Injection molding machine barrel tail vacuum pumping structure and pumping method

Abstract

The application provides a barrel tail vacuum air extraction structure and air extraction method of an injection molding machine, and belongs to the technical field of vacuum injection molding. The barrel tail vacuum air extraction structure of the injection molding machine comprises an injection molding device and a horizontal feeding barrel arranged on the injection molding device. A transfer barrel is vertically arranged on the horizontal feeding barrel. A screw rod is arranged in the transfer barrel. The barrel tail vacuum air extraction structure further comprises a sealing mechanism. The sealing mechanism comprises a first sealing plate arranged on the upper end of the transfer barrel and a second sealing plate arranged on the lower end of the transfer barrel. The upper end and the lower end of the transfer barrel can be sealed by the first sealing plate and the second sealing plate, so that a sealed cavity is formed in the transfer barrel. The application can completely seal the inside of the transfer barrel to form a sealed cavity when air extraction is needed. The size of the sealed cavity can be adjusted according to the amount and particle size of the material. The application provides sufficient loose space for the material, accelerates the escape of gas from the material, and avoids the problem that the bubbles in the semi-molten material are wrapped and cannot escape.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of vacuum injection molding, and particularly relates to a vacuum air extraction structure and method for the tail part of a material cylinder of an injection molding machine. BACKGROUND

[0002] In the injection molding process, the vacuum air extraction of the tail part of the material cylinder is an optimization technology for the exhaust of the material melting process. The core is to install a vacuum system at the tail part of the material cylinder of the injection molding machine, that is, at the position where the material just enters the heating zone, to actively extract the gas released during the material melting through negative pressure, thereby solving the gas residue problem that is difficult to handle by the traditional exhaust method (such as the material cylinder exhaust groove and the mold exhaust groove).

[0003] A high-temperature plastic injection vacuum clean feeding mechanism is disclosed in a Chinese patent with the authorization announcement number CN116277741B, which comprises a feeding assembly, a vacuum extraction assembly arranged at the output end of the feeding assembly, and a feeding assembly opposite to the feeding assembly; the feeding assembly comprises a feeding transmission end and an air extraction transmission end connected with the feeding transmission end; the vacuum extraction assembly comprises a closed barrel, an air extraction pipeline arranged in the closed barrel, and an air extraction device connected to the air extraction pipeline; the air extraction transmission end extends to the inner cavity of the closed barrel and is connected with the air extraction pipeline; the feeding assembly comprises a material receiving pipeline connected with the air extraction transmission end and a sealing joint opposite to the material receiving pipeline, and a vacuum degree detector is arranged at the joint of the sealing joint and the material receiving pipeline.

[0004] However, the above technical solution still has the following problems. After the material is vacuum extracted and sent to the heating area for heating, the components inside the material will still produce gas after being heated and volatilized. At this time, the material is softened and in a semi-molten state due to heating, and the flowability is poor, so that the gas is wrapped inside the material, and it is difficult to exhaust the gas again, which ultimately affects the quality of the injection molded part. SUMMARY

[0005] The purpose of the present application is to provide a vacuum air extraction structure and method for the tail part of the material cylinder of an injection molding machine, which aims to solve the problem that the components inside the material will still produce gas after being heated and volatilized, and the gas is wrapped inside the material, and it is difficult to exhaust the gas again.

[0006] To achieve the above purpose, the present application provides the following technical solution: a vacuum air extraction structure for the tail part of the material cylinder of an injection molding machine, comprising an injection molding device and a horizontal feeding cylinder arranged on the injection molding device, a transfer cylinder is vertically installed on the horizontal feeding cylinder, a screw is arranged inside the transfer cylinder, and the structure further comprises:

[0007] The closing mechanism is arranged at the end of the transfer cylinder, and comprises a first closing plate arranged at the upper end of the transfer cylinder and a second closing plate arranged at the lower end of the transfer cylinder, so that the upper and lower ends of the transfer cylinder can be closed by the first closing plate and the second closing plate to form a sealed cavity in the interior of the transfer cylinder.

