The progress of tooling development plays a crucial role in the overall project schedule and constitutes an essential component of the OEM’s production preparation. Next, we will discuss the die development process and schedule control, from the release of body-in-white data to the final acceptance of the dies.

1. Body Process Number Release

The body design department releases the product digital model, and the engineers of the engineering development department carry out the process pre-analysis and forecast price (as the bidding comparison data) according to the product digital model, and use the body process digital model to carry out the bidding of the mold and the corresponding process analysis. The bidding process will not be discussed in detail here. The following is a brief discussion on mold development management after calibration (I .e. determination of mold factory).

2. Feasibility analysis of body parts manufacturing process (mold developer and engineering development department)

After the mold developer receives the body process model, the process feasibility analysis of each part is carried out. In principle, the mold factory is required to conduct CAE analysis (ie, part formability simulation analysis) for all newly developed parts.

The role of CAE analysis:

Through CAE analysis, we can observe the forming process of sheet metal parts more intuitively;

Shorten the cycle of mold design and analysis;

Predict the possibility of the mold;

Optimized design is adopted to minimize the consumption of molds and steel and reduce manufacturing and production costs;

Pre-discover the potential risks of molds and parts before manufacturing;

Ensure the rationality of mold design and reduce design cost;

Through the analysis of potential problems of parts, the mold factory can put forward reasonable design change suggestions in time to promote the development work more efficiently.

The development department can make full use of the experience of on-site production and debugging according to the analysis results of the mold factory on the part CAE, check whether the process parameters are reasonable, whether the drawing supplement is reasonable, and put forward solutions in time for the risks such as wrinkling or cracking of the parts.

3. Design and countersign of DL drawing

After the end of the CAE analysis can be die DL diagram design, in most cases can also be carried out at the same time.

DL diagram design is design layout-stamping process analysis and design, which can also be called mold process flow chart, including: size of part material sheet, stamping direction and angle, stamping process arrangement, feeding direction, waste knife distribution and cutting edge direction, waste removal direction indication, CH hole, left and right part identification, marking of each process, etc.

At the same time, the DL diagram also needs to reflect the stamping equipment, die height, die material, working stroke of blank pressing ring or pressing plate, positioning method of sheet metal, pressure analysis of the completed process, etc.

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 main engine factory and countersigned. The countersigning of the DL diagram is very critical, which directly leads to the later mold design and has a great impact on the later mold development cycle. If the DL diagram is changed later, the development cycle and cost will be greatly wasted, 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 convenience of feeding in combination with the press situation.

4. Design and countersign of mold structure diagram

Die structure diagram countersign sequence: drawing die drawing countersign-reshaping flanging die countersign-trimming punching die countersign.

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 design link is very important, and the mold design link should be advanced as much as possible to strive for the manufacturing time of the subsequent mold.

The first sampling of molds is generally semi-manual samples, which only require forming. The rest of trimming and punching can be completed by line cutting. Therefore, the design of drawing dies and shaping flanging dies should be carried out first, and then the design of trimming and punching die drawings should be carried out.

The mold factory designs the mold structure diagram according to the guidance of DL diagram. After the design is completed, it also passes the internal review first. After the problem is rectified, it can be reviewed and countersigned by the development department of the main engine factory.

The development department of the main engine plant should focus on:

Mold functionality

Structural stability and strength

mold production safety

The conformity between the parameters of the mold and the mass production press.

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 required to make rectification as far as possible. Some problems may have little impact on product functions, etc., but may affect the convenience of operation and may also reduce production efficiency. In order to catch up with the time and progress, the mold factory may not be too cooperative with the changes. At this time, the courage and determination of the developers (engineers) of the main engine factory are required, because the changes in the design stage are faster than those in the later stage (after mold forming). At this time, the designers of the mold factory need to think in another, look at the problem from the perspective of the production sector.

Some of the controversial issues need to be discussed objectively in order to find the best solution. In the process of mold drawing review, engineering development and technical personnel are required to stand firm and have excellent technology and on-site debugging experience, which can reduce many problems in the later period.

