Plastic cover injection mold capable of directly recycling material handle and injection molding method

Abstract

The invention relates to a plastic cover injection mold capable of directly recycling a material handle. The plastic cover injection mold structurally comprises a fixed mold plate and a movable mold plate, a plurality of female mold injection molding units are arranged on the fixed mold plate, and a plurality of male mold injection molding units corresponding to the female mold injection molding units are arranged on the movable mold plate; the female die injection molding unit comprises a discharging port, a plurality of cavities are formed around the discharging port, pouring gates are formed in the side walls of the cavities, the pouring gate of each cavity is communicated with a short runner, the short runners are communicated with the discharging port, a partition block is arranged at the position right opposite to the discharging port, and the surface of the partition block is flush with the surface of the fixed die plate. A cavity formed by the plurality of short runners is divided into at least two cold material cavities by the separation blocks, and a cold material hole is formed between every two adjacent short runners in each cold material cavity; the male die injection molding unit comprises a plurality of male dies, and the male dies correspond to the cavities of the female die injection molding unit. According to the invention, the cost is low, the generated material petals can be directly recycled without being crushed, and a large number of plastic covers can be simultaneously subjected to injection molding processing.

Description

Technical Field

[0001] This invention relates to a plastic cap injection mold, specifically a plastic cap injection mold and injection method that allows for direct reuse of the spool. Background Technology

[0002] Aluminum-plastic caps are a common sealing structure for bottle packaging in the biopharmaceutical industry. They consist of an aluminum cap and a plastic cap, with the plastic cap being produced through injection molding. Due to the small size of the plastic cap, current technology employs a multi-cavity mold design to improve injection molding efficiency, allowing multiple products to be produced in a single injection. Injection molds are categorized into cold runner molds and hot runner molds. Cold runner molds are simple in structure and low in cost; however, with a multi-cavity design, multiple main runners are set on a single mold, each connecting to multiple branch runners. Each branch runner is connected to the cavity via a gate. After injection molding, in addition to solidifying into the product within the cavity, the material also solidifies in the main runners and branch runners, forming large, tree-like stalks. To avoid material waste, these stalks are recycled. However, due to their large size, these stalks need to be pulverized into smaller particles before being fed back into the injection molding machine. For hot runner molds, heating and insulation keep the plastic melt in a molten state, avoiding the formation of solidified material in the gating system, achieving runnerless solidification production, eliminating sprue, and saving raw materials; however, hot runner molds have a complex structure and high cost, including main runner nozzles, runner plates, sub-nozzles, heating and temperature measuring elements, etc. When adopting a multi-cavity mold design, numerous hot runners and sub-nozzles need to be designed, and all require heating and insulation facilities, making the structure relatively complex and resulting in excessively high costs.

[0003] Therefore, there is an urgent need for a low-cost plastic cap injection molding technology that allows for direct reuse of the material handle. Summary of the Invention

[0004] The purpose of this invention is to provide a plastic cap injection mold and injection method that allows direct reuse of the sprue, in order to solve the problems of cold runner molds not being able to directly reuse the sprue and hot runner molds being costly in the prior art.

[0005] The present invention is implemented as follows: a plastic cap injection mold that can directly reuse the material handle, comprising a fixed mold plate and a moving mold plate.

[0006] A plurality of cavity injection molding units are provided on the fixed template, and a plurality of punch injection molding units corresponding to the cavity injection molding units are provided on the moving template.

[0007] The injection molding unit includes an outlet, and multiple cavities are arranged around the outlet. A gate is provided on the side wall of each cavity. Each cavity gate is connected to a short runner. The multiple short runners are connected to the outlet. A partition block is provided directly opposite the outlet. The surface of the partition block is flush with the surface of the fixed mold plate. The partition block divides the cavity formed by the multiple short runners into at least two cold slug cavities. A cold slug cavity is provided between two adjacent short runners in each cold slug cavity.

[0008] The punch injection unit includes multiple punches, and the punches correspond to the cavities of the die injection unit.

