Injection syringe barrel injection mold with convenient disassembly

Abstract

This utility model discloses a convenient injection mold for syringe barrels, belonging to the field of injection mold technology. It includes a cavity template, and an upper cavity insert and a lower cavity insert installed within the cavity template. The upper cavity insert is used to form the outer surface of the syringe barrel head, and the lower cavity insert is used to form the outer surface of the syringe barrel section. The lower cavity insert has an upwardly extending top to form a mounting hole for surrounding and accommodating the upper cavity insert. The bottom of the lower cavity insert has a disassembly part for engaging with an external tool to remove the lower cavity insert and the upper cavity insert installed therein as a whole from the cavity template. This utility model's injection mold allows for quick assembly and disassembly of the target cavity insert without disassembling the template, significantly improving maintenance efficiency and effectively reducing maintenance costs.

Description

Technical Field

[0001] This utility model relates to the field of injection molding mold technology, and in particular to an injection mold for a syringe barrel that is easy to assemble and disassemble. Background Technology

[0002] In the injection molding industry, for hollow tubular plastic parts such as syringe barrels, the mold typically includes a core for molding the inner wall of the barrel and a cavity for molding the outer wall. Due to limitations in mold processing technology, and in order to achieve precise molding of complex shapes (such as the head and barrel of a syringe barrel), the cavity portion usually consists of an upper cavity insert for molding the barrel head and a lower cavity insert for molding the barrel barrel.

[0003] During the long-term use of molds, cavity inserts that come into direct contact with high-temperature, high-pressure molten plastic, especially the more complex upper cavity inserts, are considered wear parts and require regular maintenance. However, existing mold repair methods for these inserts generally suffer from the following problems: traditional repair methods require large-scale disassembly of the mold, such as... Figure 1 As shown, operators must open all the templates in the fixed mold section, such as the hot runner plate (not shown in the figure), the upper cavity template 11 (containing the upper cavity insert 2), and the lower cavity template 12 (containing the lower cavity insert 3), before they can remove the upper cavity insert 2 that needs repair. The entire process is not only cumbersome and time-consuming, greatly extending the equipment downtime and affecting production efficiency, but also poses certain safety hazards during the disassembly and assembly of heavy templates.

[0004] In particular, the above problems are more pronounced for multi-cavity molds using side-entry methods, especially for syringe molds that typically employ dozens or even hundreds of cavities to achieve high production capacity. For example... Figure 1As shown, the hot runner system of the side-entry mold includes multiple precision side-entry nozzle cores 41. One end of each nozzle core 41 is connected to the hot runner body 4, while the other end is precisely embedded in the side wall of the cavity insert. When disassembling the mold in a conventional manner, even if the repair target is only one or a few cavity inserts, the entire hot runner plate must be separated from the mold. During this process, all the hot runner bodies 4 are pulled out of the mold along with the hot runner plate. This pulling process causes friction with each nozzle core 41, resulting in unnecessary wear on the precision mating surfaces of each nozzle core 41 and the hot runner body 4. Accumulated wear affects sealing and service life, significantly increasing the potential risk of damage to fault-free cavities. Furthermore, after the hot runner body 4 is pulled out, the remaining nozzle cores 41 are suspended on the side of the cavity insert, making them prone to falling off or being damaged by impact. If necessary, they must be removed one by one, making disassembly and assembly more cumbersome. In addition, large-scale disassembly also carries the risk of pulling or squeezing the heating element circuitry. Once the circuitry is damaged, troubleshooting and repair work becomes more complex, further extending downtime.

[0005] To address some of the aforementioned issues, several improvements have emerged in existing technologies. For example, Chinese utility model patent CN223431931U discloses an easily detachable side-injection hot runner mold. This design features a split structure for the hot nozzle assembly. When the mold plate is opened, the upper hot nozzle is pulled out along with the upper mold plate, while the lower hot nozzle and nozzle core remain in the cavity plate. This eliminates the need to disassemble and assemble the side-injection nozzle cores individually, thus simplifying the disassembly and assembly process to some extent. However, during maintenance, this solution still requires separating multiple mold plates to finally remove the target insert, making the overall operation cumbersome and offering only limited improvement in maintenance efficiency.

