A pipe injection molding equipment and process

Abstract

The invention discloses a pipe injection molding device and process, belonging to the technical field of pipeline production. The pipe injection molding device comprises: a mold frame; a lower mold, comprising a lower mold base and a lower mold core, the lower mold base has an embedding opening on both sides and a first placement groove inside; an upper mold, comprising an upper mold base and an upper mold core; a core pulling block, which is installed in the embedding opening and has a tube core; a driving part, which is respectively installed on the upper mold and the mold frame. When the upper mold moves downward, the L-shaped pressure rod contacts the roller and transmits the pressure to the core pulling block through the push rod. The core pulling block pushes the wedge block downward, so that a filling gap is left between the lower mold core and the tube core, and the first spring is compressed. When the upper mold continues to move downward and fits the lower mold, the core pulling block is fully extended to form a closed injection molding space. The plastic melt fills the cavity to form a pipe. When the upper mold moves upward, the L-shaped pressure rod is away from the roller, the push rod stops applying force, the core pulling block is reset under the action of the first spring, the lower mold core is ejected, and the pipe is demolded.

Description

Technical Field

[0001] The invention relates to the technical field of pipe production, and in particular to a pipe injection molding device and process. Background Art

[0002] With the increasing global awareness of environmental protection and the increasing demand for resource recycling, the recycling of waste plastics has become one of the important topics in the plastic processing industry. After proper treatment, waste plastics can not only reduce environmental pollution, but also reduce the cost of new materials, achieving a win-win situation in economic and social benefits.

[0003] At present, the recycling and reuse of waste plastics mainly focuses on simple regeneration granulation and secondary processing. Although these methods can alleviate the environmental pressure caused by waste plastics to a certain extent, when applied to the production of high-demand pipes, the poor melt fluidity of recycled plastics and the large performance differences between different batches bring challenges to the setting of injection molding process parameters.

[0004] Especially during the injection molding process, the strong adhesion between the tube and the mold surface makes demoulding difficult, which not only affects production efficiency but also may lead to a decrease in the surface quality of the product. Summary of the invention

[0005] The purpose of the present invention is to solve the problem in the prior art that the adhesion between the pipe and the mold surface is strong, resulting in difficulty in demoulding, which not only affects the production efficiency but also may cause the surface quality of the product to deteriorate, and to propose a pipe injection molding equipment and process.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A pipe injection molding equipment comprises: a mold frame; a lower mold, which is installed on the mold frame by bolts, and comprises a lower mold base and a lower mold core, the lower mold base has embedding openings on both sides, and has a first placement groove inside, and the lower mold core is slidably installed in the placement groove; an upper mold, which is slidably installed on the mold frame by a telescopic member, and comprises an upper mold base and an upper mold core, the upper mold base has a second placement groove corresponding to the first placement groove inside, and the upper mold core is installed in the second placement groove; a core pulling block, which is slidably installed in the embedding opening and has a pipe core; a driving part, which is respectively installed on the upper mold and the mold frame, and is used to push the core pulling block to fit tightly with the lower mold to form a complete pipe injection mold.

[0008] When the upper mold moves downward and closes with the lower mold, the core pulling block will push the wedge block downward along the inclined surface, driving the lower mold core as a whole to move downward in the first placement groove, so that a gap for filling is left between the casting surface of the lower mold core and the tube core, thereby realizing the forming of the tube. Preferably, the core pulling block has an inclined surface near the bottom surface of the first placement groove, and wedge blocks are fixedly installed on both sides of the lower mold core, and the wedge blocks are in contact with the inclined surfaces.

[0009] In order to facilitate the demolding of the tube when the upper mold moves upward during the mold opening process, the contact between the wedge block and the inclined surface disappears, the first spring returns to its original state, and the lower mold core is ejected, thereby facilitating the demolding of the tube, further, the wedge block has an extension end, the mold frame has a receiving groove for accommodating the extension end, one end of the extension end located in the receiving groove is fixedly mounted with a pressure plate, the extension end is movably mounted with a first spring, and the two ends of the first spring are respectively fixedly connected to the pressure plate and the bottom surface of the groove of the receiving groove.

