Injection-molding press and method for thin-walled products

Abstract

The present application relates to the field of operation or transportation, and provides an injection molding and transfer mold for thin-walled products and a method thereof. The injection molding and transfer mold for thin-walled products comprises an upper mold and a lower mold. The upper mold comprises an upper mold plate and an upper mold core. The lower mold comprises a lower mold plate and a lower mold core, and an elastic member is arranged between the lower mold core and the lower mold plate. The lower mold is provided with a ejector pin unit. The lower mold core and the upper mold core form at least one cavity structure when the mold is closed, and a top core is arranged on the lower mold plate. The cavity structure is formed by the first mold closing, and part of the injection material is injected. The second mold closing is performed before the injection material is completely cooled, so that the space in the cavity structure is compressed, thereby promoting the injection material to flow further and completely fill each corner of the cavity, improving the molding integrity. The top core is ejected synchronously when the second mold closing is performed, so that the distance between the side walls of the cavity structure opposite to the top core is reduced, forming the thin-walled structure of the product, forming a uniform and dense thin-walled structure, and improving the quality of injection molding.

Description

Technical Field

[0001] This invention relates to the field of operation or transportation, and specifically to an injection molding die and method for thin-walled products. Background Technology

[0002] A mold is a set of molds and tools used in industrial production to obtain desired products through methods such as injection molding, blow molding, extrusion, die casting, forging, smelting, and stamping. In short, a mold is a tool used to create shaped objects; this tool is composed of various parts, and different molds are composed of different parts. It primarily achieves the shaping of objects by changing the physical state of the material being molded.

[0003] In the process of realizing this invention, the inventors discovered the following problems in the prior art: In existing thin-walled structure products, if molds are used for production, the plastic injection may not be completely filled, or flash may be generated, resulting in poor production quality or inability to be injection molded. Summary of the Invention

[0004] The purpose of this invention is to provide an injection molding die for thin-walled products, which aims to improve the problem of low pass rate or poor product quality when using existing molds to produce thin-walled products.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: an injection molding die for thin-walled products, comprising:

[0006] The upper mold includes an upper template and an upper mold core disposed within the upper template;

[0007] The lower mold includes a lower template and a lower mold core disposed within the lower template. An elastic element is provided between the lower mold core and the lower template to provide a clamping force for the lower mold core. The elastic element is also used to support the lower mold core to form a stepped surface for secondary mold closing with the lower mold.

[0008] The lower mold is also provided with an ejector pin unit for ejecting the product from the lower mold core.

[0009] When the lower mold core and the upper mold core are closed, they form at least one cavity structure. The lower mold plate is provided with a top core that penetrates the cavity of the lower mold core. When the upper mold core and the lower mold core move during mold closing, the distance between the top core and the cavity structure is adjusted to form thin-wall injection molding.

[0010] As a preferred structure of the present invention, the lower template is provided with a groove for accommodating the lower mold core, a plurality of elastic elements are disposed in the bottom of the groove, and a stroke gap for secondary mold closing is provided between the lower mold core and the bottom of the groove.

[0011] As a preferred structure of the present invention, the elastic element is formed by stacking a plurality of disc springs.

[0012] As a preferred structure of the present invention, it further includes a dial indicator, which is disposed on the outer side of the lower mold, and a detection rod is disposed on the lower mold core for contact detection with the dial indicator.

[0013] As a preferred structure of the present invention, the ejector unit includes two symmetrically arranged support plates, an ejector plate disposed in the space between the two support plates, and a plurality of ejector pins disposed on the ejector plate, wherein the plurality of ejector pins are used to eject the product from the cavity of the lower mold core.

[0014] As a preferred structure of the present invention, the ejector pin unit further includes a layer plate disposed between the support plate and the lower template, and a plurality of spring posts and limiting posts are disposed between the layer plate and the ejector pin plate, wherein the plurality of spring posts are used to provide elastic force to the ejector pin plate to limit or adjust the speed of movement.

[0015] As a preferred structure of the present invention, two tie rods are symmetrically arranged between the upper template and the ejector plate.

[0016] As a preferred structure of the present invention, the lower mold is provided with a bottom plate located on the bottom surface of the ejector pin unit, and the upper mold is provided with a top plate disposed on the upper template.

[0017] The present invention also provides an injection molding method for thin-walled products, which aims to improve the problem of low pass rate or poor product quality when using existing molds to produce thin-walled products.

