Double-screw feeding and vacuum injection rubber hot-pressing forming machine

Abstract

The invention discloses a double-screw feeding and vacuum injection rubber hot-pressing forming machine which comprises a foot stool, a mold lifting unit is arranged on the foot stool and used for lifting a mold, a mold hoisting unit is arranged above the mold lifting unit and used for hoisting the mold, a double-screw feeding unit is arranged above the mold hoisting unit, and a vacuum injection unit is arranged above the double-screw feeding unit. When the double-screw feeding mechanism is used for producing, the main screw and the auxiliary screw of the double-screw feeding unit are meshed with each other to generate violent shearing, stretching and kneading effects, so that high-viscosity rubber compound is quickly homogenized and converted into a homogeneous viscous flow state, and the high-viscosity rubber compound is subjected to high-speed shearing, stretching and kneading. A self-cleaning effect is formed in a meshing area of the screw rods, and dead angles of accumulated materials are removed through dynamic mutual wiping between the screw rods; the self-adaptive gap design is formed through the sealing assembly between the upper mold hanging rod of the mold hanging unit and the vacuum cover, smooth sliding is achieved in the cold and hot temperature difference state, clamping is avoided, and the sealing performance of the vacuum cover in the vacuumizing process is not affected through the sealing effect of the sealing ring.

Description

Technical Field

[0001] This invention relates to the technical field of hot press molding machines, and specifically to a rubber hot press molding machine with twin-screw feeding and vacuum injection. Background Technology

[0002] The plasticizing uniformity and high-pressure injection capability of single-screw reciprocating injection molding machines have made them core equipment for the production of rubber products such as automotive seals, medical plugs, and new energy battery pack buffers. Through the high-speed rotation of a single screw, intense shear heat is generated. Combined with a precise temperature control system outside the barrel, it can transform high-viscosity rubber into a homogeneous viscous flow state. The high pressure (usually 120-200MPa) accumulated at the screw head is used to inject the plastic melt into the mold cavity, achieving one-time molding and dimensional stability of rubber products. Auxiliary feeding barrels, forced feeding devices, or segmented screw designs (such as split-type or barrier-type screws) are usually selected according to process requirements. This allows them not only to efficiently process general materials such as natural rubber and styrene-butadiene rubber, but also to produce and process difficult-to-process special plastic melts such as fluororubber and silicone rubber.

[0003] However, with the explosive growth in industry demand for multi-material composites, multi-color products, and rapid production, existing single-screw reciprocating injection molding machines are prone to material retention when facing discontinuous production. The long radial conveying and low-shear zone of the single screw in the barrel can easily lead to material retention. At high temperatures, rubber materials not only melt but also undergo cross-linking reactions. The residual plastic melt forms a highly adhesive semi-solid carbonized layer under the residual heat during downtime. This semi-solid carbonized layer is difficult to reach using traditional air-jet degreasing or simple cleaning agent rinsing methods. Moreover, the uncontrollable shedding of residues can lead to defects such as black spots, impurities, or uneven physical properties in the products. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a twin-screw feeding, vacuum injection rubber thermoforming machine. During production, the twin-screw feeding mechanism utilizes the shrinking and squeezing of the gap between the two screws as they rotate to propel the molten plastic forward. Excess molten plastic is quickly flushed away. The periodic variation in the gap between the two screws also results in periodic changes in the extrusion pressure on the molten plastic, making it easy to remove and clean any residual molten plastic. The intense shearing, stretching, and kneading action generated by the interlocking of the main and auxiliary screws continuously breaks down and reassembles the molten plastic, rapidly homogenizing the high-viscosity compound into a homogeneous viscous flow state. The high pressure accumulated by the main and auxiliary screws rapidly injects the molten plastic into the mold cavity. Furthermore, the screws... The meshing area creates a self-cleaning effect. Through dynamic "mutual rubbing," it not only eliminates dead corners of material accumulation but also forms a high-vacuum zone at the screw root that facilitates venting and volatilization. This solves the problem of huge material losses during material changeover, which often requires several times the volume of molten plastic from the screw for transition. Moreover, the uncontrollable shedding of residues can lead to fatal defects such as black spots, impurities, or uneven physical properties in the finished product. The clearance between the upper mold rod and the vacuum chamber needs to be appropriately increased. The upper mold rod passes through the upper seat and enters the vacuum chamber. Temperature changes cause thermal expansion and contraction. The guide sleeve is fitted into the hole of the guide sleeve at an equal height and protrudes slightly upwards. After the screw is tightened, the guide sleeve is not completely locked and still has some room for movement, forming an adaptive clearance design. It slides smoothly without getting stuck under both hot and cold temperature conditions, thus solving the problem of the upper mold rod getting stuck when sliding up and down. The sealing effect of the sealing ring does not affect the sealing performance of the vacuum hood when evacuating. The sealing is achieved through the cooperation of the vacuum hood, sealing components, upper mold, and tray. The output end of the auxiliary oil cylinder drives the vacuum hood downward to move it so that the vacuum hood covers the tray. The two are sealed by a sealing gasket fixed around the bottom of the vacuum hood. After the vacuum pump is connected to the vacuum hood, a vacuum is drawn to achieve the effect of maintaining a vacuum during mold injection.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A twin-screw feeding, vacuum injection rubber hot press molding machine includes a stand with a mold lifting unit on the stand for lifting the mold, a mold hoisting unit above the mold lifting unit for hoisting the mold, and a twin-screw feeding unit above the mold hoisting unit for injecting molten rubber into the mold.

[0006] The tripod supports an oil tank via an oil tank mount and an electrical control box via an electrical box mount.