[0010] In order to convert the force transmitted by the roller into a driving force for the core pulling block, the core pulling block slides along the linear groove until the core pulling block is completely in contact with the lower mold to form a closed injection space. Furthermore, the driving part includes an L-shaped pressure rod, a mounting seat, a roller and a push rod. The L-shaped pressure rod is fixed to the upper mold, the mounting seat is fixedly mounted on the mold frame, the roller is rotatably mounted in the mounting seat, the L-shaped pressure rod can abut against the roller, and the two ends of the push rod are rotatably connected to the roller and the core pulling block respectively.

[0011] In order to ensure that the core pulling block can slide smoothly during the movement and maintain the linearity of its movement trajectory, further, a linear groove is opened on the inner side wall of the first placement groove, and the core pulling block is slidably installed in the linear groove.

[0012] In order to ensure accurate alignment during the mold closing process, further, a guide shaft is fixedly installed on a surface of the upper mold close to the lower mold, and a guide hole is correspondingly opened on the lower mold.

[0013] In order to minimize the mutual impact force between the upper and lower molds when closing the molds, effectively ensure that the mold will not be damaged by impact during the closing process, reduce impact vibration, and increase service life, further, a slide plate is slidably installed in the guide hole, a first airbag is installed between the slide plate and the bottom surface of the guide hole, and a second spring is fixedly installed in the first airbag.

[0014] In order to maintain the stability of the roller during the injection molding process and further form a closed injection molding space, further, a second airbag is fixedly mounted on the mounting seat, and an air pipe is fixedly connected between the second airbag and the first airbag.

[0015] In order to accelerate the curing speed of the plastic product and thus realize rapid molding, further, the lower mold and the upper mold are both provided with water channels and water inlet pipes and water outlet pipes for water circulation inside the water channels.

[0016] A pipe injection molding process mainly includes the following steps:

[0017] S1: Mold preheating. Before injection molding, ensure that the mold is in a preheated state to reduce the temperature difference between the mold and the molten plastic.

[0018] S2: Prepare the cooling system, connect the water inlet and outlet pipes, and ensure the normal operation of the cooling water circulation system;

[0019] S3: Plastic melting, the plastic raw material is passed through a heating device to reach a molten state;

[0020] S4: Injection molding, where molten plastic is injected into a mold under high pressure;

[0021] S5: Cooling molding. When the plastic enters the mold, cooling water enters the water channel inside the mold through the water inlet pipe and begins circulating cooling. The cooling water takes away the heat of the mold, accelerates the solidification of the plastic, and forms a pipe.

[0022] S6: Uniform temperature, cooling water circulates inside the mold to ensure uniform temperature of all parts of the mold;

[0023] S7: Mold opening and demoulding, the upper mold moves upward, the mold opens, and the product is taken out of the mold.

[0024] Compared with the prior art, the present invention provides a pipe injection molding device and process, which has the following beneficial effects:

[0025] 1. For the pipe injection molding equipment, when the upper mold moves downward, the L-shaped pressure rod contacts the roller and transmits the pressure to the core pulling block through the push rod. The core pulling block pushes the wedge block downward, leaving a filling gap between the lower mold core and the tube core, and the first spring is compressed. When the upper mold continues to move downward and fits with the lower mold, the core pulling block is fully extended to form a closed injection molding space. The plastic melt fills the cavity to form a pipe. When the upper mold moves upward, the L-shaped pressure rod moves away from the roller, the push rod stops applying force, the core pulling block resets under the action of the first spring, and the lower mold core is ejected, which is convenient for the demolding of the pipe. Through mechanical linkage, efficient and automated molding is achieved, improving quality and production efficiency;

[0026] 2. In the pipe injection molding equipment, when the upper mold moves downward, the guide shaft is inserted into the guide hole and presses the slide plate, which applies pressure to the first airbag. The air in the first airbag cushions the movement of the slide plate, so that the upper mold and the lower mold contact more slowly, reducing the impact force, preventing mold damage and reducing vibration, thereby increasing the service life. At the same time, the air in the first airbag is squeezed into the second airbag, which expands and presses against the roller to maintain the stability of the roller during the injection molding process, further forming a closed injection molding space. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a schematic diagram of the structure of the pipe injection molding equipment proposed by the present invention;

[0028] Figure 2 A schematic diagram of the partial structure of the upper die base of the pipe injection molding equipment proposed by the present invention;

[0029] Figure 3 A schematic diagram of the partial structure of the upper die base of the pipe injection molding equipment proposed by the present invention;

[0030] Figure 4 This is a schematic diagram of the internal structure of the guide hole of the pipe injection molding equipment proposed by the present invention;

[0031] Figure 5 This is a schematic diagram of the structure of the driving part of the pipe injection molding equipment proposed by the present invention;

[0032] Figure 6 This is a schematic diagram of the mounting base structure of the pipe injection molding equipment proposed by the present invention.