[0018] To achieve the above objectives, the present invention adopts the following technical solution: an injection molding method for thin-walled products, used for injection molding with an injection mold for thin-walled products as described above, comprising the following steps:

[0019] In the initial state, there is a stepped height difference between the lower mold core and the lower mold plate, which allows for secondary mold closing.

[0020] Turn on the injection molding machine and perform the first mold closing, so that the lower mold core and the upper mold core close together to obtain the injection cavity;

[0021] Injecting 90%-98% of the volume of injection material into the injection cavity;

[0022] The mold is closed a second time, pushing the closing surface of the lower mold core to be flush with the closing surface of the lower mold plate, so that the upper mold plate and the lower mold plate can be closed to obtain the product cavity;

[0023] The distance between the top surface and the core inside the product cavity is reduced to form a thin-walled gap, while the injection molding material completely fills the reduced product cavity.

[0024] After the injection molded part in the product cavity solidifies and forms, the injection molding machine opens the mold and removes the part, obtaining an injection molded part with a thin-walled structure on one side.

[0025] As a preferred structure of the present invention, during the first mold closing, the mold closing position error of the lower mold core is detected. If there is no error, the injection molding operation is performed; if the error value is large, the mold is opened for manual inspection or the mold closing is repeated.

[0026] By adopting the above technical solution, the present invention has the following advantages compared with the prior art:

[0027] 1. The injection molding die for the thin-walled product of this invention employs a two-stage mold-closing method for injection molding. The first mold-closing creates a cavity structure and injects a portion of the injection material, such as 95%, preventing incomplete filling due to insufficient injection pressure or excessive flow resistance. The second mold-closing, performed before the injection material has completely cooled, compresses the space within the cavity structure, promoting further flow of the injection material and completely filling all corners of the cavity, thus improving molding integrity. Simultaneously, the additional pressure applied to the material during the second mold-closing process effectively reduces flash and improves product dimensional accuracy and surface quality. Furthermore, the ejector core ejects synchronously during the second mold-closing, reducing the distance between the sidewalls of the cavity structure opposite to the ejector core (along the direction of movement), thereby forming a thin-walled structure. The compression during the flow and filling of the injection material effectively avoids incomplete filling, resulting in a more uniform and dense thin-walled structure and improving injection molding quality. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the injection molding die for the thin-walled product described in this invention;

[0029] Figure 2 A cross-sectional view of the injection mold for the thin-walled product described in this invention;

[0030] Figure 3 This is a partial enlarged view of the injection molding die for the thin-walled product described in this invention at the location where the cavity structure and the ejector core meet;

[0031] Figure 4 This is a schematic diagram of the lower mold portion of the injection molding die for the thin-walled product described in this invention.

[0032] Figure 5 A partial view of the injection molding die for the thin-walled product described in this invention;

[0033] Figure 6 This is a schematic diagram of the upper mold portion of the injection molding die for the thin-walled product described in this invention.

[0034] Figure 7 This is a partial view of the lower mold portion of the injection molding die for the thin-walled product described in this invention;

[0035] Figure 8 This is a schematic diagram of the structure of a thin-walled product, which is an injection molding die for the thin-walled product described in this invention.

[0036] Figure 9 This is a schematic diagram of the structure of another thin-walled product for the injection molding mold of the thin-walled product described in this invention;

[0037] Figure 10 This is a flowchart of the injection molding method for thin-walled products according to the present invention.

[0038] Explanation of reference numerals in the attached figures:

[0039] 100. First thin-walled product; 110. Second thin-walled product;

[0040] 10. Upper mold; 101. Upper template; 102. Upper mold core;

[0041] 20. Lower mold; 201. Lower mold plate; 202. Lower mold core; 203. Elastic component; 204. Stepped surface; 205. Ejector pin unit; 206. Ejector core;

[0042] 2011, Groove; 2012, Stroke clearance; 2013, Detection rod;

[0043] 2051, Support plate; 2052, Ejector plate; 2053, Ejector pin; 2054, Shelf; 2055, Spring column; 2056, Limiting column;

[0044] 30. Cavity structure;

[0045] 40. Dial indicator; 41. Tie rod; 42. Base plate; 43. Top plate. Detailed Implementation

[0046] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0047] Additionally, it should be noted that the terms "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer" are all based on the orientation or positional relationship shown in the accompanying drawings. They are merely for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element of the present invention must have a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0048] When an element is referred to as being "fixed to," "set on," or "contained on" another element, it can be directly on or indirectly on that other element. When an element is referred to as being "connected to," it can be directly connected to or indirectly connected to that other element.