[0007] The mold lifting unit includes a base mounted on a stand, a mold lifting drive mechanism on each side of the base, four sets of smooth guide pillars passing through the base, a horizontal adjustment mechanism above the base, a top mold mechanism at one end of the horizontal adjustment mechanism, a vacuum pump mounted on the base, and a control valve on the side of the base. The output end of the mold lifting drive mechanism is connected to the horizontal adjustment mechanism, the smooth guide pillars are slidably connected to the horizontal adjustment mechanism, the vacuum pump is connected to the control valve through an air pipe, the mold lifting drive mechanism drives the horizontal adjustment mechanism to move up and down along the smooth guide pillars, the horizontal adjustment mechanism adjusts the horizontal position of the mold, and the top mold mechanism lifts / releases the mold.

[0008] The mold lifting drive mechanism includes a mold lifting cylinder, a cylinder shaft inside the mold lifting cylinder, a connecting shaft at one end of the cylinder shaft, and a limiting nut on the connecting shaft. The mold lifting cylinder is used to transmit driving force through the cylinder shaft, and the connecting shaft is used to connect to the horizontal adjustment mechanism in conjunction with the limiting nut.

[0009] The horizontal adjustment mechanism includes a central base, two parallel and symmetrically arranged guide rails on the central base, a tray on the two guide rails, and a push-pull cylinder mounted on one side of the central base via a cylinder mounting seat. A connecting plate limits the ends of the two guide rails. The central base has four sets of smooth vertical holes that pass through vertically, and each smooth vertical hole corresponds to a smooth guide post. Each smooth guide post is provided with a smooth vertical hole. When the lifting cylinder drives the cylinder shaft to extend or retract, it will drive the central base to rise or fall along the column. The tray is slidably connected to a guide rail through a slot on each side. The output end of the push-pull cylinder is fixedly connected to the tray.

[0010] The top mold mechanism includes a cylinder bracket located below the two guide rails, a front top cylinder located below the cylinder bracket, a top extension sliding bracket located at the output end of the front top cylinder, and a top mold support plate located on the top extension sliding bracket. The top extension sliding bracket is slidably connected to the cylinder bracket. The front top cylinder is used to drive the top extension sliding bracket to move up and down through its output end. The top mold support plate is used to support the mold when the top extension sliding bracket moves up and down.

[0011] The lifting mold unit includes an upper seat, a vacuum hood located below the upper seat, an auxiliary hydraulic cylinder on each side of the upper seat, four sets of upper lifting mold rods passing through the upper seat, and a lifting mold beam located at one end of the upper lifting mold rods. The upper seat has four sets of vertically penetrating mounting holes, each corresponding to a smooth guide post. Each smooth guide post has a mounting hole, and the upper seat is limited by at least one nut fitted onto the smooth guide post. A sealing assembly allows the lifting mold rods to slide through the vacuum hood. The sealing assembly includes a guide sleeve, a sealing ring located inside the guide sleeve, a screw passing through the guide sleeve, a level sleeve fitted onto the screw, and a sliding bearing located below the guide sleeve.

[0012] The twin-screw feeding unit includes a twin-screw feeding mechanism and a metering injection mechanism located at the discharge end of the twin-screw feeding mechanism.

[0013] The twin-screw feeding mechanism includes a drive motor, a housing located at one end of the drive motor, a main screw located at the output end of the drive motor, and an auxiliary screw connected to the main screw via gears. The auxiliary screw is rotatably connected inside the housing, and the housing is provided with a feeding port.

[0014] The main screw is set to a constant pitch and a gradually changing root diameter, while the auxiliary screw is set to a constant root diameter and a gradually changing pitch and tooth thickness. When the main screw and the auxiliary screw inside the housing rotate through gear transmission, they only rotate relative to each other and their relative positions remain consistent.

[0015] The beneficial effects of this invention are as follows: 1. During production, the twin-screw feeding mechanism compresses and pushes the molten plastic forward through the contraction and compression of the gap between the two screws as they rotate. Excess molten plastic is quickly flushed away. The periodic variation in the gap between the two screws also causes the periodic variation in the extrusion pressure on the molten plastic, making it easy to squeeze out and clean up any residual molten plastic. The main and auxiliary screws continuously break down and reassemble the molten plastic through the intense shearing, stretching, and kneading action generated by their interlocking. This not only rapidly homogenizes the high-viscosity compound into a homogeneous viscous flow state in a very short time, but also rapidly injects the molten plastic into the mold cavity through the high pressure accumulated by the main and auxiliary screws. Furthermore, the meshing area of ​​the screws forms a self-cleaning effect. The dynamic "mutual rubbing" between the twin screws not only eliminates dead corners of material accumulation but also creates a high-vacuum zone at the root of the screws that is conducive to venting and devolatilization. 2. The clearance between the upper lifting mold rod and the vacuum chamber needs to be appropriately increased. The upper lifting mold rod passes through the upper seat and enters the vacuum chamber. The guide sleeve, equal height sleeve, sliding bearing, sealing ring, and adjusting nut work together to ensure smooth sliding without jamming under different temperature conditions while maintaining a seal. When thermal expansion and contraction occurs due to temperature changes, the equal height sleeve is fitted into the hole of the guide sleeve and protrudes slightly upward. After the equal height sleeve is tightened with screws, the guide sleeve is not completely locked, leaving a certain amount of room for movement. This forms an adaptive clearance design, which solves the problem of the upper lifting mold rod getting stuck when sliding up and down. The sealing effect of the sealing ring does not affect the sealing performance of the vacuum chamber when it is evacuated. 3. The sealing is achieved through the cooperation of the vacuum hood, sealing components, upper mold, and tray. The output end of the auxiliary oil cylinder drives the vacuum hood downward to move so that the vacuum hood covers the tray. The two are sealed by a sealing gasket fixed around the bottom of the vacuum hood. After the vacuum pump is connected to the vacuum hood, a vacuum is drawn to achieve the effect of maintaining a vacuum during mold injection. Attached Figure Description

[0016] Figure 1 This is the front view of the present invention.