[0009] Furthermore, it also includes a runner plate, on which a main runner is provided, the main runner corresponding to the outlet, for providing injection molding material to each outlet.

[0010] Furthermore, a pull pin is provided on the punch injection unit, the pull pin is aligned with the cold slug cavity, and an ejector rod is provided at the center of the punch.

[0011] Furthermore, the sidewall of the short flow channel is an arc-shaped structure, and the sidewall of the cold material cavity is an arc-shaped structure.

[0012] Furthermore, one of the said cavity injection units includes four or six cavities, which are evenly distributed around the center of the discharge port.

[0013] Furthermore, several of the aforementioned injection molding units are arranged in a rectangular array on the fixed template.

[0014] Furthermore, the gate is a tapered gate, and the diameter of the end of the gate that connects to the short runner is larger than the diameter of the end that connects to the cavity.

[0015] Furthermore, the width of the partition block is the same as the diameter of the discharge port, and the discharge port is connected to the cold material chamber through a conical side connection.

[0016] This invention also discloses a method for injection molding a plastic cap that allows for direct reuse of the spool, comprising the following steps: a. Install the aforementioned plastic cap injection mold with a reusable material handle in the injection molding machine; b. Start the injection molding machine and add raw material granules to the hopper of the injection molding machine; c. The raw material granules are plasticized and melted into molten material in the injection molding machine. The molten material is injected into the molded plastic cap injection mold with a reusable stalk, forming a plastic cap in the cavity and a reusable stalk in the cold slug cavity. d. After the molten material cools and solidifies, the mold is opened to obtain the finished plastic cap and the material flap; e. Collect the material fragments and add them directly to the hopper of the injection molding machine for reuse.

[0017] Furthermore, a pull pin is provided on the punch injection unit, the pull pin is aligned with the cold slug cavity, and an ejector rod is provided at the center of the punch; in step d, when the mold is opened, the plastic cap is ejected from the punch by the ejector rod, and the slug is pulled out from the cold slug cavity by the pull pin.

[0018] This invention employs a combination of hot runner and cold runner molds to produce the plastic cap portion of aluminum-plastic caps. The main runner section uses a hot runner mold, preventing material from solidifying. This section has a relatively simple structure and low manufacturing cost. The fixed and moving molds used for molding utilize cold runner molds, where material solidification only occurs in the short runners on the fixed mold, forming a stalk. Different plastic caps require dedicated molding dies due to variations in shape, pattern, design, and size. In this invention, the fixed and moving molds use cold runner molds, resulting in low manufacturing costs. The hot runner mold for the main runner section can be shared, and molds with identical outlet distribution can use the same runner plate, significantly reducing costs.

[0019] For the fixed and moving mold plates used for molding, a special short runner structure is adopted, and a partition block is set to divide it into smaller cold slug cavities. In this way, the slug formed during injection molding automatically becomes multiple small slug structures. Because of their small size, the slugs can be directly added to the injection molding machine for reuse without being crushed after leaving the mold, avoiding material waste and simplifying the reuse operation and cost.

[0020] The solution of this invention has low overall cost, does not generate waste, is easy to implement, and is suitable for batch injection molding of various types of plastic caps. Attached Figure Description

[0021] Figure 1 This is a structural diagram of the template of the present invention.

[0022] Figure 2 This is a structural diagram of the moving template of the present invention.

[0023] Figure 3 This is a structural diagram of the cavity injection molding unit of the present invention.

[0024] Figure 4 This is a structural diagram of the punch injection unit of the present invention.

[0025] Figure 5 This is a cross-sectional view of the injection mold for the plastic cap of the present invention.

[0026] Figure 6 This is a cross-sectional view of the plastic cap injection mold of the present invention from another direction.

[0027] Figure 7 The plastic cap and the formed material petals are obtained by injection molding using the plastic cap injection mold of the present invention.

[0028] Figure 8 The structure of the material petals is formed by the injection mold of the plastic cap of the present invention.

