Injection mold with pressure control mechanism

Abstract

The utility model provides an injection mold with a pressure control mechanism, and belongs to the technical field of injection molds. The injection mold with the pressure control mechanism comprises an upper mold plate, a lower mold plate and a lower seat plate, a top plate is movably clamped and embedded in the bottom of a forming cavity, the lower end of the top plate is connected with an ejector rod penetrating out of the lower mold plate, a vertical movable groove is formed in the upper end of the lower seat plate, and a piston block is arranged in the movable groove in a sliding fit mode; the lower end of the lower die plate is provided with a spring groove communicated with the movable groove, the ejector rod is sleeved with a reset spring located in the spring groove, one side of the lower base plate is provided with an exhaust channel communicated with the outside, and the piston block is provided with an L-shaped channel capable of being communicated with the exhaust channel and the movable groove when the piston block moves to the highest position. And a pressure control mechanism capable of pumping the forming cavity into a negative pressure state and pushing the piston block to move upwards is also arranged between the lower template and the lower seat plate. And the pressure control mechanism not only can pump the forming cavity into a negative pressure state, but also can assist in demolding, so that idle resources are greatly utilized.

Description

Technical Field

[0001] The utility model belongs to the technical field of injection molds and relates to an injection mold with a pressure control mechanism. Background Art

[0002] Automotive plastic parts are prone to forming bubbles on their surfaces during injection molding, resulting in substandard product quality. To address this issue, negative pressure is typically created within the mold cavity during the injection molding process to more fully fill the mold with molten plastic, thereby improving the quality and yield of the molded product. Specifically, negative pressure in the injection mold is achieved by controlling the flow of gas within the mold cavity through a negative pressure valve. A vacuum pump is then used to extract gas from the cavity, creating negative pressure that allows the molten plastic to more fully fill the mold cavity, resulting in a more refined molded product. However, existing vacuum pumps only function to extract air, taking up space and resources, resulting in a waste of resources for manufacturers. Utility Model Content

[0003] The purpose of this utility model is to address the above-mentioned problems in the existing technology and propose an injection mold with a pressure control mechanism. The vacuum pump is not only used to pump the molding cavity into a negative pressure state, but also can use the extracted gas to push the ejector rod to complete the product demoulding work, thereby greatly utilizing idle resources.

[0004] The purpose of the utility model can be achieved through the following technical solutions: an injection mold with a pressure control mechanism, comprising an upper template, a lower template and a lower seat plate, characterized in that the upper template and the lower template are combined to form a molding cavity, the lower end surface of the lower template is fixedly connected to the upper end surface of the lower seat plate, the bottom of the molding cavity is movably embedded with a top plate, the lower end of the top plate is connected to a push rod that passes through the lower template, the upper end of the top plate is provided with a vertical movable groove, a piston block is slidably fitted in the movable groove, the lower end of the push rod is connected to the piston block, the lower end of the lower template is provided with a spring groove connected to the movable groove, the push rod is sleeved with a return spring located in the spring groove, an exhaust channel connected to the outside world is provided on one side of the lower seat plate, and the piston block is provided with an L-shaped channel that can connect the exhaust channel and the movable groove when the piston block moves to the highest position. A pressure control mechanism is also provided between the lower template and the lower seat plate, which can draw the molding cavity into a negative pressure state and push the piston block to move upward.

[0005] Furthermore, the pressure control mechanism includes an exhaust pipe, an exhaust pump, a gas storage bottle, a sealing block, an air supply pipe and a valve. A mounting groove for fixing the exhaust pipe is opened on one side of the lower template. The mounting groove is connected to the molding cavity through a tapered hole. A sealing spring is provided between the front end of the exhaust pipe and the sealing block. Under the action of the sealing spring, the sealing block blocks the tapered hole. The tail end of the exhaust pipe is connected to the inlet of the exhaust pump, the outlet of the exhaust pump is connected to the inlet of the gas storage bottle, the outlet of the gas storage bottle is connected to the air supply pipe, the air supply pipe is inserted into the lower seat plate and connected to the bottom of the movable groove, and the valve is installed on the air supply pipe.

[0006] Furthermore, a plurality of air outlet holes are opened at the front end of the air extraction pipe, and a convex column for limiting and blocking the spring is also provided at the front end of the air extraction pipe.

[0007] Furthermore, a mounting ear is connected to the outer wall of the exhaust pipe, and the mounting ear is fixed to the lower template by bolts.

[0008] Furthermore, an injection molding needle tube is provided on the upper template, and a port of the injection molding needle tube is communicated with the molding cavity.