[0017] Figure 2 This is a side view of the present invention.

[0018] Figure 3 This is a top view of the present invention.

[0019] Figure 4 This is a front view of the tripod of the present invention.

[0020] Figure 5 This is a side view of the tripod, fuel tank bracket, fuel tank, electrical box bracket, and electrical control box of the present invention.

[0021] Figure 6 This is a top view of the tripod of the present invention.

[0022] Figure 7 This is a front view of the smooth guide post of the present invention.

[0023] Figure 8 This is a top view of the base of the present invention.

[0024] Figure 9 This is a front view of the base and the lifting mechanism of the present invention.

[0025] Figure 10 This is a side view of the horizontal adjustment mechanism of the present invention.

[0026] Figure 11 This is a top view of the horizontal adjustment mechanism of the present invention.

[0027] Figure 12 This is a front view of the horizontal adjustment mechanism of the present invention.

[0028] Figure 13 This is a front view of the top mold mechanism of the present invention.

[0029] Figure 14 yes Figure 2 Enlarged view of the sealing assembly in section A.

[0030] Figure 15 This is a front view of the twin-screw feeding unit of the present invention.

[0031] Figure 16 This is a structural schematic diagram of the main screw, gear, and auxiliary screw of the present invention.

[0032] Figure 17 This is a front view of the lifting formwork unit of the present invention.

[0033] Figure 18 This is a side view of the lifting formwork unit of the present invention.

[0034] Explanation of icon numbers: 1-Legged frame, 2-Oil tank frame, 20-Oil tank, 3-Electrical control box frame, 30-Electrical control box, 4-Lifting mold unit, 40-Base, 41-Lifting mold drive mechanism, 410-Lifting mold cylinder, 411-Cylinder shaft, 412-Connecting shaft, 413-Limit nut, 42-Smooth guide post, 43-Horizontal adjustment mechanism, 430-Middle seat, 431-Guide rail, 432-Pattern, 433-Cylinder mounting seat, 434-Push-pull cylinder, 435-Connecting plate, 44-Top mold mechanism, 440-Cylinder bracket, 441-Front top cylinder, 442-Top extension sliding bracket, 443-Top mold support plate, 45-Mounting bracket, 46-Vacuum pump 47-Control valve, 5-Lifting mold unit, 50-Upper seat, 51-Vacuum hood, 52-Auxiliary cylinder, 53-Lifting mold rod, 54-Lifting mold beam, 55-Nut, 56-Sealing assembly, 560-Guide sleeve, 561-Sealing ring, 562-Screw, 563-Equal height sleeve, 564-Sliding bearing, 6-Twin screw feeding unit, 60-Twin screw feeding mechanism, 600-Drive motor, 601-Housing, 602-Main screw, 603-Gear, 604-Auxiliary screw, 61-Metering injection mechanism, 610-Metering pump, 611-Flow section, 612-Heat transfer oil circulation pipe, 613-Injection nozzle. Detailed Implementation

[0035] The present invention will be further described below with reference to the accompanying drawings: Example 1: like Figure 1-18 As shown, the present invention relates to a rubber hot press molding machine with twin-screw feeding and vacuum injection, comprising a stand 1, an oil tank 20 mounted on the stand 1 via an oil tank frame 2, and an electrical control box 30 mounted on the stand 1 via an electrical control box frame 3. A mold lifting unit 4 is mounted on the stand 1 to lift the mold. A mold hoisting unit 5 is mounted above the mold lifting unit 4 to hoist the mold. A twin-screw feeding unit 6 is mounted above the mold hoisting unit 5 to inject molten rubber into the mold. The electrical control box 30 controls the coordinated operation of the mold lifting unit 4, the mold hoisting unit 5, and the twin-screw feeding unit 6. The oil tank 20 is connected to a mold lifting cylinder 410, a push-pull cylinder 434, a front push cylinder 441, an auxiliary cylinder 52, and a pull-up cylinder via branch oil pipes to provide hydraulic oil to each cylinder.