[0006] In summary, existing syringe barrel injection molds, especially side-injection molds, generally suffer from cumbersome disassembly and assembly procedures, long downtime, and low maintenance efficiency when repairing cavity inserts. Utility Model Content

[0007] The technical problem to be solved by this utility model is to overcome the above-mentioned problems and provide a syringe barrel injection mold that is easy to disassemble and assemble. It can quickly disassemble and assemble the target cavity insert without disassembling the template, thereby greatly improving maintenance efficiency and effectively reducing maintenance costs.

[0008] The technical solution of this utility model is: A convenient injection mold for disassembling and assembling a syringe barrel includes a cavity template, and an upper cavity insert and a lower cavity insert installed within the cavity template. The upper cavity insert is used to form the outer surface of the syringe barrel head, and the lower cavity insert is used to form the outer surface of the syringe barrel barrel. The lower cavity insert has an upwardly extending top to form a mounting hole for surrounding and accommodating the upper cavity insert. The bottom of the lower cavity insert has a disassembly part for engaging with an external tool to remove the lower cavity insert and the upper cavity insert installed therein as a whole from the cavity template.

[0009] This integrated "inner and outer set" structure, in which the upper cavity insert is embedded in the lower cavity insert, fundamentally changes the way cavity inserts are installed and disassembled. When maintenance is required, operators do not need to remove any templates. They can quickly remove the cavity insert as a whole by using external tools in conjunction with the disassembly part at the bottom. This greatly simplifies the disassembly and assembly steps, significantly improves maintenance efficiency, shortens downtime, and reduces maintenance costs.

[0010] Furthermore, in the aforementioned conveniently disassembled syringe barrel injection mold, the disassembly part is a disassembly threaded hole opened at the bottom of the lower cavity insert, for engaging with a special screw.

[0011] Furthermore, in the aforementioned injection mold for the easily disassembled syringe barrel, the bottom of the lower cavity insert has two symmetrically arranged disassembly threaded holes centered on the central axis. The symmetrical arrangement of these two disassembly threaded holes ensures more balanced force during disassembly, preventing the lower cavity insert from tilting or getting stuck during removal.

[0012] Furthermore, in the aforementioned easily detachable syringe barrel injection mold, inside the lower cavity insert, the inner diameter of the mounting hole is larger than the inner diameter of the cavity surface used to mold the outer surface of the barrel. The transition between the two forms a stepped surface for axial positioning of the upper cavity insert. This stepped surface provides a precise axial positioning reference for the upper cavity insert, ensuring the consistency and accuracy of its installation depth, thereby effectively guaranteeing the dimensional accuracy and quality stability of the final molded plastic part.

[0013] Furthermore, in the aforementioned easily detachable syringe barrel injection mold, an anti-cavity annular groove is formed on the inner peripheral wall between the mounting hole and the cavity surface used to form the outer surface of the barrel inside the lower cavity insert. The anti-cavity annular groove design avoids positional interference during assembly, ensuring that the bottom of the upper cavity insert can completely fit against the stepped surface, thereby further improving the accuracy of axial positioning.

[0014] Furthermore, in the aforementioned injection mold for a conveniently disassembled syringe barrel, the upper cavity insert and the mounting hole are in a transition fit. This transition fit balances positioning accuracy with ease of assembly and disassembly.

[0015] Furthermore, in the aforementioned easily disassembled syringe barrel injection mold, a set screw hole is radially formed on the peripheral wall of the mounting hole for the lower cavity insert. A set screw is screwed into the set screw hole, and the end of the set screw extends into the mounting hole to abut and fix the upper cavity insert. The set screw provides an additional radial locking force, ensuring absolute reliability of the connection between the upper and lower cavity inserts based on the transition fit.

[0016] Furthermore, in the aforementioned conveniently disassembled syringe barrel injection mold, the top of the lower cavity insert penetrates the cavity template, and the top surfaces of the upper and lower cavity inserts are flush with the upper surface of the cavity template.

[0017] Furthermore, in the aforementioned easily disassembled syringe barrel injection mold, the cavity template is an integral template structure. Since this solution eliminates the need to disassemble the template, the cavity template, which previously required separate components, can now be integrated, achieving a "subtractive design" in the structure. This simplifies the overall mold construction, reduces the number of parts, and lowers manufacturing costs.

