A screw injection molding machine with constant temperature heating of the barrel

Abstract

This invention belongs to the field of injection molding machine technology, specifically a screw injection molding machine with constant temperature heating of the barrel. The proposed solution includes: an injection unit, with a feed hopper detachably fixed to its side; a power unit, with its top fixed to the bottom of the injection unit; a barrel, with its bottom fixed to the top of the injection unit; a heating mechanism nested on the outer surface of the barrel; vertical rods, with one end fixed to the outer surface of the heating mechanism; a placement plate, fixed to the other end of the vertical rods; and a screw, with its bottom positioned at the top of the injection unit. This invention utilizes a cyclic high-temperature environment to cause significant deformation of the bimetallic strip. After bending, the active and passive layers of the bimetallic strip tightly adhere to the outer wall of the barrel. Heat is directly transferred to the barrel through the metal cap and bimetallic strip in a solid-state heat conduction manner, significantly improving heat transfer efficiency.

Description

Technical Field

[0001] This invention relates to the field of injection molding machine technology, and in particular to a screw injection molding machine with constant temperature heating of the barrel. Background Technology

[0002] Injection molding machines are the core equipment in the plastics processing industry. Screw injection molding machines rely on the screw to convey and stir plastic raw materials, and in conjunction with the barrel heating to melt the granular raw materials, finally completing the injection molding. They are widely used in the production of plastic products such as daily necessities, auto parts, and home appliances. Most existing screw injection molding machines employ single-point or segmented heating, resulting in significant circumferential and axial temperature differences in the barrel. This easily leads to localized overheating and decomposition of the raw material, as well as incomplete melting in certain areas, directly impacting the molding quality of plastic products and generating waste. Furthermore, the heating structure lacks an effective temperature control mechanism, resulting in slow start-up and difficulty in maintaining a stable temperature after reaching the process temperature. Temperature fluctuations cause dimensional deviations and surface defects in the injection molded products. The barrel exterior lacks adequate insulation, causing significant heat loss and increasing energy consumption. The high-temperature casing also poses a safety hazard of burns to operators. The heating mode is limited, failing to adjust the heating rate according to production stages. It cannot quickly raise the temperature during start-up preheating, and is prone to sustained high temperatures during normal production, making it difficult to adapt to the needs of different raw materials and production conditions. Therefore, there is an urgent need for a screw injection molding machine with constant barrel temperature heating. Summary of the Invention

[0003] Based on the technical problems in the background art, the present invention proposes a screw injection molding machine with constant temperature heating of the barrel.

[0004] This invention proposes a screw injection molding machine with constant temperature heating of the barrel, comprising: an injection molding device, on the side of which a feed hopper is detachably fixed; a power unit, the top of which is fixedly mounted on the bottom of the injection molding device; a barrel, the bottom of which is fixedly mounted on the top of the injection molding device; a heating mechanism, nested on the outer surface of the barrel; vertical rods, one end of which is fixedly mounted on the outer surface of the heating mechanism; a placement plate, the other end of which is fixedly mounted on; and a screw, the bottom of which is mounted on the top of the injection molding device. The heating mechanism includes: a heat insulation cylinder, nested on the outer surface of the barrel; two heat insulation rings, each fixedly fitted inside both ends of the heat insulation cylinder; a heat-conducting ring, the outer surface of which is fixedly mounted on the inner wall of the heat insulation cylinder; a notched ring, the outer surface of which is fixedly mounted on the inner wall of the heat insulation cylinder; a metal cylinder, both ends of which are respectively fixedly inserted through the middle of the heat-conducting ring and the notched ring; and multiple heating columns, which are fixedly inserted through the metal cylinder and the heat insulation cylinder.

[0005] Preferably, the heating mechanism further includes: a metal sheet, wherein multiple metal sheets are respectively fixedly disposed on the outer surface of the heating column; a metal cover, wherein the metal cover is fixedly sleeved on the end of the heating column; an extension edge, wherein the extension edge is integrally formed and fixedly disposed on the outer surface of the metal cover; a threaded hole, wherein the threaded hole opening is disposed between the metal cover and the extension edge; an active plate, wherein the active plate is detachably fixedly disposed on the outer surface of the metal cover; and a passive layer, wherein the passive layer is fixedly disposed on the outer surface of the active plate by rivets.

[0006] Preferably, the heating mechanism further includes: a threaded bolt, the threaded bolt being threadedly embedded in a threaded hole in the middle of the metal cover; an air inlet pipe, one end of which is fixedly disposed on the outer surface of the heat insulation cylinder; an elbow pipe, one end of which is fixedly disposed on the outer surface of the heat insulation cylinder; a blower, the air outlet of which is nested at the other end of the air inlet pipe; a return pipe, the return pipe being nested at the air inlet of the blower; and a long guide pipe, one end of which is fixedly disposed on the outer surface of the return pipe.