[0036] like Figure 1-3As shown in Figure 7-13, the lifting mold unit 4 includes a base 40 mounted on the stand 1, a lifting mold drive mechanism 41 on each side of the base 40, four sets of smooth guide pillars 42 passing through the base 40, a horizontal adjustment mechanism 43 above the base 40, a top mold mechanism 44 at one end of the horizontal adjustment mechanism 43, a vacuum pump 46 mounted on the base 40 via a mounting bracket 45, and a control valve 47 on the side of the base 40. The output end of the lifting mold drive mechanism 41 is connected to the horizontal adjustment mechanism 43, the smooth guide pillars 42 are slidably connected to the horizontal adjustment mechanism 43, and the vacuum pump 46 is connected to the control valve 47 via an air pipe. The mold drive mechanism 41 drives the horizontal adjustment mechanism 43 to move up and down along the smooth guide post 42. The horizontal adjustment mechanism 43 adjusts the horizontal position of the mold. The ejector mechanism 44 lifts / releases the mold. The mold lifting drive mechanism 41 includes a mold lifting cylinder 410, a cylinder shaft 411 disposed within the mold lifting cylinder 410, a connecting shaft 412 disposed at one end of the cylinder shaft 411, and a limiting nut 413 disposed on the connecting shaft 412. The mold lifting cylinder 410 transmits driving force through the cylinder shaft 411. The connecting shaft 412 is connected to the horizontal adjustment mechanism 43 in conjunction with the limiting nut 413. The horizontal adjustment mechanism 43 includes... The system comprises a central base 430, two parallel and symmetrically arranged guide rails 431 on the central base 430, a tray 432 on the two guide rails 431, and a push-pull hydraulic cylinder 434 located on one side of the central base 430 via a hydraulic cylinder mounting seat 433. A connecting plate 435 limits the ends of the two guide rails 431. The central base 430 has four sets of smooth vertical holes that extend vertically, each corresponding to a smooth guide post 42. Each smooth guide post 42 has a smooth vertical hole. When the lifting cylinder 410 drives the cylinder shaft 411 to extend or retract, it will cause the central base 430 to rise and fall along the column. The tray 432 is connected to a push-pull hydraulic cylinder 434 via a slot on each side. The guide rail 431 is slidably connected, and the output end of the push-pull cylinder 434 is fixedly connected to the tray 432. The top mold mechanism 44 includes a cylinder bracket 440 located below the two guide rails 431, a front top cylinder 441 located below the cylinder bracket 440, a top extension sliding bracket 442 located at the output end of the front top cylinder 441, and a top mold support plate 443 located on the top extension sliding bracket 442. The top extension sliding bracket 442 is slidably connected to the cylinder bracket 440. The front top cylinder 441 is used to drive the top extension sliding bracket 442 to move up and down through its output end. The top mold support plate 443 is used to support the mold when the top extension sliding bracket 442 moves up and down.

[0037] like Figure 1-3As shown in Figures 14-18, the lifting mold unit 5 includes an upper seat 50, a vacuum hood 51 located below the upper seat 50, an auxiliary hydraulic cylinder 52 located on each side of the upper seat 50, four sets of upper lifting mold rods 53 passing through the upper seat 50, and a lifting mold beam 54 located at one end of the upper lifting mold rods 53. The upper seat 50 is provided with four sets of vertically penetrating mounting holes, which correspond one-to-one with the smooth guide posts 42. Each smooth guide post 42 is provided with a mounting hole, and the upper seat 50 is limited by at least one nut 55 sleeved on the smooth guide post 42. The lifting mold rods slide through the vacuum hood 51 through a sealing assembly 56. The sealing assembly 56 includes a guide sleeve 560, a sealing ring 561 located in the guide sleeve 560, a screw 562 passing through the guide sleeve 560, a height-equalizing sleeve 563 sleeved on the screw 562, and a sliding bearing 564 located below the guide sleeve 560.

[0038] like Figure 1-3 As shown in Figures 15-16, the twin-screw feeding unit 6 includes a twin-screw feeding mechanism 60 and a metering injection mechanism 61 located at the discharge end of the twin-screw feeding mechanism 60. The twin-screw feeding mechanism 60 includes a drive motor 600, a housing 601 located at one end of the drive motor 600, a main screw 602 located at the output end of the drive motor 600, and an auxiliary screw 604 meshing with the main screw 602 via a gear 603. The auxiliary screw 604 is rotatably connected within the housing 601, and the housing 601 is provided with a feeding device. The metering injection mechanism 61 includes a metering pump 610, a heat transfer oil circulation pipe 612 located below the metering pump 610 through a flow section 611, and an injection nozzle 613 located at the end of the heat transfer oil circulation pipe 612. The heat transfer oil circulation pipe 612 passes through the vacuum shroud 51. A sealing bushing is fitted on the heat transfer oil circulation pipe 612 to keep the heat transfer oil circulation pipe 612 and the vacuum shroud 51 sealed when the vacuum shroud 51 moves up and down. The injection nozzle 613 is welded to the heat transfer oil circulation pipe 612.