[0033] In the figure: 100, mold frame; 110, receiving groove; 200, lower mold; 210, lower mold base; 211, embedding port; 201, linear groove; 212, first placement groove; 220, lower mold core; 221, wedge block; 222, extension end; 223, pressing plate; 224, first spring; 230, guide hole; 240, slide plate; 250, first airbag; 251, air pipe; 260, second Spring; 300, upper mold; 310, upper mold base; 311, second placement groove; 320, upper mold core; 330, guide shaft; 400, core pulling block; 410, tube core; 420, inclined surface; 500, driving unit; 510, L-shaped pressure rod; 520, roller; 530, push rod; 540, mounting seat; 541, second airbag; 600, waterway; 610, water inlet pipe; 620, water outlet pipe. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0035] In the description of the present invention, it is necessary to understand that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0036] Embodiment 1:

[0037] Reference Figure 1-6 , which is the first embodiment of the present invention, provides a pipe injection molding device, through which high efficiency of pipe molding is achieved, including a mold frame 100, a lower clamping mold 200, an upper clamping mold 300, a core pulling block 400 and a driving unit 500.

[0038] Specifically, the lower clamping mold 200 is installed on the mold frame 100 by bolts, and includes a lower mold base 210 and a lower mold core 220. The lower mold base 210 has embedding openings 211 on both sides and a first placement groove 212 inside. The lower mold core 220 is slidably installed in the first placement groove 212.

[0039] Specifically, the upper mold 300 is slidably installed on the mold frame 100 through a telescopic part. Optionally, the telescopic part is a cylinder, and together with the lower mold 200, forms a complete mold, including an upper mold base 310 and an upper mold core 320. The upper mold base 310 has a second placement groove 311 corresponding to the first placement groove 212, and the upper mold core 320 is installed in the second placement groove 311.

[0040] Specifically, the core-pulling block 400 is slidably installed in the embedding port 211 and has a tube core 410 to form an internal cavity of the tube.

[0041] Better, refer to Figure 5 The core pulling block 400 is a rectangular structure as a whole, and the bottom surface of the groove of the core pulling block 400 close to the first placement groove 212 has an inclined surface 420, and this inclined surface 420 is for cooperating with the lower mold core 220. Wedge blocks 221 are fixedly installed on both sides of the lower mold core 220, and the wedge blocks 221 abut against the inclined surface 420. When the upper mold 300 moves downward and closes with the lower mold 200, the core pulling block 400 will push the wedge block 221 to move downward along the inclined surface 420, driving the lower mold core 220 to move downward in the first placement groove 212 as a whole, so that a gap for filling is left between the casting surface of the lower mold core 220 and the tube core 410, thereby realizing the molding of the tube, and in order to ensure that the core pulling block 400 can slide smoothly during the movement and maintain the linearity of its movement trajectory, a straight groove 201 is opened on the inner side wall of the first placement groove 212, and the core pulling block 400 is slidably installed in the straight groove 201.

[0042] Furthermore, when the upper mold 300 moves downward and closes with the lower mold 200, the core pulling block 400 will push the wedge block 221 to move downward along the inclined surface 420. Since the wedge block 221 has an extension end 222, the mold frame 100 has a receiving groove 110 inside to accommodate the extension end 222. One end of the extension end 222 located in the receiving groove 110 is fixedly installed with a pressure plate 223, and a first spring 224 is movably installed on the extension end 222. The two ends of the first spring 224 are fixedly connected to the pressure plate 223 and the bottom surface of the receiving groove 110 respectively. At this time, the first spring 224 is compressed. When the upper mold 300 continues to move downward and is completely fitted with the lower mold 200, the core pulling block 400 is fully extended to form an inner cavity of the tube. During the mold opening process, when the upper mold 300 moves upward, the contact between the wedge block 221 and the inclined surface 420 disappears, and the first spring 224 returns to its original state, ejecting the lower mold core 220, thereby facilitating the demolding of the tube, and having good flexibility and applicability.