[0007] Preferably, the heating mechanism further includes: valve one, with both ends of valve one nested at the other ends of the long guide pipe and the elbow pipe respectively; valve two, with valve two nested at the end of the return pipe; exhaust pipe, with one end of the exhaust pipe fixedly disposed on the outer surface of the heat insulation cylinder; valve three, with valve three nested at the other end of the exhaust pipe; connecting wires, with multiple connecting wires electrically connected to the end of the heating column respectively; embedding port, with the embedding port opening disposed at the end of the heating column; and through ports, with multiple through ports opening disposed in the metal cylinder.

[0008] Preferably, the heat insulation cylinder has openings at both ends, and the interior of the heat insulation cylinder is connected to the interior of the air inlet pipe through the openings. The interior of the heat insulation cylinder is also connected to the interior of the exhaust pipe through the openings. One end of the return pipe has an opening with a notch, and the interior of the return pipe is connected to the interior of the long conduit through the notch, so that the interiors of the air inlet pipe, elbow pipe, blower, return pipe, long conduit, and valve one are connected.

[0009] Preferably, the metal cylinder is movably fitted inside the heat insulation cylinder, and the metal cylinder divides the space inside the heat insulation cylinder into two mutually nested heating spaces. The heating column is embedded in the two heating spaces and is fixed through the through-hole of the metal cylinder.

[0010] Preferably, the notch ring opening is provided with a notch, the notches of the two heating space notch rings are kept in communication, the inside of the air inlet pipe is kept in communication with one of the heating spaces, the inside of the exhaust pipe is kept in communication with the other heating space, and the two sides of the multiple metal sheets are respectively fixedly disposed on the outer surface of the material cylinder and the inner wall of the heat insulation cylinder, and the multiple metal sheets are disposed inside one of the heating spaces.

[0011] Preferably, the expansion coefficient of the active sheet is greater than that of the passive layer, the active sheet and the passive layer are in an arc shape and are kept in close contact to form a bimetallic sheet, the bimetallic sheet is arranged around the outer surface of the barrel, the thermal conductivity of the heat insulation cylinder is less than 0.03 W / (m・K), and the heat conduction ring, the notched ring, the barrel and the metal cylinder are all made of metal.

[0012] Preferably, the outer surface of the metal cover is arc-shaped, the thickness of the active plate is greater than the thickness of the passive plate, and the active plate and the passive plate are detachably fixed on the outer surface of the metal cover by threaded bolts. The threaded bolts move through the middle of the active plate and the passive plate, and both the active plate and the passive plate are located in the gap between the material cylinder and the heat insulation cylinder.

[0013] Preferably, the screw is inserted into the interior of the barrel, the power output end of the power unit is fixed to the screw, and the other end of the barrel is integrally molded and closed to form an injection nozzle.