[0039] In use, the stand 1, fuel tank frame 2, and electrical box frame 3 are welded together to form a foundation. Four sets of smooth guide posts 42 connect the upper seat 50, middle seat 430, and base 40 into a single unit. Each of the upper seat 50 and base 40 is limited on its upper and lower surfaces by a nut 55 in conjunction with the smooth guide post 42. The middle seat 430 can move freely up and down along the smooth guide post 42 through smooth vertical holes. The main screw 602 is set with a constant pitch and a gradually changing root diameter; the auxiliary screw 604 is set with a constant root diameter and a gradually changing pitch and tooth thickness. The relative positions of the main screw 602 and auxiliary screw 604 inside the housing 601 remain unchanged; only relative rotation occurs. The relative positions of the main and auxiliary screws during rotation are controlled by gear 603. The molten plastic enters through the gap between the two screws. When the twin screws rotate, the gap between the two screws contracts, squeezing and pushing the molten plastic forward. This squeezing force is double-acting and pulsating, changing periodically through the gap between the two screws. The squeezing pressure on the molten plastic also changes periodically, making it easy to squeeze out and clean any residual molten plastic. However, the upper die rod 53 often jams when the temperature changes, even with the addition of a strong spring. To completely solve the jamming problem, when the upper lifting mold rod 53 passes through the vacuum cover 51, the different temperatures and varying degrees of thermal expansion and contraction inside and outside the vacuum cover 51 can easily cause jamming. To ensure smooth lifting of the vacuum cover 51 and the upper lifting mold rod 53 under different temperature variations, the clearance between the upper lifting mold rod 53 and the vacuum cover 51 needs to be appropriately increased. The upper lifting mold rod 53 passes through the upper seat 50 into the vacuum cover 51, and through the cooperation of the guide sleeve 560, the equalizing sleeve 563, the sliding bearing 564, and the sealing ring 561, it ensures smooth sliding under different temperature conditions without jamming, while maintaining a sealed seal. Temperature changes cause thermal expansion... During cold shrinkage, the equal-height sleeve 563 is installed inside the hole of the guide sleeve 560 and protrudes slightly upwards. After the equal-height sleeve 563 is tightened by the screw 562, the guide sleeve 560 is not completely locked, leaving some room for movement, forming an adaptive gap design. This solves the problem of jamming. The sealing effect of the sealing ring 561 does not affect the sealing performance of the vacuum cover 51 when vacuuming. In some existing technologies, when vacuuming the mold, each mold needs to have an additional vacuum channel, which increases the material and manufacturing costs. Moreover, because the vacuum channel is prone to clogging, the frequency of mold cleaning and maintenance increases. This invention solves the problem by using the vacuum cover 51 and the sealing component 560. 6. The upper mold and tray 432 cooperate to complete the seal. The vacuum pump 46 is connected to the vacuum hood 51 to draw a vacuum, so as to maintain the vacuum effect during mold injection. Since the mold is generally equipped with an exhaust hole, the gas in the cavity will be extracted from the exhaust hole. In the absence of plastic melt, idling can easily wear down the parts. The present invention also adds a material interruption detection alarm device to avoid the twin screw running idle during production. Specifically, a photoelectric switch is installed at the inlet. The photoelectric switch is electrically connected to the electrical control box 30. If there is plastic melt blocking it, the photoelectric switch is turned on (normal signal). If there is no plastic melt blocking it, the photoelectric switch is turned off (abnormal signal alarm).

[0040] Example 2: like Figure 1-18 As shown, the present invention relates to a twin-screw feeding, vacuum injection rubber hot press molding machine, including a stand 1, an oil tank 20 mounted on the stand 1 via an oil tank frame 2, and an electrical control box 30 mounted on the stand 1 via an electrical control box frame 3. The electrical control box 30 is used to control the coordinated operation of the mold lifting unit 4, the mold hoisting unit 5, the twin-screw feeding unit 6, etc. The oil tank 20 is used to connect to the mold lifting cylinder 410, the push-pull cylinder 434, the front push cylinder 441, the auxiliary cylinder 52, and the pull-up cylinder through various branch oil pipes, respectively, to provide hydraulic oil to each cylinder.

[0041] like Figure 1-3As shown in Figure 7-13, a mold lifting unit 4 is provided on the stand 1. The mold lifting unit 4 is used to lift the mold. The mold lifting unit 4 includes a base 40 on the stand 1, a mold lifting drive mechanism 41 on each side of the base 40, four sets of smooth guide pillars 42 passing through the base 40, a horizontal adjustment mechanism 43 above the base 40, a top mold mechanism 44 at one end of the horizontal adjustment mechanism 43, a vacuum pump 46 on the base 40 via a mounting bracket 45, and a control valve 47 on the side of the base 40. The output end of the mold lifting drive mechanism 41 is connected to the horizontal adjustment mechanism 43, the smooth guide pillars 42 are slidably connected to the horizontal adjustment mechanism 43, and the vacuum pump 46... The mold lifting drive mechanism 41 is connected to the control valve 47 via an air pipe. It drives the horizontal adjustment mechanism 43 to move up and down along the smooth guide post 42. The horizontal adjustment mechanism 43 adjusts the horizontal position of the mold. The ejector mechanism 44 lifts / releases the mold. The mold lifting drive mechanism 41 includes a mold lifting cylinder 410, a cylinder shaft 411 within the cylinder lifting cylinder 410, a connecting shaft 412 at one end of the cylinder shaft 411, and a limiting nut 413 on the connecting shaft 412. The mold lifting cylinder 410 transmits driving force through the cylinder shaft 411, and the connecting shaft 412 is connected to the horizontal adjustment mechanism 43 in conjunction with the limiting nut 413. The horizontal adjustment mechanism 43... The system includes a central base 430, two parallel and symmetrically arranged guide rails 431 on the central base 430, a tray 432 on the two guide rails 431, and a push-pull hydraulic cylinder 434 located on one side of the central base 430 via a hydraulic cylinder mounting seat 433. A connecting plate 435 limits the ends of the two guide rails 431. The central base 430 has four sets of smooth vertical holes that pass through vertically, each corresponding to a smooth guide post 42. Each smooth guide post 42 has a smooth vertical hole. When the lifting cylinder 410 drives the cylinder shaft 411 to extend or retract, it will drive the central base 430 to rise and fall along the columns. The tray 432 has a slot on each side, which engages with the side of the guide rail 431 for sliding connection. The output end of the push-pull cylinder 434 is fixedly connected to the tray 432; the top mold mechanism 44 includes a cylinder bracket 440 located below the two guide rails 431, a front top cylinder 441 located below the cylinder bracket 440, a top extension sliding bracket 442 located at the output end of the front top cylinder 441, and a top mold support plate 443 located on the top extension sliding bracket 442. The top extension sliding bracket 442 is slidably connected to the cylinder bracket 440. The front top cylinder 441 is used to drive the top extension sliding bracket 442 to move up and down through the output end. The top mold support plate 443 is used to support the mold when the top extension sliding bracket 442 moves up and down. The base 40 and the smooth guide post 42 are limited by a nut 55.