[0049] Unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0050] Example 1

[0051] Please refer to Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 and Figure 6 As shown, this embodiment provides an injection molding die for a thin-walled product, including an upper mold 10 and a lower mold 20. The upper mold 10 includes an upper template 101 and an upper mold core 102 disposed within the upper template 101. The lower mold 20 includes a lower template 201 and a lower mold core 202 disposed within the lower template 201. An elastic element 203 is provided between the lower mold core 202 and the lower template 201 to provide a clamping force for the lower mold core 202. The elastic element 203 is also used to support the lower mold core 202 to form a stepped surface 204 for secondary mold closing with the lower mold 20. The lower mold 20 is also provided with an ejector pin unit 205 for ejecting the product from the lower mold core 202; the lower mold core 202 and the upper mold core 102 form at least one cavity structure 30 when the mold is closed. The lower mold plate 201 is provided with a core 206 that penetrates the cavity of the lower mold core 202. When the upper mold core 102 and the lower mold core 202 move during mold closing, the gap between the core 206 and the cavity structure 30 is adjusted to form a thin-walled injection molding, thereby obtaining a product structure with a thin wall. This thin wall formation can be applied to the structure of fingerprint covers, for example... Figure 8 and Figure 9The first thin-walled product 100 and the second thin-walled product 110 shown below are explained as thin-walled products.

[0052] Specifically, when injection molding thin-walled products (such as...) Figure 8 and Figure 9 As shown, the injection molding machine performs the first mold closing operation, closing the upper mold core 102 and the lower mold core 202. The elastic element 203 provides the clamping force required for mold closing, forming a sealed product cavity (i.e., cavity structure 30). At this point, molten plastic can be injected into the product cavity, but the injected molten plastic does not completely fill the cavity; for example, it fills 95% of the product cavity space. Then, the mold closing operation is performed again, pushing the upper mold 10 to continue moving, causing the lower mold core 202 to press against the elastic element 203 until it is flush with the closing surface of the lower mold plate 201, forming the mold closing of the upper mold plate 101 and the lower mold plate 201 (the upper mold core 102 and the lower mold core 202 are always in the closed state). This completes the second mold closing operation. Since the ejector core 206 is fixed to the lower mold plate 201 and penetrates the lower mold core 202, during the secondary mold closing process, the ejector core 206 gradually moves towards the cavity direction of the upper mold core 102 relative to the cavity structure 30, reducing the distance between the ejector core 206 and the top surface of the cavity structure 30, i.e., reducing the space of the cavity structure 30, so that the molten plastic can completely fill it; at the same time, it can form a thin-walled structure with the top surface of the cavity structure 30. This operation can maintain the stability of mold closing during injection molding and avoid flash or material shortage defects caused by sudden pressure changes. By controlling the stroke of the secondary mold closing and the relative displacement of the ejector core 206, the molding thickness of the thin-walled area can be precisely controlled, ensuring the stroke quality of the thin-walled structure of the product, and effectively improving the dimensional accuracy and surface quality of the thin-walled product.

[0053] The elastic element 203 disclosed herein can be a disc spring. By utilizing the stacked design of multiple disc springs, it can provide stable elastic support force and sufficient compression stroke. At the same time, the number of disc springs and the preload can be adjusted according to requirements to adapt to the molding of thin-walled products with different thickness requirements.

[0054] like Figure 2 and Figure 4 As shown, in this disclosure, the lower mold plate 201 is provided with a groove 2011 for accommodating the lower mold core 202. Several elastic elements 203 are disposed within the bottom of the groove 2011. A stroke clearance 2012 for secondary mold closing is provided between the lower mold core 202 and the bottom of the groove 2011. The size of this stroke clearance 2012 is designed according to the compression required for thin-wall injection molding, thus obtaining the required thin-wall thickness. For example, to injection mold a 1.5mm thin-wall product (such as...) Figure 8 and Figure 9As shown in the diagram, the initial distance between the ejector core 206 and the top surface of the cavity is 5mm. During the secondary mold closing process, by controlling the downward stroke of the upper mold 10 to 3.5mm, the initial distance between the ejector core 206 and the top surface of the cavity is 1.5mm. Therefore, the stroke clearance 2012 must be greater than or equal to 3.5mm to achieve precise control of the secondary mold closing compression, thus ensuring that the injection-molded product achieves a thin-walled structure.