[0008] The air extraction mechanism is arranged at one side of the transfer cylinder, and comprises an air extraction frame slidingly arranged at one side of the transfer cylinder, a plurality of sealing blocks arranged on the side of the air extraction frame close to the screw rod, a displacement slot arranged in the interior of the transfer cylinder and matched with the sealing blocks, an arc-shaped surface on the side of the sealing blocks close to the screw rod, which is matched with the inner wall of the transfer cylinder and can be combined to form a complete sealing cavity, a plurality of long strip-shaped air extraction holes arranged on the displacement slot in the moving direction of the sealing blocks, and the air extraction holes can be opened or closed when the sealing blocks reciprocate, so that the sealing cavity can be air extracted when the air extraction holes are opened.

[0009] Further technical solutions of the present application are that the side of the transfer cylinder away from the air extraction mechanism is provided with a vibration mechanism, the vibration mechanism comprises a vibration box, a sliding plate slidingly arranged in the interior of the vibration box, a knocking column arranged on the side of the sliding plate close to the transfer cylinder, a spring connected to the side of the sliding plate away from the knocking column, the other end of the spring is connected to the inner wall of the vibration box, sealing plates arranged on the two sides of the air extraction frame, guide grooves slidingly matched with the sealing plates arranged on the two sides of the vibration box, negative pressure holes penetratingly arranged on the two sides of the vibration box, the negative pressure holes being in the guide grooves and penetrating the guide grooves, and a pressure stabilizing hole arranged on the surface of the vibration box away from the transfer cylinder.

[0010] Further technical solutions of the present application are that the first closing plate is symmetrically arranged in two, a first sliding groove is horizontally arranged at the upper end of the transfer cylinder, so that the first closing plate can reciprocate away from or close to the screw rod along the upper end of the transfer cylinder, a closing block is arranged on one side of the first closing plate, the closing block is slidingly arranged on the outer side of the transfer cylinder, a connecting rod is rotationally connected to the side of the closing block away from the first closing plate, a push plate is rotationally connected to the other end of the connecting rod, a placing box is arranged on the second feeding cylinder, a first driving device for driving the push plate to reciprocate is arranged in the placing box, a recess is arranged on the side of the first closing plate close to the screw rod, and the recess is matched with the rotating rod part of the screw rod without spiral blades.

[0011] Further technical solutions of the present application are that the second closing plate can reciprocate close to or away from the screw rod, a second sliding groove is arranged on the upper end of the second feeding cylinder along the length direction thereof, and the second sliding groove is arranged directly below the screw rod, the second sliding groove is slidingly matched with the second closing plate, a second driving device for driving the second closing plate to reciprocate is arranged in the placing box, a blanking hole is arranged on the second sliding groove, the blanking hole penetrates the upper side of the second feeding cylinder and is located directly below the screw rod, and the width of the second closing plate is greater than the diameter of the blanking hole.

[0012] A further technical solution of the present invention is that the air extraction frame is located near the side of the placement box and can move horizontally, a third driving device for driving the air extraction frame to move back and forth is installed inside the placement box, and an air extraction port communicating with the air extraction hole is provided on the side wall of the transfer cylinder near the air extraction frame.

[0013] A further technical solution of the present invention is that the horizontal feeding cylinder includes a first feeding cylinder and a second feeding cylinder arranged in parallel. The first feeding cylinder is located directly above the second feeding cylinder, and the transfer cylinder is located between the first feeding cylinder and the second feeding cylinder. The discharge end of the first feeding cylinder is connected to the top of the transfer cylinder, and the feed end of the second feeding cylinder is connected to the bottom of the transfer cylinder.

[0014] A further technical solution of the present invention is that the screw is disposed inside the transfer cylinder and can rotate on a fixed axis. The upper end of the screw passes through the first feeding cylinder and extends to the upper end of the first feeding cylinder. The part of the screw extending from the upper end of the transfer cylinder is a rotating rod without helical blades. A motor for driving the screw to rotate on a fixed axis is installed at the upper end of the first feeding cylinder.

[0015] A method for vacuum evacuation at the tail end of the barrel of an injection molding machine includes the following steps:

[0016] S1. When the first feeding cylinder starts feeding, the bottom of the transfer cylinder is closed by the second sealing plate and the first sealing plate is opened. Then the material that has been preheated by the first feeding cylinder is fed into the transfer cylinder.

