Blowing mold and blowing needle

Abstract

According to the blowing mold and the blowing needle, a material storage cavity is formed in the blowing mold and used for storing additional plastic blanks, and the blowing needle is matched with the material storage cavity to scrape the plastic blanks in the material storage cavity in the moving process and accurately guide the plastic blanks to a bottle opening forming area, so that sufficient material supply at a bottle opening is ensured; therefore, the completeness and the wall thickness uniformity of bottle opening forming are obviously improved. The utility model does not need to greatly reform the existing blow molding equipment, can be easily integrated into the existing production line only by additionally arranging the material storage cavity and the port structure in the mold, has the characteristics of low implementation cost and strong compatibility, enhances the sealing performance and the service life of the product due to the improvement of the bottle opening forming quality, and is suitable for large-scale production. And the production rejection rate is obviously reduced, and the overall production efficiency and economic benefits are improved.

Description

Technical Field

[0001] This utility model relates to plastic container manufacturing equipment, and more particularly to a blow molding mold and blow needle. Background Technology

[0002] Blow molding is a common manufacturing process for plastic containers, widely used in beverage bottles, cosmetic bottles, and pharmaceutical packaging. In traditional blow molding, a plastic preform is extruded or injected to form an initial tube, which is then placed into a mold cavity. Compressed air is injected into the tube through a blow gun, causing it to expand and conform to the inner wall of the mold cavity, ultimately forming the desired plastic container. This process offers advantages such as high production efficiency, low cost, and wide applicability, making it the mainstream technology in the plastic container manufacturing industry.

[0003] However, in actual production, due to factors such as uneven distribution of the preform and unstable temperature control, traditional blow molding processes often suffer from insufficient plastic preform at the bottle neck, leading to defects such as incomplete bottle neck molding, uneven wall thickness, or micro-cracks. This problem is particularly pronounced when manufacturing thin-walled containers or complex-shaped products, affecting not only the product's sealing performance and lifespan but also increasing the scrap rate and reducing production efficiency. Currently, there is a lack of blow molding die structure designs that can effectively solve the bottle neck molding problem. Utility Model Content

[0004] In order to overcome the shortcomings of the prior art, this utility model provides a blow molding mold and blow needle for solving the molding quality defects caused by insufficient plastic preform at the bottle mouth during the blow molding process.

[0005] The technical solution adopted by this utility model to solve its technical problem is:

[0006] A blow molding die includes an upper mold and a lower mold, the upper mold and the lower mold cooperating to form a cavity, a bottle opening is provided between the upper mold and the lower mold, the bottle opening is connected to the cavity: a storage cavity is provided on the side of the bottle opening away from the cavity, the storage cavity is used to store plastic preforms during the blow molding process, and the plastic preforms in the storage cavity are replenished to the molding area of ​​the bottle opening by the movement of the blow needle.

[0007] Furthermore, the storage cavity has a first port and a second port; the first port is located on the side of the storage cavity facing the blow needle inlet, for the blow needle to enter the storage cavity; the second port is located at the connection between the storage cavity and the bottle mouth, for connecting the storage cavity and the bottle mouth; wherein, the blow needle enters the storage cavity through the first port, scrapes the plastic preform in the storage cavity during the movement, and then replenishes the plastic preform to the molding area of ​​the bottle mouth through the second port.

[0008] Furthermore, the storage chamber has a columnar structure, and the cross-sectional area of ​​the storage chamber is smaller than the cross-sectional area of ​​the bottle opening.

[0009] Furthermore, the inner wall surface of the storage cavity has a guide layer to guide the plastic preform to flow along a preset path to the molding area of ​​the bottle mouth.

[0010] Furthermore, the guiding layer is a polytetrafluoroethylene material layer with a surface roughness of Ra0.1-0.5μm.

[0011] Furthermore, both the first port and the second port are circular structures coaxial with the storage cavity, and the first port and the second port have the same diameter.

[0012] Furthermore, the diameters of the first and second ports are 50%-70% of the diameter of the storage chamber.

[0013] Furthermore, the inner diameter of the storage cavity gradually decreases along the axial direction from the first port to the second port, forming a conical structure.

