A hot runner structure for injection molding of PETG plastic

Abstract

This utility model relates to a hot runner structure for injection molding of PETG plastic, including a hot nozzle and a cooling jacket. The cooling jacket is fitted over the hot nozzle and has a cooling channel inside. The cooling channel includes an annular channel, a first connecting channel, and a second connecting channel. The annular channel is a broken "C"-shaped ring surrounding the outlet of the hot nozzle. A first interface and a second interface are provided on the outer surface of the cooling jacket, which are respectively connected to the two ends of the annular channel through the first and second connecting channels. This utility model uses a "C"-shaped annular channel surrounding the outlet, and the cooling water enters from one end of the annular channel and flows out from the other end, allowing the cooling water to flow along a single arc path of the annular channel, thereby uniformly cooling the outlet and preventing the whitening of the product surface after injection molding due to excessively high temperature or large temperature difference at the outlet.

Description

Technical Field

[0001] This utility model relates to the field of hot runner technology for injection molds. Background Technology

[0002] PETG is a high-performance thermoplastic polyester material characterized by high transparency, high temperature resistance, hydrolysis resistance, and chemical resistance. Many existing medical-grade products are manufactured using PETG injection molding. A commonly used injection molding structure for PETG is a hot runner system with hot nozzles. However, when using hot nozzles for injection molding, PETG is prone to surface whitening due to excessively high temperatures or uneven cooling, which is extremely detrimental to the production of products requiring high transparency. Utility Model Content

[0003] To address the aforementioned problems, this invention proposes a more optimized hot runner structure for injection molding of PETG plastic.

[0004] This utility model is achieved using the following technical solution: This utility model proposes a hot runner structure for injection molding of PETG plastic, including a hot nozzle with a dispensing port and a cooling sleeve fitted over the hot nozzle. The cooling sleeve has a cooling channel inside, which includes an annular channel, a first connecting channel, and a second connecting channel. The annular channel is in the shape of a broken "C" ring and surrounds the dispensing port. A first interface and a second interface are provided on the outer surface of the cooling sleeve. The first interface and the second interface are respectively connected to the two ends of the annular channel through the first connecting channel and the second connecting channel.

[0005] Preferably, the first interface serves as the cooling water inlet, the second interface serves as the cooling water outlet, the disconnected portion of the annular flow channel is configured to be closer to the second interface, and the first connecting flow channel extends spirally to a position further out of the annular flow channel.

[0006] Preferably, the first interface and the second interface are located on the circumferential end face of the cooling sleeve.

[0007] Preferably, the first interface and the second interface are located on the axial end face of the cooling sleeve.

[0008] Preferably, the cooling jacket is made using a 3D printing process.

[0009] Preferably, the arc of the annular flow channel is between 320° and 350°.

[0010] The present invention has the following beneficial effects: The present invention adopts a "C"-shaped annular flow channel surrounding the outlet, and the cooling water enters from one end of the annular flow channel and flows out from the other end, so that the cooling water can flow along a single arc path of the annular flow channel, thereby uniformly cooling the outlet and avoiding the phenomenon of whitening of the product surface after injection molding due to excessive temperature or large temperature difference at the outlet. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of the hot runner structure used for injection molding of PETG plastic in the embodiment; Figure 2 This is a schematic diagram of the hot runner and cooling jacket in the embodiment; Figure 3 This is a cross-sectional view of the hot nozzle and cooling jacket in the embodiment; Figure 4 This is a schematic diagram of the cooling jacket in the embodiment; Figure 5 This is a schematic diagram of the cooling flow channel in the embodiment. Detailed Implementation

[0012] To further illustrate the various embodiments, the present invention provides accompanying drawings. These drawings are part of the disclosure of the present invention and are mainly used to illustrate the embodiments, and can be used in conjunction with the relevant descriptions in the specification to explain the operating principles of the embodiments. With reference to these drawings, those skilled in the art should be able to understand other possible implementations and the advantages of the present invention. Components in the drawings are not drawn to scale, and similar component symbols are generally used to represent similar components.

[0013] The present invention will now be further described in conjunction with the accompanying drawings and specific embodiments.

[0014] See Figure 1-5 As shown, as a preferred embodiment of the present invention, a hot runner structure for injection molding of PETG plastic is provided, including a hot nozzle 1 and a cooling jacket 2. Molten PETG plastic enters through the hot nozzle 1 and is injected into the mold cavity through the outlet 11 at the lower end of the hot nozzle 1. The hot nozzle 1 is a commonly used structure in the art. Furthermore, a needle valve can be provided in the hot nozzle 1 to form a needle valve type hot runner. Precise control of the molten plastic can be achieved by controlling the opening and closing of the needle valve.

