Adjustable shear preheating and high utilization rate rubber molding mold and molding method

Abstract

An adjustable shear preheating and high-utilization rubber molding die and molding method are disclosed, relating to the field of injection molding die technology. The technical solution includes an upper mold fixing plate and a lower mold fixing plate. The lower mold is fixed to the upper surface of the lower mold fixing plate, and an upper mold plate is fixed to the lower surface of the upper mold fixing plate. The beneficial effects of this technical solution are: after the rubber fills the lower mold cavity, a blocking valve, driven by a hydraulic cylinder, blocks the flow of rubber from the inner flow channel into the mold cavity. The blocking valve has two air passages, a first air passage and a second air passage. The second air passage pressurizes the mold cavity through the inner flow channel opening, while the first air passage pressurizes the inner flow channel, pushing the rubber raw material into the injection molding machine barrel. This prevents the mold from heating and pressurizing, thus avoiding vulcanization of the rubber in the inner flow channel and preventing waste of raw materials.

Description

Technical Field

[0001] This invention relates to the field of injection molding mold technology, and in particular to an adjustable shear preheating and high utilization rubber molding mold and molding method. Background Technology

[0002] Rubber injection molds heat and pressurize rubber material within a mold cavity, causing a vulcanization reaction to obtain the final part shape. During the injection molding process, the rubber raw material is preheated in the barrel to save vulcanization time and improve production efficiency.

[0003] Preheated rubber is first extruded into the mold runner and then flows into the mold cavity. After the mold cavity is filled, the rubber is further pressurized through the barrel, and the corresponding pressure exerts a squeezing effect on the material inside the mold cavity through the rubber in the runner. The mold itself or the rubber injection molding machine has a heating device that continuously heats the material in the cavity and runner simultaneously. Ultimately, the rubber inside the mold is pressurized and heated, and after a certain period of time, the rubber completes the vulcanization reaction, producing the final part.

[0004] Because the material in the runner undergoes the same pressurization and heating process as the material in the mold cavity, and also completes the vulcanization reaction, it cannot be reused after mold opening. After the part is formed, it can only be removed from the mold, which affects the utilization rate of the rubber raw materials. Therefore, a new rubber injection molding mold and method are proposed to improve material utilization. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of current methods that require pressure and heating during the vulcanization reaction of rubber, which leads to the vulcanization reaction of rubber materials not in the mold cavity, resulting in waste of raw materials. The invention proposes an adjustable shear preheating and high-utilization rubber molding die and molding method.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] An adjustable shear preheating and high utilization rubber molding die includes an upper mold fixing plate and a lower mold fixing plate. The lower mold is fixed on the upper surface of the lower mold fixing plate, and an upper template is fixed on the lower surface of the upper mold fixing plate. An inner runner plate is fixed on the lower surface of the upper template. Adjustment components are provided at both ends of the inner runner plate. The adjustment components are equipped with blocking valves that block rubber material. Two annular runners are provided on the upper surface of the inner runner plate. The two annular runners are connected in the middle. An inner gate is provided near the blocking valve in each of the two annular runners. Two runner valves are provided in each annular runner.

[0008] Preferably, the adjusting assembly includes a hydraulic cylinder, the piston rod of the hydraulic cylinder is connected to a shut-off valve, and both ends of the upper surface of the inner flow channel plate are provided with a first mounting position and a second mounting position. The shut-off valve is located at the second mounting position, the hydraulic cylinder is located at the first mounting position, the second mounting position is L-shaped, and the horizontal section of the second mounting position is connected to the annular flow channel.

[0009] Preferably, the annular flow channel includes two semi-circular flow channels and two horizontal flow channels. Two flow channel valves are located in the two horizontal flow channels respectively. Each flow channel valve includes two first flow channel valve nozzles and two second flow channel valve nozzles. The two first flow channel valve nozzles and the two second flow channel valve nozzles are located on two opposite side walls of the horizontal flow channels respectively. A first limiting component is provided on the first flow channel valve nozzle, and a second limiting component is provided on the second flow channel valve nozzle.