[0017] S2. When there is a certain amount of material in the transfer cylinder, close the first sealing plate to seal the top of the transfer cylinder and form a sealed cavity inside the transfer cylinder. Then, move the air extraction frame away from the screw according to the amount of material to adjust the size of the sealed cavity.

[0018] S3. Based on the distance the suction frame moves, keep the suction area of ​​the suction port at a certain size and perform suction inside the sealed cavity.

[0019] S4. Based on the distance the air extraction frame moves, the negative pressure hole is opened to a certain size synchronously through the sealing plate. The cavity between the slide plate and the transfer cylinder in the vibration box is pulsed through the negative pressure hole. Then, the transfer cylinder is vibrated by the striking column to assist in the exhaust.

[0020] S5. After negative pressure evacuation and knocking-assisted venting, the gas inside the sealed cavity is completely discharged. Then, the second sealing plate is opened, the bottom of the transfer cylinder is opened, and the material is sent into the second feeding cylinder through the transfer cylinder.

[0021] S6. After the material is fed into the second feeding cylinder, the second sealing plate closes again, and then the first sealing plate is opened to transport the next batch of material.

[0022] Compared with the prior art, the beneficial effects of the present invention are:

[0023] 1. This invention provides a sealing mechanism at both ends of the transfer cylinder and a movable air extraction frame and sealing block on the side wall. This allows the interior of the transfer cylinder to be completely sealed to form a sealed cavity when air extraction is required. This facilitates the extraction of gas from the material after initial heating. Furthermore, the size of the sealed cavity can be adjusted according to the amount of material and the particle size, providing sufficient loose space for the material and accelerating the escape of gas from the material. This avoids the problem of air bubbles being trapped inside the semi-molten material and unable to escape.

[0024] 2. By setting a vibration mechanism on the side of the transfer cylinder, and using the striking column in the vibration mechanism to strike the inner wall of the transfer cylinder during negative pressure suction, the material inside the sealed cavity can be loosened, the air bubbles can be broken, and the air bubbles can be discharged faster. At the same time, the continuous vibration prevents the material inside the sealed cavity from adhering to the inner wall of the transfer cylinder, which facilitates the transportation of materials. Attached Figure Description

[0025] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0026] Figure 1 This is a schematic diagram of the overall structure of a specific embodiment of the present invention;

[0027] Figure 2 This is a schematic diagram of the structure of the horizontal feeding cylinder and the transfer cylinder in a specific embodiment of the present invention;

[0028] Figure 3 This is a partial cross-sectional view of the horizontal feeding cylinder and the transfer cylinder in a specific embodiment of the present invention;

[0029] Figure 4 for Figure 3 Enlarged structural diagram at point A;

[0030] Figure 5 for Figure 3 Enlarged structural diagram at point B;

[0031] Figure 6 This is a schematic diagram of the installation structure of the first sealing plate in a specific embodiment of the present invention;

[0032] Figure 7 This is a schematic diagram of the structure of the air extraction mechanism and the vibration mechanism in a specific embodiment of the present invention;

[0033] Figure 8 This is a schematic diagram of the installation structure of the air extraction bracket in a specific embodiment of the present invention;

[0034] Figure 9 This is a partial cross-sectional view of the vibration mechanism in a specific embodiment of the present invention.

[0035] In the diagram: 1. Injection molding device; 2. Horizontal feed cylinder; 21. First feed cylinder; 22. Second feed cylinder; 221. Placement box; 222. Second chute; 223. Drop hole; 3. Transfer cylinder; 31. Screw; 32. Motor; 33. First chute; 34. Relief groove; 341. Air extraction hole; 342. Air extraction port; 4. Sealing mechanism; 41. First sealing plate; 411. Groove; 42. Sealing block; 43. Connecting rod; 44. Push plate; 45. First drive device; 46. Second sealing plate; 47. Second drive device; 5. Air extraction mechanism; 51. Air extraction frame; 511. Sealing block; 52. Third drive device; 53. Sealing plate; 6. Vibration mechanism; 61. Vibration box; 62. Slide plate; 621. Striking post; 63. Spring; 64. Guide groove; 65. Negative pressure hole; 66. Pressure stabilizing hole. Detailed Implementation

[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. 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.

[0037] Please see Figures 1-9 The present invention provides the following technical solution: a vacuum extraction structure at the tail end of the barrel of an injection molding machine, comprising an injection molding device 1, a horizontal feeding cylinder 2, a transfer cylinder 3, a sealing mechanism 4, an extraction mechanism 5, and a vibration mechanism 6.

