Forming process and forming mold for machining sheet metal plastic-coated part

Abstract

The invention relates to the technical field of metal plate plastic-coated part machining, in particular to a forming process and a forming mold for machining a metal plate plastic-coated part, and the forming process comprises the steps of manufacturing a hard mold, designing a prototype, manufacturing a soft mold, manufacturing a metal plate plastic-coated part forming mold, manufacturing a sprue, fixing a metal plate part and pouring a product. The forming die comprises an upper base plate and a lower base plate, the upper base plate is provided with a hard die upper die, and the lower base plate is provided with a hard die lower die; a silica gel soft mold is arranged in the hard mold upper mold and the hard mold lower mold; a metal plate positioning pin, a stainless steel positioning column and a forming insert pin are connected in the metal hard mold in a penetrating manner; a pouring gate is arranged on the hard mold upper mold; the uncontrollable forming characteristic of the silica gel mold is converted into the controllability of machining through hard mold positioning, the uniform and thin soft mold forming cavity better avoids forming errors caused by expansion of the soft mold, and the forming effect of the metal plate plastic-coated part is improved.

Description

Technical Field

[0001] The invention relates to the technical field of sheet metal plastic-coated parts processing, and in particular to a molding process and a molding die for processing sheet metal plastic-coated parts. Background Art

[0002] Sheet metal plastic-coated parts are made by pouring plastic-coated materials on a metal body. They are an electronic control connection product that can be used in new energy vehicles and electronic control electromechanical products.

[0003] In the prior art, sheet metal overmolded parts are generally formed by injection molding and silicone mold molding.

[0004] 1. Injection molding: using various types of steel to process the cavity, through a variety of processing techniques such as machining, heat treatment, wire cutting, electric spark processing auxiliary structures, and core pulling, demolding, water channels and other structures, assembling the mold frame positioning, and finally using the injection molding machine to inject plastic particles into the mold, with high efficiency, high precision, a wide range of materials, complete supporting facilities and other characteristics. The disadvantages are obvious: the mold process is complex and the cycle is long; the mold cost is high, and the cost of small batch products is too high.

[0005] 2. Silicone mold molding: In recent years, the process of 3D printing prototype + silicone mold + vacuum molding has been increasingly used in the field of product research and development. 3D printing is not limited to integrated product structure, and prototypes can be quickly obtained from three-digit molds; the elastic characteristics of silicone can ignore core pulling and demolding, and directly open the mold quickly; two-component polyurethane AB material is used for stirring and curing at room temperature; overall, products with customer performance can be obtained quickly at a lower cost. The disadvantages are also obvious: short mold life, low mold precision, and repeatability accuracy is greatly affected by manual labor, so it is basically limited to the field of sample production; In summary, according to market demand, fast delivery of high-quality products in small batches with multiple varieties is the trend in the design and development of automobile, electronic and other products. For example, under multiple brands of new energy vehicles, the delivery volume is small or expected to be uncontrollable, and the injection molding process and silicone mold molding process cannot meet the supply needs of the above products well.

[0006] Therefore, we need a new molding process and molding mold for processing sheet metal plastic-coated parts to meet the market supply demand for small-batch, low-cycle sheet metal plastic-coated parts. Summary of the invention

[0007] In view of the shortcomings of the prior art described above, the purpose of the present invention is to provide a molding process and a molding mold for processing sheet metal plastic-coated parts, so as to solve the problem that the prior art cannot well meet the market supply demand for small-batch, low-cycle sheet metal plastic-coated parts.