[0055] like Figure 1 and Figure 2 As shown, this disclosure also includes a dial indicator 40, which is disposed on the outer surface of the lower mold 20. A detection rod 2013 is disposed on the lower mold core 202 to contact and detect the dial indicator 40. The dial indicator 40 is used to measure mechanical measurements such as shape and position errors. By measuring shape and position errors, it can detect whether there is a deviation in the movement of the lower mold core 202, and determine whether there is any offset or tilting during the mold closing process between the lower mold core 202 and the upper mold core 102. By monitoring the displacement changes of the lower mold core 202 in real time during the secondary mold closing process, the synchronization and accuracy of the mold closing action are ensured. This effectively avoids defects such as flash, material shortage, or uneven product wall thickness caused by mold closing problems, and allows for timely adjustments and corrections, ensuring production quality.

[0056] like Figure 1 and Figure 7 As shown, the ejector unit 205 of this disclosure includes an ejector plate 2052 and an ejector pin 2053. A return spring can also be designed on the ejector pin 2053. One end of the ejector pin 2053 is connected to the ejector plate 2052, and the other end passes through the lower mold plate 201 and the lower mold core 202 and extends into the cavity. The return spring is sleeved on the outer periphery of the ejector pin 2053 and is used to push the ejector plate 2052 to return to its original position after the mold is opened. When the secondary mold closing is completed and the product has cooled and solidified, the injection molding machine drives the upper mold 10 to retract. At the same time, the ejector unit 205 moves, and the ejector plate 2052 drives the ejector pin 2053 to move forward, smoothly ejecting the molded thin-walled product from the lower mold core 202, avoiding product deformation or damage due to uneven ejection force, and ensuring the reliability and integrity of product demolding.

[0057] like Figure 1 and Figure 7 As shown, the ejector unit 205 of this disclosure also includes a layer plate 2054 disposed between the support plate 2051 and the lower template 201. Several sets of spring posts 2055 and limiting posts 2056 are disposed between the layer plate 2054 and the ejector plate 2052. The spring posts 2055 are used to provide elastic force to the ejector plate 2052 to limit or adjust the speed of movement.

[0058] Specifically, the spring post 2055 includes a columnar structure and a spring sleeved on the columnar structure. One end of the spring abuts against the shelf plate 2054, and the other end abuts against the ejector plate 2052. To improve the fatigue life and stress uniformity of the spring, a groove structure can be designed on the shelf plate 2054 to accommodate part of the spring, making the spring more evenly stressed during compression, reducing deformation fatigue caused by uneven loading, and thus extending its service life. The limiting post 2056 is used to limit the stroke range of the ejector plate 2052, preventing the spring from being over-compressed and failing, and ensuring the stability and consistency of each ejection action. This structure works together to ensure the smooth ejection of thin-walled products during demolding, improving the reliability and production efficiency of injection molds for thin-walled products.

[0059] like Figure 1 As shown, two tie rods 41 are symmetrically arranged between the upper mold plate 101 and the ejector plate 2052. One end of the tie rod 41 is fixed to the ejector plate 2052, and the other end is fixed to the upper mold plate 101. During the mold opening process, the tie rods 41 move upward synchronously with the upper mold plate 101, and drive the ejector plate 2052 to rise synchronously, realizing the linkage between the ejector plate 2052 and the upper mold plate 101, ejecting the product from the mold structure, thereby ensuring the continuity and precise coordination of the demolding action. The symmetrical arrangement of the two tie rods 41 also effectively balances the force distribution of the ejector plate 2052 during the movement, avoiding jamming or tilting caused by uneven force on one side, further improving the stability and reliability of the ejection system.

[0060] like Figure 1 and Figure 7 As shown, the lower mold 20 of this disclosure is provided with a base plate 42 located on the bottom surface of the ejector pin unit 205, and the upper mold 10 is provided with a top plate 43 disposed on the upper template 101. The design of the base plate 42 and the top plate 43 can provide a protective effect for the use of the mold. Lifting rings can also be designed to facilitate the lifting and transportation of the mold, improving the ease of operation and safety of the mold during installation and replacement.

