One-time rapid flexible demolding structure for thin-walled plastic parts

Abstract

This utility model discloses a one-time rapid flexible demolding structure for thin-walled plastic parts, relating to the field of injection mold technology. The utility model includes a lower mold with a demolding mechanism in the middle for rapid demolding of the molded plastic parts. The demolding mechanism includes a pressure relief component comprising a mounting plate disposed at the lower part of the lower mold. Sliding rods are fixedly installed at the four corners of the top of the mounting plate, and sealing rings are fixedly installed in the middle of each sliding rod. After injection molding is completed, a drive cylinder moves the mounting plate and sliding rods downwards, causing the sealing rings to disengage from the air supply chamber. The air supply chamber and the pressure relief chamber then connect. At this time, the rubber ring and the ejector nozzle move downwards or deform synchronously, forming a gas flow gap. External gas enters the molding cavity through the air supply chamber and the pressure relief chamber, quickly balancing the air pressure and preventing the plastic parts from sticking tightly to the molding cavity due to adhesion, ensuring smooth demolding and preventing damage to thin-walled parts due to forced demolding.

Description

Technical Field

[0001] This utility model relates to the field of injection mold technology, specifically to a one-time rapid flexible demolding structure for thin-walled plastic parts. Background Technology

[0002] Injection molds are tools used to produce plastic products; they are also tools that give plastic products a complete structure and precise dimensions. Injection molding is a processing method used to mass-produce certain complex-shaped parts. Specifically, it refers to injecting heated and molten plastic into the mold cavity under high pressure by an injection molding machine, and obtaining the molded product after cooling and solidification.

[0003] Reference patent document: Patent publication number CN221968768U, patent publication date 2024-11-08, relates to a multi-cavity injection molding die for small-weight thin-walled plastic parts, including a lower mold and an upper mold for forming thin-walled plastic parts. During the injection molding process, the lower mold and the upper mold are brought close together, so that the interconnected ejector multi-cavity molding component abuts against the upper part of the multi-cavity molding die to form a complete cavity. Molten material is injected into the cavity through the injection molded part, which can form two plastic parts and multiple matching plastic part cavities at one time, forming an integrated molding process with good overall quality. After injection molding is completed, the mold is opened, and the ejector rod cooperates with the ejection structure of the interconnected ejector multi-cavity molding component for demolding. The structure that fits tightly against the cavity greatly shortens the demolding distance and improves the ejection efficiency, making it highly practical.

[0004] Based on the search of patent numbers and the shortcomings of existing technologies, the following was found:

[0005] Traditionally, thin-walled plastic parts are usually ejected by ejector pins after injection molding. However, because thin-walled parts have a large contact area with the mold core surface during injection molding, they are prone to vacuum adsorption after cooling. This makes ejection more difficult due to the vacuum adsorption, requiring greater ejection force. Furthermore, the poor rigidity and easy deformation of thin-walled plastic parts make them prone to cracking or permanent deformation during ejection.

[0006] Therefore, this utility model provides a one-time rapid flexible demolding structure for thin-walled plastic parts. Utility Model Content

[0007] To address the problem that the vacuum adhesion formed between the thin-walled part and the core during traditional ejector demolding can drastically increase the ejection force, easily leading to cracking or permanent deformation of thin-walled parts with poor rigidity, the purpose of this invention is to provide a one-time rapid and flexible demolding structure for thin-walled plastic parts.

[0008] To achieve the above objectives, this utility model provides the following technical solution: a one-time rapid flexible demolding structure for thin-walled plastic parts, comprising a lower mold, wherein a demolding mechanism is provided in the middle of the lower mold for rapid demolding of the molded plastic parts, the demolding mechanism comprising:

[0009] The pressure relief assembly includes a mounting plate located at the bottom of the lower mold. Sliding rods are fixedly installed at the four corners of the top of the mounting plate, and sealing rings are fixedly installed in the middle of the sliding rods. Four evenly distributed pressure relief chambers are opened at the top of the lower mold. The sealing rings are slidably locked in the middle of the pressure relief chambers. Rubber rings are fixedly installed at the top of the sliding rods. Top nozzles are fixedly installed at the top center of the rubber rings, and the diameter of the top nozzles is smaller than the diameter of the rubber rings. The top nozzles and rubber rings are slidably locked in the upper part of the pressure relief chambers. A drive assembly is provided at the bottom of the mounting plate.

[0010] The push-out assembly, located on the upper part of the sliding rod, is used for demolding the attached injection molded part.

[0011] Preferably, the push assembly includes a push cylinder fixedly installed on the upper part of the sliding rod, and a push handle is slidably engaged in the middle of the push nozzle, with the bottom end of the push handle fixedly installed on the drive end of the push cylinder.

[0012] Preferably, the drive assembly includes a drive cylinder fixedly installed on the lower part of the lower mold, and the bottom center of the mounting plate is fixedly installed on the drive end of the drive cylinder.

[0013] Preferably, the lower part of the lower mold has a cavity, and the mounting plate is slidably engaged in the middle of the cavity.

[0014] Preferably, the upper part of the lower mold has an air supply chamber, which is interconnected with multiple pressure relief chambers.

