Glue melting mechanism of injection molding machine, injection molding machine and glue melting method

Abstract

The invention discloses an injection molding machine glue melting mechanism, an injection molding machine and a glue melting method.The injection molding machine glue melting mechanism comprises an injection table front plate, a glue melting barrel and a hopper, the glue melting barrel and the hopper are installed on the injection table front plate, a plasticizing screw is arranged in the glue melting barrel and the injection table front plate, a screw groove for material conveying is formed between the glue melting barrel and the injection table front plate, the hopper is communicated with the screw groove in the position of a screw conveying section, and the plasticizing screw is located on a platform; the device further comprises an air extractor communicated with the screw groove of the screw conveying section, and the air extractor enables the screw groove of the screw conveying section to form suction force relative to particle rubber input by the communicated hopper. According to the glue melting mechanism of the injection molding machine, the injection molding machine and the glue melting method, the structure is compact, feeding is uniform, and the plasticizing effect is good.

Description

Technical Field

[0001] This invention relates to the technical field of plastic molding machinery, specifically to a melting mechanism for an injection molding machine, an injection molding machine, and a melting method. Background Technology

[0002] In plastic molding equipment such as injection molding machines and extruders, the plasticizing screw is the core component for melting and plasticizing plastic granules. In the traditional plasticizing process, the granular rubber material mainly relies on its own gravity to fall from the hopper into the screw channel of the melting barrel, where it is conveyed forward and gradually melts under the action of the rotating screw. However, due to the light weight and large differences in flowability of the rubber granules, problems such as uneven feeding and insufficient material intake can easily occur, affecting plasticizing efficiency and quality, and even leading to material shortages or incomplete plasticizing.

[0003] Therefore, the aforementioned technical problems need to be solved. Summary of the Invention

[0004] To address the above-mentioned technical problems, this invention provides a melting mechanism for an injection molding machine, as well as an injection molding machine and a melting method, which has a compact structure, uniform feeding, and good plasticizing effect.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows:

[0006] A melting mechanism for an injection molding machine includes a front plate of an injection unit and a melting cylinder and a hopper mounted thereon. A plasticizing screw is disposed in the melting cylinder and the front plate of the injection unit, forming a screw groove for conveying material between them. The hopper is connected to the screw groove at the material conveying section of the screw. The front plate of the injection unit is located on a platform. The machine also includes an air extraction device connected to the screw groove at the material conveying section of the screw. The air extraction device causes the screw groove at the material conveying section of the screw to form a suction force relative to the granular plastic material input into the hopper.

[0007] In a further optimized design, the screw conveying section of the plasticizing screw is provided with interconnected axial and radial air channels. The air extraction device connects to the screw groove of the screw conveying section through the axial and radial air channels. The air extraction device extracts air from the screw groove of the screw conveying section, forcing the granular rubber material into the screw groove under the action of external atmospheric pressure.

[0008] The melting mechanism of this injection molding machine features radial air channels at the bottom of the screw groove in the feeding section of the plasticizing screw. The vacuum device creates a vacuum in the screw groove of the feeding section through the axial and radial air channels. This allows the granular rubber material to not only bear its own weight but also atmospheric pressure during the process of entering the barrel and plasticizing screw. This results in a more compacted rubber material entering the screw groove, ensuring the consistency of the rubber particles entering the barrel and improving plasticizing efficiency.

[0009] To further optimize the design, an external air channel is provided in the front plate of the positioning injection station, which forms an outer positioning wall corresponding to the screw groove of the screw conveying section. The air extraction device is connected to the screw groove of the screw conveying section through the external air channel.

[0010] Further optimization of the scheme: the external air connection channel includes several radial sections that are radially opposite to the screw groove of the screw conveying section and horizontal sections that are horizontally parallel to it.

[0011] In a further optimized design, the shank of the plasticizing screw is provided with an air groove surrounding the screw, and the bottom of the air groove is provided with an air outlet communicating with the axial air passage. The air outlet pipe is connected to the air extraction device.

[0012] By incorporating an annular air groove in the shank of the plasticized screw, a transit space for gas flow is provided between the rotating screw and the fixed vacuum pipeline. This structure allows for stable gas communication between the screw and the external pipeline even at high speeds, preventing pipeline entanglement or connection failure caused by screw rotation and ensuring the continuity and reliability of vacuuming.