[0008] To achieve the above-mentioned purpose and other related purposes, the present invention provides a molding process for processing sheet metal plastic-coated parts, comprising the following steps: S1. Making a hard mold: using two metal plates as an upper substrate and a lower substrate, fixing a metal material between the upper substrate and the lower substrate; fixing the upper substrate and the lower substrate with the metal material fixed on a CNC machine tool, and making the metal material into a metal hard mold; the metal hard mold includes a separable hard mold upper mold and a hard mold lower mold; S2. Design prototype: Use additive manufacturing technology to print out the prototype of sheet metal plastic parts; S3, making a soft mold: placing the prototype in a metal hard mold, inserting a plurality of sheet metal positioning pins in the lower mold of the hard mold just below the corresponding sheet metal printing position of the prototype, connecting a plurality of sheet metal positioning inserts to the sheet metal positioning pins, and the upper ends of the sheet metal positioning inserts abut against the corresponding sheet metal printing position on the prototype; S4. Making a sheet metal overmolding mold: Based on the prototype, a silicone soft mold is made in a metal hard mold by 3D printing the prototype. After printing, the silicone soft mold is opened along the upper and lower mold separation contours of the metal hard mold. After opening the mold, the prototype is taken out to obtain a sheet metal overmolding mold with a cavity; S5. Making a gate: opening a gate on the sheet metal overmolding mold, with one end of the gate penetrating to the outside of the hard mold upper mold and the other end penetrating to the cavity; S6. Fixing the sheet metal part: placing the sheet metal part in the sheet metal overmolding part forming mold, with the lower end of the sheet metal part fixed on the sheet metal positioning insert and the upper end extending into the cavity; S7, Casting products: Pour the plastic material from the gate into the cavity, and after pouring, place it in an oven together with the sheet metal plastic molding mold to solidify and form; S8. After the plastic part is wrapped around the sheet metal part and fixed into shape, it is taken out and aired to room temperature before the mold is opened. The product is taken out and the excess material at the gate is removed to obtain the finished sheet metal plastic part.

[0009] In one embodiment of the present invention, in the step S1, stainless steel positioning columns are embedded on the mold bodies of the hard mold upper mold and the hard mold lower mold near the outer edge of the silicone soft mold to position the molding accuracy of the silicone soft mold.

[0010] In one embodiment of the present invention, molding pins are embedded in the upper and lower ends of the hard mold upper mold and the hard mold lower mold corresponding to the upper cavity of the silicone soft mold.

[0011] In one embodiment of the present invention, in the step S1, the metal material is detachably fixed to the upper substrate and the lower substrate by bolts.

[0012] In one embodiment of the present invention, in the step S2, the size of the prototype is uniformly enlarged by 5-10 mm compared to the size of the target molded product of the sheet metal overmolded part.

[0013] In one embodiment of the present invention, in the step S7, pouring the molded part material includes vacuum pouring and injection molding.

[0014] A forming die for processing sheet metal plastic-coated parts, comprising an upper base plate and a lower base plate, wherein the upper base plate is provided with a hard mold upper die, and the lower base plate is provided with a hard mold lower die that can be molded relative to the hard mold upper die; A silicone soft mold is provided between the hard mold upper mold and the hard mold lower mold, and the silicone soft mold has a cavity; The lower die of the hard die is provided with a sheet metal positioning pin, and the sheet metal positioning pin is connected with a plurality of sheet metal positioning inserts; The upper mold and the lower mold of the hard mold are both provided with a first stainless steel positioning column on the mold body close to the outer edge of the silicone soft mold; The upper and lower ends of the hard mold upper mold and the hard mold lower mold corresponding to the upper mold cavity of the silicone soft mold are both provided with molding pins; The hard mold upper mold is provided with a gate, one end of the gate passes through the upper base plate to the outside, and the other end passes through the cavity.