[0010] When rubber material flows through the valve nozzle in the flow channel, its velocity changes due to the reduced cross-section, resulting in different flow velocities at different points on the nozzle. This velocity difference between different parts of the rubber causes shear deformation, and some of the deformation energy is converted into heat energy, raising the temperature of the rubber material.

[0011] Preferably, the first limiting component includes a threaded rod, a threaded hole is provided on the first flow channel valve nozzle, one end of the threaded rod is threaded into the threaded hole, the end of the threaded rod located in the horizontal flow channel is rotatably connected to a second fixing block, and the end of the threaded rod away from the horizontal flow channel is fixed to a connecting block.

[0012] Preferably, the second limiting component includes a first fixing block located inside the second flow channel valve nozzle, and a limiting block is provided at one end of the first fixing block away from the horizontal flow channel.

[0013] Preferably, the blocking valve includes two first air passages and one second air passage, the second air passage being located between the two first air passages, the two first air passages being L-shaped, the air outlets of the two first air passages being correspondingly arranged with the annular flow channel, and the air outlet of the second air passage being correspondingly arranged with the inner gate.

[0014] Preferably, the upper mold fixing plate is provided with a feed port, the upper mold plate is provided with a through hole, the feed port and the through hole are provided correspondingly, and the lower mold is provided with two cavities, which are respectively provided with two ingates.

[0015] Preferably, two guide posts are fixed on the lower surface of the upper mold fixing plate, and two guide sleeves are fixed on the upper surface of the lower mold fixing plate, with the two guide posts and two guide sleeves being arranged correspondingly.

[0016] An adjustable shear preheating and high-utilization rubber molding method includes the following steps:

[0017] S1: The rubber is conveyed from the barrel through the inlet of the upper mold fixing plate and through the through hole of the upper template into the annular flow channel on the inner flow channel plate;

[0018] S2: The rubber is delivered to the corresponding cavity of the lower mold through two internal gates on the annular runner;

[0019] S3: When the rubber fills the cavity of the lower mold, the hydraulic cylinder pushes the blocking valve forward to separate the rubber in the annular flow channel from the rubber in the lower mold cavity. At the same time, the second air outlet in the blocking valve blocks the inner gate.

[0020] S4: The air pump supplies air to the two first air passages and the first air passage, squeezing the rubber in the annular flow channel back into the barrel. At the same time, the second air passage fills the cavity of the mold with air through the inner gate and pressurizes it to meet the pressure required for rubber vulcanization.

[0021] S5: When the rubber in the current mold cavity has completed vulcanization, the air pump stops filling the shut-off valve with air. The upper mold fixing plate drives the inner flow channel plate to move upward through the upper template. The inner flow channel plate separates from the lower mold, and the rubber in the lower mold can be taken out from the cavity.

[0022] S6: Repeat steps S1-S5 for continuous injection molding.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows: A flow channel valve is installed on the flow channel. The flow channel valve adjusts the deformation of the rubber in the inner flow channel by adjusting the width of the horizontal flow channel. By controlling the deformation, the temperature rise of the rubber caused by deformation is controlled, and the rubber preheating is achieved without a heating device. After the rubber fills the lower mold cavity, the blocking valve, driven by the hydraulic cylinder, blocks the flow of rubber in the inner flow channel into the mold cavity. At the same time, the blocking valve has two first air passages and a second air passage. The second air passage pressurizes the mold cavity by inflating the inner flow channel, while the first air passage pressurizes the inner flow channel to push the rubber raw material into the injection molding machine barrel, thus preventing the rubber in the inner flow channel from vulcanizing due to mold heating and pressurization, and avoiding waste of raw materials. Attached Figure Description

[0024] To more clearly illustrate the technical solution of the present invention, the accompanying drawings used in the description will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the glue injection process in the mold according to a specific embodiment of the present invention.

[0026] Figure 2 This is a schematic diagram of the pressure holding process in the mold according to a specific embodiment of the present invention.

[0027] Figure 3 This is a schematic diagram of the glue injection process of the inner flow channel plate in a specific embodiment of the present invention.