[0042] like Figure 1-3As shown in Figures 14-18, a lifting mold unit 5 is provided above the lifting mold unit 4. This lifting mold unit 5 is used to lift the mold. The lifting mold unit 5 includes an upper base 50, a vacuum hood 51 located below the upper base 50, an auxiliary hydraulic cylinder 52 located on each side of the upper base 50, four sets of upper lifting mold rods 53 passing through the upper base 50, and a lifting mold beam 54 located at one end of the upper lifting mold rods 53. The four sets of upper lifting mold rods 53 are divided into two groups parallel to the guide rail 431, and are respectively fixedly connected to a lifting mold beam 54 to form a... Two sets of lifting beams 54 are provided. The upper seat 50 has four sets of vertically penetrating mounting holes, which correspond one-to-one with the smooth guide posts 42. Each smooth guide post 42 has a mounting hole, and the upper seat 50 is limited by at least one nut 55 fitted onto the smooth guide post 42. The vacuum hood 51 has a lifting through hole through which the upper lifting rod 53 passes. A sealing component 56 allows the upper lifting rod 53 to slide and seal through the vacuum hood 51. The lifting beams 54 have lifting grooves. The sealing component 56 includes guides. The guide sleeve 560, the sealing ring 561 located inside the guide sleeve 560, the screw 562 passing through the guide sleeve 560, the equalizing sleeve 563 fitted onto the screw 562, and the sliding bearing 564 located below the guide sleeve 560 are all included. The upper lifting mold rod 53 passes through the guide sleeve 560 and the sliding bearing 564 in sequence. It is installed in the offset hole of the guide sleeve 560 through the equalizing sleeve 563 and protrudes upward. The screw 562 passes through the equalizing sleeve 563 for locking, and one end is inserted into the vacuum cover 51 for threaded connection. The guide sleeve 560 is not completely locked onto the vacuum cover 51, leaving some room for movement, forming an adaptive gap design. During deformation, the upper hanging mold rod 53 slides through the guide sleeve 560. The guide sleeve 560 can swing slightly freely by offset, so that its axis centerline is consistent with the upper hanging mold rod 53, and it will not get stuck. After the upper hanging mold rod 53 is lowered, so that the mold on the tray 432 is horizontally aligned with the hanging mold groove on the hanging mold beam 54, the initial height is fixed by the nut 55 sleeved on the upper hanging mold rod 53.

[0043] The advantage of this embodiment lies in the following: By appropriately increasing the clearance between the upper lifting mold rod 53 and the vacuum chamber 51, when the upper lifting mold rod 53 passes through the upper seat 50 and enters the vacuum chamber 51, temperature changes cause thermal expansion and contraction. This expansion and contraction is mitigated by the equalizing sleeve 563, which is installed in the hole of the guide sleeve 560 and protrudes upwards above the upper surface of the guide sleeve. After the equalizing sleeve 563 is locked by the screw 562, it is threaded through the guide sleeve 560 and connected to the vacuum chamber. However, the guide sleeve 560 is not completely locked, allowing for some movement and forming an adaptive clearance design. This ensures smooth sliding without jamming under varying temperature conditions, thus solving the problem of the upper lifting mold rod 53 being obstructed by the guide sleeve 560 during vertical sliding. The "stuck" problem is solved by the sealing ring 561 without affecting the sealing performance of the vacuum cover 51 during vacuuming. The sealing is achieved through the cooperation of the vacuum cover 51, the sealing component 56, the upper mold, and the tray 432. The output end of the auxiliary cylinder 52 drives the vacuum cover 51 downward to move, so that the vacuum cover 51 covers the tray 432. The two are sealed by a sealing gasket fixed to the bottom surface of the vacuum cover 51. After the vacuum pump 46 is connected to the vacuum cover 51, a vacuum is drawn, which achieves the effect of maintaining a vacuum during mold injection.

[0044] like Figure 1-3 As shown in Figures 15-16, a twin-screw feeding unit 6 is provided above the mold unit 5. The twin-screw feeding unit 6 is used to inject rubber melt into the mold. The twin-screw feeding unit 6 includes a twin-screw feeding mechanism 60 and a metering injection mechanism 61 located at the discharge end of the twin-screw feeding mechanism 60. The twin-screw feeding mechanism 60 includes a drive motor 600, a housing 601 located at one end of the drive motor 600, a main screw 602 located at the output end of the drive motor 600, and an auxiliary screw 604 connected to the main screw 602 via a gear 603. 604 is rotatably connected within housing 601, which has a feed inlet. The metering injection mechanism 61 includes a metering pump 610, a heat transfer oil circulation pipe 612 located below the metering pump 610 via a flow section 611, and an injection nozzle 613 located at the end of the heat transfer oil circulation pipe 612. The main screw 602 has a constant pitch and a gradually changing root diameter, while the auxiliary screw 604 has a constant root diameter and gradually changing pitch and tooth thickness. Here, A1=B1=C1 indicates a constant pitch, A2>B2>C2 indicates a gradually changing pitch and tooth thickness, and D represents the root diameter of the main and auxiliary screws. The relative positions of the main screw 602 and the auxiliary screw 604 inside the housing 601 remain unchanged when they rotate via the gear 603; only relative rotation occurs. The molten plastic enters through the gap between the two screws. When the twin screws rotate, the gap between the two screws contracts, squeezing and pushing the molten plastic forward. This squeezing force is a pulsating type with the twin screws acting simultaneously. The "pulsating type" means that the squeezing pressure on the molten plastic by the main screw 602 and the auxiliary screw 604 rotating relative to each other changes periodically. Residual molten plastic is squeezed out and cleaned.