[0014] The beneficial effects of this invention are as follows: During initial startup and restart of the equipment, valves two and three are closed, and valve one is opened. The entire pipeline forms a closed-loop airflow circuit. The blower drives air to circulate repeatedly between the insulation cylinder and the pipeline. Hot air continuously exchanges heat within the double-layer heating space, and the heat is repeatedly utilized. Simultaneously, the circulating high-temperature environment causes the bimetallic strip to deform significantly upon heating. After bending, the active and passive layers tightly adhere to the outer wall of the cylinder. Heat is directly transferred to the cylinder through the metal cover and bimetallic strip in a solid-state heat conduction manner, significantly improving heat transfer efficiency. When Once the barrel temperature reaches the production set value, when switching working modes, valve one is closed and valves two and three are opened, disconnecting the closed-loop circulation. The hot air after heat exchange is directly discharged through the exhaust pipe and is no longer recycled. The overall ambient temperature inside the chamber decreases, the bimetallic strip deformation decreases, and it detaches from the outer wall of the barrel. Heat is slowly transferred to the barrel only through air convection, reducing the heating rate. This mode can accurately maintain a constant barrel temperature, avoiding temperature overshoot caused by continuous strong heating, perfectly adapting to continuous mass production conditions and ensuring long-term stability of injection molding process parameters. The heating mode switching can be completed by opening and closing the three sets of valves, eliminating the need for complex frequency conversion and power conversion electrical control systems. This makes it easy for operators to learn and reduces the probability of electrical control system failures, making it suitable for use in various production workshops. The active layer has a greater coefficient of thermal expansion and thickness than the passive layer. When the temperature around the barrel rises, the active layer deforms more, causing the entire bimetallic strip to bend and adhere to one side of the barrel, enhancing solid heat conduction and accelerating barrel heating. When the temperature approaches the set threshold, the airflow mode switches, causing the ambient temperature to drop, and the bimetallic strip gradually resets and detaches from the barrel. The heat conduction method is changed to low-speed air convection, which slows down the heating rate. Closed-loop temperature control is completed by physical deformation, which offsets temperature fluctuations in real time and stabilizes the barrel temperature within the process requirements range. The bimetallic strip is arranged close to the outer wall of the barrel, which is very close to the heat source and the heated body. The temperature sensing is instantaneous and can make deformation response according to temperature changes in the first time, effectively suppressing the phenomenon of sudden changes in barrel temperature. Compared with traditional electronic temperature control elements, this physical temperature control structure has strong anti-interference ability, is not affected by workshop voltage fluctuations and electromagnetic environment, and has stable temperature control accuracy over long-term use. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the overall structure of a screw injection molding machine with constant temperature heating of the barrel proposed in this invention; Figure 2 This is a schematic diagram of the heating mechanism of a screw injection molding machine with constant temperature heating of the barrel, as proposed in this invention. Figure 3 This is a cross-sectional schematic diagram of the heating mechanism of a screw injection molding machine with constant temperature heating of the barrel, as proposed in this invention. Figure 4 This is a disassembly diagram of the heating mechanism of a screw injection molding machine with constant temperature heating of the barrel, as proposed in this invention. Figure 1 ; Figure 5 This is a disassembly diagram of the heating mechanism of a screw injection molding machine with constant temperature heating of the barrel, as proposed in this invention. Figure 2 ; Figure 6 This is a disassembly diagram of the heating mechanism of a screw injection molding machine with constant temperature heating of the barrel, as proposed in this invention. Figure 3 ; Figure 7 This is a schematic diagram of the injection molding device structure of a screw injection molding machine with constant temperature heating of the barrel, as proposed in this invention. Figure 8 This is a schematic diagram of the heating column structure of a screw injection molding machine with constant temperature heating of the barrel, as proposed in this invention. Figure 9 This invention provides a schematic diagram of the disassembly of the heating column of a screw injection molding machine with constant temperature heating of the barrel. Figure 1 ; Figure 10 This invention provides a schematic diagram of the disassembly of the heating column of a screw injection molding machine with constant temperature heating of the barrel. Figure 2 .

[0016] In the diagram: 1. Injection molding unit; 2. Power unit; 3. Feed hopper; 4. Barrel; 5. Insulation cylinder; 51. Insulation ring; 52. Heat-conducting ring; 53. Notched ring; 54. Metal cylinder; 55. Heating column; 56. Metal sheet; 57. Metal cover; 58. Extension edge; 59. Threaded hole; 510. Active plate; 511. Passive layer; 512. Threaded bolt; 513. Air inlet pipe; 514. Elbow pipe; 515. Blower; 516. Return pipe; 517. Long guide pipe; 518. Valve 1; 519. Valve 2; 520. Exhaust pipe; 521. Valve 3; 522. Connecting line; 523. Embedding port; 524. Through port; 6. Vertical rod; 7. Placement plate; 8. Screw. Detailed Implementation

[0017] Reference Figures 1 to 10 A screw injection molding machine with constant temperature heating of the barrel includes: an injection unit 1, on the side of which a feed hopper 3 is detachably fixed; the injection unit 1 is the supporting base of the whole machine, used to integrate and assemble various functional components; the detachable feed hopper 3 facilitates raw material loading, equipment cleaning and maintenance, and can prevent raw material spillage; a power unit 2, the top of which is fixedly installed at the bottom of the injection unit 1; the power unit 2, as a power output component, provides power for the rotation of the screw 8 and the pushing of raw materials, ensuring stable operation of raw material mixing, conveying and injection molding; and a barrel 4, the bottom of which is fixedly installed at the top of the injection unit 1; the barrel 4 is the core barrel for raw material melting and conveying, receiving the raw material fed in by the feed hopper 3, and is externally coordinated with a heating mechanism to achieve full heating and ensure that the raw material is fully melted.