[0018] The beneficial effects of this utility model are: 1. The integrated "inner and outer set" structure, in which the upper cavity insert is embedded in the lower cavity insert, fundamentally changes the way cavity inserts are installed and disassembled. When it is necessary to replace the easily damaged upper cavity insert, the operator does not need to disassemble any mold template. The cavity insert can be taken out from the bottom as a whole with special tools while the mold is open, and then the upper cavity insert can be taken out from the lower cavity insert. The whole process only takes a few minutes. Compared with the traditional maintenance method, it not only greatly simplifies the disassembly and assembly steps, improves maintenance efficiency, and shortens equipment downtime, thereby effectively reducing maintenance costs, but also greatly reduces the skill requirements and labor intensity of maintenance personnel, and avoids the safety hazards caused by disassembling and assembling heavy templates. 2. Since there is no need to disassemble the template, this solution avoids collateral damage to fault-free components. Especially for multi-cavity side-feeding molds, it avoids all unnecessary friction and wear between the hot nozzle body and the nozzle core, and eliminates the possibility of pulling and damaging the heating circuit. This not only significantly reduces spare parts and maintenance costs, but also improves the overall reliability and service life of the mold. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of an injection mold for a syringe barrel in the prior art.

[0020] Figure 2 This is a structural schematic diagram of an embodiment of the present utility model.

[0021] Figure 3 This is a schematic diagram showing the disassembly of the upper cavity insert and the lower cavity insert in an embodiment of this utility model.

[0022] In the diagram: 1. Cavity template; 11. Upper cavity template; 12. Lower cavity template; 2. Upper cavity insert; 3. Lower cavity insert; 31. Mounting hole; 32. Removal threaded hole; 33. Cavity surface; 34. Stepped surface; 35. Clearing ring groove; 36. Set threaded hole; 4. Hot nozzle body; 41. Nozzle core. Detailed Implementation

[0023] The present invention will now be further described in conjunction with the accompanying drawings and embodiments: In the description of this utility model, it should be understood that the orientation or positional relationship indicated by terms such as "upper", "lower", "inner", and "outer" is based on the orientation or positional relationship shown in the accompanying drawings and is only for the convenience of describing this utility model, and is not intended to indicate or imply that the device or component referred to must have a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0024] This embodiment provides a conveniently assembled and disassembled syringe barrel injection mold. Its structure is suitable for various syringe barrel injection molds, especially for side-injection multi-cavity molds with complex structures and more cumbersome maintenance. Figure 1 The diagram shown is a schematic diagram of the fixed mold part of one embodiment of the present invention applied to a side-entry glue mold. Some templates are omitted in the figure, and the focus is on the internal structure of the cavity template.

[0025] like Figure 2 As shown, the fixed mold portion of the mold includes a cavity template 1. An upper cavity insert 2 and a lower cavity insert 3 are installed within the cavity template 1. The upper cavity insert 2 is used to form the outer surface of the syringe barrel head, and the lower cavity insert 3 is used to form the outer surface of the syringe barrel. The top of the lower cavity insert 3 extends upwards, forming a mounting hole 11 for surrounding and accommodating the upper cavity insert 2. The upper cavity insert 2 is embedded within the lower cavity insert 3, forming an integrated "inner and outer fitting" structure. The bottom of the lower cavity insert 3 has a disassembly part. In this embodiment, the disassembly part specifically consists of two symmetrically arranged disassembly threaded holes 12 centered on the central axis of the lower cavity insert 3. The two disassembly threaded holes 12 are used to engage with external special screws (not shown in the figure). By applying external pulling force, the lower cavity insert 3 and the upper cavity insert 2 installed within it can be removed downwards from the cavity template 1 as a whole without disassembling the template.

[0026] Since there is no need to disassemble the template, the cavity template 1 preferably adopts an integrated template structure. The top of the lower cavity insert 3 penetrates the cavity template 1, and in the installed state, the top surfaces of the upper cavity insert 2 and the lower cavity insert 3 are flush with the upper surface of the cavity template 1.

[0027] like Figure 3 As shown, to achieve precise positioning, the inner diameter of the mounting hole 11 inside the lower cavity insert 3 is larger than the inner diameter of the cavity surface 13 used to form the outer surface of the cylindrical part. A stepped surface 14 is formed at the transition between the mounting hole 11 and the cavity surface 13 to axially position the upper cavity insert 2. To ensure that the bottom of the upper cavity insert 2 can completely fit with the stepped surface 14 and avoid interference caused by machining the rounded corners, a clearance groove 15 is formed at the root of the stepped surface 14, that is, on the inner peripheral wall between the mounting hole 11 and the cavity surface 13.