[0038] The injection molding unit 1 is placed horizontally on the ground. A horizontal feeding cylinder 2 is installed on the injection molding unit 1 for feeding material in the horizontal direction. The side wall of the horizontal feeding cylinder 2 has a heating function to heat the transported material. A transfer cylinder 3 is vertically installed on the horizontal feeding cylinder 2. The transfer cylinder 3 is hollow and used for feeding material in the vertical direction. A sealing mechanism 4 is located at the end of the transfer cylinder 3. The sealing mechanism 4 can seal both ends of the transfer cylinder 3 to form a sealed cavity inside, and the sealed cavity contains the pre-heated material. A vacuuming mechanism 5 is located on one side of the transfer cylinder 3. The vacuuming mechanism 5 extracts the gas in the sealed cavity and removes the gas from the pre-heated material. A vibration mechanism 6 is located on the side of the transfer cylinder 3 away from the vacuuming mechanism 5. When the sealed cavity is vacuumed, the vibration mechanism 6 can start synchronously and knock the transfer cylinder 3 to help loosen the material and accelerate the discharge of gas from the material.

[0039] Please see Figures 1-3The horizontal feeding cylinder 2 includes a first feeding cylinder 21 and a second feeding cylinder 22 arranged in parallel. The first feeding cylinder 21 is located directly above the second feeding cylinder 22, and the transfer cylinder 3 is located between the first feeding cylinder 21 and the second feeding cylinder 22. The discharge end of the first feeding cylinder 21 is connected to the top of the transfer cylinder 3, so that the material heated by the first feeding cylinder 21 can directly enter the top of the transfer cylinder 3 during discharge. The bottom of the transfer cylinder 3 is connected to the inlet end of the second feeding cylinder 22, and the material passing through the transfer cylinder 3 is fed into the second feeding cylinder 22 from its bottom for further heating. Finally, the completely molten material is discharged from the second feeding cylinder 22 and used for injection molding.

[0040] Please see Figures 2-5 The transfer cylinder 3 includes a screw 31, which is located inside the transfer cylinder 3 and can rotate on a fixed axis. The upper end of the screw 31 passes through the first feeding cylinder 21 and extends to the upper end of the first feeding cylinder 21. The part of the screw 31 extending from the upper end of the transfer cylinder 3 is a rotating rod without spiral blades. A motor 32 is installed at the upper end of the first feeding cylinder 21. The output end of the motor 32 is connected to the top of the screw 31. The motor 32 can drive the screw 31 to rotate on a fixed axis and transport the pre-heated material from the first feeding cylinder 21 downward to the second feeding cylinder 22.

[0041] Please see Figures 3-7 The sealing mechanism 4 includes a first sealing plate 41 disposed on the upper end of the transfer cylinder 3. Two first sealing plates 41 are symmetrically arranged. A first sliding groove 33 is horizontally disposed on the upper end of the transfer cylinder 3, allowing the first sealing plate 41 to slide back and forth along the upper end of the transfer cylinder 3, moving away from or towards the screw 31. A sealing block 42 is disposed on one side of the first sealing plate 41, and the sealing block 42 is slidably disposed on the outer side of the transfer cylinder 3. A connecting rod 43 is rotatably connected to the side of the sealing block 42 away from the first sealing plate 41, and a push plate 44 is rotatably connected to the other end of the connecting rod 43. A placement box 221 is disposed on the second feeding cylinder 22, and the placement box 221 is disposed on the side of the transfer cylinder 3 away from the vibration mechanism 6. A first driving device 45 is installed in the placement box 221. The output end of the first driving device 45 is connected to the push plate 44, and the first driving device 45 can drive the push plate 44 to move back and forth, moving closer to or away from the transfer cylinder 3. A groove 411 is opened on the side of the first sealing plate 41, and the groove 411 cooperates with the rotating rod part of the upper end of the screw 31 without spiral blades.