[0043] Specifically, the driving unit 500 is respectively installed on the upper clamping mold 300 and the mold frame 100, and is used to push the core-pulling block 400 to be close to the lower clamping mold 200 to form a complete pipe injection mold.

[0044] Better, refer to Figure 5 The driving part 500 includes an L-shaped pressure rod 510, a mounting seat 540, a roller 520 and a push rod 530. The L-shaped pressure rod 510 is fixed to the upper mold 300, the mounting seat 540 is fixedly mounted on the mold frame 100, and the roller 520 is rotatably mounted in the mounting seat 540. The L-shaped pressure rod 510 can abut against the roller 520 and apply pressure. The two ends of the push rod 530 are respectively rotatably connected to the roller 520 and the core pulling block 400, and the force transmitted by the roller 520 is converted into a driving force for the core pulling block 400, so that the core pulling block 400 slides along the linear groove 201 until the core pulling block 400 is completely close to the lower mold 200 to form a closed injection molding space.

[0045] By setting the above structure, when the upper mold 300 moves downward, the L-shaped pressure rod 510 gradually approaches and finally contacts the roller 520. After the roller 520 is pressed by the L-shaped pressure rod 510, the pressure is transmitted to the core-pulling block 400 through the push rod 530. The core-pulling block 400 pushes the wedge block 221 downward along the inclined surface 420, driving the lower mold core 220 to move downward in the first placement groove 212, so that a gap for filling is left between the casting surface of the lower mold core 220 and the tube core 410, and the first spring 224 is compressed. When the upper mold 300 continues to move downward and is completely fitted with the lower mold 200, the core-pulling block 400 is fully extended to form the inner cavity of the tube, and at the same time a closed In the closed injection molding space, the plastic melt enters the mold through the gate, fills the cavity formed by the lower mold core 220 and the core pull block 400, and forms a pipe. When the upper mold 300 moves upward, the L-shaped pressure rod 510 gradually moves away from the roller 520, and the roller 520 loses the pressure from the L-shaped pressure rod 510. The push rod 530 no longer applies thrust to the core pull block 400. After the wedge block 221 is separated from the inclined surface 420, the core pull block 400 is reset under the elastic force of the first spring 224, and the lower mold core 220 is ejected under the action of the first spring 224, which facilitates the demoulding of the pipe. Through precise mechanical linkage, high efficiency and automation in the process of pipe injection molding are achieved. Especially in terms of the control and reset of the core pull block 400, the cooperation of the first spring 224 and the wedge block 221 ensures the smooth sliding and accurate reset of the core pull block 400, thereby improving the quality and production efficiency of pipe molding.

[0046] Embodiment 2:

[0047] Reference Figure 1-6 , which is the second embodiment of the present invention. This embodiment is different from the first embodiment in that: this embodiment provides a pipe injection molding device, through which the durability of the upper clamping mold 300 and the lower clamping mold 200 is achieved.

[0048] Specifically, a guide shaft 330 is fixedly installed on one side of the upper mold 300 close to the lower mold 200, which is used to guide the vertical movement of the upper mold 300 to ensure accurate alignment during the mold closing process. A corresponding guide hole 230 is opened on the lower mold 200, and the guide shaft 330 passes through the guide hole 230 to ensure that the relative movement between the upper mold 300 and the lower mold 200 is smooth and accurate.

[0049] Better, refer to Figure 4 and Figure 6A slide plate 240 is slidably installed in the guide hole 230 and slides with the movement of the guide shaft 330 to reduce the direct contact between the guide shaft 330 and the guide hole 230, thereby reducing wear. A first airbag 250 is installed between the slide plate 240 and the bottom surface of the guide hole 230 to play a buffering role. A second spring 260 is fixedly installed in the first airbag 250 to provide additional elastic support, further enhance the buffering effect, reduce the impact of the impact on the mold, and can drive the first airbag 250 to reset.

[0050] Furthermore, a second airbag 541 is fixedly mounted on the mounting seat 540 , and an air pipe 251 is fixedly connected between the second airbag 541 and the first airbag 250 for balancing the air pressure between the two airbags.