[0028] In this embodiment, the upper cavity insert 2 and the mounting hole 11 are fitted with a transition fit. To further prevent minor rotation of the upper cavity insert 2 during injection molding, a set screw hole 16 is radially formed on the peripheral wall of the mounting hole 11 of the lower cavity insert 3. A set screw (not shown in the figure) is screwed into the set screw hole 16, and the end of the set screw extends into the mounting hole 11 to radially abut against and fix the upper cavity insert 2.

[0029] The maintenance process for the injection mold of this utility model is as follows: When it is necessary to repair or replace any damaged upper cavity insert 2, first, the fixed mold part and the moving mold part of the mold should be in the open state. The operator can then operate on the cavity insert that needs repair without touching other fault-free cavities. The operator uses a special screw to screw into the two disassembly threaded holes 12 at the bottom of the target lower cavity insert 3 from the bottom of the cavity template 1. Then, by pulling down the special screw, the lower cavity insert 3 and its internal upper cavity insert 2 can be removed from the cavity template 1 as a whole. After that, by loosening the set screw in the set screw hole 16, the upper cavity insert 2 can be removed from the lower cavity insert 3 for individual repair or replacement. After the replacement is completed, the reassembled cavity insert is pressed into the cavity template 1 from the bottom. The whole process is convenient and efficient, and there is no need to disassemble the template. It is worth noting that, in cases such as Figure 2 In the side-injection mold application shown, although one end of the side-injection nozzle core 41 is embedded in the side wall of the lower cavity insert 3, the other end is in a flat contact with the hot nozzle body 4. Therefore, during the process of removing the cavity insert as a whole from the bottom, the nozzle core 41 will be taken out along with the lower cavity insert 3, and there will be no jamming problem.

[0030] Finally, it is understood that those skilled in the art can make various other corresponding changes and modifications based on the technical concept of this utility model, and all such changes and modifications should fall within the protection scope of the claims of this utility model.

Claims

1. A conveniently detachable injection mold for a syringe barrel, comprising a cavity template, and an upper cavity insert and a lower cavity insert installed within the cavity template, wherein the upper cavity insert is used to form the outer surface of the syringe barrel head, and the lower cavity insert is used to form the outer surface of the syringe barrel section, characterized in that: The top of the lower cavity insert extends upward to form a mounting hole for surrounding and accommodating the upper cavity insert. The bottom of the lower cavity insert is provided with a disassembly part, which is used to cooperate with an external tool to remove the lower cavity insert and the upper cavity insert installed therein as a whole from the cavity template.

2. The syringe barrel injection mold for easy assembly and disassembly according to claim 1, characterized in that: The disassembly part is a disassembly threaded hole opened at the bottom of the lower cavity insert, which is used to cooperate with a special screw.

3. The syringe barrel injection mold for easy assembly and disassembly according to claim 2, characterized in that: The bottom of the lower cavity insert has two symmetrically arranged disassembly threaded holes centered on the central axis.

4. The syringe barrel injection mold for easy assembly and disassembly according to claim 1, characterized in that: Inside the lower cavity insert, the inner diameter of the mounting hole is larger than the inner diameter of the cavity surface used to form the outer surface of the cylindrical part, and a stepped surface is formed at the transition between the two for axial positioning of the upper cavity insert.

5. The syringe barrel injection mold for easy assembly and disassembly according to claim 4, characterized in that: Inside the lower cavity insert, an air-avoiding groove is formed on the inner peripheral wall between the mounting hole and the cavity surface used to form the outer surface of the cylindrical part.

6. The syringe barrel injection mold for easy assembly and disassembly according to claim 1, characterized in that: The upper cavity insert and the mounting hole are in a transition fit.

7. The syringe barrel injection mold for easy assembly and disassembly according to claim 6, characterized in that: The lower cavity insert mounting hole has a radially formed set screw hole on its peripheral wall. A set screw is screwed into the set screw hole, and the end of the set screw extends into the mounting hole to abut against and fix the upper cavity insert.

8. The syringe barrel injection mold for easy assembly and disassembly according to claim 1, characterized in that: The top of the lower cavity insert penetrates the cavity template, and the top surfaces of the upper and lower cavity inserts are flush with the upper surface of the cavity template.

9. The syringe barrel injection mold for easy assembly and disassembly according to claim 1, characterized in that: The cavity template is an integral template structure.

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