[0013] In a further optimized design, an air sleeve is fitted over the shank of the plasticizing screw. The air sleeve has a radial air channel that communicates with the air groove. The air sleeve and the plasticizing screw are dynamically sealed together.

[0014] The air jacket provides a stable connection interface between the rotating plasticized screw and the fixed vacuum pipeline; the pumping device is connected to the radial air passage on the air jacket through an air pipe, and the dynamic sealing structure between the air jacket and the screw shank ensures that the vacuum level is maintained when the screw is rotating.

[0015] In a further optimized design, multiple radial air channels are distributed axially at the bottom of the screw groove in the screw conveying section. This axial distribution of multiple radial air channels ensures that the vacuum effect covers the entire conveying section, enhancing the uniformity and effectiveness of the negative pressure. The granular rubber compound is subjected to negative pressure attraction at different positions upon entering the conveying section, avoiding the localized uneven feeding that might occur with a single radial air channel, and significantly improving the uniformity and density of the feed.

[0016] Further optimization of the scheme also includes a positioning guide rod, which is fixedly installed and parallel to the axis of the plasticizing screw;

[0017] The positioning guide rod passes through the air sleeve, restricting the air sleeve from rotating with the plasticizing screw. The air sleeve can move synchronously along the positioning guide rod as the plasticizing screw moves axially.

[0018] The positioning guide rod solves the rotation constraint problem of the air sleeve, keeping it stationary while the plasticizing screw rotates, thus preventing the air tubes connected to the air sleeve from becoming entangled. Simultaneously, the air sleeve can move axially along the positioning guide rod with the plasticizing screw, adapting to the axial movement of the plasticizing screw during injection, ensuring reliable vacuum connection and stable operation in any working position.

[0019] In a further optimized design, sealing rings are provided on the inner sides of both ends of the air sleeve, and these sealing rings are in sealing engagement with the outer circular surface of the plasticizing screw. The sealing rings at both ends form a reliable dynamic sealing structure, which is simple in structure, easy to replace, and has a good sealing effect.

[0020] Further optimizations include a plasticizing motor that drives the plasticizing screw and a heating coil that heats the melt cylinder. The melt cylinder provides the working chamber for plasticizing, the plasticizing motor drives the screw to rotate to achieve material conveying and shearing, and the heating coil provides the heat required for melting.

[0021] In a further optimized design, the rear end of the plasticizing screw is equipped with a plug for sealing the end of the axial air passage. The plug ensures the airtightness of the axial air passage, so that the negative pressure generated by the suction is entirely applied to the bottom of the screw groove in the screw conveying section.

[0022] An injection molding machine includes the melting mechanism of any of the above-described injection molding machines.

[0023] A melting method, employing the above-mentioned melting mechanism of an injection molding machine, includes the following steps:

[0024] Step 1: Activate the heating coil to heat the melting cylinder;

[0025] Step 2: Start the vacuum device to create a vacuum inside the screw groove of the screw conveying section through the radial air passage, axial air passage and pipeline, so that the area is under negative pressure;

[0026] Step 3: Start the plasticizing motor to drive the plasticizing screw to rotate;

[0027] Step 4: Under the combined action of its own gravity and the atmospheric pressure outside the hopper, the granular rubber material is forcibly sucked in and tightly filled into the screw groove of the screw conveying section;

[0028] Step 5: The granular rubber compound gradually melts under the radiant heating of the heating coil and the shear heating of the plasticizing screw, forming molten rubber compound, which is then conveyed to the front end of the nozzle to complete the plasticizing process.

[0029] This method is simple and easy to implement, and can significantly improve plasticizing efficiency and product quality, achieving a forced, dense, and uniform feeding effect for granular rubber materials.

[0030] The injection molding machine melting mechanism, injection molding machine, and melting method of the present invention have the following technical advantages compared with the prior art:

[0031] 1. The feeding method is changed from passive to active, significantly improving the filling density: In the existing technology, granular rubber materials rely solely on gravity to fall, resulting in loose and unstable feeding. This invention uses an air extraction device to create negative pressure inside the screw channel of the screw conveyor section, forcing the rubber material into the screw channel under the combined action of gravity and suction. The feeding is denser and more uniform, ensuring plasticizing quality.