[0018] In this invention, a heating mechanism is nested on the outer surface of the barrel 4; the heating mechanism is arranged around the barrel 4, which can uniformly heat the barrel and, together with the matching structure, achieve temperature control and constant temperature maintenance, providing a stable heat source for raw material melting; vertical rods 6, one end of multiple vertical rods 6 is fixedly set on the outer surface of the heating mechanism; placement plate 7, placement plate 7 is fixedly set on the other end of multiple vertical rods 6; the vertical rods 6 and placement plate 7 form a support assembly, supporting and positioning the heating mechanism, pipelines and lines, reducing the impact of operating vibration, improving the overall structural stability of the equipment, and can also serve as an auxiliary maintenance platform; screw 8, the bottom of the screw 8 is set on the top of the injection molding device 1; the screw 8 extends into the barrel 4, and under the drive of the power device 2, completes the mixing, conveying and extrusion of raw materials, realizing the directional conveying and injection molding of molten raw materials.

[0019] In this invention, the heating mechanism includes: a heat insulation cylinder 5, which is nested on the outer surface of the material cylinder 4; the heat insulation cylinder 5 has low thermal conductivity, which can prevent internal heat from dissipating outward, reduce energy consumption, and at the same time prevent external components from being affected by high temperature and prevent personnel from being burned; two heat insulation rings 51, which are respectively fixedly sleeved on the inner sides of both ends of the heat insulation cylinder 5; the heat insulation rings 51 seal and insulate both ends of the heat insulation cylinder 5, block the heat loss channels at the ends, and further enhance the overall heat preservation effect; and a heat conduction ring 52, whose outer surface is fixedly disposed on the inner wall of the heat insulation cylinder 5; the heat conduction ring 52 is made of metal and has both positioning and heat conduction functions, fixing the metal cylinder 54 while quickly transferring heat to ensure smooth heat conduction.

[0020] In this invention, a notched ring 53 is fixedly disposed on the outer surface of the heat insulation cylinder 5 on the inner wall. The notched ring 53 limits and fixes the metal cylinder 54 on one hand, and forms an airflow channel by its own notch on the other hand, connecting the two heating spaces inside the heat insulation cylinder 5 to ensure normal air circulation. The two ends of the metal cylinder 54 are respectively fixed through the middle of the heat-conducting ring 52 and the notched ring 53. The metal cylinder 54 is a heat-conducting carrier, which is used to install and fix the heating column 55, and also divides the inside of the heat insulation cylinder 5 into two independent heating spaces, regulates the airflow and heat distribution, and achieves uniform heating in different zones. Multiple heating columns 55 are fixed through the metal cylinder 54 and the heat insulation cylinder 5. The heating columns 55 can be obtained by purchasing from the market or by private customization. The heating column 55 is the core heating element. After being powered on, it continuously generates heat energy to heat the air and metal components inside the cavity. The multiple sets of layout can achieve uniform heating of the cylinder in all four directions.

[0021] In this invention, the heating mechanism further includes: metal sheets 56, multiple metal sheets 56 are respectively fixedly disposed on the outer surface of the heating column 55; the metal sheets 56 increase the heat exchange area, accelerate the heat transfer speed of the heating column 55, improve heating efficiency, and at the same time strengthen the structural connection strength; metal cover 57, the metal cover 57 is fixedly sleeved on the end of the heating column 55; the metal cover 57 protects and seals the end of the heating column 55, and at the same time serves as an intermediate heat-conducting connector, transferring heat to the active plate 510, passive layer plate 511 and other temperature control components; extension edge 58, the extension edge 58 is integrally formed and fixedly disposed on the outer surface of the metal cover 57; the extension edge 58 enlarges the installation contact surface, facilitates the assembly and fixation of the threaded hole 59 and the threaded bolt 512, and improves the connection firmness.

[0022] In this invention, the heating column 55 has a threaded hole 59, the opening of which is located between the metal cover 57 and the extension edge 58. The threaded hole 59 provides an assembly point for the threaded bolt 512, enabling the detachable installation of the active plate 510 and the passive layer plate 511, facilitating subsequent disassembly, maintenance, and replacement. The active plate 510 is detachably fixed to the outer surface of the metal cover 57. The active plate 510 is a component of the bimetallic sheet, and relies on its own thermal expansion characteristics to deform with temperature changes, thereby achieving temperature linkage adjustment. The passive layer plate 511 is fixed to the outer surface of the active plate 510 by rivets. The passive layer plate 511 and the active plate 510 cooperate to form a bimetallic sheet. Due to their different coefficients of expansion, they undergo differentiated deformation after heating, thereby changing the heat conduction path and efficiency.

