1. Release of bodywork technology
The body design department publishes the product digital model, and the engineering staff of the engineering development department conducts process pre-analysis and pre-quotation based on the product digital model (as bid comparison data), and uses the body process digital model to conduct mold bidding and corresponding process analysis. The bidding process will not be discussed in detail here. The following is a brief discussion of mold development management after the bidding (that is, to determine the
mold factory).
2. Feasibility analysis of manufacturing process of body parts (mold developer and engineering development department)
After the mold developer receives the digital model of the car body process, it performs a process feasibility analysis on each part. In principle, the mold factory is required to conduct CAE analysis (ie simulation analysis of part formability) on all newly developed parts.
The role of CAE analysis:
Through CAE analysis, we can visually observe the forming process of parts and sheets;
Shorten the cycle of mold design and analysis;
Predict the possibility of the mold;
Use optimized design to minimize the consumption of molds and steel, and reduce manufacturing costs;
Discover the potential risks of molds and parts in advance before manufacturing;
Ensure the rationality of mold design and reduce design costs;
Through the analysis of the potential problems of the parts, the mold factory can promptly propose reasonable design changes and promote the development work more efficiently.
The development department can make full use of the experience of on-site production and debugging based on the analysis results of the CAE of the parts by the mold factory, check whether the process parameters are reasonable, and whether the replenishment is reasonable, and propose timely solutions to the risks of wrinkling or cracking of the parts.
3. Design and signing of DL diagram
After the CAE analysis is completed, the mold DL diagram design can be carried out, and in most cases, it can also be carried out simultaneously.
DL diagram design is design layout—the stamping process analysis and design, which can also be called the mold process flow chart, including: the size of the part sheet, the direction and angle of the stamping, the process arrangement of the stamping, the feeding direction, the distribution of the scrap knife and the cutting edge direction , Indication of waste removal direction, CH hole, identification of left and right parts, labeling of each process, etc.
At the same time, the DL diagram also needs to reflect the stamping equipment, mold height, mold material, working stroke of the blank holder or pressure plate, positioning method of the plate material, and pressure analysis of the completed process.
After the DL design is completed, in principle, the internal audit should be completed in the mold factory. After the rectification of the internal audit problem is completed, it can be provided to the development department of the host factory and a countersign. The countersign of the DL diagram is very critical, which directly leads to the design of the later mold, and It also has a great impact on the later mold development cycle. If the DL diagram is changed later, the development cycle and cost will cause a lot of waste. The engineering development department mainly reviews the rationality of the part process, the correctness of the machine parameters, The rationality of the process supplement, the material utilization rate, and the ease of feeding in conjunction with the press.
4. Design and registration of mold structure drawing
Signing order of mold structure drawing: drawing signing of drawing die drawing — signing of shaping and flanging tools — signing of trimming and punching tools.
Because the casting and processing cycle of the mold is a hard time and cannot be compressed, in order to ensure the progress of the project, the mold structure drawing design link is very important. The mold design link time should be advanced as much as possible to fight for the subsequent mold manufacturing time.
The first sampling of the mold is generally a semi-manual sample, which only needs to be formed. The remaining trimming and punching can be completed by wire cutting, so the design of the drawing die and shaping and flanging mold should be carried out first, and then the trimming and punching class Design of mold drawing.
The mold factory designs the mold structure according to the DL diagram. After the design is completed, it will also pass the internal review. After the problem is rectified, the review will be signed by the development department of the host plant.
The OEM development department should focus on:
Mold functionality
Structural stability and strength
Mold production safety
Conformity of various mold parameters with mass production presses
Convenience of commissioning and production
Consistency of the material of the main parts of the mold and the terms required by the technical agreement
For the problems found in the review, the mold factory should be rectified as much as possible. Some problems may have little effect on product functions, etc., but may affect the convenience of the operation, or may reduce production efficiency. In order to hurry up and schedule, the mold factory may not be too cooperative to change. At this time, a OEM developer (engineer )'S courage and determination, because the changes in the design stage are faster than those in the later stage (after the molding of the mold). At this time, the designers of the mold factory need to think differently and look at the problem from the perspective of the production department.
Some controversial issues require objective discussions by multiple parties to find the best solution. In the process of mold drawing review, engineering development technicians are required to have a firm stand and have strong technical and field debugging experience, which can reduce many problems in the later stage.
5. Release of casting digital model and review and rectification of real foam (Polylong)
After the mold structure drawing design review is completed, the foam type can be produced. In the real foam stage, the project team needs to release casting data to ensure the castability of the real model. The real foam model is a kind of material formed by high-temperature foaming of polystyrene. It is NC processed according to the mold structure drawing, and Consider the appropriate mold processing margin (8-10 days) and foam shrinkage.