[0051] When the upper mold 300 moves downward, the guide shaft 330 is inserted into the guide hole 230 and presses the slide plate 240. The slide plate 240 applies false pressure to the first air bag 250, and the air in the first air bag 250 applies a buffering force to the slide plate 240, so that the contact between the upper mold 300 and the lower mold 200 is slower, which can ensure that the mutual impact force between the upper mold 300 and the lower mold 200 is minimized when the upper mold 300 and the lower mold 200 are molded, effectively ensuring that the mold will not be damaged by impact during the mold closing process, and reducing impact vibration and improving the service life; at the same time, further, when the air in the first air bag 250 enters the second air bag 541 through squeezing, the second air bag 541 expands and presses against the roller 520, maintaining the stability of the roller 520 during the injection molding process, and further forming a closed injection molding space.

[0052] Embodiment 3:

[0053] Reference Figure 1-6 , which is the third embodiment of the present invention. This embodiment is different from the second embodiment in that: this embodiment provides a pipe injection molding device, through which rapid prototyping of pipes is achieved.

[0054] Specifically, refer to Figure 2 The lower mold 200 and the upper mold 300 are both provided with a water channel 600 and an inlet pipe 610 and an outlet pipe 620 for water circulation inside the water channel 600, which are used to cool the mold and accelerate the curing speed of the plastic product, thereby realizing rapid molding. Optionally, the water channel 600 can be designed to be distributed in a mesh to ensure uniform cooling of all parts of the mold.

[0055] When rapid prototyping is required, cooling water enters the water channel 600 inside the mold through the water inlet pipe 610. The cooling water circulates in the water channel 600, taking away the heat from the mold and accelerating the solidification process of the plastic. The circulation of cooling water inside the mold ensures that the temperature of various parts of the mold is uniform, avoiding product quality problems caused by uneven temperature. The cooled water is discharged from the mold through the water outlet pipe 620 and returned to the external cooling system. The discharged water can be re-cooled by a cooling tower or other cooling device and then introduced into the mold again through the water inlet pipe 610 to form a closed-loop circulation system.

[0056] A pipe injection molding process mainly includes the following steps:

[0057] S1: Mold preheating. Before injection molding, ensure that the mold is in a preheated state to reduce the temperature difference between the mold and the molten plastic.

[0058] S2: Cooling system preparation, connect the water inlet pipe 610 and the water outlet pipe 620, and ensure the normal operation of the cooling water circulation system;

[0059] S3: Plastic melting, the plastic raw material is passed through a heating device to reach a molten state;

[0060] S4: Injection molding. When the upper mold 300 moves downward, the L-shaped pressure rod 510 gradually approaches and finally contacts the roller 520. After the roller 520 is pressed by the L-shaped pressure rod 510, the pressure is transmitted to the core pulling block 400 through the push rod 530. The core pulling block 400 pushes the wedge block 221 downward along the inclined surface 420, driving the lower mold core 220 to move downward in the first placement groove 212, so that a gap for filling is left between the casting surface of the lower mold core 220 and the tube core 410. The first spring 224 is compressed. When the upper mold 300 continues to move downward and is completely fitted with the lower mold 200, the core pulling block 400 is fully extended to form the inner cavity of the tube and a closed injection molding space. In the closed injection molding space, the plastic melt enters the mold through the gate, fills the cavity formed by the lower mold core 220 and the core pulling block 400, and forms a tube.

[0061] S5: Cooling and molding. When the plastic enters the mold, cooling water enters the water channel 600 inside the mold through the water inlet pipe 610 to start circulating cooling. The cooling water takes away the heat of the mold, accelerates the solidification of the plastic, and forms a pipe.

[0062] S6: Uniform temperature, cooling water circulates inside the mold to ensure uniform temperature of all parts of the mold;

[0063] S7: Mold opening and demoulding. When the upper mold 300 moves upward, the L-shaped pressure rod 510 gradually moves away from the roller 520. The roller 520 loses the pressure from the L-shaped pressure rod 510, and the push rod 530 no longer applies thrust to the core pulling block 400. After the wedge block 221 is separated from the inclined surface 420, the core pulling block 400 is reset under the elastic force of the first spring 224, and the lower mold core 220 is ejected under the action of the first spring 224, which facilitates the demoulding of the tube.