[0014] A blow needle, which is suitable for the blow molding mold described above, has a micro-textured structure on its outer surface to enhance adhesion to the plastic preform when passing through the storage cavity, so as to uniformly carry the plastic preform in the storage cavity into the molding area of ​​the bottle mouth.

[0015] Furthermore, the microtexture structure includes spiral grooves distributed along the axial direction of the blow needle, the depth of the spiral grooves being 0.01-0.1 mm and the pitch of the spiral grooves being 0.5-2 mm.

[0016] The beneficial effects of this utility model are:

[0017] This invention relates to a blow molding die that incorporates a storage cavity for storing additional plastic preforms. During its movement, the blow needle scrapes these preforms from the storage cavity and precisely guides them to the bottle neck forming area, ensuring a sufficient material supply at the bottle neck. This significantly improves the integrity and wall thickness uniformity of the bottle neck forming process. This design does not require major modifications to existing blow molding equipment; simply adding a storage cavity and its port structure to the die allows for easy integration into existing production lines. It features low implementation cost and strong compatibility. Furthermore, the improved bottle neck forming quality enhances the product's sealing performance and lifespan, significantly reducing the scrap rate and improving overall production efficiency and economic benefits. Attached Figure Description

[0018] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0019] Figure 1 This is an assembly diagram of the present invention;

[0020] Figure 2 This is an exploded view of the structure of this utility model;

[0021] Figure 3 This is an exploded structural diagram of the second embodiment of the present invention;

[0022] Figure 4 This is an assembly diagram of the second embodiment of the present invention.

[0023] in,

[0024] 1. Upper mold; 2. Lower mold; 3. Cavity; 4. Bottle mouth; 5. Material storage cavity; 51. First port; 52. Second port; 6. Blow needle; 61. Microtexture structure. Detailed Implementation

[0025] The following will clearly and completely describe the concept, specific structure, and technical effects of this utility model in conjunction with embodiments and accompanying drawings, so as to fully understand the purpose, features, and effects of this utility model. Obviously, the described embodiments are only a part of the embodiments of this utility model, not all of them. Other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are all within the scope of protection of this utility model. Furthermore, all connections / linkages involved in the patent do not simply refer to direct contact between components, but rather to the ability to form a better connection structure by adding or reducing connecting accessories according to specific implementation conditions. The various technical features in this utility model can be combined interactively without contradicting each other.

[0026] Reference Figure 1 , Figure 2A blow molding die includes an upper mold 1 and a lower mold 2. The upper mold 1 and the lower mold 2 cooperate to form a cavity 3. A bottle opening 4 is provided between the upper mold 1 and the lower mold 2, and the bottle opening 4 communicates with the cavity 3. A storage cavity 5 is provided on the side of the bottle opening 4 away from the cavity 3. The storage cavity 5 is used to store plastic preforms during the blow molding process, and the plastic preforms in the storage cavity 5 are replenished to the forming area of ​​the bottle opening 4 by the movement of the blow needle 6. It can be understood that the blow molding die provided by this utility model forms the cavity 3 required for manufacturing plastic containers through the cooperation of the upper mold 1 and the lower mold 2. When these two mold parts are closed, they form a bottle opening 4 structure at a specific position. The bottle opening 4 remains in communication with the cavity 3, allowing compressed air during the blow molding process to smoothly enter the cavity 3. A storage cavity 5 is provided on the side of the bottle opening 4 away from the cavity 3. This storage cavity 5 can store additional plastic preforms during the blow molding process. As the blow needle 6 moves into the cavity 3 during the blow molding process, it scrapes the plastic preform stored in the storage chamber 5 and guides this extra material to the molding area of ​​the bottle neck 4. This solves the problem of insufficient plastic preform at the bottle neck 4, which is common in traditional blow molding processes. For example, in the production of beverage bottles, since the bottle neck 4 needs to have sufficient strength and sealing performance, this storage chamber 5 design ensures a sufficient supply of material at the bottle neck 4, avoiding quality defects such as uneven wall thickness or micro-cracks.