[0042] When the push plate 44 approaches the transfer cylinder 3, the two first sealing plates 41 move away from each other under the action of the connecting rod 43 and the first sliding groove 33. At this time, the top of the transfer cylinder 3 is open, and the material can be transported normally. When it is necessary to vacuum the material after the transfer cylinder 3 has been preheated, the push plate 44 moves away from the transfer cylinder 3, and the first sealing plates 41 move closer to each other until they contact each other. At this time, the grooves 411 on the two first sealing plates 41 just contact and fit completely with the rotating rod part of the upper end of the screw 31 that does not have a spiral blade. This keeps the grooves 411 and the rotating rod part of the screw 31 sealed. At this time, the transfer cylinder 3 is completely separated from the first feeding cylinder 21 by the first sealing plate 41.

[0043] Please see Figures 3-7 The sealing mechanism 4 also includes a second sealing plate 46 disposed at the bottom of the transfer cylinder 3. The second sealing plate 46 can reciprocate to move closer to or away from the screw 31. A second sliding groove 222 is provided at the upper end of the second feeding cylinder 22 along its length direction, and the second sliding groove 222 is located directly below the screw 31. The second sliding groove 222 and the second sealing plate 46 are slidably engaged, allowing the second sealing plate 46 to reciprocate along the second sliding groove 222. A second driving device 47 is installed in the placement box 221. The output end of the second driving device 47 is connected to the second sealing plate 46, and the second driving device 47 can drive the second sealing plate 46 to reciprocate to move closer to or away from the screw 31. A discharge hole 223 is provided on the second sliding groove 222. The discharge hole 223 penetrates the upper side of the second feeding cylinder 22 and is located directly below the screw 31. The width of the second sealing plate 46 is greater than the diameter of the discharge hole 223, so that it can completely cover the discharge hole 223.

[0044] When the second sealing plate 46 moves away from the screw 31, the bottom of the transfer cylinder 3 opens, allowing the material to be transported normally. When it is necessary to vacuum the material after the transfer cylinder 3 has been preliminarily heated, the second sealing plate 46 moves and approaches the screw 31, then completely covers the discharge hole 223 and completely separates the transfer cylinder 3 from the second feeding cylinder 22. When both the upper and lower ends of the transfer cylinder 3 are closed, a sealed cavity is formed inside, which is then evacuated by the vacuuming mechanism 5.

[0045] Please see Figure 5 and Figures 7-9The suction mechanism 5 includes a suction frame 51 slidably disposed on one side of the transfer cylinder 3. The suction frame 51 is located near the placement box 221 and can move horizontally. Multiple sealing blocks 511 are disposed on the side of the suction frame 51 near the screw 31. A clearance groove 34 is provided inside the transfer cylinder 3 to cooperate with the sealing blocks 511. When the suction frame 51 moves, the sealing blocks 511 can reciprocate along the clearance groove 34. A third drive device 52 is installed inside the placement box 221. The output end of the third drive device 52 is connected to the suction frame 51, which can drive the suction frame 51 to reciprocate, moving closer to or away from the screw 31. The surface of the sealing block 511 near the screw 31 is an arc-shaped surface, and this arc-shaped surface is adapted to the inner wall of the transfer cylinder 3. When the sealing block 511 moves along the clearance groove 34 to the limit position near the screw 31, the arc-shaped surface on the sealing block 511 cooperates with the inner wall of the transfer cylinder 3 and can form a complete sealing cavity of adjustable size. Multiple elongated air extraction holes 341 are provided on the clearance groove 34 along the moving direction of the sealing block 511. An air extraction port 342 communicating with the air extraction holes 341 is provided on the side wall of the transfer cylinder 3 near the air extraction frame 51. When the transfer cylinder 3 is feeding normally, the sealing block 511 completely covers the air extraction holes 341.