[0015] Preferably, the upper part of the lower mold is provided with a plurality of evenly distributed ejector pins, and the middle part of the lower mold is provided with a forming cavity.

[0016] Beneficial effects

[0017] This invention provides a one-time rapid flexible demolding structure for thin-walled plastic parts. Compared with the prior art, it has the following advantages:

[0018] 1. After injection molding is completed, the drive cylinder moves the mounting plate and sliding rod downward, causing the sealing ring to disengage from the blocked state of the air supply chamber. The air supply chamber and the pressure relief chamber are connected. At this time, the rubber ring and the ejector will move downward or deform synchronously to form a gas flow gap. External gas enters the molding cavity through the air supply chamber and the pressure relief chamber, quickly balancing the air pressure and preventing the plastic parts from sticking tightly to the molding cavity due to adsorption force. This ensures smooth demolding and prevents thin-walled parts from being damaged due to forced demolding.

[0019] 2. After the pressure is released, the ejector pin moves upward to push the plastic part. At the same time, the ejector cylinder drives the push handle to move upward along the ejector nozzle through hole. The top of the push handle directly contacts the bottom of the plastic part to assist the ejector pin in pushing the plastic part out of the mold, forming a multi-point push force. This can prevent excessive local force from causing deformation of the plastic part and achieve non-destructive demolding. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of this utility model.

[0021] Figure 2 This is a cross-sectional structural diagram of the present invention.

[0022] Figure 3 This is a schematic diagram of the pressure relief component of this utility model.

[0023] Figure 4 This is a schematic diagram of the cross-sectional structure of the sliding rod of this utility model.

[0024] Figure 5 This is a schematic diagram of the gas delivery chamber structure of this utility model.

[0025] In the diagram: 1. Lower mold; 11. Ejector pin; 12. Molding cavity; 2. Demolding mechanism; 21. Pressure relief assembly; 211. Mounting plate; 2111. Cavity; 212. Pressure relief cavity; 213. Sliding rod; 214. Sealing ring; 215. Rubber ring; 216. Ejector nozzle; 217. Drive cylinder; 218. Air supply cavity; 22. Push assembly; 221. Push cylinder; 222. Push handle. Detailed Implementation

[0026] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0027] Please see Figure 1-5 This utility model provides a technical solution: a one-time rapid flexible demolding structure for thin-walled plastic parts, including a lower mold 1, and a demolding mechanism 2 provided in the middle of the lower mold 1 for rapid demolding of the molded plastic parts. The demolding mechanism 2 includes:

[0028] The pressure relief assembly 21 includes a mounting plate 211 disposed at the lower part of the lower mold 1. Sliding rods 213 are fixedly installed at the four corners of the top of the mounting plate 211, and sealing rings 214 are fixedly installed in the middle of each sliding rod 213. Four evenly distributed pressure relief chambers 212 are opened at the upper part of the lower mold 1. The sealing rings 214 are slidably engaged in the middle of each pressure relief chamber 212. The diameter of the sliding rods 213 is smaller than the diameter of the pressure relief chamber 212 to ensure smooth gas passage. The sealing rings 214 can tightly contact the inner wall of the pressure relief chamber 212 to prevent gas leakage before demolding, thus avoiding affecting the molding quality of the injection molded part. Rubber rings 215 are fixedly installed on the upper part, and nozzles 216 are fixedly installed on the top center of each rubber ring 215. The diameter of nozzles 216 is smaller than that of rubber rings 215. Both rubber rings 215 and nozzles 216 are flexible. If the pressure difference is too large when moving downward, the rubber rings 215 and nozzles 216 will deform during the pulling process, so that they are no longer in close contact with the inner wall of the pressure relief chamber 212, causing the pressure relief gas to communicate with the outside, thereby balancing the gas pressure and avoiding the generation of vacuum adsorption. The nozzles 216 and rubber rings 215 are slidably locked on the upper part of the pressure relief chamber 212. The bottom end of the mounting plate 211 is provided with a drive assembly.

[0029] The push assembly 22 is located on the upper part of the sliding rod 213 and is used for demolding the injection molded part.

[0030] The push assembly 22 includes a push cylinder 221 fixedly installed on the upper part of the sliding rod 213. The middle part of the nozzle 216 is slidably fitted with a push handle 222. The bottom end of the push handle 222 is fixedly installed on the drive end of the push cylinder 221. The upper surface of the push handle 222 is flush with the upper surface of the nozzle 216 and the upper surface of the molding cavity 12 to ensure the quality of the molded part. At the same time, during demolding, the push cylinder 221 can push the push handle 222 to move to one side of the molded part to assist the ejector pin 11 and the pressure relief assembly 21 in completing the demolding of the molded part.