[0015] As described above, the molding process and molding die for processing sheet metal plastic-coated parts of the present invention have the following beneficial effects: 1. The present invention makes a major innovation in the production method of the forming mold of the sheet metal overmolded parts. The sheet metal overmolded parts are formed by using a metal mold in combination with a silicone mold. The principle is that all product structures with precision requirements and installation requirements use metal molds to ensure precision, and other structures use the easy demoulding property of the silicone mold to quickly obtain parts. Ultimately, for customers, the mold cost is greatly reduced (compared with the injection mold, the cost is reduced by 80~90%), and the mold production cycle is greatly shortened (from 30-40 days for injection molds to within 3~4 days, shortened by 90%). Although the life of the soft mold part of the mold is still low, the soft mold part has a longer service life. Under the premise of ensuring product accuracy, the hard mold can quickly obtain a new mold by replacing the soft mold part (4-10 hours). It is suitable for the production of small and medium-sized batches of products rather than large batches, and for the molding of various thermosetting plastics and modified material parts, especially row-molded parts with metal inserts that have precision requirements, such as sheet metal overmolded parts and connectors for new energy vehicles. It has been well received by customers in the fields of medical equipment, new energy vehicles, etc., especially in the three-electric system of new energy electronic control, motor and battery, which can meet the non-standard requirements of copper busbar sheet metal for transmitting high voltage electricity and non-standard requirements of automotive parts, with a wide range of applications and good practicality.

[0016] 2. The present invention converts the uncontrollable molding characteristics of the silicone mold into controllable machining through hard mold positioning. The uniform and thin soft mold molding cavity better avoids the molding error caused by the expansion of the soft mold itself. The specific method includes: all key positioning are integrated into an integral hard mold, and the accuracy is guaranteed by CNC numerical control processing. Aluminum is usually used for hard mold production, and the processing accuracy can be controlled within ±0.03-0.05mm. A few are made of steel, and the accuracy can be controlled to ±0.01-0.03mm; the soft mold is a molding cavity with a wall thickness uniformly offset by 5~10mm outward according to the product shape. Due to the uniform offset, the cavity thickness is guaranteed to be consistent, thereby avoiding the difference in cavity size caused by different thicknesses of the soft rubber cavity, and can well avoid the trouble caused by the expansion of the soft mold to the molding. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 Shown is a perspective structural schematic diagram of a forming mold for processing sheet metal plastic-coated parts disclosed in the present invention.

[0018] Figure 2 Shown is a schematic diagram of the upper mold structure of a molding die for processing sheet metal plastic-coated parts disclosed in the present invention.

[0019] Figure 3 Shown is a schematic diagram of the lower mold structure of a molding mold for processing sheet metal plastic-coated parts disclosed in the present invention.

[0020] Component number description Upper substrate 1; lower substrate 2; hard mold upper mold 3; hard mold lower mold 4; silicone soft mold 5; cavity 6; sheet metal positioning pin 7; sheet metal positioning insert 8; stainless steel positioning column 9; gate 10; molding pin 11. DETAILED DESCRIPTION

[0021] The following is a description of the implementation of the present invention by means of specific embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification.

[0022] See also Figures 1 to 3. It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings in this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention, so they have no substantial technical significance. Any modification of the structure, change in the proportional relationship, or adjustment of the size should still fall within the scope of the technical content disclosed by the present invention without affecting the effects and purposes that can be achieved by the present invention. At the same time, the terms such as "upper", "lower", "left", "right", "middle" and "one" quoted in this specification are only for the convenience of description, and are not used to limit the scope of the implementation of the present invention. Changes or adjustments in their relative relationships should also be regarded as the scope of the implementation of the present invention without substantially changing the technical content.