[0029] In the diagram: 1. Fixed mold plate; 2. Moving mold plate; 3. Runner plate; 4. Cavity injection unit; 5. Punch injection unit; 6. Exit gate; 7. Short runner; 8. Cold slug well; 9. Cold slug cavity; 10. Gate; 11. Cavity; 12. Separator block; 13. Material separator groove; 14. Punch; 15. Ejector pin; 16. Pull pin; 17. Main runner. Detailed Implementation

[0030] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0032] like Figures 1-6 As shown, this invention first proposes a plastic cap injection mold that can directly reuse the material handle. Its structure mainly includes a fixed mold plate 1 and a moving mold plate 2. Several cavity injection units 4 are set on the fixed mold plate 1, and several punch injection units 5 are set on the moving mold plate 2. The number and position distribution of the cavity injection units 4 and the punch injection units 5 correspond to each other. The injection molding of plastic caps is realized through the cavity injection units 4 and the punch injection units 5. A large number of plastic caps can be injection molded at one time, resulting in high production efficiency.

[0033] Generally, the concave injection unit 4 and the convex injection unit 5 are arranged in a rectangular array on a rectangular template, which has a high space utilization rate.

[0034] like Figure 3As shown, the injection molding unit 4 specifically includes an outlet 6, which is located at the center of the injection molding unit 4. Multiple cavities 11 are arranged around the outlet 6, either symmetrically or evenly distributed around the outlet 6. A gate 10 is provided on the side wall of each cavity 11. Each cavity 11's gate 10 is connected to a short runner 7, which is connected to the outlet 6. The outlet 6 is connected to the cavity 11 through the short runner 7 and the gate 10.

[0035] A single injection molding unit 4 may include 4 or 6 cavities 11 or more cavities 11, and the number of cavities 11 is generally an even number.

[0036] Multiple short channels 7 are simultaneously connected to the discharge port 6, intersecting to form interconnected cavities. A partition block 12 is provided in the cavity directly opposite the discharge port 6. The surface of the partition block 12 is flush with the surface of the fixed template 1, thereby dividing the cavity formed by the multiple short channels 7 into at least two cold material cavities 9. Each cold material cavity 9 contains at least two short channels 7, and a cold material cavity 8 is provided between two adjacent short channels 7 in each cold material cavity 9.

[0037] The separator 12 can be an integral structure with the fixed template 1, or it can be a plug-in structure.

[0038] The cold slug well 8 is connected to the outlet 6, and the short flow channels 7 are located on both sides of the cold slug well 8. The material output from the outlet 6 will first enter the cold slug well 8 directly, and then enter the short flow channels 7 on both sides. This allows the first material flowing out of the outlet 6 to enter the cold slug well 8, and the subsequent material enters the cavity 11 through the short flow channels 7, thereby ensuring the quality of the plastic cap.

[0039] For the cavity formed by the short runner 7 and the cold slug cavity 8, since it is divided into multiple cold slug cavities 9 by the partition block 12, the material is cooled into smaller slug lobes in the cold slug cavity 9 during injection molding. Compared with the slug stalk formed by the traditional cold runner mold, the volume of the slug lobes is greatly reduced.

[0040] In this design, the sidewalls of both the short flow channel 7 and the cold material cavity 8 are curved, and the cold material formed after cooling of the material filling the short flow channel 7 and the cold material cavity 8 is part of a sphere. This structure can minimize the volume of the cold material cavity 9, thereby reducing the formation of cold material and making the volume of the cold material fragments as small as possible.

[0041] A material separation groove 13 is provided around the outer ring of the injection unit 4. When a malfunction occurs in one injection unit 4 and material overflows, the material will be blocked by the material separation groove 13 to prevent it from affecting other injection units 4.

[0042] In one embodiment of the present invention, a cavity injection unit 4 has four cavities 11 distributed in it, the four cavities 11 correspond to four short runners 7, the separator block 12 separates the four short runners 7 in pairs, and each cold slug cavity 9 includes two short runners 7 and a cold slug cavity 8 between the two short runners 7.

[0043] The resulting material petals are long in one direction but narrow in other directions. This shape allows the material petals to enter the screw assembly of the injection molding machine smoothly without prior crushing.