5. Foundry model release and foam model (styrofoam) review and rectification

After the design review of the mold structure diagram, the foam type can be made. In the foam solid stage, the project team needs to release casting data to ensure the castability of the solid type. The foam solid type is a material formed by high-temperature foaming of polystyrene. NC processing is carried out according to the mold structure diagram, and appropriate mold processing allowance (8-10 days) and foam shrinkage are considered.

The production cycle of Stolfoam is generally about one week. After the production is completed, it needs to be reviewed on site. One is to ensure consistency with the mold structure diagram. The second is to check whether the problems in the mold structure diagram review are rectified in place, or the problems not found in the design diagram review. The review of Stolfoam is an indispensable process in the mold making process, because it is the last step in the mold structure change. Once it enters the casting stage, the mold structure is difficult to change.

6. Mold casting

After the production and rectification of Stulon 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 transported back to the mold factory for casting inspection, mainly to check whether there are large casting defects, such as casting cracks, etc. Among them, defects such as sand inclusion in castings need to be processed before they can be seen.

7. NC digital model release and NC processing of its mold

NC machining can be carried out after the mold casting is completed, but only if the NC data has been released, the mold factory can carry out numerical control programming according to the NC data of the product, and then carry out NC machining of the mold. NC machining of the mold can be roughly divided into: dragon milling-assembly-semi-finishing-finishing, etc. During NC machining, whether the casting has defects such as sand inclusion or cracks can be found, after NC processing is completed, the mold needs to be heat treated to achieve the required hardness. The NC processing cycle of the mold is generally 20-25 days. Under the condition of tight project development time, how to reasonably arrange the NC processing time is very important. 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 machine tool idle, in order to ensure the progress.

8. Die fitter, debugging and sampling process

The fitter stage of the die includes: die benchmark punching-die clamping-die test-sampling, etc. After NC machining of the die, there is still a certain margin for subsequent fitter. The fitter debugging mainly checks the grinding rate of the upper and lower dies and the guiding grinding rate to ensure that qualified stamping parts are punched out. Through die fitter debugging, the quality of the die can be identified, and the blanking size can also be determined.

9. Mold pre-acceptance

The mold factory can apply to the development department of the main engine factory for pre-acceptance after completing the production of all the bearing molds and debugging by itself within the planned time. The mold factory needs to provide the self-inspection report of the mold and the qualified rate of the stamping parts. After receiving the pre-acceptance application from the mold factory, the development department of the main engine factory organizes personnel to carry out pre-acceptance in the mold factory, mainly from three aspects of static and dynamic stamping parts quality, dynamic and static inspection is carried out in accordance with the standard, and the inspection of stamping parts is divided into three aspects: surface quality, shape and size accuracy and rigidity.

In principle, the problems found in the pre-acceptance process require packaging and shipment after the mold factory completes the rectification. However, if some problems do not affect the production quality and the rectification is less difficult, in the case of tight schedule, the mold factory is allowed to send fitters to the production area for continuous rectification.

10. Debugging and Acceptance of Mold Quantity Origin

Due to the difference of machine tools and the difference of mold surface grinding rate, etc., to ensure the quality of the parts, after the mold passes the pre-acceptance, it needs to be debugged after moving to the mass production area. Generally, the first round of drawing mold grinding time is 1-2 months, while the whole mold debugging cycle lasts for half a year or more. The mold mass production area debugging process always focuses on the following aspects:

The stamping parts shall be clamped on the welding fixture to verify the coordination of the die, clamp, gauge, gauge and welding fixture;

To ensure the accuracy of the stamping parts, the stamping parts on the inspection, the requirements of the pass rate is generally more than 90%;

The mold factory shall be responsible for the rectification of problems found on the inspection fixture of stamping parts or problems or defects fed back during welding debugging;

Conformity inspection of dynamic and static inspection items of moulds;

Continuous production reliability of molds on mass production presses, I .e. continuous production scrap rate requirements of less than 2%

Mold debugging and rectification cycle is long, will be the above several items are completed and production stable operation after 3 months, the engineering development department can organize mold users, security personnel, quality inspectors, etc. for the final acceptance of the mold and sign the final acceptance report.

After the final acceptance of the mold is completed, the development of the mold is 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 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, improve production efficiency, and bring considerable economic benefits to the company.