[0023] Example 1, please refer to Figure 1-3 This embodiment provides a molding process for processing sheet metal plastic-coated parts, comprising the following steps: S1, making a hard mold: using two metal plates as an upper substrate 1 and a lower substrate 2, fixing a metal material between the upper substrate 1 and the lower substrate 2, specifically, in the step S1, the metal material is detachably fixed to the upper substrate 1 and the lower substrate 2 by bolts; fixing the upper substrate 1 and the lower substrate 2 with the metal material fixed on a CNC machine tool, and making the metal material into a metal hard mold; the metal hard mold includes a separable hard mold upper mold 3 and a hard mold lower mold 4; S2. Design prototype: Use additive manufacturing technology to print out the prototype of the sheet metal overmolded part. The size of the prototype is evenly enlarged by 5-10mm compared to the size of the target molded product of the sheet metal overmolded part. S3, making a soft mold: placing the prototype in a metal hard mold, inserting a plurality of sheet metal positioning pins 7 in the hard mold lower mold 4 directly below the corresponding sheet metal printing position of the prototype, and connecting a plurality of sheet metal positioning inserts 8 to the sheet metal positioning pins 7, and the upper ends of the sheet metal positioning inserts 8 abut against the corresponding sheet metal printing position on the prototype; S4, making a sheet metal overmolding mold: based on the prototype, a silicone soft mold 5 is made in a metal hard mold by 3D printing the prototype, and after printing, the silicone soft mold is opened along the upper and lower mold separation contours of the metal hard mold, and after opening the mold, the prototype is taken out to obtain a sheet metal overmolding mold with a cavity 6; S5, making a gate 10: a gate 10 is provided on the sheet metal overmolding forming mold, one end of the gate 10 penetrates to the outside of the hard mold upper mold 3, and the other end penetrates to the cavity 6; an exhaust port (this structure is not shown in the attached drawings) may also be provided on the sheet metal overmolding forming mold, one end of the exhaust port penetrates to the outside of the hard mold upper mold 3, and the other end penetrates to the cavity 6; S6, fixing the sheet metal part: placing the sheet metal part in the sheet metal overmolding forming mold, with the lower end of the sheet metal part fixed on the sheet metal positioning insert 8 and the upper end extending into the cavity 6; S7, pouring the product: pouring the plastic material from the gate 10 into the cavity 6, and placing it together with the sheet metal plastic molding mold in an oven for curing and molding; S8. After the plastic part is wrapped around the sheet metal part and fixed into shape, it is taken out and aired to room temperature before opening the mold. The product is taken out and excess material at 10 places of the gate is removed to obtain the finished sheet metal plastic part.

[0024] In step S1, stainless steel positioning columns 9 are embedded on the mold bodies of the hard mold upper mold 3 and the hard mold lower mold 4 near the outer edge of the silicone soft mold to locate the molding accuracy of the silicone soft mold. Molding pins 11 are embedded on the upper and lower ends of the hard mold upper mold 3 and the hard mold lower mold 4 corresponding to the upper mold cavity 6 of the silicone soft mold 5.

[0025] In the step S7, the casting of plastic parts includes vacuum casting and injection molding. After the mold is completed, there are two ways to form it later: vacuum casting or injection molding. Among them, the soft and hard integrated molds are different. Vacuum casting is performed by vacuum equipment to form a negative pressure in the mold cavity 6, and the AB mixed polyurethane resin is poured at room temperature, and then cured and molded by an oven in the later stage; the hard mold part uses stainless steel positioning columns and molding pins to ensure the accuracy requirements, and the rest are soft molds, which have the advantages of fast and low-cost molding, and are suitable for the manufacturing needs of dozens to hundreds of sets of small batch production products. For products of hundreds to thousands of sets, injection molding is required to improve production efficiency and reduce production costs. Because injection molding requires higher pressure, the soft mold is mainly concentrated in the complex structure and side core pulling part, and no draft angle is required. It should be noted that the soft mold material needs to be hard silicone with high temperature resistance and hardness greater than 60 degrees. If necessary, the silicone needs to be demolded together with the product. The injection pressure needs to be adjusted to suitable parameters according to the product structure. For small and medium batch products, although the production efficiency is slightly lower to a certain extent, it still greatly improves the delivery cycle overall.

[0026] The present invention converts the uncontrollable molding characteristics of the silicone mold into controllable machining through hard mold positioning. The uniform and thin soft mold molding cavity 6 can better avoid the molding error caused by the expansion of the soft mold itself. The specific method includes: all key positioning are integrated into an integral hard mold, and the accuracy is guaranteed by CNC numerical control processing. Aluminum is usually used for hard mold production, and the processing accuracy can be controlled within ±0.03-0.05mm. A few are made of steel, and the accuracy can be controlled to ±0.01-0.03mm; the soft mold is a molding cavity 6 with a wall thickness uniformly offset by 5~10mm outward according to the product shape. Due to the uniform offset, the thickness of the cavity 6 is guaranteed to be consistent, thereby avoiding the size difference of the cavity 6 caused by the different thickness of the soft rubber cavity 6, and can well avoid the trouble caused by the expansion of the soft mold to the molding.