[0031] The drive assembly includes a drive cylinder 217 fixedly installed at the lower part of the lower mold 1. The bottom center of the mounting plate 211 is fixedly installed at the drive end of the drive cylinder 217. Driven by the drive cylinder 217, the mounting plate 211 can move up and down. When moving downward, it will drive multiple sliding rods 213 to move down synchronously, so that the sealing ring 214 no longer blocks the air supply cavity 218. At this time, the rubber ring 215 moves down or deforms synchronously, so that the gas can be discharged through the gap between it and the pressure relief cavity 212, so that it can contact the rear of the molded part. This can prevent the molded part from forming a vacuum negative pressure between it and the molding cavity 12 during demolding, which would increase the difficulty of demolding. After demolding is completed, the drive cylinder 217 moves up so that the sealing ring 214 blocks the air supply cavity 218. At the same time, the rubber ring 215 and the ejector 216 are reset, preparing for the next injection molding.

[0032] The lower part of the lower mold 1 has a cavity 2111. The mounting plate 211 is slidably locked in the middle of the cavity 2111. The mounting plate 211 is in contact with the side wall of the cavity 2111, so that it guides the up and down movement of the mounting plate 211 and ensures the stability of the up and down movement of the mounting plate 211.

[0033] The upper part of the lower mold 1 is provided with an air supply cavity 218, which is an annular cavity and is connected to multiple pressure relief cavities 212.

[0034] The upper part of the lower mold 1 is provided with a plurality of evenly distributed ejector pins 11. One end of the ejector pin 11 is embedded in the interior of the lower mold 1, and the other end is flush with the inner wall of the molding cavity 12. The molding cavity 12 is opened in the middle of the lower mold 1.

[0035] Furthermore, any content not described in detail in this specification is existing technology known to those skilled in the art.

[0036] During operation, in the injection molding process, the molten plastic is injected into the molding cavity 12 of the lower mold 1 to form a thin-walled plastic part. When demolding is required after injection molding, the drive cylinder 217 is activated, which drives the mounting plate 211 to move downward. The mounting plate 211 drives the four sliding rods 213 to move downward synchronously, so that the sealing ring 214 is no longer in close contact with the pressure relief cavity 212, thereby opening the communication channel between the gas supply cavity 218 and the pressure relief cavity 212. Since the diameter of the sliding rod 213 is smaller than the diameter of the pressure relief cavity 212, the gas can flow through the gap. If there is too large a vacuum negative pressure between the molded part and the molding cavity 12, when moving downward, the rubber ring 215 and the ejector nozzle 216 will deform due to the pressure difference (if the pressure difference is not large, it will move downward normally) and no longer be in close contact with the inner wall of the pressure relief cavity 212, so that the pressure relief cavity 212 is connected to the outside atmosphere, quickly balances the air pressure, avoids the vacuum adsorption effect, and reduces the demolding resistance.

[0037] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0038] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A one-time rapid flexible demolding structure for thin-walled plastic parts, comprising a lower mold (1), characterized in that: The lower mold (1) is provided with a demolding mechanism (2) in the middle, which is used for quick demolding of the molded plastic parts. The demolding mechanism (2) includes: The pressure relief assembly (21) includes a mounting plate (211) located at the bottom of the lower mold (1). Sliding rods (213) are fixedly installed at the four corners of the top of the mounting plate (211). Sealing rings (214) are fixedly installed in the middle of the sliding rods (213). Four evenly distributed pressure relief chambers (212) are opened at the top of the lower mold (1). Sealing rings (214) are slidably locked in the middle of the pressure relief chambers (212). Rubber rings (215) are fixedly installed at the top of the sliding rods (213). Top nozzles (216) are fixedly installed at the middle of the top of the rubber rings (215). The diameter of the top nozzles (216) is smaller than the diameter of the rubber rings (215). The top nozzles (216) and the rubber rings (215) are slidably locked in the upper part of the pressure relief chambers (212). A drive assembly is provided at the bottom of the mounting plate (211). The push assembly (22) is located on the upper part of the sliding rod (213) and is used for demolding the attached injection molded part.

2. The one-time rapid flexible demolding structure for thin-walled plastic parts according to claim 1, characterized in that: The push assembly (22) includes a push cylinder (221) fixedly installed on the upper part of the sliding rod (213), and a push handle (222) is slidably attached to the middle part of the push nozzle (216). The bottom end of the push handle (222) is fixedly installed on the drive end of the push cylinder (221).

3. The one-time rapid flexible demolding structure for thin-walled plastic parts according to claim 1, characterized in that: The drive assembly includes a drive cylinder (217) fixedly installed on the lower part of the lower mold (1), and the bottom center of the mounting plate (211) is fixedly installed on the drive end of the drive cylinder (217).

4. The one-time rapid flexible demolding structure for thin-walled plastic parts according to claim 1, characterized in that: The lower mold (1) has a cavity (2111) at its lower part, and the mounting plate (211) is slidably locked in the middle of the cavity (2111).

5. The one-time rapid flexible demolding structure for thin-walled plastic parts according to claim 1, characterized in that: The upper part of the lower mold (1) is provided with an air supply chamber (218), which is connected to multiple pressure relief chambers (212).

6. The one-time rapid flexible demolding structure for thin-walled plastic parts according to claim 1, characterized in that: The upper part of the lower mold (1) is provided with a plurality of evenly distributed ejector pins (11), and the middle part of the lower mold (1) is provided with a forming cavity (12).

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