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How to reduce the mold cost from the design link

2021-09-04

How to reduce the mold cost from the design link

Mould industry is the basic industry of national economy. Mould is the basic technology equipment of military industry, machinery, electronics and light industry. With the development of production, science and technology, the intensification of competition in the economic and trade market, accelerate the upgrading of products, which put forward higher requirements on the quantity, quality, cost and delivery time of molds. The success or failure of mold development lies in design. Can say this is what our personage inside course of study place consensuses, a lot of units have this kind of feeling --, be not afraid to process not to come out, be afraid to design not to come out. It can be seen that a mold, its design difficulty is much more difficult than processing. The author believes that a successful mold, it is not only able to complete the predetermined stamping task, but also to make the mold in its own processing, adjustment, maintenance, wearing parts consumption and a series of processes, the total cost to achieve the minimum, this is the highest realm of mold design.

 

Methods to reduce mold cost

The cost of mold is mainly composed of the following parts: material cost, design cost, processing cost (including debugging cost), packaging cost and transportation cost, taxes, other costs (such as commercial operation, pay management fees, etc.). Among them, the cost of materials, processing fees and taxes should account for at least 80% of the total cost of the mold. And material cost and processing cost are decided by design drawing, the material that uses what grade, need how many raw materials, mold parts processing needs to go what kind of technological route, whether have good debugging performance, modify times, these all depend on the design again. Therefore, mold design is the most critical link. So control mold cost must proceed from the design. In order to achieve the purpose of reducing costs, it is necessary to do the following work:

1. First of all, the formulation of the overall design scheme should be reasonable, that is to say, the design concept should be correct, from stamping process, layout to the determination of the overall structure should comply with the relevant principles or laws. Such as layout scheme formulated, in accordance with the conventional design rules for the first step is to try out of the guide hole, and then the second step will have to be set are nail guidance is, no matter how small interval can not open, if not this arrangement, from the initial feed precision, to the whole mold step distance accuracy cannot be guaranteed, all equal to lost the locating datum, the precision of the stamping is not.

How to effectively control the process of blanking, bending, drawing, folding and edging of the strip, and how to use the structure to ensure that the blank is formed in accordance with the design intention. The formulation of these schemes requires the designer to have a relatively full understanding of the deformation law of materials. At the same time, the current plan to carry out the necessary proofreading accounting, such as the size of the expansion size, the number of deep drawing, the value of the initial gap, the deviation of the pressure center, the size of the blank holder force, unloading force or push force, the length of the spring and the amount of compression should be calculated and used as the theoretical basis of the design. Try to use a more mature structure.

When designing the mold structure, it is best to imagine the assembly, operation and deformation process of the mold in the future. In this way, many unrealistic assembly problems or interference generated in operation can be found in advance, and problems such as preventing feeding and positioning instability can be solved from the beginning of the design. Because once the mold appears big design error, will lead to mold scrap. The author has seen such a pair of mould, it's the last station to complete the cut off, call 87 ° bend, the three movements, layout is not wrong, not thoughtful, due to the structural design of only meet the requirements of the acute Angle bending, and designed for oscillating punch set under the baffle block out parts, unable to work continuously, put an already complicated problems are easy to handle, Finally, the mold was scrapped. Later, another new mold was made to change the structure, the punch was changed to straight-through type, and the concave die was changed to bevel. After removing the baffle, the mold could be accepted. So there must be no big problems with the overall scheme.

2. Before determining the stamping process route and layout, cost estimation will be carried out for various schemes, so as to provide a basis for decision-making. For example, a stamping piece can be finished with a few pairs of single-step die stamping, can also be completed with a pair of stepping die (progressive die) stamping, can also be completed with composite die stamping, which scheme should be adopted in the end, to see which scheme of the lowest comprehensive cost.

3. To implement the promotion and application of standard parts, use standard parts as much as possible. The reason is simple, because standard parts can be mass produced, so their market price is relatively cheaper. Another advantage is to shorten the mold manufacturing cycle, so that the total amount of work reduced at least half. At present, the market is very rich in mold standard parts, various, complete specifications. Such as springs, dies, guide pieces, screw plugs, punch and die guide holes, guide pins, test pins, small pressure plates, float pins, push rods, etc., these parts can be purchased from specialized manufacturers, thus eliminating the design and processing work. Reduce the pressure of production links, speed up the progress, and in turn to promote sales.