[0028] Figure 4 This is a schematic diagram of the flow during the pressure holding process of the inner flow channel plate in a specific embodiment of the present invention.

[0029] Figure 5 This is a schematic diagram of the flow channel valve installation structure in a specific embodiment of the present invention.

[0030] Figure 6 This is a schematic diagram of the blocking valve installation structure according to a specific embodiment of the present invention.

[0031] Figure 7 This is a cross-sectional view of the blocking valve installation in a specific embodiment of the present invention.

[0032] Figure 8 This is a schematic diagram of the blocking valve in a specific embodiment of the present invention.

[0033] Figure 9 This is a schematic diagram of the flow channel of the blocking valve in a specific embodiment of the present invention.

[0034] Figure 10 This is a schematic diagram of the flow channel valve in a specific embodiment of the present invention.

[0035] Figure 11 This is a schematic diagram of the structure of the first limiting component in a specific embodiment of the present invention.

[0036] In the diagram: 1 Hydraulic cylinder, 2 Inner flow channel plate, 3 Blocking valve, 4 First flow channel valve nozzle, 5 Second flow channel valve nozzle, 6 First fixing block, 7 Second fixing block, 8 Connecting block, 9 Upper mold fixing plate, 10 Guide post, 11 Upper template, 12 Guide sleeve, 13 Lower mold, 14 Lower mold fixing plate, 15 Threaded rod, 16 Limiting block, 201 Inner gate, 202 Second mounting position, 203 Annular flow channel, 204 First mounting position, 301 First air passage, 302 Second air passage, 901 Inlet, 1101 Through hole, 1301 Cavity. Detailed Implementation

[0037] To make the objectives, features, and advantages of this invention more apparent and understandable, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings of the specific embodiments. Obviously, the embodiments described below are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this patent, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this patent.

[0038] Reference Figure 1-11An adjustable shear preheating and high-utilization rubber molding die includes an upper mold fixing plate 9 and a lower mold fixing plate 14. A lower mold 13 is fixed to the upper surface of the lower mold fixing plate 14, and an upper template 11 is fixed to the lower surface of the upper mold fixing plate 9. An inner flow channel plate 2 is fixed to the lower surface of the upper template 11. The upper template 11 connects the upper mold fixing plate 9 and the inner flow channel plate 2 with bolts. Adjustment components are provided at both ends of the inner flow channel plate 2. After the rubber is delivered, the adjustment components adjust the position of the blocking valve 3 to block the rubber. Simultaneously, the air passage on the blocking valve 3 can pressurize the cavity 1301. The adjustment components are equipped with a blocking valve 3 to block the rubber material. Two annular flow channels 203 are provided on the upper surface of the inner flow channel plate 2. The middle position is connected. The upper mold fixing plate 9 is provided with a feed port 901, and the upper mold plate 11 is provided with a through hole 1101. The feed port 901 and the through hole 1101 are set accordingly. The rubber is transported through the feed port 901 and the through hole 1101 to the position where the two annular flow channels 203 are connected. Then the rubber is transported into the two annular flow channels 203. The two annular flow channels 203 are provided with an inner gate 201 near the blocking valve 3. The rubber is transported into the cavity 1301 through the inner gate 201. Two flow channel valves are provided in each annular flow channel 203. The lower mold 13 is provided with two cavities 1301. The two cavities 1301 are respectively set with two inner gates 201. A heating device is provided in the lower mold 13 to heat the rubber inside.

[0039] Reference Figure 3-9 The adjusting assembly includes a hydraulic cylinder 1, whose piston rod is connected to a shut-off valve 3. Both ends of the upper surface of the inner flow channel plate 2 are provided with a first mounting position 204 and a second mounting position 205. The shut-off valve 3 is located in the second mounting position 205, and the hydraulic cylinder 1 is located in the first mounting position 204. The second mounting position 205 is L-shaped. Figure 7 As shown, the hydraulic cylinder 1 controls the movement of the shut-off valve 3, which in turn controls the rubber to move to the lower mold 13. The horizontal section of the second mounting position 205 is connected to the annular flow channel 203, which facilitates the shut-off valve 3 to move into the annular flow channel 203 to control the rubber.