[0061] Example 2

[0062] like Figure 10 As shown, this embodiment provides an injection molding method for thin-walled products, used for injection molding with an injection mold for thin-walled products as described in Embodiment 1. The structure of the injection mold can be found in Embodiment 1. The injection molding method for thin-walled products disclosed herein includes the following steps:

[0063] S101. In the initial state, the lower mold core 202 and the lower mold plate 201 form a stepped height difference for secondary mold closing.

[0064] Specifically, the lower mold core 202 and the lower mold plate 201 form a stepped surface 204 in the initial state, thus forming the lower mold core 202 as the first mold closing surface and the lower mold plate 201 as the second mold closing surface. This allows for two mold closing actions to form the thin-walled structure of the product.

[0065] S102. Start the injection molding machine and perform the first mold closing, so that the lower mold core 202 and the upper mold core 102 close together to obtain the injection cavity.

[0066] This disclosure utilizes an injection molding machine for the first mold closing, causing the lower mold core 202 and the upper mold core 102 to initially close, forming an injection cavity for molding the main structure of the product. The cavity between the lower mold core 202 and the upper mold core 102 reaches a preset initial closed state. Multiple sets of disc springs between the lower mold core 202 and the lower mold plate 201 provide mold closing pressure, ensuring that the pressure distribution is uniform and stable during the first mold closing, guaranteeing the reliability of the mold closing process, and avoiding flash or uneven filling due to insufficient pressure.

[0067] S1021. During the first mold closing, check the mold closing position error of the lower mold core 202. If there is no error, proceed with the injection molding operation. If the error value is large, open the mold for manual inspection or re-close the mold.

[0068] This disclosure utilizes a dial indicator 40 to monitor the mold-closing position accuracy of the lower mold core 202 in real time. This ensures precise alignment between the lower mold core 202 and the upper mold core 102 during mold closing, guaranteeing sealing after mold closing and preventing flash during subsequent injection molding. It also ensures the molding accuracy of thin-walled areas of the product. When the positional error exceeds a set threshold, the system automatically alarms and stops the injection molding process to prevent defective products. After confirming that the mold closing is correct, the injection molding machine is started for melt injection, improving production quality.

[0069] S103. Injecting 90%-98% of the volume of injection material into the injection cavity.

[0070] In this disclosure, when injecting into the injection cavity, the injection volume is controlled to be between 90% and 98% of the injection cavity capacity, preferably 95%, so as to reserve sufficient space for subsequent pressure holding and shrinkage compensation during secondary mold closing.

[0071] S104. Perform a second mold closing, pushing the mold closing surface of the lower mold core 202 to be flush with the mold closing surface of the lower mold plate 201, so that the upper mold plate 101 and the lower mold plate 201 close together to obtain the product cavity; the distance between the top surface and the core 206 in the product cavity is reduced, forming a thin-walled gap, and the injection molding material is completely filled into the reduced product cavity.

[0072] This disclosure performs a secondary mold closing action immediately after injection molding, with the mold closing interval controlled within 0.1-1.0 seconds to prevent premature cooling of the injection molded material. At this time, the lower mold core 202 continues to move downwards under the action of the drive mechanism until its mold closing surface is completely flush with the mold closing surface of the lower mold plate 201, achieving a tight fit between the upper mold plate 101 and the lower mold plate 201, completing the secondary mold closing. At this point, the distance between the ejector core 206 located in the product cavity and the top surface of the cavity is further compressed (the ejector core 206 is fixed and therefore does not move with the lower mold core 202, thus changing the volume within the product cavity), forming a precise thin-walled structural gap. Simultaneously, due to the reduced size of the product cavity, 90% to 98% of the injection mold cavity capacity can completely fill the product cavity, achieving pressure holding and shrinkage compensation, effectively eliminating defects such as shrinkage cavities or porosity inside the product.

[0073] Furthermore, after the secondary mold closing is completed, the gap between the ejector core 206 and the top of the product cavity is precisely controlled within the range of 0.1mm to 0.3mm (preferably 0.15mm) to ensure the structural density and dimensional accuracy of the thin-walled area. Simultaneously, this ensures efficient pressure transmission during the thin-walled molding process, preventing insufficient shrinkage due to excessive gaps.

[0074] S105. After the injection molded part in the product cavity has solidified, the injection molding machine opens the mold and removes the part to obtain an injection molded part with a thin wall structure on one side.