[0027] Embodiment 2, this embodiment provides a forming mold for processing sheet metal plastic-coated parts, comprising an upper substrate 1 and a lower substrate 2, wherein the upper substrate 1 is provided with a hard mold upper mold 3, and the lower substrate 2 is provided with a hard mold lower mold 4 that can be molded relative to the hard mold upper mold 3; A silicone soft mold 5 is provided between the hard mold upper mold 3 and the hard mold lower mold 4, and the silicone soft mold 5 has a cavity 6; The hard mold lower mold 4 is penetrated by a sheet metal positioning pin 7, and the sheet metal positioning pin 7 is connected to a plurality of sheet metal positioning inserts 8; The upper hard mold 3 and the lower hard mold 4 are both provided with a first stainless steel positioning column 9 on the mold bodies close to the outer edge of the silicone soft mold 5; The upper and lower ends of the hard mold upper mold 3 and the hard mold lower mold 4 corresponding to the upper mold cavity 6 of the silicone soft mold 5 are both provided with molding pins 11; The hard mold upper mold 3 is provided with a gate 10 , one end of the gate 10 passes through the upper substrate 1 to the outside, and the other end passes through the cavity 6 .

[0028] The present invention makes a major innovation in the production method of the forming mold of the sheet metal overmolded parts. The sheet metal overmolded parts are formed by using a metal mold in combination with a silicone mold. The principle is that all product structures with precision requirements and installation requirements use metal molds to ensure precision, and other structures use the easy demoulding property of the silicone mold to quickly obtain parts. Ultimately, for customers, the mold cost is greatly reduced (compared with the injection mold, the cost is reduced by 80~90%), and the mold production cycle is greatly shortened (from 30-40 days for injection molds to within 3~4 days, shortened by 90%). Although the life of the soft mold part of the mold is still low, the hard and soft mold parts are much shorter. Under the premise of ensuring product accuracy, the new mold can be quickly obtained by replacing the soft mold part (4-10 hours). It is suitable for the production of small and medium-sized batches of products rather than large quantities, and for the molding of various thermosetting plastics and modified material parts, especially plastic-plated products with metal inserts that have precision requirements, such as sheet metal plastic-plated parts and connectors for new energy vehicles. It has been well received by customers in the fields of medical equipment, new energy vehicles, etc., especially in the three-electric system of new energy electronic control, motor and battery, which can meet the non-standard requirements of copper sheet metal for transmitting high voltage electricity and non-standard requirements of automotive parts, with a wide range of applications and good practicality.

[0029] In summary, the present invention converts the uncontrollable molding characteristics of the silicone mold into controllable machining through hard mold positioning. The uniform and thin soft mold molding cavity 6 better avoids the molding error caused by the expansion of the soft mold itself. The specific method includes: all the key positioning are integrated into an integral hard mold, and the accuracy is guaranteed by CNC numerical control processing. Aluminum is usually used for hard mold production, and the processing accuracy can be controlled within ±0.03-0.05mm. A few are steel materials, and the accuracy can be controlled to ±0.01-0.03mm; the soft mold is a molding cavity 6 with a wall thickness of 5~10mm uniformly offset outward according to the product shape. Due to the uniform offset, the thickness of the cavity 6 is guaranteed to be consistent, thereby avoiding the difference in cavity size caused by different thicknesses of the soft rubber cavity 6, and can well avoid the trouble caused by the expansion of the soft mold to the molding. Therefore, the present invention effectively overcomes the various shortcomings of the prior art and has a high industrial utilization value.