[0032] 2. The vacuum structure is integrated inside the screw, unlike traditional barrel venting: Existing technologies typically place the vacuum structure on the barrel, mainly for venting. This invention integrates the air channel inside the screw, with the vacuum action located directly at the bottom of the screw groove in the feeding section, specifically for assisting feeding. This results in a more compact structure and more targeted functionality.

[0033] 3. The rotary sealing structure solves the problem of vacuum connection of moving parts: Through the combined design of annular air groove, air sleeve, sealing ring and positioning guide rod, the vacuum system can still maintain reliable sealing and stable connection under the dual motion state of screw rotation and axial movement.

[0034] 4. Improved plasticizing efficiency and product quality, with strong adaptability: Due to the increased feed density, the rubber compound is heated more evenly and sheared more fully during subsequent conveying and melting, resulting in improved plasticizing efficiency and more stable melt quality. Attached Figure Description

[0035] Figure 1 This is a cross-sectional front view of a specific first embodiment of the injection molding machine melting mechanism of the present invention;

[0036] Figure 2 yes Figure 1 A cross-sectional view of the plasticizing screw;

[0037] Figure 3 yes Figure 1 Cross-sectional view of the air-insulated sleeve;

[0038] Figure 4 This is a cross-sectional front view of a specific second embodiment of the injection molding machine melting mechanism of the present invention;

[0039] Figure 5 yes Figure 4 Cross-sectional view of the melt cylinder.

[0040] In the diagram: 1. Head nozzle; 2. Molten rubber; 3. Heating coil; 4. Plasticizing screw; 5. Molten rubber cylinder; 6. Screw conveying section; 7. Radial air passage; 8. Hopper; 9. Granular rubber; 10. Front plate of injection station; 11. Air sleeve; 11a guide positioning hole; 12. Positioning guide rod; 13. Sealing ring; 14. Air groove; 15. Air outlet; 16. Axial air passage; 17. Transmission device; 18. Plasticizing motor; 19. Plug; 20. Air extraction hole; 21. Motor support; 22. Platform; 23. Air pipe; 24. Air extraction device; 25. Cylinder air hole; 26. Front plate hole; 27. Horizontal section; 28. Hole plug; 29. ​​Radial section; 30. External air passage. Detailed Implementation

[0041] The present invention will now be described in further detail with reference to the embodiments shown in the accompanying drawings.

[0042] like Figures 1 to 3 As shown, this is a first embodiment of the injection molding machine melting mechanism of the present invention. Figure 4 and Figure 5 As shown, this is a second embodiment of the injection molding machine melting mechanism of the present invention.

[0043] like Figure 1 As shown, the injection molding machine melting mechanism of the first embodiment includes a plasticizing screw 4 and an air extraction device 24. The screw conveying section 6 of the plasticizing screw 4 is provided with an axial air passage 16 in the inside, and at least one radial air passage 7 is provided at the bottom of the screw groove of the screw conveying section 6. The radial air passage 7 is connected to the axial air passage 16. The axial air passage 16 is sealed and connected to the air extraction device 24. The air extraction device 24 performs vacuuming on the inside of the screw groove of the screw conveying section 6, so that the granular rubber material 9 is forced to fill into the screw groove under the action of external atmospheric pressure.

[0044] In this injection molding machine's melting mechanism, the bottom of the screw groove of the plasticizing screw 4's screw conveying section 6 is provided with a radial air passage 7. The vacuum device 24 evacuates the screw groove of the screw conveying section 6 through the axial air passage 16 and the radial air passage 7. This allows the granular rubber material 9 to not only bear its own weight but also the effect of atmospheric pressure during the process of entering the barrel and the plasticizing screw 4. This makes the rubber material more compact when entering the screw groove, ensuring the consistency of the rubber material particles entering the barrel and the plasticizing efficiency.

[0045] like Figure 1 and Figure 2 As shown, the shank of the plasticizing screw 4 is provided with an air groove 14 surrounding the screw, and the bottom of the air groove 14 is provided with an air outlet 15 that communicates with the axial air passage 16. The air outlet 15 is connected to the air extraction device 24.