[0023] In this invention, the heating mechanism further includes: a threaded bolt 512, which is threadedly embedded in a threaded hole 59 in the middle of a metal cover 57; the threaded bolt 512, in conjunction with the threaded hole 59, locks and fixes the active plate 510 and passive layer 511 assembly, making disassembly and assembly convenient and ensuring that the assembly does not shift during operation; an air inlet pipe 513, one end of which is fixedly set on the outer surface of the heat insulation cylinder 5; the air inlet pipe 513 serves as an air inlet channel, introducing the cold air delivered by the blower 515 into the heating space inside the heat insulation cylinder 5, thus constructing an airflow circulation loop; and an elbow pipe 514, one end of which is fixedly set on the outer surface of the heat insulation cylinder 5; the elbow pipe 514 changes the airflow direction, connects the pipeline assembly, adapts to the equipment structure layout, and ensures stable airflow delivery.

[0024] In this invention, a blower 515 has its outlet nested at the other end of an inlet pipe 513. The blower 515 provides power to the entire airflow system, driving air to circulate within the heating space of the pipe and the insulation cylinder 5, achieving heat exchange and temperature control. A return pipe 516 is nested at the inlet of the blower 515. The return pipe 516 guides the circulated airflow back to the blower 515, completing a closed-loop airflow circulation and realizing the recycling of thermal energy. A long conduit 517 has one end fixed to the outer surface of the return pipe 516. The long conduit 517 connects the elbow pipe 514 and the return pipe 516, extending the airflow path and cooperating with valves to switch between different working modes.

[0025] In this invention, the heating mechanism further includes: a valve 518, the two ends of which are nested at the other ends of the long conduit 517 and the elbow 514, respectively; the valve 518 is used to switch the airflow between the long conduit 517 and the elbow 514, and to switch the rapid heating mode of the equipment; a valve 519, which is nested at the end of the return pipe 516; the valve 519 controls the main airflow of the return pipe 516, and works with the valves 518 and 521 to switch the heating mode and adjust the airflow circulation state; and an exhaust pipe 520, one end of which is fixedly installed on the outer surface of the heat insulation cylinder 5; the exhaust pipe 520 is an open exhaust channel, which discharges the hot air inside the heat insulation cylinder 5 to the outside of the equipment in the slow heating mode.

[0026] In this invention, valve 3 521 is nested at the other end of exhaust pipe 520; valve 3 521 controls the opening and closing of exhaust pipe 520, and when opened, hot air can be discharged to achieve non-circulating heating operation; connecting wire 522, multiple connecting wires 522 are electrically connected to the end of heating column 55 respectively; connecting wire 522 supplies power to heating column 55 to ensure the normal operation of heating element and realize the conversion of electrical energy into heat energy; embedding port 523, the embedding port 523 is set at the end of heating column 55; embedding port 523 provides embedding point for connecting wire 522 to ensure stable circuit connection and prevent wire from falling off or poor contact; through port 524, multiple through ports 524 are set in metal cylinder 54; through port 524 is used to pass through and fix heating column 55, limit the installation position of heating column 55, and ensure assembly accuracy and structural stability.

[0027] In this invention, the heat insulation cylinder 5 has openings at both ends, and the interior of the heat insulation cylinder 5 is connected to the interior of the air inlet pipe 513 and the interior of the exhaust pipe 520 through the openings. One end of the return pipe 516 has a notch, and the interior of the return pipe 516 is connected to the interior of the long conduit 517 through the notch, thus maintaining communication between the interiors of the air inlet pipe 513, the elbow pipe 514, the blower 515, the return pipe 516, the long conduit 517, and the valve 518. The openings of the heat insulation cylinder 5 and the notch of the return pipe 516 form a complete airflow path, allowing the air inlet pipe 513, the elbow pipe 514, the blower 515, the return pipe 516, the long conduit 517, and the interior space of the heat insulation cylinder 5 to communicate with each other. Depending on the opening and closing state of the valve, two flow modes are realized: closed-loop airflow and open-loop exhaust airflow, to match different heating requirements.

[0028] In this invention, a metal cylinder 54 is movably fitted inside an insulation cylinder 5, dividing the space inside the insulation cylinder 5 into two nested heating spaces. A heating column 55 is embedded in the two heating spaces and is fixed through the through-hole 524 of the metal cylinder 54. The metal cylinder 54 divides the space into two layers, allowing for layered air heating and heat conduction. The heating column 55 is arranged across the layers and fixed through the through-hole 524, providing heat to both spaces simultaneously, ensuring uniform temperature in both spaces and improving the overall heating effect.