[0064] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A pipe injection molding device, characterized in that: include: Mould frame (100); The lower mold (200) is installed on the mold frame (100) by bolts, and comprises a lower mold base (210) and a lower mold core (220). The lower mold base (210) has an embedding opening (211) on both sides and a first placement groove (212) inside. The lower mold core (220) is slidably installed in the first placement groove (212); An upper mold (300) is slidably mounted on the mold frame (100) via a telescopic member, and comprises an upper mold base (310) and an upper mold core (320); the upper mold base (310) has a second placement groove (311) corresponding to the first placement groove (212) inside, and the upper mold core (320) is mounted in the second placement groove (311); A core-pulling block (400) is slidably mounted in the embedding opening (211) and has a tube core (410); A driving unit (500) is respectively mounted on the upper clamping mold (300) and the mold frame (100) and is used to push the core-pulling block (400) to be in close contact with the lower clamping mold (200) to form a complete tube injection mold; The driving part (500) comprises an L-shaped pressure rod (510), a mounting seat (540), a roller (520) and a push rod (530); the L-shaped pressure rod (510) is fixed to the upper clamping mold (300); the mounting seat (540) is fixedly mounted on the mold frame (100); the roller (520) is rotatably mounted in the mounting seat (540); the L-shaped pressure rod (510) can abut against the roller (520); and the two ends of the push rod (530) are rotatably connected to the roller (520) and the core-pulling block (400) respectively; A guide shaft (330) is fixedly mounted on a surface of the upper clamping mold (300) close to the lower clamping mold (200), and a guide hole (230) is correspondingly provided on the lower clamping mold (200); A slide plate (240) is slidably installed in the guide hole (230), a first air bag (250) is installed between the slide plate (240) and the bottom surface of the guide hole (230), and a second spring (260) is fixedly installed in the first air bag (250); A second airbag (541) is fixedly mounted on the mounting seat (540), and an air pipe (251) is fixedly connected between the second airbag (541) and the first airbag (250).

2. A pipe injection molding device according to claim 1, characterized in that: The bottom surface of the core-pulling block (400) close to the first placement groove (212) has an inclined surface (420), and wedge blocks (221) are fixedly installed on both sides of the lower mold core (220), and the wedge blocks (221) are in contact with the inclined surface (420).

3. A pipe injection molding device according to claim 2, characterized in that: The wedge block (221) has an extension end (222), and the mold frame (100) has an interior containing groove (110) capable of accommodating the extension end (222). One end of the extension end (222) located in the containing groove (110) is fixedly mounted with a pressing plate (223), and a first spring (224) is movably mounted on the extension end (222), and two ends of the first spring (224) are respectively fixedly connected to the pressing plate (223) and the bottom surface of the groove of the containing groove (110).

4. The pipe injection molding equipment according to claim 1, characterized in that: A linear groove (201) is provided on the inner side wall of the first placement groove (212), and the core pulling block (400) is slidably installed in the linear groove (201).

5. The pipe injection molding equipment according to claim 1, characterized in that: The lower clamping mold (200) and the upper clamping mold (300) are both provided with a water channel (600) and a water inlet pipe (610) and a water outlet pipe (620) for circulating water inside the water channel (600).

6. A pipe injection molding process, using a pipe injection molding device according to any one of claims 1 to 5, characterized in that: The main steps include: S1: Mold preheating. Before injection molding, ensure that the mold is in a preheated state to reduce the temperature difference between the mold and the molten plastic. S2: Prepare the cooling system, connect the water inlet pipe (610) and the water outlet pipe (620), and ensure the normal operation of the cooling water circulation system; S3: Plastic melting, the plastic raw material is passed through a heating device to reach a molten state; S4: Injection molding, where molten plastic is injected into a mold under high pressure; S5: Cooling and molding. When the plastic enters the mold, cooling water enters the water channel (600) inside the mold through the water inlet pipe (610) to start circulating cooling. The cooling water takes away the heat of the mold, accelerates the solidification of the plastic, and forms a pipe. S6: Uniform temperature, cooling water circulates inside the mold to ensure uniform temperature of all parts of the mold; S7: Mold opening and demoulding, the upper mold (300) moves upward, the mold opens, and the product is taken out of the mold.

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