[0046] By providing an annular air groove 14 at the shank of the plasticizing screw 4, a transfer space for gas flow is provided between the rotating screw and the fixed vacuum pipeline. This structure allows the screw to maintain stable gas communication with the external pipeline through the annular air groove 14 even when rotating at high speed, avoiding problems such as pipeline entanglement or connection failure caused by screw rotation, and ensuring the continuity and reliability of vacuuming.

[0047] like Figure 1 and Figure 3 As shown, an air sleeve 11 is fitted over the shank of the plasticizing screw 4. The air sleeve 11 has an air extraction hole 20, which is connected to the air groove 14. The air sleeve 11 and the plasticizing screw 4 are dynamically sealed together.

[0048] The air sleeve 11 provides a stable connection interface between the rotating plasticized screw 4 and the fixed vacuum pipeline; the air extraction device 24 is connected to the air extraction hole 20 on the air sleeve 11 through an air pipe, and the dynamic sealing structure between the air sleeve 11 and the screw shank ensures that the vacuum is maintained when the screw is rotating.

[0049] like Figure 1 and Figure 2 As shown, multiple radial air channels 7 are distributed axially at the bottom of the screw groove in the screw conveying section 6. The axial distribution of multiple radial air channels 7 ensures that the vacuum effect covers the entire conveying section, enhancing the uniformity and effectiveness of the negative pressure. The granular rubber compound 9 is subjected to negative pressure attraction at different positions upon entering the conveying section, avoiding the localized uneven feeding that might occur with only a single radial air channel 7, and significantly improving the uniformity and density of the feed.

[0050] like Figure 1 and Figure 3 As shown, the injection molding machine melting mechanism of this embodiment also includes a positioning guide rod 12, which is fixedly set and parallel to the axis of the plasticizing screw 4; the positioning guide rod 12 is set through the guide positioning hole 11a of the air sleeve 11, restricting the air sleeve 11 from rotating with the plasticizing screw 4, and the air sleeve 11 can move synchronously along the positioning guide rod 12 with the axial movement of the plasticizing screw 4.

[0051] The positioning guide rod 12 solves the rotation constraint problem of the air sleeve 11, keeping the air sleeve 11 stationary when the plasticizing screw 4 rotates, thus preventing the air tube connected to the air sleeve 11 from getting tangled. At the same time, the air sleeve 11 can move axially along the positioning guide rod 12 with the plasticizing screw 4, adapting to the axial movement of the plasticizing screw 4 during the injection process, ensuring the reliability of the vacuum connection and stable operation in any working position.

[0052] like Figure 1As shown, sealing rings 13 are provided on the inner sides of both ends of the air sleeve 11, and the sealing rings 13 are sealed to the outer circular surface of the plasticizing screw 4. The sealing rings 13 at both ends form a reliable dynamic sealing structure, which is simple in structure, easy to replace, and has a good sealing effect.

[0053] like Figure 1 As shown, the injection molding machine melting mechanism of this embodiment also includes a melting cylinder 5, a plasticizing motor 18 that drives the plasticizing screw 4 to rotate, and a heating coil 3 that heats the melting cylinder 5. The melting cylinder 5 provides a working cavity for plasticizing, the plasticizing motor 18 drives the screw to rotate to realize material conveying and shearing, and the heating coil 3 provides the heat required for melting.

[0054] like Figure 1 As shown, the molten glue cylinder 5 is installed on the front plate 10 of the injection stage, and the plasticizing screw 4 is installed inside the molten glue cylinder 5 and can move axially along the inner hole of the molten glue cylinder 5. The rear end of the plasticizing screw 4 is fixed to the plasticizing motor 18 through the transmission device 17, and the plasticizing screw 4 can rotate with the plasticizing motor 18. The front plate 10 of the injection stage is fixed on the platform 22, and the plasticizing motor 18 is installed on the motor support 21. The motor support 21 is installed on the platform 22 and can move axially along the platform 22. The hopper 8 is installed on the front plate 10 of the injection stage and is connected to the feed port of the molten glue cylinder 5. The granular glue material 9 is stored in the hopper 8.