[0009] The injection molding machine closes the upper and lower mold plates and activates the vacuum pump, initially pumping air out of the vacuum duct, creating a negative pressure. Due to the pressure difference between the molding cavity and the mounting slot, the sealing block is pushed toward the mounting slot, compressing the sealing spring and shortening it. This opens the tapered hole, allowing the air in the molding cavity to be extracted. The vacuum pump then discharges the extracted air into a gas cylinder for temporary storage. Molten plastic is then injected through the injection needle into the molding cavity, filling it completely. After the product cools and sets, the upper and lower mold plates separate, and a valve is opened, allowing high-pressure gas from the gas cylinder to flow through the gas supply pipe into the movable slot. The pressure in the movable slot increases, pushing the piston upward until it contacts the lower mold plate. This forces the ejector pin and ejector plate to rise, ejecting the product from the molding cavity of the lower mold plate. The L-shaped channel on the piston block aligns and connects with the exhaust channel, allowing the high-pressure gas in the movable slot to exit the mold. The return spring then drives the piston block downward, returning the ejector plate to its original position.

[0010] Compared with the existing technology, the injection mold with pressure control mechanism has the following advantages:

[0011] 1. The pressure control mechanism can not only pump the molding cavity into a negative pressure state, but also store the extracted air in the gas cylinder. When demoulding, the valve is opened to release the high-pressure gas to complete demoulding and deflation.

[0012] 2. One vacuum pump completes the two processes of vacuuming and demoulding, making full use of idle resources. No cylinder is needed to push the material, and the structure inside the mold is simpler and has fewer parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a cross-sectional view of the injection mold with a pressure control mechanism.

[0014] Figure 2 This is a schematic diagram of the installation of the exhaust pipe.

[0015] In the figure, 1. upper template; 2. lower template; 3. lower seat plate; 4. molding cavity; 5. top plate; 6. ejector pin; 7. movable groove; 8. piston block; 9. spring groove; 10. return spring; 11. exhaust channel; 12. L-shaped channel; 13. exhaust pipe; 14. exhaust pump; 15. gas cylinder; 16. sealing block; 17. air supply pipe; 18. valve; 19. mounting groove; 20. tapered hole; 21. sealing spring; 22. air outlet; 23. boss; 24. mounting ear; 25. injection molding needle. DETAILED DESCRIPTION

[0016] The following are specific embodiments of the present invention and the accompanying drawings to further describe the technical solution of the present invention, but the present invention is not limited to these embodiments.

[0017] like Figure 1 As shown, the injection mold with a pressure control mechanism includes an upper template 1, a lower template 2 and a lower seat plate 3. After the upper template 1 and the lower template 2 are closed, a molding cavity 4 is formed. The lower end surface of the lower template 2 is fixedly connected to the upper end surface of the lower seat plate 3. A top plate 5 is movably embedded in the bottom of the molding cavity 4. The lower end of the top plate 5 is connected to a push rod 6 that passes through the lower template 2. The upper end of the lower seat plate 3 is provided with a vertical movable groove 7. A piston block 8 is slidably fitted in the movable groove 7. The lower end of the push rod 6 is connected to the piston block 8. The lower end of the lower template 2 is provided with a spring groove 9 connected to the movable groove 7. A return spring 10 is sleeved on the push rod 6 and is located in the spring groove 9. An exhaust channel 11 connected to the outside is provided on one side of the lower seat plate 3. The piston block 8 is provided with an L-shaped channel 12 that can connect the exhaust channel 11 and the movable groove 7 when the piston block 8 moves to the highest position. A pressure control mechanism is also provided between the lower template 2 and the lower seat plate 3, which can pump the molding cavity 4 into a negative pressure state and push the piston block 8 to move upward.

[0018] The pressure control mechanism includes an exhaust pipe 13, an exhaust pump 14, a gas cylinder 15, a blocking block 16, an air supply pipe 17 and a valve 18. A mounting groove 19 for fixing the exhaust pipe 13 is opened on one side of the lower template 2. The mounting groove 19 is connected to the molding cavity 4 through a tapered hole 20. A blocking spring 21 is provided between the front end of the exhaust pipe 13 and the blocking block 16. Under the action of the blocking spring 21, the blocking block 16 blocks the tapered hole 20. The tail end of the exhaust pipe 13 is connected to the inlet of the exhaust pump 14, the outlet of the exhaust pump 14 is connected to the inlet of the gas cylinder 15, the outlet of the gas cylinder 15 is connected to the air supply pipe 17, the air supply pipe 17 is inserted into the lower seat plate 3 and is connected to the bottom of the movable groove 7, and the valve 18 is installed on the air supply pipe 17.

[0019] like Figure 2As shown, a plurality of air outlet holes 22 are opened at the front end of the exhaust pipe 13, and the front end of the exhaust pipe 13 also has a boss 23 for limiting and blocking the spring 21. A mounting ear 24 is connected to the outer wall of the exhaust pipe 13, and the mounting ear 24 is fixed to the lower template 2 by bolts.