[0040] Reference Figure 3-5The annular flow channel 203 includes two semi-circular flow channels and two horizontal flow channels. The two semi-circular flow channels located in the middle of the inner flow channel plate 2 are connected. The inner gate 201 is located on the semi-circular flow channels at both ends of the inner flow channel plate 2. Two flow valves are located in the two horizontal flow channels respectively. The flow valves change the cross-sectional area of ​​the rubber material that can flow in the horizontal flow channels. This cross-sectional area is smaller than the cross-sectional area of ​​the horizontal flow channels. The flow valves include two first flow valve nozzles 4 and two second flow valve nozzles 5. The two first flow valve nozzles 4 and two second flow valve nozzles 5 are located on two opposite side walls of the horizontal flow channels respectively. A first limiting component is provided on the first flow valve nozzle 4. The first limiting component includes a threaded rod 15. A threaded hole is provided on the first flow valve nozzle 4. One end of the threaded rod 15 is threaded into the threaded hole. The end of the threaded rod 15 located in the horizontal flow channel is rotatably connected to a second fixing block 7. The position of the second fixing block 7 is adjusted by adjusting the threaded rod 15. The change in the position of the second fixing block 7 adjusts the flow valve. The cross-sectional area through which the flow channel valve can pass is adjusted. A connecting block 8 is fixed at the end of the threaded rod 15 away from the horizontal flow channel. A second limiting component is provided on the second flow channel valve 5. The second limiting component includes a first fixing block 6, which is L-shaped. The horizontal section of the first fixing block 6 is engaged in the second flow channel valve 5. The first fixing block is located in the second flow channel valve 5. A limiting block 16 is provided at the end of the first fixing block 6 away from the horizontal flow channel. The size of the limiting block 16 is adjusted according to the flow rate of the rubber material, thereby adjusting the position of the first fixing block 6 in the horizontal flow channel. The cooperation of the first limiting component and the second limiting component realizes the adjustment of the cross-sectional area through which the flow channel valve can pass, adjusts the shear volume of the rubber during the rubber flow, and thus adjusts the heat rise of the rubber deformation. The material far from the flow channel wall has a high flow velocity, and the material close to the wall has a low flow velocity. As the overall average flow velocity increases, the difference between the flow velocity of the material in the middle part of the flow channel and the flow velocity on both sides becomes larger, resulting in greater shear deformation of the material and higher temperature rise. By controlling the overall flow rate of the rubber material, the cross-sectional area of ​​the flow channel valves, and the number of flow channel valves, the degree of heating of the rubber material can be controlled to reach the final required preheating temperature, which is generally lower than the minimum temperature required for vulcanization.

[0041] Reference Figure 8-9 The shut-off valve 3 includes two first air passages 301 and one second air passage 302. The second air passage 302 is located between the two first air passages 301. The two first air passages 301 are L-shaped. The first air passages 301 inflate the annular flow channel 203 with air, thus squeezing the material in the flow channel back into the barrel. Figure 2The direction of rubber flow, the material in the flow channel during the extrusion process, and the speed of return flow are controlled to avoid large temperature rise. The material in the extrusion return cylinder does not get a long time of heat preservation and the temperature is relatively low, so it fails to undergo vulcanization reaction and can be used as raw material for the next injection molding. The air outlets of the two first air channels 301 are set to correspond to the annular flow channel 203, and the air outlet of the second air channel 302 is set to correspond to the ingate 201. The second air channel 302 vents air into the mold cavity, which generates a squeezing effect on the rubber material in the mold, ensuring the pressure required for the vulcanization of the rubber material. The temperature required for the vulcanization of the rubber material is provided by the mold itself or the heating device on the injection molding equipment.

[0042] Reference Figure 1-2 Two guide pillars 10 are fixed on the lower surface of the upper mold fixing plate 9, and two guide sleeves 12 are fixed on the upper surface of the lower mold fixing plate 14. The two guide pillars 10 and the two guide sleeves 12 are set in a corresponding manner to ensure that the upper mold fixing plate 9 is misaligned when it moves.