[0055] like Figure 1 As shown, the rear end of the plasticizing screw 4 is provided with a plug 19 for sealing the end of the axial air passage 16. The plug 19 ensures the sealing of the axial air passage 16, so that the negative pressure formed by vacuuming is entirely applied to the bottom of the screw groove of the screw conveying section 6.

[0056] like Figure 4 and Figure 5 As shown, the second embodiment of the injection molding machine melting mechanism of the present invention differs from the first embodiment in that the air extraction device 24 is connected to the melting cylinder 5 through the external air passage 30 pipeline, and the radial air passage 7, air sleeve 11, positioning guide rod 12, sealing ring 13, air groove 14, air outlet 15 and axial air passage 16 on the screw feed section 6 are eliminated; the external air passage 30 includes several radial sections 25 that are radially opposite to the screw feed section 6 and horizontal sections 27 that are horizontal; the radial section 29 includes cylinder air hole 25 and front plate hole 26.

[0057] The melt cylinder 5 has several cylinder air holes 25 corresponding to the hopper 8. The front plate 10 of the injection stage has a front plate hole 26 that communicates with the cylinder air holes 25 and a horizontal section 27 that communicates with them. The horizontal section 27 is connected to the air extraction device 24 through the air pipe 23. The end of the front plate hole 26 is sealed by the hole plug 28.

[0058] The present invention also discloses an injection molding machine, including the injection molding machine melting mechanism of the first embodiment described above, or the injection molding machine melting mechanism of the second embodiment described above.

[0059] The present invention also discloses a melting method, employing the melting mechanism of an injection molding machine as described in the first embodiment above, comprising the following steps:

[0060] Step 1: Activate heating coil 3 to heat the melting cylinder 5;

[0061] Step 2: Start the vacuum device 24 to create a vacuum inside the screw groove of the screw conveying section 6 through the radial air passage 7, the axial air passage 16 and the pipeline, so that the area is under negative pressure.

[0062] Step 3: Start the plasticizing motor 18 to drive the plasticizing screw 4 to rotate;

[0063] Step 4: Under the combined action of its own gravity and the atmospheric pressure outside the hopper, the granular rubber material 9 is forcibly sucked in and tightly filled into the screw groove of the screw conveying section 6;

[0064] Step 5: The granular rubber material 9 gradually melts under the radiant heating of the heating coil 3 and the shear heating of the plasticizing screw 4, forming molten rubber material, which is then conveyed to the front end of the head nozzle to complete the plasticizing process.

[0065] Specifically, such as Figure 1 As shown, the heating coil 3 heats the material, and the air extraction device 24 evacuates the air from the screw groove of the screw conveying section 6 of the plasticizing screw 4 through the air pipe, axial air passage 16 and radial air passage 7. The plasticizing motor 18 drives the plasticizing screw 4 to rotate, and the granular rubber material 9 enters the screw conveying section 6 of the plasticizing screw 4 under atmospheric pressure and its own gravity and is tightly compacted. After being radiated and heated by the heating coil 3 and sheared by the plasticizing screw 4, the granular rubber material 9 becomes molten rubber material 2 and flows to the front of the head nozzle 1 and the melt cylinder 5, thus completing the plasticizing process.

[0066] The melting method of the injection molding machine melting mechanism using the second embodiment described above is similar to the method described above.

[0067] The injection molding machine melting mechanism, injection molding machine, and melting method of the present invention have a compact device structure; the use of the melting mechanism and melting method results in uniform feeding, good plasticizing effect and improved plasticizing efficiency, and more stable melt quality.

[0068] In summary, as described in the specification and figures, this invention has been manufactured into actual samples and tested multiple times. The test results demonstrate that the invention achieves its intended purpose, and its practicality is beyond doubt. The embodiments described above are merely for illustrative purposes and are not intended to limit the scope of the invention. Any equivalent embodiments made by those with common knowledge in the relevant technical field, utilizing the technical content disclosed in this invention without departing from the scope of the technical features and similar features of this invention, based on partial modifications or alterations, are within the protection scope of this invention.