[0045] Working principle: First, the push-pull cylinder 434 of the horizontal adjustment mechanism 43 is activated, and its output end drives the tray 432 forward along the guide rail 431 until it is directly below the top mold support plate 443 of the top mold mechanism 44, at which point the push-pull cylinder 434 stops working. Second, the mold is placed on the top mold support plate 443 of the top mold mechanism 44, and the front push cylinder 441 is activated, and its output end drives the extension sliding bracket 442 downward to release the mold onto the tray 432 of the horizontal adjustment mechanism 43, at which point the front push cylinder 441 stops working. Third, the push-pull cylinder 434 is activated, and its output end drives the tray 432 backward along the guide rail 431, causing the mold to slide into the lifting slot on the lifting beam 54 until the tray 432 returns to directly below the vacuum chamber 51. The push-pull cylinder 434 stops working; fourth, the lifting cylinder 410 starts, the cylinder shaft 411 pushes the cylinder to push the middle seat 430 upward, the mold will drive the lifting rod to slide upward along the mold rod hole on the upper seat 50, rise to the injection nozzle 613 inserted into the injection hole of the mold, and the lifting cylinder 410 stops working; fifth, the auxiliary cylinder 52 starts, the output end drives the vacuum cover 51 downward to move, so that the vacuum cover 51 covers the tray 432, and the two are sealed by a sealing gasket fixed to the bottom surface of the vacuum cover 51, and the auxiliary cylinder 52 stops working; sixth, the vacuum pump 46 starts, through the control valve 47 connected by the air pipe, one end of the control valve 47 is connected to the vacuum cover 51 through the air pipe, the vacuum pump 46 evacuates the vacuum cover 51. In vacuum mode, vacuum pump 46 stops working; seventh, molten rubber enters the machine housing 601 through the inlet, drive motor 600 starts, driving main screw 602 to rotate, which in turn drives auxiliary screw 604 to rotate synchronously through gear 603. The main and auxiliary screws simultaneously extrude and push the molten rubber towards the outlet of machine housing 601 and into the flow section 611. Simultaneously, metering pump 610 starts, metering the molten rubber flowing into the flow section 611 and pumping it to the heat transfer oil circulation pipe 612. Metering pump 610 also feeds information back to the control box 30. The molten rubber is injected into the mold through injection nozzle 613 via the heat transfer oil circulation pipe 612. After injection molding is completed, drive motor 600 stops working, and molten rubber stops entering the machine housing 601. 1; Eighth, by opening the air gate of the control valve 47 to restore pressure inside the vacuum chamber 51, the lifting cylinder 410 is started, the cylinder shaft 411 retracts, and the cylinder pulls the middle seat 430 down to its original position. The mold's own weight will drive the lifting rod to slide down along the mold rod hole on the upper seat 50 until the injection nozzle 613 is completely separated from the mold. The mold's descent process is synchronized with the descent of the tray 432. The lifting cylinder 410 stops working. At this time, the mold is still on the tray 432. Ninth, the push-pull cylinder 434 is started, and the output end drives the tray 432 forward along the guide rail 431. The mold will slide out along the lifting groove on the lifting beam 54. After reaching directly below the top mold support plate 443 of the top mold mechanism 44, the push-pull cylinder 434 stops working.Tenth, open the locking device on the mold. The front ejector cylinder 441 starts, and its output end drives the ejector sliding bracket 442 upward. The side ejector plates 443 lift the upper mold off the lower mold. The front ejector cylinder 441 stops working. Remove the injection molded part and clean the upper and lower mold cavities. Eleventh, the front ejector cylinder 441 starts, and its output end drives the ejector sliding bracket 442 downward, closing the upper mold onto the lower mold. The front ejector cylinder 441 stops working and locks the locking device on the mold.

[0046] Then repeat the above steps to continuously inject the workpiece.

[0047] Each time a new injection molding cycle begins and cleaning is required, a cleaning cylinder is placed on tray 432 to replace the mold. Through steps one through nine, residual molten plastic carried over from the initial rubber melt is removed. This process achieves the removal of residual molten plastic: the main screw 602 has a constant pitch but a gradually changing root diameter, while the auxiliary screw 604 has a constant root diameter but a gradually changing pitch and tooth thickness. The relative positions of the main screw 602 and auxiliary screw 604 within the housing 601 remain constant. The relative positions of the main and auxiliary screws during rotation are controlled by gear 603. The molten plastic is removed from the two screws. The plastic melt enters through the gap between the two screws. When the twin screws rotate, the gap between the two screws contracts, squeezing and pushing the plastic melt forward. This squeezing force is double-acting and pulsating. For example, in a river with flat terrain and slow flow, silt will settle and is not easily carried away; in a river with uneven terrain and rapid flow, silt is easily washed away. When the twin screw feeding mechanism 60 changes material during production, it quickly washes away the remaining plastic melt without leaving any residue. Through the periodic change of the gap between the two screws, the squeezing pressure on the plastic melt also changes periodically, and the residual plastic melt is easily squeezed out and cleaned.

[0048] The superiority of this embodiment also lies in the fact that during production, the twin-screw feeding mechanism 60, through the contraction and compression of the gap between the two screws as the twin screws rotate, pushes the plastic melt forward, and the excess plastic melt is quickly flushed away. Through the periodic change of the gap between the two screws, the extrusion pressure on the plastic melt also changes periodically, and the residual plastic melt is easily squeezed out and cleaned. The main and auxiliary screws, through the intense shearing, stretching and kneading action generated by their interlocking, continuously break and reassemble the plastic melt, which can not only quickly homogenize and transform the high-viscosity compound into a homogeneous viscous flow state in a very short time, but also rapidly inject the plastic melt into the mold cavity through the high pressure accumulated by the main and auxiliary screws.

