has another advantage in that it is convenient for interference inspection and can perform motion interference analysis, which solves a difficult problem in 2D design.my countrycar mouldThe industry development trend analysis is as follows.
Automobile molds are the basic process equipment of the automobile industry. More than 90% of parts in automobile production require mold forming. According to reports, it takes about 1,500 sets of molds to manufacture an ordinary car, of which about 1,000 are stamping molds. In the development of new models, 90% of the workload revolves around changes in automobile molds. About 60% of the development costs of new models are used for the development of body and stamping processes and equipment. About 40% of the vehicle manufacturing cost is the cost of body stamping parts and their assembly.
Development Of Digital Mold Technology
The rapid development of digital mold technology in recent years is an effective way to solve many problems faced in the development of automobile molds. The so-called digital mold technology is the application of computer technology or computer-aided technology (CAX) in the mold design and manufacturing process.
Summarizing the successful experience of the application of computer-aided technology in domestic and foreign automobile mold enterprises, the digital automobile mold technology mainly includes the following aspects:
Product Design
1.Board Selection
On the premise of meeting the vehicle strength requirements, companies should try to adopt more common and mature technologies on the market. For example, the inner panel of a front anti-collision beam of our company is made of Swedish knife-edge material DOCO860.
Due to the high strength of the panel, the opening springback after molding developed according to the general process is up to 8mm, and the arc rebound is up to 15mm. For these problems, we can only conduct multiple tests through springback compensation, which not only has a long cycle, but also causes serious material waste.
2.Product Structure
When developing multiple models, more consideration should be given to product versatility. In addition, the product structure must be simplified to avoid increasing the mold process or complicating the mold structure.
3.Application Of Synchronous Engineering
Stamping Synchronous Engineering (SE) means that in the product design stage, stamping process engineers intervene in advance to analyze the product process, eliminate errors and defects in the design stage, and shorten the mold development cycle. As can be seen from the figure, using synchronous engineering eliminates a process link, allowing tooling manufacturing to start in the shortest possible time, providing sufficient time for manufacturing.
There are currently two types of production lines used by enterprises: manual production lines and automatic production lines. As far as the automatic line is concerned, in order to ensure that the production waste materials can slide down automatically, the angle between the sliding plate and the workbench must be greater than 20°. In addition, the automatic line mold feeding height requirements are consistent. Finally, in order to ensure that the waste materials can slide down freely, the height of all molds must be increased. . However, for the entire vehicle, reducing the mold height is an effective way to save mold development costs. Using a manual production line does not have the problems involved above. Each enterprise can choose production methods and production equipment according to its own situation, and ultimately achieve small input and large output.
Mold Process
1.Consider the blanking process first, and then the drawing process
With the application of high-strength steel plates in automobile production, in order to ensure that high-strength plates can be formed, the forming method after blanking has a higher success rate. Compared with blanking and drawing, there is no blank holder, and the material utilization rate is greatly improved. However, the drawing process can easily ensure product quality and the debugging cycle can be shortened. Therefore, the two should be considered together to formulate the optimal process.
2.Use nesting technology for blanking production
The waste material after blanking some parts can be reused to produce small parts of the same material.
(3) To the maximum extent, it is required to achieve the method of closing the left and right parts of the mold or one mold with multiple cavities.
The products we develop are almost all symmetrical. If the left and right parts are molded together for production, we only need to add the size of the symmetrical part to the mold width (length) of the single piece, which is the mold outline size of the new process. In comparison, a set of guide mechanisms can be saved and the weight of the overall mold can be reduced. For narrow and long parts, it is recommended to use one mold with multiple cavities for production.
Mold Design
In the mold structure design, some structures are redundant. For example, in order to ensure smooth pick-up, a pneumatic ejection device is often retained on the mold, which is rarely used in actual production.
The requirements for the service life of the mold directly affect the material selection of the mold. Our company generally requires the service life of the mold to be 500,000 sprints. However, in the current multi-variety, small and medium-sized batch production, it is somewhat unreasonable to continue to require the service life of the mold to be 500,000 sprints. The mold wall thickness can be appropriately reduced to reduce costs.
At present, the casting level in our country is low, and mixed casting is difficult to achieve. Taking flanging molds as an example, the working part materials generally choose high-hardness, wear-resistant materials such as GM series, MoGr alloy, and air-cooled steel. Adopting a split insert structure, on the premise of meeting the high life requirements of the mold, you can choose integral inserts or split inserts according to the size of the parts required for the working part.
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