[0046] When both ends of the transfer cylinder 3 are closed and a sealed cavity is formed inside, the material inside the sealed cavity is relatively tightly packed after initial heating and transportation. First, the third drive device 52 is started to move the suction frame 51, which simultaneously moves the sealing block 511 along the relief groove 34 and away from the screw 31. At this time, the arc-shaped surface of the sealing block 511 near the screw 31 is no longer in contact with the material, the sealed cavity becomes larger, and some of the gas inside is extracted as the sealing block 511 moves. The sealing block 511 continues to move and gradually brings the suction port 341 inside the sealed cavity. Then, the gas inside the sealed cavity is extracted through the suction port 342 and extracted through the suction port 341. Because the volume of the sealed cavity increases at this time, it provides sufficient loose space for the material. The semi-molten material forms a loosely packed state due to the release of volume constraints. The negative pressure can directly act on the surface of the bubbles, accelerating the gas from escaping from the material. This avoids the problem that the semi-molten material is prone to forming a tight packing in the closed cavity due to its high viscosity, and the internal bubbles are trapped and unable to escape. Furthermore, due to the different particle sizes of different materials or the different feeding amounts, the amount of material in the sealed cavity varies. When the material particles are smaller or the feeding amount is greater, the material after initial heating is more tightly packed. At this time, the sealing block 511 is further away from the screw 31, the sealed cavity becomes larger, and the suction area of ​​the suction port 342 becomes larger, making it easier to extract gas.

[0047] Please see Figure 3 , Figures 7-9The vibration mechanism 6 includes a vibration box 61, which is located on the side of the transfer cylinder 3 away from the placement box 221. A sliding plate 62 is slidably arranged inside the vibration box 61. A striking post 621 is arranged on the side of the sliding plate 62 near the transfer cylinder 3. A spring 63 is connected to the side of the sliding plate 62 away from the striking post 621. The other end of the spring 63 is connected to the inner wall of the vibration box 61. Sealing plates 53 are arranged on both sides of the air extraction frame 51. Guide grooves 64 that slide with the sealing plates 53 are arranged on both sides of the vibration box 61. Negative pressure holes 65 are arranged through both sides of the vibration box 61. The negative pressure holes 65 are located on the side of the sliding plate 62 near the transfer cylinder 3, and the negative pressure holes 65 are exactly in and through the guide grooves 64. When the transfer cylinder 3 is in normal feeding mode, the negative pressure holes 65 can be completely sealed by the sealing plates 53. A pressure stabilizing hole 66 is arranged on the side of the vibration box 61 away from the transfer cylinder 3. The pressure stabilizing hole 66 is used to balance the air pressure inside the vibration box 61.

[0048] When the suction mechanism 5 starts working, the suction frame 51 moves. At this time, the sealing plate 53 moves and gradually opens the negative pressure hole 65. Pulse suction is performed on the cavity between the slide plate 62 and the transfer cylinder 3 through the negative pressure hole 65. At this time, the slide plate 62 moves rapidly to the side of the transfer cylinder 3 under the influence of pressure and vibrates by striking the transfer cylinder 3 with the striking column 621. This helps to loosen the material inside the sealed cavity and break the air bubbles, accelerating the expulsion of air bubbles. The striking column 621 also prevents the material from adhering to the inner wall of the transfer cylinder 3. At the same time, the suction frame 51 moves a different distance due to different material amounts, which can synchronously change the opening size of the negative pressure hole 65, thereby adjusting the pulse suction and the striking force to adapt to different material suction needs. After one pulse suction, the slide plate 62 returns to its original position under the action of the spring 63 and is ready for the next pulse suction.

[0049] After the sealed cavity is evacuated, the evacuation frame 51 is first reset to reduce the size of the sealed cavity. Then, the second sealing plate 46 at the bottom of the transfer cylinder 3 is opened, and the motor 32 is started to drive the screw 31 to work, feeding the material in the sealed cavity into the second feeding cylinder 22. After the material is fed in, the second sealing plate 46 is closed and the first sealing plate 41 is opened, feeding the next batch of preheated material from the first feeding cylinder 21 into the transfer cylinder 3. When there is enough material in the transfer cylinder 3, the first sealing plate 41 is closed, and then the next batch of material is vacuumed to ensure that the completely melted material in the second feeding cylinder 22 is completely isolated from the outside air, avoiding secondary air intake from affecting the injection molding quality.

[0050] A method for vacuum evacuation at the tail end of the barrel of an injection molding machine includes the following steps:

[0051] S1. When the first feeding cylinder 21 starts feeding, the bottom of the transfer cylinder 3 is closed by the second sealing plate 46 and the first sealing plate 41 is opened. Then the material that has been preheated by the first feeding cylinder 21 is fed into the transfer cylinder 3.

[0052] S2. When there is a certain amount of material in the transfer cylinder 3, the first sealing plate 41 is closed to seal the top of the transfer cylinder 3, forming a sealed cavity inside the transfer cylinder 3. Then, the vacuum frame 51 is moved away from the screw 31 according to the amount of material to adjust the size of the sealed cavity.