[0044] Among them, the gate 10 is a conical gate 10. The diameter of the end of the gate 10 that connects to the short runner 7 is larger than the diameter of the end that connects to the cavity 11, so that when the material petal comes out of the cold material cavity 9, the cold material formed at the gate 10 comes out with the material petal.

[0045] The width of the separator 12 is the same as the diameter of the discharge port 6. The discharge port 6 is connected to the cold material chamber 9 through a conical side connection port, so that the flow area between the cold material chamber 9 and the discharge port 6 is small, and the material can be smoothly disconnected at this position when the material is dislodged.

[0046] like Figure 4 As shown, the punch injection unit 5 includes multiple punches 14, which protrude from the surface of the moving template 2. The punches 14 correspond to the cavities 11, and the gap between the punches 14 and the cavities 11 after mold closing is used to form the product. The number and distribution of the punches 14 in the punch injection unit 5 correspond to the cavities 11 in the die injection unit 4.

[0047] Furthermore, a pull pin 16 is provided on the injection molding unit 5, which corresponds to the cold slug cavity 8. An ejector rod 15 is provided at the center of the punch 14. After injection molding, the plastic cap is ejected from the punch 14 by the ejector rod 15, and at the same time, the pull pin 16 pulls the material fragments out of the cold slug cavity 9. The material fragments are cut off at the gate 10 and the outlet 6. Then the pull pin 16 retracts to remove the material fragments from the pull pin 16. The removed material fragments are collected and subsequently added back to the injection molding machine for reuse.

[0048] Meanwhile, since the pull pin 16 extends into the cold slug cavity 8, the hole used to accommodate the pull pin 16 during injection molding reduces the volume of material filling the cold slug cavity 8, thereby saving material.

[0049] In one embodiment of the present invention, when a cavity injection unit 4 has four cavities 11, a corresponding punch injection unit 5 has four punches 14.

[0050] The present invention also includes a flow channel plate 3, on which a main flow channel 17 is provided. The main flow channel 17 corresponds to the discharge port 6 and is simultaneously connected to each discharge port 6 to provide injection molding raw materials to each discharge port 6.

[0051] A heating device is provided on the flow channel plate 3 to heat the material in the main flow channel 17 and keep it in a molten state.

[0052] A heat insulation device (this part of the structure is omitted in the figure) is provided between the flow channel plate 3 and the fixed template 1. The flow channel plate 3 and the fixed template 1 can be separated by an object with heat insulation function to reduce the heat loss to the fixed template 1.

[0053] A nozzle (not shown in the figure) is installed between the main channel 17 and the discharge port 6, through which the material is output to the discharge port 6.

[0054] The present invention also discloses a plastic cap injection molding method that allows for direct reuse of the material handle, comprising the following steps.

[0055] a. Install the aforementioned plastic cap injection mold with a reusable stalk in the injection molding machine.

[0056] b. Start the injection molding machine and add raw material granules to the hopper of the injection molding machine.

[0057] c. The raw material granules are plasticized and melted in the injection molding machine to form molten material. The molten material is injected into the molded plastic cap injection mold with a reusable stalk, forming a plastic cap in cavity 11 and a reusable stalk in cold slug cavity 9.

[0058] d. After the molten material cools and solidifies, the mold is opened to obtain the finished plastic cap and the material piece.

[0059] e. Collect the material fragments and add them directly to the hopper of the injection molding machine for reuse.

[0060] A pull pin 16 is provided on the injection unit 5 of the punch, and the pull pin 16 corresponds to the cold slug cavity 8. An ejector rod 15 is provided at the center of the punch 14. In step d, when the mold is opened, the plastic cap is ejected from the punch 14 by the ejector rod 15, and the material piece is pulled out from the cold slug cavity 9 by the pull pin 16.

[0061] When producing different plastic caps, replace the fixed mold plate 1 and the moving mold plate 2 with different ones. Other structures do not need to be changed. Adjust the parameters of the injection molding machine.

