A stamping die in-mold urethane bulging structure and forming process

Abstract

The present invention discloses a bulging structure and forming process of a stamping die in a rubber mold, comprising a bulging structure of rubber and a concave film entry block in the bulging step. The rubber bulging structure is arranged above the concave film entry block in the bulging step, and the corners of the rubber bulging structure are optimized. Material is added to the straight surface at the corner of the rubber bulging structure to meet the bulging amount of the product corner, and material is reduced by a curved surface concave at the corner of the rubber bulging structure to absorb the bulging amount of the rubber. The invention also includes milling grooves at places where the rubber and the product are not in contact, so as to reduce the bulging amount at places where the rubber and the product are not in contact; and slotting at the junction of the rubber and the product opening to reduce the wear of the rubber at the contact place between the product edge and the rubber during the rubber bulging process. The unique milling groove and structural design disclosed in the present invention not only prolong the service life of the rubber and make the mold easy to repair, but also improve production capacity and save costs.

Description

Technical Field

[0001] The present invention relates to the technical field of stamping dies, in particular to a stamping die in-die urethane bulging structure and a forming process. Background Art

[0002] Polyurethane elastomer, also known as polyurethane (PU) elastomer, is a new type of material between plastic and rubber that has good strength, small compression deformation, a smooth, glossy and dense surface, and has both the rigidity of plastic and the elasticity of rubber. It can be used for a long time in a temperature range of -40°C to 80°C. Its wear resistance and self-lubrication are far superior to most engineering plastics. At the same time, it has good oil and oxide resistance, making it a widely used alternative rubber on the market.

[0003] In the stamping die industry, PU is primarily used in die stripping devices to replace springs, performing the functions of die stripping and unloading. In JTI Out Case dies, PU is used for the die bulging structure. In production, the inner cavity of JTI Out Case products is larger than the opening. Conventional PU cannot be used to form these products using conventional stamping methods, nor can it meet the requirements of product drawings. Summary of the Invention

[0004] The purpose of the present invention is to solve the deficiencies of the prior art and to provide an in-mold urethane bulging structure and forming process that meets the structural size requirements of the product after stamping.

[0005] In order to achieve the above purpose, a bulging structure of polyurethane foam in a stamping die is designed. The bulging structure of polyurethane foam is arranged above the concave film entry block in the bulging step, and the corners of the bulging structure of polyurethane foam are optimized. Material is added to the straight surface at the corner of the bulging structure of polyurethane foam to meet the bulging amount of the product corner, and material is reduced by the curved surface at the corner of the bulging structure of polyurethane foam to absorb the bulging amount of polyurethane foam; grooves are milled at the places where the polyurethane foam and the product do not contact to reduce the bulging amount at the places where the polyurethane foam and the product do not contact; grooves are cut at the junction of the polyurethane foam and the product opening to reduce the wear of polyurethane foam at the contact places between the product edge and the polyurethane foam during the bulging process of polyurethane foam.

[0006] The present invention also includes the following preferred technical solutions:

[0007] Preferably, the urethane foaming structure is made of black urethane foam.

[0008] Preferably, the concave film block in the bulging step is an assembled structure.

[0009] A forming process of a bulging structure of a polyurethane foam is also designed. The specific forming process is as follows:

[0010] S1: stretching the product into a set shape, wherein the set shape is smaller than the final product structure;

[0011] S2: The product with a set shape is bulged to the size of the final product through the use of PU. The PU bulges inside the product and is compressed by closing the mold to bulge the PU. The outside of the product is the mold cavity.

[0012] S3: Finally, the excess material at the outlet is removed through CNC process to obtain the final product.

[0013] Preferably, the forming process of the bulging structure of the polyurethane foam includes preheating the polyurethane foam by blanking the mold for a set time before production.

[0014] Compared with the prior art, the present invention has the following advantages:

[0015] 1. The optimized urethane foam stamping and bulging process will not damage the product surface, and the structural dimensions of the product after bulging meet the requirements of the product drawings;

[0016] 2. Unique milling groove and structural design make the service life of the rubber long and the mold easy to maintain;

[0017] 3. Increased production capacity, reduced manpower, low price of polyurethane foam, and cost savings;

[0018] 4. The bulging process of the Urea mold is simple in structure and has a wide range of market applications;

[0019] 5. High yield rate, stable structure, size and appearance of products. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a diagram of the actual product structure of JTI Outer Case.

[0021] Figure 2 Schematic diagram of the optimized bulging structure of polyurethane foam.

[0022] Figure 3 This is a schematic diagram of the optimization of the corner of the rubber.

[0023] Figure 4 This is a schematic diagram of the structure of the optimized urethane milling and grooving.

[0024] In the figure: 1. Straight surface feeding area 2. Curved surface concave material reduction area 3. Milling groove 4. Slotting 5. Glue 6. Bulging step: Concave film into the block. DETAILED DESCRIPTION

[0025] See also Figure 1, is a diagram of the actual structure of the JTI Out Case product. It can be seen from the figure that the inner cavity structure of the JTI Outer Case product is larger than the opening structure. Conventional stamping cannot be used to form it and cannot meet the requirements of the product drawing.