[0053] S3. Based on the distance the vacuum frame 51 moves, the vacuum area of ​​the vacuum port 342 is kept at a certain size, and the air is evacuated from the sealed cavity.

[0054] S4. According to the distance the air extraction frame 51 moves, the negative pressure hole 65 is opened to a certain size through the sealing plate 53. The cavity between the slide plate 62 and the transfer cylinder 3 in the vibration box 61 is pulsed through the negative pressure hole 65. Then, the transfer cylinder 3 is vibrated by the striking column 621 to assist in exhaust.

[0055] S5. After negative pressure evacuation and knocking-assisted venting, the gas inside the sealed cavity is completely discharged. Then, the second sealing plate 46 is opened, the bottom of the transfer cylinder 3 is opened, and the material is sent into the second feeding cylinder 22 through the transfer cylinder 3.

[0056] S6. After the material is fed into the second feeding cylinder 22, the second sealing plate 46 closes again, and then the first sealing plate 41 is opened to transport the next batch of material.

Claims

1. A vacuum extraction structure for the tail end of the barrel of an injection molding machine, comprising an injection molding device (1) and a horizontal feeding cylinder (2) disposed on the injection molding device (1), the horizontal feeding cylinder (2) comprising a horizontally disposed second feeding cylinder (22), a transfer cylinder (3) vertically mounted on the horizontal feeding cylinder (2), and a screw (31) disposed inside the transfer cylinder (3), characterized in that, Also includes: The sealing mechanism (4) is set at the end of the transfer cylinder (3). The sealing mechanism (4) includes a first sealing plate (41) set at the upper end of the transfer cylinder (3) and a second sealing plate (46) set at the lower end of the transfer cylinder (3). The first sealing plate (41) and the second sealing plate (46) can seal the upper and lower ends of the transfer cylinder (3) to form a sealed cavity inside. The air extraction mechanism (5) is set on one side of the transfer cylinder (3). The air extraction mechanism (5) includes an air extraction frame (51) that is slidably set on one side of the transfer cylinder (3). The air extraction frame (51) has multiple sealing blocks (511) on the side near the screw (31). The transfer cylinder (3) has a relief groove (34) that cooperates with the sealing block (511). The surface of the sealing block (511) near the screw (31) is an arc surface. The arc surface is adapted to the inner wall of the transfer cylinder (3) and can be combined to form a complete sealing cavity. Multiple long strip-shaped air extraction holes (341) are set on the relief groove (34) along the moving direction of the sealing block (511). When the sealing block (511) moves back and forth, it can open or close the air extraction holes (341). When the air extraction holes (341) are open, they can extract air from the sealing cavity. The second sealing plate (46) can reciprocate to move closer to or further away from the screw (31). The upper end of the second feeding cylinder (22) is provided with a second sliding groove (222) along its length direction, and the second sliding groove (222) is located directly below the screw (31). The second sliding groove (222) slides in cooperation with the second sealing plate (46). A placement box (221) is provided on the second feeding cylinder (22). A second driving device (47) for driving the second sealing plate (46) to reciprocate is installed in the placement box (221). A dropping hole (223) is provided on the second sliding groove (222). The dropping hole (223) penetrates the upper side of the second feeding cylinder (22) and is located directly below the screw (31). The width of the second sealing plate (46) is greater than the diameter of the dropping hole (223). The horizontal feeding cylinder (2) also includes a horizontally arranged first feeding cylinder (21), which is located directly above the second feeding cylinder (22). The transfer cylinder (3) is located between the first feeding cylinder (21) and the second feeding cylinder (22). The discharge end of the first feeding cylinder (21) is connected to the top of the transfer cylinder (3), and the feed end of the second feeding cylinder (22) is connected to the bottom of the transfer cylinder (3).