[0075] The injection-molded product disclosed herein can be a fingerprint cover, for example, obtained by injection molding from a thermoplastic material. One side wall of the fingerprint cover has a thin-walled structure with a thickness controlled at approximately 0.15 mm. Due to its relatively small size, it can be molded relatively quickly during injection molding. Traditional direct injection molding methods are prone to causing flash or material shortages, while this disclosure effectively avoids the above defects through secondary mold closing and precise shrinkage control. The thin-walled area is fully compacted during the holding pressure stage, resulting in stable product dimensions, no shrinkage or flash on the surface, and clear and complete details. After removal, the fingerprint cover is inspected and found to have uniform thin-wall thickness with tolerances controlled within ±0.02 mm, meeting high-precision assembly requirements.

[0076] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. An injection molding die for thin-walled products, characterized in that, include: The upper mold includes an upper template and an upper mold core disposed within the upper template; The lower mold includes a lower template and a lower mold core disposed within the lower template. An elastic element is provided between the lower mold core and the lower template to provide a clamping force for the lower mold core. The elastic element is also used to support the lower mold core to form a stepped surface for secondary mold closing with the lower mold. The lower mold is also provided with an ejector pin unit for ejecting the product from the lower mold core. When the lower mold core and the upper mold core are closed, they form at least one cavity structure. The lower mold plate is provided with a top core that penetrates the cavity of the lower mold core. When the upper mold core and the lower mold core move during mold closing, the distance between the top core and the cavity structure is adjusted to form thin-wall injection molding.

2. The injection molding die for thin-walled products according to claim 1, characterized in that, The lower template is provided with a groove for accommodating the lower mold core, and a plurality of elastic elements are disposed in the bottom of the groove. A travel clearance for secondary mold closing is provided between the lower mold core and the bottom of the groove.

3. The injection molding die for thin-walled products according to claim 1 or 2, characterized in that, The elastic element is formed by stacking several disc springs.

4. The injection molding die for thin-walled products according to claim 1, characterized in that, It also includes a dial indicator, which is disposed on the outer side of the lower mold, and the lower mold core is provided with a detection rod that makes contact with the dial indicator for detection.

5. The injection molding die for thin-walled products according to claim 1, characterized in that, The ejector unit includes two symmetrically arranged support plates, an ejector plate disposed in the space between the two support plates, and a plurality of ejector pins disposed on the ejector plate. The plurality of ejector pins are used to eject the product from the cavity of the lower mold core.

6. The injection molding die for thin-walled products according to claim 5, characterized in that, The ejector pin unit also includes a layer plate disposed between the support plate and the lower template. Several sets of spring posts and limiting posts are disposed between the layer plate and the ejector pin plate. Several spring posts are used to provide elastic force to the ejector pin plate to limit or adjust the movement speed.

7. The injection molding die for thin-walled products according to claim 5, characterized in that, Two tie rods are symmetrically arranged between the upper template and the ejector plate.

8. The injection molding die for thin-walled products according to claim 1, characterized in that, The lower mold is provided with a bottom plate located on the bottom surface of the ejector pin unit, and the upper mold is provided with a top plate located on the upper template.

9. An injection molding method for thin-walled products, characterized in that, An injection molding die for injection molding of a thin-walled product as described in any one of claims 1-8 includes the following steps: In the initial state, there is a stepped height difference between the lower mold core and the lower mold plate, which allows for secondary mold closing. Turn on the injection molding machine and perform the first mold closing, so that the lower mold core and the upper mold core close together to obtain the injection cavity; Injecting 90%-98% of the volume of injection material into the injection cavity; The mold is closed a second time, pushing the closing surface of the lower mold core to be flush with the closing surface of the lower mold plate, so that the upper mold plate and the lower mold plate can be closed to obtain the product cavity; The distance between the top surface and the core inside the product cavity is reduced to form a thin-walled gap, while the injection molding material completely fills the reduced product cavity. After the injection molded part in the product cavity solidifies and forms, the injection molding machine opens the mold and removes the part, obtaining an injection molded part with a thin-walled structure on one side.

10. The injection molding method for thin-walled products according to claim 9, characterized in that, During the first mold closing, the mold closing position error of the lower mold core is checked. If there is no error, the injection molding operation is performed. If the error value is large, the mold is opened for manual inspection or the mold closing is repeated.

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