[0043] An adjustable shear preheating and high-utilization rubber molding method includes the following steps:

[0044] S1: Rubber is conveyed from the barrel through the inlet 901 of the upper mold fixing plate 9 and through the through hole 1101 of the upper template 11 into the annular flow channel 203 on the inner flow channel plate 2. When it flows in the annular flow channel 203, the positions of the first fixing block 6 and the second fixing block 7 are adjusted according to the type and amount of rubber. When the second fixing block 7 is adjusted, the connecting block 8 drives the threaded rod 15 to rotate. The threaded rod 15 adjusts the position of the second fixing block 7 in the annular flow channel 203. When the first fixing block 6 is adjusted, according to the position of the first fixing block 6 in the annular flow channel 203, limit blocks 16 of different sizes are placed to adjust the cross-sectional area of ​​the annular flow channel 203, thereby controlling the shear and heat generation of the rubber material in the flow channel. After multiple tests, the positions of the first fixing block 6 and the second fixing block 7 are determined, thereby controlling the overall flow rate of the rubber material, the cross-sectional area of ​​the flow channel valve, and the number of flow channel valves in the flow channel. This can achieve control of the original heating degree of the rubber and ultimately reach the required preheating temperature.

[0045] S2: Rubber is delivered to the cavity 1301 corresponding to the lower mold 13 through the two inner gates 201 on the annular flow channel 203;

[0046] S3: When the rubber fills the cavity 1301 of the lower mold 13, the hydraulic cylinder 1 pushes the blocking valve 3 forward to block the rubber in the annular flow channel 203 from the rubber in the cavity 1301 of the lower mold 13. At the same time, the outlet of the second air passage 302 in the blocking valve 3 blocks the inner gate 201.

[0047] S4: The air pump supplies air to the two first air passages 301 and the first air passage 301. The two first air passages 301 squeeze the rubber in the annular flow channel 203 back into the material cylinder. At the same time, the second air passage 302 pressurizes the mold cavity 1301 of the lower mold 13 through the inner gate 201 to meet the pressure required for rubber vulcanization.

[0048] S5: When the rubber in the cavity 1301 of the lower mold 13 is vulcanized, the air pump stops supplying air to the shut-off valve 3. The upper mold fixing plate 9 drives the inner flow channel plate 2 to move upward through the upper mold plate 11. The inner flow channel plate 2 and the lower mold 13 separate, and the rubber in the lower mold 13 can be taken out from the cavity, completing one production process.

[0049] S6: Repeat steps S1-S5 for continuous injection molding.

[0050] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A rubber molding die with adjustable shear preheating and high utilization rate, characterized in that: The system includes an upper mold fixing plate (9) and a lower mold fixing plate (14). The lower mold (13) is fixed on the upper surface of the lower mold fixing plate (14), and the upper template (11) is fixed on the lower surface of the upper mold fixing plate (9). The inner flow channel plate (2) is fixed on the lower surface of the upper template (11). Adjustment components are provided at both ends of the inner flow channel plate (2). The adjustment components are provided with blocking valves (3) that block rubber materials. Two annular flow channels (203) are provided on the upper surface of the inner flow channel plate (2). The two annular flow channels (203) are connected in the middle. An inner gate (201) is provided near the blocking valve (3) of the two annular flow channels (203). Two flow channel valves are provided in each annular flow channel (203). The upper mold fixing plate (9) is provided with a feed port (901), the upper mold plate (11) is provided with a through hole (1101), the feed port (901) and the through hole (1101) are provided in correspondence, the lower mold (13) is provided with two cavities (1301), and the two cavities (1301) are respectively provided with two inlet gates (201); The rubber is conveyed through the inlet (901) and through hole (1101) to the position where the two annular channels (203) are connected, and then conveyed into the two annular channels (203); The blocking valve (3) includes two first air passages (301) and one second air passage (302); the air outlets of the two first air passages (301) and the annular flow channel (203) are respectively arranged, and the air outlets of the second air passage (302) and the inner gate (201) are respectively arranged.