Claims

1. A melting mechanism for an injection molding machine, comprising a front plate (10) of an injection unit and a melting cylinder (5) and a hopper (8) mounted thereon, wherein a plasticizing screw (4) is disposed in the melting cylinder (5) and the front plate (10), forming a conveying groove therebetween, and the hopper (8) is connected to the groove at the conveying section (6) of the screw; the front plate (10) of the injection unit is located on a platform (22), characterized in that: It also includes an air extraction device (24) connected to the screw groove of the screw conveying section (6), which causes the screw groove of the screw conveying section (6) to form a suction force relative to the granular rubber material input into the connected hopper (8).

2. The injection molding machine melting mechanism according to claim 1, characterized in that, The screw conveying section (6) of the plasticizing screw (4) is provided with an axial air passage (16) and a radial air passage (7) that are connected. The air extraction device (24) is connected to the screw groove of the screw conveying section (6) through the axial air passage (16) and the radial air passage (7).

3. The injection molding machine melting mechanism according to claim 1, characterized in that, An external air passage (30) is provided in the front plate (10) of the positioning injection stage, which forms an outer positioning wall corresponding to the screw groove of the screw conveying section (6). The air extraction device (24) is connected to the screw groove of the screw conveying section (6) through the external air passage (30).

4. The injection molding machine melting mechanism according to claim 3, characterized in that, The external air passage (30) includes several radial sections (29) that are radially opposite to the screw groove of the screw conveying section (6) and horizontal sections (27) that are horizontal to each other.

5. The injection molding machine melting mechanism according to claim 2, characterized in that, The shank of the plasticizing screw (4) is provided with an air groove (14) surrounding the screw, and the bottom of the air groove (14) is provided with an air outlet (15) communicating with the axial air passage (16). The air outlet (15) is connected to the air extraction device (24).

6. The injection molding machine melting mechanism according to claim 5, characterized in that, An air sleeve (11) is fitted over the shank of the plasticizing screw (4). The air sleeve (11) has an air extraction hole (20) which is connected to the air groove (14). The air sleeve (11) and the plasticizing screw (4) are dynamically sealed together.

7. The injection molding machine melting mechanism according to claim 2, characterized in that, The radial air passages (7) are distributed axially at the bottom of the screw groove in the screw conveying section (6).

8. The injection molding machine melting mechanism according to claim 2, characterized in that, It also includes a positioning guide rod (12), which is fixedly installed and parallel to the axis of the plasticizing screw (4); The positioning guide rod (12) is provided through the air sleeve (11) to restrict the air sleeve (11) from rotating with the plasticizing screw (4). The air sleeve (11) can move synchronously along the positioning guide rod (12) with the axial movement of the plasticizing screw (4).

9. The injection molding machine melting mechanism according to claim 6, characterized in that, The air sleeve (11) is provided with sealing rings (13) on the inner side of both ends, and the sealing rings (13) are sealed to the outer surface of the plasticizing screw (4).

10. The injection molding machine melting mechanism according to claim 2, characterized in that, It also includes a plasticizing motor (18) that drives the plasticizing screw (4) to rotate and a heating coil (3) that heats the melt cylinder (5).

11. The injection molding machine melting mechanism according to claim 2, characterized in that, The rear end of the plasticizing screw (4) is provided with a plug (19) for sealing the end of the axial air passage (16).

12. An injection molding machine, characterized in that, Includes the injection molding machine melting mechanism as described in any one of claims 1 to 11.

13. A melt adhesive method, characterized in that, The injection molding machine melting mechanism according to claim 10 includes the following steps: Step 1: Activate the heating coil (3) to heat the melting cylinder (5); Step 2: Start the air extraction device (24) to extract air from the screw groove of the screw conveying section (6) through the radial air passage (7), axial air passage (16) and pipeline, so that the area forms a negative pressure; Step 3: Start the plasticizing motor (18) to drive the plasticizing screw (4) to rotate; Step 4: Under the combined action of its own gravity and the atmospheric pressure outside the hopper, the granular rubber material (9) is forcibly sucked in and tightly filled into the screw groove of the screw conveying section (6); Step 5: The granular rubber material (9) gradually melts under the radiation heating of the heating coil (3) and the shear heating of the plasticizing screw (4), forming molten rubber material and conveying it to the front end of the head nozzle to complete the plasticizing process.

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