[0029] In this invention, the notched ring 53 has a notch, and the notches of the two heating spaces are connected. The interior of the air inlet pipe 513 is connected to one of the heating spaces, and the interior of the exhaust pipe 520 is connected to the other heating space. The two sides of the multiple metal plates 56 are respectively fixedly disposed on the outer surface of the material cylinder 4 and the inner wall of the heat insulation cylinder 5. The multiple metal plates 56 are disposed inside one of the heating spaces. The notch of the notched ring 53 enables airflow between the two heating spaces inside the heat insulation cylinder 5 and regulates the airflow direction. The metal plates 56 are mounted in the heating space to enhance heat conduction efficiency and accelerate the heating speed of the material cylinder 4.

[0030] In this invention, the expansion coefficient of the active sheet 510 is greater than that of the passive layer 511. The active sheet 510 and the passive layer 511 are in an arc shape and are closely fitted to form a bimetallic sheet. The bimetallic sheet is arranged around the outer surface of the barrel 4. The thermal conductivity of the heat insulation cylinder 5 is less than 0.03 W / (m·K). The heat-conducting ring 52, the notched ring 53, the barrel 4, and the metal cylinder 54 are all made of metal. Due to the difference in expansion coefficients, the active sheet 510 and the passive layer 511 produce different deformations after being heated, thereby adjusting their fit with the barrel 4 and controlling the heat conduction efficiency. The low thermal conductivity of the heat insulation cylinder 5 reduces heat loss. The metal heat-conducting ring 52, the notched ring 53, the barrel 4, and the metal cylinder 54 can quickly transfer heat energy, ensuring sensitive heating and temperature control response.

[0031] In this invention, the outer surface of the metal cover 57 is arc-shaped, and the thickness of the active plate 510 is greater than the thickness of the passive layer 511. The active plate 510 and the passive layer 511 are detachably and fixedly mounted on the outer surface of the metal cover 57 by a threaded bolt 512. The threaded bolt 512 moves through the middle of the active plate 510 and the passive layer 511. Both the active plate 510 and the passive layer 511 are located in the gap between the barrel 4 and the insulation cylinder 5. The arc-shaped metal cover 57 is adapted to the peripheral assembly structure, and the thickness difference further amplifies the deformation difference between the active plate 510 and the passive layer 511, improving the temperature control accuracy. The threaded bolt 512 realizes the stable assembly of the components, arranges the active plate 510 and the passive layer 511 in the peripheral gap of the barrel 4, shortens the heat conduction distance, and improves the heat conduction efficiency.

[0032] In this invention, the screw 8 is inserted into the inside of the barrel 4, the power output end of the power device 2 is fixed to the screw 8, and the other end of the barrel 4 is integrally formed to form an injection nozzle; the power device 2 directly drives the screw 8 to rotate and advance inside the barrel 4 to realize the conveying, stirring and pressurization of raw materials; the integrally formed injection nozzle at the end of the barrel 4 can stably output molten raw materials to ensure the injection molding quality.

[0033] In operation, firstly, current is supplied to multiple heating columns 55 via connecting wire 522. The heating columns 55 generate high-speed heating of the air in the two heating spaces. The blower 515 drives the air into the intake pipe 513. The air enters the heat insulation cylinder 5 through the intake pipe 513 and flows inside the heat insulation cylinder 5. Then, the air passes through the notch in the notch ring 53, entering from one heating space to the other, allowing the hot air to enter the metal cylinder 54. The air then flows back through the elbow pipe 514 and the return pipe 516 to the blower 515. Air circulates inside and outside the metal cylinder 54. During the airflow, the heat from the heating column 55 and the metal sheet 56 is carried away. The heat from the air is then conducted to the material cylinder 4, raising the temperature of the material cylinder 4 and heating the raw material inside. The raw material is poured into the feed hopper 3, which guides the raw material into the material cylinder 4. The power unit 2 drives the screw 8 to rotate inside the material cylinder 4. The rotation of the screw 8 stirs and conveys the raw material, which is heated and melted inside the material cylinder 4. Then, the screw 8 moves and pushes the raw material through the injection nozzle into the mold, completing the injection molding process. Heating adjustment, rapid heating mode, open valve 1 518, close valve 2 519 and valve 3 521, elbow pipe 514 and long pipe 517 are internally connected, air flows through blower 515, air inlet pipe 513, heat insulation cylinder 5, elbow pipe 514, valve 1 518, long pipe 517 and blower 515 to form a circulation flow, air flows in the gap between material cylinder 4 and metal cylinder 54, and then passes around metal cylinder 54 through the notch of notched ring 53, air flows in the gap between metal cylinder 54 and heat insulation cylinder 5, air flows inside and outside metal cylinder 54, air can heat active plate 510 and passive layer plate 511, bimetallic strip bends after being heated, after the air temperature rises to a certain extent, passive layer plate 511 is tightly attached to the surface of material cylinder 4, heat from heating column 55 is directly conducted to material cylinder 4 through metal cover 57, active plate 510 and passive layer plate 511, so that a large amount of heat can be conducted to material cylinder 4, which can quickly heat the heat inside material cylinder 4; Heating adjustment, slow heating mode, valve one 518 closed, air cannot flow inside the elbow pipe 514 and long pipe 517, valve two 519 and valve three 521 open, blower 515 is running, air is drawn into blower 515 through return pipe 516, air enters the interior of heat insulation cylinder 5 through air inlet pipe 513, air flows in the gap between metal cylinder 54 and material cylinder 4, air is heated by heating column 55, active plate 510, passive layer plate 511 and metal cover 57, hot air heats material cylinder 4, hot air is discharged through exhaust pipe 520, hot air cannot be recycled, the temperature of active plate 510 and passive layer plate 511 is insufficient, the bending degree of active plate 510 and passive layer plate 511 is insufficient, the passive layer plate 511 cannot be tightly attached to the surface of material cylinder 4, heat cannot be quickly conducted to material cylinder 4, material cylinder 4 can be slowly heated.