[0062] The plastic cap and the formed material petals obtained by injection molding according to the present invention are as follows: Figure 7 As shown, one injection molding unit can produce four plastic caps and simultaneously form two material segments.

[0063] This invention employs a special short runner structure and incorporates a partition block 12 to divide it into smaller cold slug cavities 9. This allows the slug formed during injection molding to automatically morph into multiple small slug segments, the specific structure of which is as follows: Figure 8As shown, the material fragments are very small in volume, and except for their larger size in the length direction, their size in other directions is much smaller than that in the length direction. After leaving the mold, they can be directly added to the screw device of the injection molding machine for reuse without being crushed, thus avoiding material waste and simplifying the reuse operation and cost.

[0064] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A plastic cap injection mold with a directly reusable stalk, characterized in that, Includes fixed templates and dynamic templates; A plurality of cavity injection molding units are provided on the fixed template, and a plurality of punch injection molding units corresponding to the cavity injection molding units are provided on the moving template. The cavity injection unit includes an outlet, and multiple cavities are arranged around the outlet. A gate is provided on the side wall of each cavity. Each cavity gate is connected to a short runner. The multiple short runners are connected to the outlet. A partition block is provided at the position directly opposite the outlet. The surface of the partition block is flush with the surface of the fixed mold plate. The partition block divides the cavity formed by the multiple short runners into at least two cold slug cavities. A cold slug cavity is provided between two adjacent short runners in each cold slug cavity. The punch injection unit includes multiple punches, and the punches correspond to the cavities of the die injection unit.

2. The plastic cap injection mold with a directly reusable material handle according to claim 1, characterized in that, It also includes a runner plate, on which a main runner is provided, the main runner corresponding to the outlet, for providing injection molding material to each outlet.

3. The plastic cap injection mold with a directly reusable material handle according to claim 1, characterized in that, A pull pin is provided on the punch injection unit, the pull pin is aligned with the cold slug cavity, and an ejector rod is provided at the center of the punch.

4. The plastic cap injection mold with a directly reusable material handle according to claim 1, characterized in that, The sidewall of the short flow channel has an arc surface structure, and the sidewall of the cold material cavity has an arc surface structure.

5. The plastic cap injection mold with a directly reusable material handle according to claim 1, characterized in that, One of the aforementioned injection molding units includes four or six cavities, which are evenly distributed around the center of the discharge port.

6. The plastic cap injection mold with a directly reusable stalk as described in claim 1, characterized in that, Several of the aforementioned injection molding units are arranged in a rectangular array on the fixed template.

7. The plastic cap injection mold with a directly reusable material handle according to claim 1, characterized in that, The gate is a tapered gate, and the diameter of the end of the gate that connects to the short runner is larger than the diameter of the end that connects to the cavity.

8. The plastic cap injection mold with a directly reusable stalk as described in claim 1, characterized in that, The width of the partition block is the same as the diameter of the discharge port, and the discharge port is connected to the cold material chamber through a conical side connection.

9. A method for injection molding a plastic cap that allows for direct reuse of the material handle, characterized in that, Includes the following steps: a. An injection mold for a plastic cap with a reusable stalk as described in any one of claims 1 to 8 is installed in an injection molding machine; b. Start the injection molding machine and add raw material granules to the hopper of the injection molding machine; c. The raw material granules are plasticized and melted into molten material in the injection molding machine. The molten material is injected into the molded plastic cap injection mold with a reusable stalk, forming a plastic cap in the cavity and a reusable stalk in the cold slug cavity. d. After the molten material cools and solidifies, the mold is opened to obtain the finished plastic cap and the material flap; e. Collect the material fragments and add them directly to the hopper of the injection molding machine for reuse.

10. The injection molding method for a plastic cap with a directly reusable stalk according to claim 9, characterized in that, A pull pin is provided on the punch injection unit, and the pull pin is aligned with the cold slug cavity. An ejector rod is provided at the center of the punch. In step d, when the mold is opened, the plastic cap is ejected from the punch by the ejector rod, and the material piece is pulled out from the cold slug cavity by the pull pin.

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