[0027] In some embodiments, refer to Figure 3 , 4 The storage chamber 5 is designed with two ports: a first port 51 and a second port 52. The first port 51 is located on the side of the storage chamber 5 facing the inlet of the blow needle 6, and its main function is to provide a channel for the blow needle 6 to enter the storage chamber 5. The second port 52 is located at the connection between the storage chamber 5 and the bottle neck 4, establishing a connection between the two. In the actual blow molding process, the blow needle 6 first enters the storage chamber 5 through the first port 51. As the blow needle 6 moves within the storage chamber 5, it scrapes the pre-stored plastic preform. The blow needle 6 then continues forward and, through the second port 52, precisely delivers the scraped plastic preform to the molding area of ​​the bottle neck 4.

[0028] Furthermore, both the first port 51 and the second port 52 are circular structures coaxial with the storage cavity 5, and the diameters of the first port 51 and the second port 52 are the same. The coaxial circular structure and identical diameter of the first port 51 and the second port 52 ensure that after the blow needle 6 enters the storage cavity 5 through the first port 51, it can enter the forming area of ​​the bottle mouth 4 through the second port 52 with the same diameter, thus guaranteeing the continuity and stability of the blow needle 6's movement path. The coaxial design allows the blow needle 6 to pass through the storage cavity 5 along a straight path, reducing deflection and vibration during movement and improving the accuracy of plastic preform scraping and conveying. The identical diameter design avoids potential resistance changes and jamming phenomena that the blow needle 6 may encounter when passing through different ports.

[0029] Furthermore, the diameters of the first port 51 and the second port 52 are 50%-70% of the diameter of the storage cavity 5. The port diameters are smaller than the diameter of the storage cavity 5, creating a "contraction-expansion-contraction" spatial structure. When the blow needle 6 enters the storage cavity 5 through the first port 51, the space within the storage cavity 5 relatively expands, which is beneficial for the storage and scraping of the plastic preform. When the blow needle 6 carries the plastic preform through the second port 52, a certain compression effect is created, causing the plastic preform to flow along a preset direction. This 50%-70% range ensures the smooth passage of the blow needle 6 while maintaining appropriate spatial changes, achieving effective control over the flow of the plastic preform.

[0030] In some embodiments, the storage cavity 5 has a columnar structure, and the cross-sectional area of ​​the storage cavity 5 is smaller than that of the bottle opening 4. Because the cross-sectional area of ​​the storage cavity 5 is smaller, when the plastic preform enters the bottle opening 4 region with a larger cross-sectional area through the second port 52, the plastic preform will naturally spread out, thereby achieving full coverage of the forming area of ​​the bottle opening 4.

[0031] In some embodiments, a guide layer structure is specially designed on the inner wall surface of the storage cavity 5. This guide layer guides the plastic preform within the storage cavity 5 along a pre-set path, ensuring that the plastic preform flows precisely to the molding area of ​​the bottle neck 4. The guide layer, together with the columnar storage cavity 5 and the dual-port structure, forms a complete plastic preform guiding system. The guide layer is made of a special polymer material that is heat-resistant and smooth, preferably polytetrafluoroethylene (PTFE), with a surface roughness of Ra 0.1-0.5 μm. Besides PTFE, high molecular weight polyethylene, polyimide, or boron nitride composite coatings can also be used.

[0032] In some embodiments, the storage chamber 5 employs a conical structure (not shown), whose inner diameter gradually decreases axially from the first port 51 to the second port 52, forming a conical structure that tapers towards the bottle opening 4. When the blow needle 6 enters the storage chamber 5 through the first port 51 and begins to scrape the plastic preform, the gradually narrowing shape of the storage chamber 5 naturally generates a guiding force, causing the plastic preform to flow along the conical channel towards the second port 52, and forming a certain pressure gradient as the inner diameter decreases. This pressure gradient helps the plastic preform maintain continuity and stability during flow, reducing eddies or stagnation that may occur during material flow.

[0033] In addition to providing a blow molding mold structure, this invention also provides a blow needle 6 for use with it. The surface of the blow needle 6 has a fine textured structure 61, as shown in the figure. Figure 2 These micro-textures may manifest as small grooves, bumps, or specific surface treatment patterns, used to enhance the adhesion between the surface of the blow needle 6 and the plastic preform within the storage cavity 5 as the blow needle 6 moves through the storage cavity 5. Because the plastic preform exhibits a certain degree of viscosity at high temperatures, these micro-textures provide a larger contact surface area and stronger mechanical gripping ability, enabling the plastic preform to adhere more effectively to the surface of the blow needle 6 and be uniformly carried into the molding area of ​​the bottle neck 4 as the blow needle 6 moves.