[0034] Feeding and starting: Pour the plastic granules into the feed hopper 3, and the material will fall naturally into the material cylinder 4; turn on the power, and the connecting wire 522 supplies power to the heating column 55. The heating column 55 starts to heat up, and at the same time, the blower 515 and the power unit 2 are started.

[0035] Rapid heating mode: When rapid heating is required upon initial startup, the operator opens valve 1 (518) and closes valves 2 (519) and 3 (521). Blower 515 drives air to circulate along blower 515 → air inlet pipe 513 → heating space inside heat insulation cylinder 5 → elbow pipe 514 → valve 1 (518) → long pipe 517 → return pipe 516 → blower 515. The circulating hot air heats the bimetallic strip. The active strip 510 has a larger deformation, causing the entire structure to bend so that the passive strip 511 is tightly attached to the outer wall of the barrel 4. Heat is quickly conducted to the barrel 4 through the metal cover 57 and the bimetallic strip, and the raw material melts rapidly.

[0036] Slow constant temperature operation: When the barrel temperature reaches the process requirements, switch modes: close valve 1 518, open valve 2 519 and valve 3 521; outside air enters the heating space for heat exchange through blower 515 and air inlet pipe 513, and the hot air after heat exchange is directly discharged from exhaust pipe 520 without recycling; the temperature of the bimetallic strip decreases, the deformation decreases, and it separates from the barrel 4. Heat is transferred slowly only through the air to achieve low-speed constant temperature heating and avoid overheating of the raw materials.

[0037] Injection Molding: The power unit 2 drives the screw 8 to rotate continuously, stirring and pushing the molten raw material. The raw material is finally extruded from the injection nozzle at the end of the barrel 4 and enters the mold to complete the injection molding operation.

[0038] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A screw injection molding machine with constant temperature heating of the barrel, characterized in that: include: The side of the injection molding device (1) is detachably fixed with a feed hopper (3). The top of the power unit (2) is fixedly installed at the bottom of the injection molding device (1); The bottom of the barrel (4) is fixedly installed on the top of the injection molding device (1); Heating mechanism, which is nested on the outer surface of the material cylinder (4); Vertical rods (6), one end of multiple vertical rods (6) is fixedly set on the outer surface of the heating mechanism; Placement plate (7) is fixedly installed at the other end of multiple vertical rods (6); The bottom of the screw (8) is located at the top of the injection molding device (1); The heating mechanism includes: A heat insulation cylinder (5) is nested on the outer surface of the material cylinder (4); Heat insulation rings (51), two heat insulation rings (51) are respectively fixedly sleeved on the inner sides of both ends of the heat insulation cylinder (5); A heat-conducting ring (52) is fixedly disposed on the outer surface of the heat-conducting ring (5) on the inner wall of the heat insulation cylinder (5); A notched ring (53) is fixedly disposed on the outer surface of the notched ring (5) to the inner wall of the heat insulation cylinder (5); The metal cylinder (54) has its two ends fixed through the middle of the heat-conducting ring (52) and the notched ring (53), respectively. Heating columns (55), multiple heating columns (55) are fixed through and fixed in the metal cylinder (54) and the heat insulation cylinder (5).

2. A screw injection molding machine with constant temperature heating of the barrel according to claim 1, characterized in that, The heating mechanism further includes: Metal sheets (56), multiple metal sheets (56) are respectively fixedly disposed on the outer surface of the heating column (55); A metal cap (57) is fixedly sleeved on the end of the heating column (55); The extension edge (58) is integrally formed and fixedly installed on the outer surface of the metal cover (57); A threaded hole (59) is provided with its opening located between the metal cap (57) and the extension edge (58); Active plate (510), which is detachably and fixedly mounted on the outer surface of metal cover (57); The passive layer (511) is fixed to the outer surface of the active layer (510) by rivets.