[0049] In some embodiments, in order to ensure that the lifting rod slides up and down in sync with the mold and pallet 432, a lifting cylinder is provided on the top of the upper seat 50. The lifting rod is fixedly connected by a lifting plate provided at the output end of the lifting cylinder. The lifting cylinder is electrically connected to the electrical control box 30.

[0050] In some embodiments, the parameters of the outer diameter, root diameter, pitch, tooth thickness (thickness of a single thread), module, and number of teeth of the main and auxiliary screws are preferably matched as follows: main screw 602 has a diameter of Ø45mm, a pitch of 45mm, a root diameter that gradually changes from Ø25 to Ø39mm, and a thread protrusion thickness of 6mm; auxiliary screw 604 has a diameter of Ø45mm, a root diameter that gradually changes from Ø26 to Ø33mm, and a thread protrusion thickness that gradually changes from 6 to 15mm; the parameters of the gears 603 on both the main and auxiliary screws are set as follows: module 2.5, number of teeth... With a pressure angle of 20 degrees, the superior effect of the 16-point screw is that the main and auxiliary screws continuously break down and reorganize the plastic melt through intense shearing, stretching and kneading caused by their interlocking. This not only rapidly homogenizes the high-viscosity compound into a homogeneous viscous flow state in a very short time, but also rapidly injects the plastic melt into the mold cavity through the high pressure accumulated by the main and auxiliary screws. Furthermore, the meshing area of ​​the screws forms a self-cleaning effect. Through dynamic pulsating mutual friction, not only are dead corners of material accumulation eliminated, but a high vacuum zone is also formed at the root of the screw, which is conducive to venting and devolatilization.

[0051] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of the present invention. Therefore, any equivalent changes or modifications made by those skilled in the art to the structure, features and principles of the present invention without departing from the spirit of the present invention should fall within the protection scope of the patent application of the present invention.

Claims

1. A twin screw rubber injection, vacuum compression molding machine comprising a foot stand, characterized in that: The lifting mechanism is arranged on the foot stool, and a mold lifting unit is arranged on the foot stool to lift the mold.

2. A twin screw feed, vacuum injection rubber thermo compression molding machine according to claim 1, characterized in that: An oil tank is arranged on the foot stool through an oil tank frame, and an electric control box is arranged through an electric box frame.

3. A twin screw feed, vacuum injection rubber thermo compression molding machine according to claim 1, characterized in that: The lifting mechanism includes a base arranged on the foot stool, a lifting mechanism arranged on each side of the base, four smooth guide columns arranged on the base, a horizontal adjusting mechanism arranged above the base, a top mold mechanism arranged at one end of the horizontal adjusting mechanism, a vacuum pump arranged on the base through a mounting frame, and a control valve arranged on the side of the base.

4. A twin screw rubber injection thermoforming machine according to claim 3, characterized in that: The lifting mechanism includes a lifting oil cylinder, a cylinder shaft arranged in the lifting oil cylinder, a connecting shaft arranged at one end of the cylinder shaft, and a limiting nut arranged on the connecting shaft.

5. A twin screw feed, vacuum injection rubber thermo compression molding machine according to claim 4, characterized in that: The horizontal adjusting mechanism includes a middle base, two guide rails arranged in parallel and symmetrically on the middle base, a tray arranged on the two guide rails, and a push-pull oil cylinder arranged on one side of the middle base through an oil cylinder mounting seat.

6. A twin screw feed, vacuum injection rubber thermo compression molding machine according to claim 5, characterized in that: The top mold mechanism includes an oil cylinder support arranged below the two guide rails, a front top oil cylinder arranged below the oil cylinder support, a top extension sliding support arranged at the output end of the front top oil cylinder, and a top mold support plate arranged on the top extension sliding support.

7. A twin screw feed, vacuum injection rubber thermo compression molding machine according to claim 1, characterized in that: The lifting mechanism includes a base arranged on the foot stool, a lifting mechanism arranged on each side of the base, four smooth guide columns arranged on the base, a horizontal adjusting mechanism arranged above the base, a top mold mechanism arranged at one end of the horizontal adjusting mechanism, a vacuum pump arranged on the base through a mounting frame, and a control valve arranged on the side of the base. The lifting mechanism includes a base arranged on the foot stool, a lifting mechanism arranged on each side of the base, four smooth guide columns arranged on the base, a horizontal adjusting mechanism arranged above the base, a top mold mechanism arranged at one end of the horizontal adjusting mechanism, a vacuum pump arranged on the base through a mounting frame, and a control valve arranged on the side of the base.

8. A twin screw feed, vacuum injection rubber thermo compression molding machine according to claim 1, characterized in that: The double-screw feeding unit comprises a double-screw feeding mechanism and a metering injection mechanism arranged at the discharging end of the double-screw feeding mechanism.

9. A twin screw rubber injection thermoforming machine according to claim 8, characterized in that: The double-screw feeding mechanism comprises a driving motor, a casing arranged at one end of the driving motor, a main screw rod arranged at the output end of the driving motor, and an auxiliary screw rod connected with the main screw rod through a gear.

10. A twin-screw rubber injection thermoforming machine according to claim 9, characterized in that: The main screw rod is arranged as equal pitch, the bottom diameter is arranged as gradual change, the auxiliary screw rod is arranged as equal bottom diameter, the pitch and the tooth thickness are arranged as gradual change, and the main screw rod and the auxiliary screw rod in the casing only rotate relatively when rotating through the gear transmission, and the relative positions are consistent.

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