[0034] Furthermore, the fine texture is preferably a spiral groove distributed along the axial direction of the blow needle 6. The spiral shape can produce a spiral conveying effect during the rotation and movement of the blow needle 6. The depth of these grooves is controlled within the range of 0.01-0.1mm, while the pitch of the spiral grooves is set to 0.5-2mm. The range of groove depth ensures sufficient adhesion of the plastic preform, while avoiding structural strength problems and cleaning difficulties that may be caused by excessively deep grooves, while the design of the pitch affects the conveying rate and distribution uniformity of the plastic preform. For example, during production, the blow needle 6 may employ a spiral groove design with a depth of 0.05 mm and a pitch of 1 mm. When this blow needle 6 passes through the storage chamber 5, the plastic preform in the storage chamber 5 will fill these precise spiral grooves and be evenly conveyed to the forming area of ​​the bottle mouth 4 of the pharmaceutical bottle as the blow needle 6 rotates and moves. This precisely controlled spiral groove can achieve quantitative delivery and uniform distribution of the plastic preform. Especially for pharmaceutical bottle mouth 4 structures that require precise sealing performance, this design can ensure that all parts of the bottle mouth 4 receive sufficient and uniform material supply, thereby significantly improving the sealing reliability and product quality of the packaging and meeting the stringent standard requirements of pharmaceutical packaging.

[0035] The above is a detailed description of the preferred embodiments of the present utility model. However, the present utility model is not limited to the described embodiments. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present utility model. All such equivalent modifications or substitutions are included within the scope defined by the claims of this application.

Claims

1. A blow molding die, comprising an upper mold and a lower mold, wherein the upper mold and the lower mold cooperate to form a cavity, and a bottle opening is provided between the upper mold and the lower mold, the bottle opening communicating with the cavity, characterized in that: A storage chamber is provided on the side of the bottle opening away from the mold cavity. The storage chamber is used to store plastic preforms during the blow molding process, and the plastic preforms in the storage chamber are replenished to the molding area of ​​the bottle opening by the movement of the blow needle.

2. The blow molding die according to claim 1, characterized in that, The storage chamber has a first port and a second port; The first port is located on the side of the storage chamber facing the inlet of the blow needle, and is used for the blow needle to enter the storage chamber; The second port is located at the connection between the storage chamber and the bottle opening, and is used to connect the storage chamber and the bottle opening; The blow needle enters the storage chamber through the first port and scrapes the plastic preform in the storage chamber during its movement. Then, it replenishes the plastic preform to the molding area of ​​the bottle mouth through the second port.

3. The blow molding die according to claim 2, characterized in that, The storage chamber has a columnar structure, and its cross-sectional area is smaller than that of the bottle opening.

4. The blow molding die according to claim 3, characterized in that, The inner wall surface of the storage cavity has a guide layer to guide the plastic preform to flow along a preset path to the molding area of ​​the bottle mouth.

5. The blow molding die according to claim 4, characterized in that, The guiding layer is a polytetrafluoroethylene material layer with a surface roughness of Ra0.1-0.5μm.

6. The blow molding die according to claim 3, characterized in that, Both the first port and the second port are circular structures coaxial with the storage cavity, and the first port and the second port have the same diameter.

7. The blow molding die according to claim 6, characterized in that, The diameters of the first and second ports are 50%-70% of the diameter of the storage chamber.

8. The blow molding die according to claim 3, characterized in that, The inner diameter of the storage cavity gradually decreases from the first port to the second port along the axial direction, forming a conical structure.

9. A blow needle, characterized in that, The blow needle is applicable to the blow molding die according to any one of claims 1-8. The outer surface of the blow needle is provided with a fine texture structure (61) to enhance the adhesion to the plastic preform when passing through the storage cavity, so as to uniformly carry the plastic preform in the storage cavity into the molding area of ​​the bottle mouth.

10. The blow needle according to claim 9, characterized in that, The microtexture structure includes spiral grooves distributed along the axial direction of the blow needle, the depth of the spiral grooves being 0.01-0.1 mm and the pitch of the spiral grooves being 0.5-2 mm.

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