[0026] See also Figure 2 This is a schematic diagram of the optimized bulging structure of Ulyaph 5. During the development process, it was found that the product corner size and product line mark could not meet the product requirements at the same time. When the bulging amount of Ulyaph 5 was small, the product line mark was light but the corner size did not meet the requirements. When the product corner size met the requirements, the product line mark was heavy and difficult to remove by polishing. Through continuous DOE verification of Ulyaph 5, this problem was finally solved by optimizing the structure of Ulyaph 5.

[0027] See also Figure 3 , which is a schematic diagram of the optimization of the corners of the rubber 5. The corners around the product need to expand a lot, and the corners around the rubber 5 are severely worn, which affects the service life of the rubber 5. By optimizing the structure of the corners of the rubber 5, the service life of the rubber 5 is improved. The rubber is added at the feeding point 1 directly to meet the expansion of the product corners. The curved surface of the rubber 5 is recessed at the reduction point 2 to absorb the expansion of the rubber 5 and improve the service life of the rubber 5.

[0028] See also Figure 4 , which is a schematic diagram of the structure of the optimized milling groove 3 and slotting 4 of the rubber 5. During the bulging process of the rubber 5, the rubber 5 will also bulge at the places where it does not contact the product, causing wear at the contact places between the rubber 5 and the product opening, affecting the service life of the rubber 5. Milling grooves 3 at the places where the rubber 5 and the product do not contact can reduce the bulging amount at the places where the rubber 5 and the product do not contact, thereby reducing the wear at the places where the rubber 5 and the product opening and increasing the service life of the rubber 5. When the mold is pressed down, the rubber 5 bulges, and the rubber 5 on the outside of the product bulges outward: as shown by the black arrow, the rubber 5 at the contact places between the edge of the product and the rubber 5 will wear, thereby affecting the service life of the rubber 5. Slotting 4 at the places where the rubber 5 and the product opening are combined can reduce the wear of the rubber 5 and increase the service life of the rubber 5.

[0029] Since the die block 6 in the bulging step is an assembled structure, there will be line marks on the product after bulging at the assembly joint. The line marks here are related to the bulging amount of the polyurethane foam 5. After a large number of DOE verifications, we found that if the mold downtime exceeds 30 minutes, the deformation of the polyurethane foam 5 during production will affect the product line marks. Every time the production is stopped for more than 30 minutes, the problem is solved by preheating the polyurethane foam 5 by idling the mold for 30 minutes before production.

[0030] At present, similar products mainly adopt engineering molds and shrinking processes, which have the problems of multiple mold stations, high labor costs and unstable dimensions. The use of continuous molds and polyurethane bulging process can improve the above situation. Refer to Table 1 for a comparison of production parameters:

[0031] Table 1

[0032] Production time (S) Production quantity per hour Number of molds Machine operators Support staff Total manpower yield Continuous Die 2.5 1440 1 1 2 3 98% Engineering mold 7.5 480 4 4 2 6 92%

[0033] As shown in Table 1, the use of continuous die plus polyurethane bulging process has the following advantages:

[0034] S1: High production capacity, the production capacity of one line of continuous mold is equivalent to the production capacity of three lines of engineering molds;

[0035] S2: less manpower, the manpower of one line of engineering mold is equivalent to the manpower of two lines of continuous mold;

[0036] S3: High yield, continuous mold production products with stable structure, size and appearance;

[0037] S4: Urea is cheap, has a long service life, and the mold is easy to repair;

[0038] S5: The die bulging process has a simple structure.

[0039] The above description is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent replacement or change made by any technician familiar with the technical field within the technical scope disclosed by the present invention based on the technical solution and novel concept of the present invention should be covered by the scope of protection of the present invention.

Claims

1. A stamping die in-mold urethane bulging structure, characterized by: The urethane bulging structure is arranged above the die block of the bulging step. The straight surface of the urethane bulging structure at the corner is used to add material to meet the bulging amount of the product corner. The curved surface at the corner of the urethane bulging structure is concave to reduce material to absorb the bulging amount of the urethane. Milling grooves at the places where the rubber and the product do not contact each other, so as to reduce the amount of bulging at the places where the rubber and the product do not contact each other; A groove is formed at the junction of the urethane foam and the product opening to reduce the wear of the urethane foam at the contact point between the product edge and the urethane foam during the bulging process of the urethane foam.

2. The in-mold urethane bulging structure of a stamping die according to claim 1, characterized in that: The urethane bulging structure adopts black urethane.

3. The in-mold urethane bulging structure of a stamping die according to claim 1, characterized in that: The bulging step die block is an assembled structure.

4. A forming process using the bulging structure of the urethane foam in the stamping die according to any one of claims 1 to 3, characterized in that: The specific molding process is as follows: S1: stretching the product into a set shape, wherein the set shape is smaller than the final product structure; S2: The product with a set shape is bulged to the size of the final product through the use of PU. The PU bulges inside the product and is compressed by closing the mold to bulge the PU. The outside of the product is the mold cavity. S3: Finally, the excess material at the mouth is removed through CNC process to obtain the final product.

5. A molding process according to claim 4, characterized in that The process includes: preheating the rubber by setting a time through mold blanking before production.

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