3. A screw injection molding machine with constant temperature heating of the barrel according to claim 2, characterized in that, The heating mechanism further includes: Threaded bolt (512), the threaded bolt (512) is threaded into the threaded hole (59) in the middle of the metal cap (57); An air inlet pipe (513) is fixedly installed on the outer surface of the heat insulation cylinder (5) at one end; Elbow pipe (514), one end of elbow pipe (514) is fixedly installed on the outer surface of heat insulation cylinder (5); Blower (515), the air outlet of blower (515) is nested at the other end of air inlet pipe (513); A return pipe (516) is nested on the air inlet of the blower (515); A long conduit (517) is fixed at one end to the outer surface of the return pipe (516).

4. A screw injection molding machine with constant temperature heating of the barrel according to claim 3, characterized in that, The heating mechanism further includes: Valve 1 (518) has two ends nested in the other end of the long conduit (517) and the elbow (514), respectively; Valve 2 (519) is nested at the end of the return pipe (516); An exhaust pipe (520) is fixedly installed on the outer surface of the heat insulation cylinder (5) at one end; Valve three (521) is nested at the other end of the exhaust pipe (520); Connecting wires (522), multiple connecting wires (522) are electrically connected to the ends of the heating column (55); An insert (523) is provided at the end of the heating column (55); Through-hole (524), multiple through-holes (524) are set in the metal cylinder (54).

5. A screw injection molding machine with constant temperature heating of the barrel according to claim 4, characterized in that, The heat insulation cylinder (5) has openings at both ends, and the interior of the heat insulation cylinder (5) is connected to the interior of the air inlet pipe (513) through the openings. The interior of the heat insulation cylinder (5) is connected to the interior of the exhaust pipe (520) through the openings. One end of the return pipe (516) has an opening with a notch, and the interior of the return pipe (516) is connected to the interior of the long conduit (517) through the notch, so that the interiors of the air inlet pipe (513), elbow pipe (514), blower (515), return pipe (516), long conduit (517) and valve (518) are connected.

6. A screw injection molding machine with constant temperature heating of the barrel according to claim 5, characterized in that, The metal cylinder (54) is movably sleeved inside the heat insulation cylinder (5). The metal cylinder (54) divides the space inside the heat insulation cylinder (5) into two mutually nested heating spaces. The heating column (55) is embedded in the two heating spaces and is fixed through the through-hole (524) of the metal cylinder (54).

7. A screw injection molding machine with constant temperature heating of the barrel according to claim 6, characterized in that, The notched ring (53) has a notch, and the notches of the two heating space notched rings (53) are connected. The interior of the air inlet pipe (513) is connected to one of the heating spaces, and the interior of the exhaust pipe (520) is connected to the other heating space. The two sides of the multiple metal plates (56) are respectively fixed on the outer surface of the material cylinder (4) and the inner wall of the heat insulation cylinder (5), and the multiple metal plates (56) are set inside one of the heating spaces.

8. A screw injection molding machine with constant temperature heating of the barrel according to claim 7, characterized in that, The expansion coefficient of the active sheet (510) is greater than that of the passive layer (511). The active sheet (510) and the passive layer (511) are in an arc shape and are attached to form a bimetallic sheet. The bimetallic sheet is arranged around the outer surface of the barrel (4). The thermal conductivity of the heat insulation cylinder (5) is less than 0.03 W / (m・K). The heat conduction ring (52), the notched ring (53), the barrel (4) and the metal cylinder (54) are all made of metal.

9. A screw injection molding machine with constant temperature heating of the barrel according to claim 8, characterized in that, The outer surface of the metal cover (57) is arc-shaped. The thickness of the active plate (510) is greater than the thickness of the passive plate (511). The active plate (510) and the passive plate (511) are detachably fixed on the outer surface of the metal cover (57) by a threaded bolt (512). The threaded bolt (512) moves through the middle of the active plate (510) and the passive plate (511). The active plate (510) and the passive plate (511) are both located in the gap between the material cylinder (4) and the heat insulation cylinder (5).

10. A screw injection molding machine with constant temperature heating of the barrel according to claim 9, characterized in that, The screw (8) is inserted into the inside of the barrel (4), the power output end of the power device (2) is fixed to the screw (8), and the other end of the barrel (4) is integrally molded and closed to form an injection nozzle.

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