[0015] The cooling jacket 2 is fitted over the hot nozzle 1. The cooling jacket 2 contains a cooling channel 20, which includes an annular channel 23, a first connecting channel 21, and a second connecting channel 22. The annular channel 23 is a C-shaped, discontinuous ring; or, in other words, it is a circular arc that is essentially enclosed but not completely circular. In this embodiment, the arc of the annular channel 23 is between 320° and 350°. The annular channel 23 surrounds the outer periphery of the dispensing port 11 to precisely and uniformly cool the molten plastic at the dispensing port 11. A first interface 24 and a second interface 25 are provided on the outer surface of the cooling jacket 2. The first interface 24 and the second interface 25 are connected to the two ends of the annular channel 23 via the first connecting channel 21 and the second connecting channel 22, respectively. One of the first interface 24 and the second interface 25 serves as a cooling water inlet, and the other serves as a cooling water outlet. The hot runner structure of this embodiment also includes a cooling water control module for controlling the on / off state and flow rate of the cooling water. The cooling water control module may also be configured with a controller and a temperature sensing module for sensing the outlet 11. After obtaining the temperature feedback from the temperature sensing module, the controller is used to control the cooling water for cooling.

[0016] In this embodiment, the annular flow channel 23 surrounding the outlet 11 in a "C" shape is adopted, and the cooling water enters from one end of the annular flow channel 23 and flows out from the other end. This allows the cooling water to flow along a single arc path of the annular flow channel 23, thereby uniformly cooling the outlet 11 and avoiding the phenomenon of whitening of the product surface after injection molding due to excessive temperature or large temperature difference at the outlet 11.

[0017] Furthermore, in this embodiment, the first interface 24 serves as a cooling water inlet, and the second interface 2 serves as a cooling water outlet. The first interface 24 and the second interface 25 are located on opposite sides of the cooling jacket 2. The disconnected portion 231 of the annular flow channel is configured to be closer to the second interface 25, and the first connecting flow channel 21 extends spirally to a position further outward from the annular flow channel 23. The spirally extending first connecting flow channel 21 can, on the one hand, accelerate the flow rate of the cooling water, and on the other hand, allow the first connecting flow channel 21 to gradually approach the annular flow channel 23, enabling the cooling effect to be generated gradually and avoiding the problem of a large temperature difference at the outlet 11 due to excessively rapid cooling.

[0018] In this embodiment, the first interface 24 and the second interface 25 are located on the circumferential end face of the cooling sleeve 2, which shortens the length of the first connecting channel 21 and the second connecting channel 22, making the cooling sleeve 2 easier to manufacture. In other embodiments, the first interface 24 and the second interface 25 can also be located on the axial end face of the cooling sleeve 2, which makes the sealing of the first interface 24 and the second interface 25 more reliable.

[0019] In this embodiment, the cooling jacket 2 is made using 3D printing technology to ensure the integrity and sealing of the cooling channel 2.

[0020] Although the present invention has been specifically shown and described in conjunction with preferred embodiments, those skilled in the art should understand that any changes in form and detail made to the present invention without departing from the spirit and scope of the present invention as defined in the appended claims fall within the protection scope of the present invention.

Claims

1. A hot runner structure for PETG plastic injection molding comprising a hot nozzle, said hot nozzle comprising a dispensing orifice, characterized in that: It also includes a cooling jacket, which is fitted over the hot nozzle. The cooling jacket has a cooling channel inside, which includes an annular channel, a first connecting channel and a second connecting channel. The annular channel is in the shape of a broken "C" ring and is arranged around the outer periphery of the dispensing port. A first interface and a second interface are provided on the outer surface of the cooling jacket. The first interface and the second interface are respectively connected to the two ends of the annular channel through the first connecting channel and the second connecting channel.

2. The hot runner structure for PETG plastic injection molding according to claim 1, characterized in that: The first interface serves as the cooling water inlet, and the second interface serves as the cooling water outlet. The disconnected portion of the annular flow channel is configured to be closer to the second interface, and the first connecting flow channel extends spirally to a position further out of the annular flow channel.

3. The hot runner structure for PETG plastic injection molding according to claim 1, characterized in that: The first interface and the second interface are located on the circumferential end face of the cooling sleeve.

4. The hot runner structure for PETG plastic injection molding according to claim 1, characterized in that: The first interface and the second interface are located on the axial end face of the cooling sleeve.

5. The hot runner structure for PETG plastic injection molding according to claim 1, wherein: The cooling jacket is made using 3D printing technology.

6. The hot runner structure for PETG plastic injection molding according to claim 1, characterized in that: The curvature of the annular flow channel is between 320° and 350°.

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