2. The adjustable shear preheating and high-utilization rubber molding die according to claim 1, characterized in that: The adjustment assembly includes a hydraulic cylinder (1), the piston rod of the hydraulic cylinder (1) is connected to the shut-off valve (3), and both ends of the upper surface of the inner flow channel plate (2) are provided with a first mounting position (204) and a second mounting position (205). The shut-off valve (3) is located at the second mounting position (205), the hydraulic cylinder (1) is located at the first mounting position (204), the second mounting position (205) is L-shaped, and the horizontal section of the second mounting position (205) is connected to the annular flow channel (203).

3. The adjustable shear preheating and high-utilization rubber molding die according to claim 1, characterized in that: The annular flow channel (203) includes two semi-circular flow channels and two horizontal flow channels. Two flow channel valves are located in the two horizontal flow channels respectively. The flow channel valves include two first flow channel valve nozzles (4) and two second flow channel valve nozzles (5). The two first flow channel valve nozzles (4) and the two second flow channel valve nozzles (5) are located on two opposite side walls of the horizontal flow channels respectively. A first limiting component is provided on the first flow channel valve nozzle (4), and a second limiting component is provided on the second flow channel valve nozzle (5).

4. The adjustable shear preheating and high-utilization rubber molding die according to claim 3, characterized in that: The first limiting component includes a threaded rod (15), a threaded hole is provided on the first flow channel valve nozzle (4), one end of the threaded rod (15) is threaded in the threaded hole, the end of the threaded rod (15) located in the horizontal flow channel is rotatably connected to a second fixing block (7), and the end of the threaded rod (15) away from the horizontal flow channel is fixed with a connecting block (8).

5. The adjustable shear preheating and high-utilization rubber molding die according to claim 3, characterized in that: The second limiting component includes a first fixing block (6), which is located inside the second flow channel valve nozzle (5), and a limiting block (16) is provided at one end of the first fixing block (6) away from the horizontal flow channel.

6. The adjustable shear preheating and high-utilization rubber molding die according to claim 1, characterized in that: The second airway (302) is located between the two first airways (301), and the two first airways (301) are arranged in an L-shape.

7. The adjustable shear preheating and high-utilization rubber molding die according to claim 1, characterized in that: The lower surface of the upper mold fixing plate (9) is fixed with two guide pillars (10), and the upper surface of the lower mold fixing plate (14) is fixed with two guide sleeves (12). The two guide pillars (10) and the two guide sleeves (12) are set accordingly.

8. A method for adjusting shear preheating and achieving high utilization rate in rubber molding, characterized in that, The adjustable shear preheating and high utilization rubber molding die as described in claim 2 includes the following steps: S1: The rubber is fed from the barrel through the inlet (901) of the upper mold fixing plate (9) and through the through hole (1101) of the upper template (11) into the annular flow channel (203) on the inner flow channel plate (2); S2: The rubber is delivered to the cavity (1301) corresponding to the lower mold (13) through the two inner gates (201) on the annular flow channel (203); S3: When the rubber fills the cavity (1301) of the lower mold (13), the hydraulic cylinder (1) pushes the blocking valve (3) forward to separate the rubber in the annular flow channel (203) from the rubber in the cavity (1301) of the lower mold (13), and at the same time, the outlet of the second air passage (302) in the blocking valve (3) blocks the inner gate (201); S4: The air pump supplies air to the two first air passages (301) and the second air passage (302), squeezing the rubber in the annular flow channel (203) back into the barrel. At the same time, the second air passage (302) pressurizes the cavity (1301) of the lower mold (13) through the inner gate (201) to meet the pressure required for rubber vulcanization. S5: When the rubber in the cavity (1301) of the lower mold (13) is vulcanized, the air pump stops filling the shut-off valve (3) with air. The upper mold fixing plate (9) drives the inner flow channel plate (2) to move upward through the upper template (11). The inner flow channel plate (2) and the lower mold (13) separate, and the rubber in the lower mold (13) is taken out from the cavity. S6: Repeat steps S1-S5 for continuous injection molding.

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