[0020] An injection needle 25 is provided on the upper mold plate 1 , and a port of the injection needle 25 is communicated with the molding cavity 4 .

[0021] Working process: The injection molding machine closes the upper and lower mold plates 1 and 2, then activates the vacuum pump 14, which first draws air from the vacuum pipe 13, creating a negative pressure. Due to the pressure difference between the molding cavity 4 and the mounting slot 19, the blocking block 16 is pushed toward the mounting slot 19, squeezing the blocking spring 21 and shortening it. The tapered hole 20 opens, and the air in the molding cavity 4 is subsequently drawn out. The vacuum pump 14 discharges the drawn air into the gas cylinder 15 for temporary storage. The molten plastic material is then injected into the molding cavity 4 through the injection needle 25, filling it completely. After the product is cooled and shaped, the upper template 1 is separated from the lower template 2, and the valve 18 is opened to allow the high-pressure gas in the gas cylinder 15 to be transported to the movable groove 7 through the gas supply pipe 17. The air pressure in the movable groove 7 increases, and the piston block 8 is pushed upward until it abuts against the lower template 2. At this time, the ejector rod 6 and the top plate 5 also rise together to push the product out of the molding cavity 4 of the lower template 2, and the L-shaped channel 12 on the piston block 8 is aligned and connected with the exhaust channel 11 at night. The high-pressure gas in the movable groove 7 is discharged from the mold, and the return spring 10 drives the piston block 8 to move downward, and the top plate 5 returns to its original position.

[0022] The specific embodiments described herein are merely illustrative of the spirit of the present invention. Persons skilled in the art may make various modifications, additions, or substitutions to the described specific embodiments without departing from the spirit of the present invention or exceeding the scope defined by the appended claims.

Claims

1. An injection mold with a pressure control mechanism, comprising an upper mold plate (1), a lower mold plate (2) and a lower seat plate (3), characterized in that: After the upper template (1) and the lower template (2) are molded together, a molding cavity (4) is formed. The lower end surface of the lower template (2) is fixedly connected to the upper end surface of the lower base plate (3). A top plate (5) is movably embedded at the bottom of the molding cavity (4). The lower end of the top plate (5) is connected to a top rod (6) passing through the lower template (2). The upper end of the lower base plate (3) is provided with a vertical movable groove (7). A piston block (8) is slidably fitted in the movable groove (7). The lower end of the top rod (6) is connected to the piston block (8). The lower end of the lower template (2) is provided with a movable groove (7). The invention relates to a mold forming machine having a plurality of molds and a plurality of movable grooves (7). The mold forming machine has a plurality of movable grooves (7) connected to each other, a return spring (10) located in the spring groove (9) is sleeved on the push rod (6), an exhaust passage (11) connected to the outside is opened on one side of the lower seat plate (3), an L-shaped passage (12) is opened on the piston block (8) and can connect the exhaust passage (11) and the movable groove (7) when the piston block (8) moves to the highest position, and a pressure control mechanism is provided between the lower mold plate (2) and the lower seat plate (3) to pump the molding cavity (4) into a negative pressure state and push the piston block (8) to move upward.

2. The injection mold with a pressure control mechanism according to claim 1, characterized in that: The pressure control mechanism comprises an air extraction pipeline (13), an air extraction pump (14), an air storage bottle (15), a blocking block (16), an air supply pipeline (17) and a valve (18). A mounting groove (19) for fixing the air extraction pipeline (13) is provided on one side of the lower template (2). The mounting groove (19) is communicated with the molding cavity (4) via a tapered hole (20). A blocking spring (21) is provided between the front end of the air extraction pipeline (13) and the blocking block (16). Under the action of the blocking spring (21), the blocking block (16) blocks the tapered hole (20), the tail of the air extraction pipe (13) is communicated with the inlet of the air extraction pump (14), the outlet of the air extraction pump (14) is communicated with the inlet of the gas storage bottle (15), the outlet of the gas storage bottle (15) is communicated with the air supply pipe (17), the air supply pipe (17) is inserted into the lower seat plate (3) and is communicated with the bottom of the movable groove (7), and the valve (18) is installed on the air supply pipe (17).

3. The injection mold with a pressure control mechanism according to claim 2, characterized in that: A plurality of air outlet holes (22) are formed at the front end of the air extraction pipe (13), and a protruding column (23) for limiting and blocking the spring (21) is also provided at the front end of the air extraction pipe (13).

4. The injection mold with a pressure control mechanism according to claim 3, characterized in that: A mounting ear (24) is connected to the outer wall of the air extraction pipe (13), and the mounting ear (24) is fixed to the lower template (2) by bolts.

5. The injection mold with a pressure control mechanism according to claim 1, characterized in that: An injection needle tube (25) is provided on the upper mold plate (1), and a port of the injection needle tube (25) is communicated with the molding cavity (4).

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