The production cycle of Styrofoam is generally about one week. After the production is completed, it needs to be reviewed on the spot. One is to ensure consistency with the mold structure drawing. The second is to check whether the problems in the mold structure drawing review are rectified in place, or the problems that were not found in the design drawing review. The Styrofoam review is an indispensable process in the mold making process because it is the final change in the mold structure. First, once it enters the casting stage, it is difficult to change the mold structure.
6. Mold casting
After the production and rectification of Styrofoam is completed, it can be shipped to the foundry for casting. The specific process will not be discussed in detail here. The mold casting cycle is 15-20 days. The mold casting is carried back to the mold factory for casting inspection. The main check is whether there are Large casting defects, such as casting cracks. Among them, defects such as sand inclusions in the castings can only be seen after processing.
7. NC digital model release and NC processing of mold
After the mold casting is completed, NC processing can be performed, but the premise is that NC data has been released, and the mold factory can perform NC programming based on the NC data of the product, and then perform NC processing of the mold. The NC processing of the mold can be roughly divided into: dragon milling-group Vertical-semi-finishing-finishing, etc. During the NC machining process, it can be found whether the casting has defects such as sand inclusions or cracks. After NC machining is completed, the mold needs to be heat-treated to achieve the required hardness. NC machining of the mold The cycle is generally 20-25 days. In the case of tight project development time, it is very important how to arrange NC processing time reasonably. Engineering developers can go to the site to control the progress and supervise the mold factory to prepare a reasonable processing plan. Try not to let the CNC machining machine idle to ensure the progress.
8. Mold fitter, debugging, sampling process
The fitter stage of the mold includes: mold benchmarking and-mold clamping-trial mode-sampling, etc. After the NC machining of the mold, there is still a certain margin for the subsequent fitter. The fitter debugging mainly checks the research and development rate of the upper and lower molds, and the research and development rate of the guide. To ensure that qualified stamping parts are stamped out, the quality of the mold can be identified through debugging by the mold fitter, and the size of the blank can also be determined.
9. Mold pre-acceptance
After the mold factory completes the production of all the molds produced within the planned time and is qualified for self-debugging, it can apply for pre-acceptance to the development department of the host factory. The mold factory needs to provide the self-test report of the mold and the qualification rate of the stamped parts. After receiving the pre-acceptance application from the mold factory, organize the personnel to the mold factory for pre-acceptance, mainly to accept the mold from the static and dynamic stamping quality of the mold. The dynamic and static inspections are performed according to the standard. The inspection of the stamping parts is divided into surface quality , Three dimensions of shape accuracy and rigidity.
The problems found in the pre-acceptance process require in principle packaging and shipping after the rectification of the mold factory is completed, but some problems will not be affected if the quality of the production is affected and the rectification is difficult. In the case of tight schedules, the mold production plant is allowed to be left to the mass production site. Self-designed locksmiths continue to make corrections.
10. Debugging and acceptance of the mold mass production site
Due to differences in machine tools, differences in mold profile and rate, etc., it is necessary to ensure the quality of the parts. After the pre-acceptance of the mold is qualified, it needs to be debugged after moving to the mass production site. Generally, the first round of the drawing mold is 1-2. Month, and the debugging cycle of the entire mold is as long as half a year or more, the debugging process of the mass production site always focuses on the following aspects:
The stamping parts need to be clamped on the welding fixture to verify the coordination of the mold, clamp, inspection tool, inspection tool and welding fixture;
To ensure the accuracy of stamping parts, place the stamping parts on the inspection tool for inspection, and the qualification rate is generally above 90%;
The problems found on the inspection tool of the stamping parts or the problems or defects fed back during the welding and debugging process shall be rectified by the mold factory;
Compliance inspection of mold dynamic and static inspection items;
The continuous production reliability of the mold on the mass production press, that is, the continuous production scrap rate requirement is less than 2%
The mold debugging and rectification cycle is long. After all the above rectifications have been completed and the production has been running stably for 3 months, the engineering development department can organize the mold users, security personnel, and quality inspection personnel to conduct the final acceptance of the mold and sign the final acceptance report.
After the final acceptance of the mold, the development of the mold is considered to be completed in stages. However, as long as the mold is not scrapped and the mold life cycle continues, the work of the engineering development department will never end, but it will be handed over to the production system and process department for use, management, and maintenance. Under good use and maintenance, the mold can extend the service life, reduce the scrap rate, and improve the production efficiency, bringing considerable economic benefits to the company.
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