[0030] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A molding process for processing sheet metal plastic-coated parts, characterized in that: The steps include: S1. Making a hard mold: using two metal plates as an upper substrate and a lower substrate, fixing a metal material between the upper substrate and the lower substrate; fixing the upper substrate and the lower substrate with the metal material fixed on a CNC machine tool, and making the metal material into a metal hard mold; the metal hard mold includes a separable hard mold upper mold and a hard mold lower mold; S2. Design prototype: Use additive manufacturing technology to print out the prototype of sheet metal plastic parts; S3, making a soft mold: placing the prototype in a metal hard mold, inserting a plurality of sheet metal positioning pins in the lower mold of the hard mold just below the corresponding sheet metal printing position of the prototype, connecting a plurality of sheet metal positioning inserts to the sheet metal positioning pins, and the upper ends of the sheet metal positioning inserts abut against the corresponding sheet metal printing position on the prototype; S4. Making a sheet metal overmolding mold: Based on the prototype, a silicone soft mold is made in a metal hard mold by 3D printing the prototype. After printing, the silicone soft mold is opened along the upper and lower mold separation contours of the metal hard mold. After opening the mold, the prototype is taken out to obtain a sheet metal overmolding mold with a cavity; S5. Making a gate: opening a gate on the sheet metal overmolding mold, with one end of the gate penetrating to the outside of the hard mold upper mold and the other end penetrating to the cavity; S6. Fixing the sheet metal part: placing the sheet metal part in the sheet metal overmolding part forming mold, with the lower end of the sheet metal part fixed on the sheet metal positioning insert and the upper end extending into the cavity; S7, Casting products: Pour the plastic material from the gate into the cavity, and after pouring, place it in an oven together with the sheet metal plastic molding mold to solidify and form; S8. After the plastic part is wrapped around the sheet metal part and fixed into shape, it is taken out and aired to room temperature before the mold is opened. The product is taken out and the excess material at the gate is removed to obtain the finished sheet metal plastic part.

2. The molding process for processing sheet metal plastic-coated parts according to claim 1, characterized in that: In the step S1, stainless steel positioning columns are embedded on the mold bodies of the hard mold upper mold and the hard mold lower mold near the outer edge of the silicone soft mold to position the molding accuracy of the silicone soft mold.

3. The molding process for processing sheet metal plastic-coated parts according to claim 2, characterized in that: The upper and lower ends of the hard mold upper mold and the hard mold lower mold corresponding to the upper mold cavity of the silicone soft mold are both embedded with molding pins.

4. The molding process for processing sheet metal plastic-coated parts according to claim 1, characterized in that: In the step S1, the metal material is detachably fixed to the upper substrate and the lower substrate by bolts.

5. The molding process for processing sheet metal plastic-coated parts according to claim 1, characterized in that: In the step S2, the size of the prototype is uniformly enlarged by 5-10 mm compared to the size of the target molded product of the sheet metal overmolded part.

6. The molding process for processing sheet metal plastic-coated parts according to claim 1, characterized in that: In the step S7, pouring the plastic material includes vacuum pouring and injection molding.

7. A forming die for processing sheet metal plastic-coated parts, characterized in that: It comprises an upper base plate and a lower base plate, wherein the upper base plate is provided with a hard mold upper mold, and the lower base plate is provided with a hard mold lower mold which can be molded relative to the hard mold upper mold; A silicone soft mold is provided between the hard mold upper mold and the hard mold lower mold, and the silicone soft mold has a cavity; The lower die of the hard die is provided with a sheet metal positioning pin, and the sheet metal positioning pin is connected with a plurality of sheet metal positioning inserts; The upper mold and the lower mold of the hard mold are both provided with a first stainless steel positioning column on the mold body close to the outer edge of the silicone soft mold; The upper and lower ends of the hard mold upper mold and the hard mold lower mold corresponding to the upper mold cavity of the silicone soft mold are both provided with molding pins; The hard mold upper mold is provided with a gate, one end of the gate passes through the upper base plate to the outside, and the other end passes through the cavity.

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