4. The process review of non-standard parts design should not be ignored. In actual production, the reason for the scrap of parts is sometimes not the operator, but the unreasonable design. For example, a plate worth thousands of yuan, due to a sharp corner of the hole cracking and scrap, in this case can the responsibility to heat treatment? Because the wall thickness of the die insert design is too weak, deformation occurs after cutting holes and scrap processing, can this be blamed on the slow walking wire operator? Have such a feeling, a complex shaped hole, if the design on the splicing ways, the convex and concave mold processing are relatively easy, with tool grinder can ensure dimensional accuracy requirements, it is designed to be integrated, walking wire must be followed or jig grinding machine processing, the processing cost hundreds of thousands of yuan. Sometimes punch design is too long and thin, impact resistance is too poor, resulting in frequent shutdown and maintenance replacement in stamping production, increase costs and delay production. The phenomenon described above is often encountered, so, for non-standard parts, before putting into production, we must carry out the process review, by senior designers or craftsmen to check whether the drawings meet the factory process conditions. Such as size can not beyond the range of existing equipment, reference should always be consistent, curve (surface) processing to avoid interference phenomenon, be careful not to have easily when quenching cracking Angle, but clamping surface to enough, dimensional accuracy, form and position tolerances of easy to control, for some parts that can not be a design specification to allow room for modification, etc. With the process inspection, we can reduce a lot of additional costs due to unreasonable design, thus reducing factory losses. Some enterprises for the division of labor is clear, convenient management, design work and process work division, respective tube respective, internal consumption is relatively large.


5. Material selection should be appropriate. Now people have realized the value of resources, the price of mold raw materials rises and rises again, especially alloy tool steel, some prices have more than twice the original. Such as high-speed steel W6Mo5 Cr4V2, the original price of less than 40 yuan/kg, now rose to more than 80 yuan/kg. Cemented carbide YG15 original price of 300 yuan/kg, now up to 700 yuan/kg above. Import material price is more tall outrageous, if the ordinary die steel SKD11 of Japan is 70 yuan/kg, hard alloy D30 is 3000 yuan/kg, the hard alloy CD650 of the United States is 3000 yuan/kg, than the domestic material of the same performance is taller than 3 times above. Therefore, in the selection of mold materials, as long as the performance conditions such as strength and hardness of parts can be met, and the expected life can be achieved, we should try to use cheap raw materials, and blindly pursue expensive materials, seemingly in order to improve the quality of the mold, in fact, is an unreasonable use of resources, but also a waste. Domestic mold materials such as T8, T10, CrWMn, Cr12MoV and so on are relatively much cheaper, so it is recommended to choose them first. Especially when the mold size is large, the choice of material should be more careful. Some key parts, if you must use YG15 and other wear resistant hard alloy materials, can be designed into the form of hot insert or local welding, the amount of its try to reduce as little as possible, so as to save a lot of money.

6. The mold must be tested several times before leaving the factory, and the problems found in each test mold are designed and modified in the factory and thoroughly solved, it is best to debug to a certain degree before packaging and shipping out. Avoid problems after the mold is delivered to the user, when the site is likely to have no professional equipment and operators to cooperate, it is very difficult to repair or transform the mold only by fitter. Waste of time, increase the cost of the second, maybe the mold will eventually have to be shipped back to the factory repair, that will be more trouble, these costs are bound to greatly exceed the budget. At the same time also delayed the user's production schedule, resulting in a negative impact. In short, to minimize the mold outside adjustment time and workload.

7. The design of drawings should be standardized. The actual size of the graph on the computer must be consistent with the marked size, and the name must be unique. The name and figure number must not be repeated. Doing so seems to be a little more troublesome and slower, but it can bring great convenience to the follow-up work. Whether it is proofreading or processing programming or checking the size, you can call the drawing file directly from the computer. Ensure that the design pattern has a clear guiding role in production. On the whole, it not only saves a lot of time, but also improves the accuracy of size and shape expression. It can effectively avoid scrapping or repairing caused by misunderstanding, and effectively reduce unnecessary loss and waste.

Conclusion:

If the above points are to be well implemented, a series of relevant systems should be established as a guarantee. In this way, the enterprise's mold design and development level and benefit will be significantly improved.