2. The vacuum extraction structure at the tail end of the barrel of an injection molding machine according to claim 1, characterized in that: A vibration mechanism (6) is provided on the side of the transfer cylinder (3) away from the suction mechanism (5). The vibration mechanism (6) includes a vibration box (61). A sliding plate (62) is slidably arranged inside the vibration box (61). A striking column (621) is provided on the side of the sliding plate (62) close to the transfer cylinder (3). A spring (63) is connected to the side of the sliding plate (62) away from the striking column (621). The other end of the spring (63) is connected to the inner wall of the vibration box (61). Sealing plates (53) are provided on both sides of the suction frame (51). Guide grooves (64) that slide with the sealing plates (53) are provided on both sides of the vibration box (61). Negative pressure holes (65) are provided through both sides of the vibration box (61). The negative pressure holes (65) are located in the guide grooves (64) and pass through the guide grooves (64). A pressure stabilizing hole (66) is provided on the side of the vibration box (61) away from the transfer cylinder (3).

3. The vacuum extraction structure at the tail end of the barrel of an injection molding machine according to claim 2, characterized in that: Two first sealing plates (41) are symmetrically arranged. A first sliding groove (33) is horizontally arranged at the upper end of the transfer cylinder (3), so that the first sealing plate (41) can slide back and forth along the upper end of the transfer cylinder (3) away from or near the screw (31). A sealing block (42) is arranged on one side of the first sealing plate (41). The sealing block (42) is slidably arranged on the outer side of the transfer cylinder (3). A connecting rod (43) is rotatably connected to the side of the sealing block (42) away from the first sealing plate (41). A push plate (44) is rotatably connected to the other end of the connecting rod (43). A first driving device (45) for driving the push plate (44) to move back and forth is installed in the placement box (221). A groove (411) is opened on one side of the first sealing plate (41). The groove (411) cooperates with the rotating rod part of the upper end of the screw (31) where no spiral blade is provided.

4. The vacuum extraction structure at the tail end of the barrel of an injection molding machine according to claim 3, characterized in that: The air extraction frame (51) is located near the placement box (221) and can move horizontally. The placement box (221) is equipped with a third driving device (52) that drives the air extraction frame (51) to move back and forth. The side wall of the transfer cylinder (3) near the air extraction frame (51) is provided with an air extraction port (342) that communicates with the air extraction hole (341).

5. The vacuum extraction structure at the tail end of the barrel of an injection molding machine according to claim 4, characterized in that: The screw (31) is set inside the transfer cylinder (3) and can rotate on a fixed axis. The upper end of the screw (31) passes through the first feeding cylinder (21) and extends to the upper end of the first feeding cylinder (21). The part of the screw (31) extending from the upper end of the transfer cylinder (3) is a rotating rod without helical blades. The upper end of the first feeding cylinder (21) is equipped with a motor (32) that drives the screw (31) to rotate on a fixed axis.

6. A method for vacuum evacuation at the tail end of the barrel of an injection molding machine, characterized in that, The vacuum extraction structure at the tail end of the injection molding machine barrel as described in claim 5 includes the following steps: S1. When the first feeding cylinder (21) starts feeding, the bottom of the transfer cylinder (3) is closed by the second sealing plate (46) and the first sealing plate (41) is opened. Then the material that has been preheated by the first feeding cylinder (21) is sent into the transfer cylinder (3). S2. When there is a certain amount of material in the transfer cylinder (3), the first sealing plate (41) is closed to seal the top of the transfer cylinder (3) and form a sealed cavity inside the transfer cylinder (3). Then, the vacuum rack (51) is moved away from the screw (31) according to the amount of material to adjust the size of the sealed cavity. S3. Based on the distance the vacuum frame (51) moves, the vacuum area of ​​the vacuum port (342) is kept at a certain size, and the air is evacuated from the sealed cavity. S4. According to the distance the air extraction frame (51) moves, the negative pressure hole (65) is opened to a certain size through the sealing plate (53). The cavity between the slide plate (62) and the transfer cylinder (3) in the vibration box (61) is pulsed through the negative pressure hole (65). Then, the transfer cylinder (3) is vibrated by the striking column (621) to assist in exhaust. S5. After negative pressure evacuation and knocking to assist in venting, the gas inside the sealed cavity is completely discharged. Then, the second sealing plate (46) is opened, and the bottom of the transfer cylinder (3) is opened, so that the material is sent into the second feeding cylinder (22) through the transfer cylinder (3). S6. After the material is fed into the second feeding cylinder (22), the second sealing plate (46) closes again, and then the first sealing plate (41) is opened to transport the next batch of materials.

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