Hot runner injection mold with adjustable runner size

Abstract

The invention belongs to the technical field of injection molding, and particularly relates to a hot runner injection mold with an adjustable runner size. According to the invention, the die assembly is sleeved with the girdling assembly, and the girdling assembly surrounds the die assembly gap of the die assembly. Besides, the annular cutting blades are further arranged at the positions, surrounding the mold closing assembly, of the annular cutting assembly and the mold closing gap, the annular cutting assembly can move along the mold closing gap, and burrs existing at the mold closing gap are automatically cut off in the moving process. In this way, after injection molding of the plastic part is completed, the girdling assembly can immediately cut off burrs generated in the mold closing gap. By the adoption of the structural design, the defects of low efficiency and the like in a traditional manual cutting mode can be overcome, and the injection molding part body can be prevented from being scratched.

Description

Technical Field

[0001] This invention belongs to the field of injection molding technology, specifically relating to a hot runner injection mold with adjustable runner size. Background Technology

[0002] Hot runner injection molding is an advanced injection molding technology that integrates a heating system, such as hot nozzles, manifolds, and temperature control units, into the mold to keep the plastic in the gating system in a molten state at all times, thus eliminating the need to remove the solidified material from the runner during the molding process. Typically, hot runner injection molds are mounted on an injection molding machine and connected to the injection unit to achieve the delivery and injection of molten plastic.

[0003] In related technologies, the principle of adjustable hot runner size is achieved by controlling the injection quantity and injection time, thereby realizing an effect similar to changing the runner size. For example, the opening and closing of the gate and the degree of opening can be controlled by moving the needle valve, thus adjusting the effective size of the runner. Alternatively, heating elements can be used to precisely control the temperature of the molten plastic within the runner, thereby affecting its flow properties by changing its viscosity, ultimately achieving control over the effective size of the runner.

[0004] In practical applications, burrs often form at the mold closing gap of hot runner injection molds. These burrs typically need to be removed manually with hand-held tools after mold opening. This method is not only time-consuming and labor-intensive but also inefficient. Furthermore, it is prone to scratching the surface of the injection molded part due to operational errors, thereby damaging the product. Summary of the Invention

[0005] The purpose of this invention is to provide a hot runner injection mold with adjustable runner size to solve the problem of low burr removal efficiency in injection molded parts in related technologies.

[0006] The specific technical solution adopted by this invention is as follows: A hot runner injection mold with adjustable runner size includes: a base, a horizontal injection assembly, a mold clamping assembly, an adjustable runner mechanism, and a ring cutting assembly; Both the horizontal injection assembly and the mold clamping assembly are assembled on the top of the base. The horizontal injection assembly is used to convey molten plastic, and the mold clamping assembly is used to form the injection cavity. The adjustable flow channel mechanism is integrated into the mold clamping assembly and is used to precisely adjust the effective cross-sectional area of ​​the hot flow pipe. The ring-cutting component surrounds the mold-closing gap of the mold-closing component and is used to automatically remove the burrs at the mold-closing gap after injection molding.

[0007] In some possible implementations, the mold closing assembly includes a fixed mold unit, a moving mold unit, and a mold closing drive device; The fixed mold unit includes a fixed template and a fixed mold; the fixed mold is fixedly disposed on the side of the fixed template facing the moving mold unit; The moving mold unit includes a moving template, a moving mold, and a guide rod. The moving mold is fixedly disposed on the side of the moving template facing the fixed mold. One end of the guide rod is fixed to the fixed template, and the other end is slidably engaged with the moving template. The mold closing drive device is fixed to the top of the base, and its drive end is fixedly connected to the moving mold plate, which is used to drive the moving mold to move towards the fixed mold and close the mold to form an injection cavity.

[0008] In some possible implementations, the circumferential cutting assembly includes a rectangular frame fitted around the outside of the fixed mold, the inner diameter of the rectangular frame being larger than the outer diameter of the fixed mold, and straight blades being fixedly connected to its four inner surfaces near the fixed mold, with the cutting edges of each straight blade facing the mold-closing gap between the fixed mold and the moving mold.

[0009] In some possible implementations, the circumferential cutting assembly further includes a drive cylinder positioned transversely inside the fixed template, with its drive end fixedly connected to the rectangular frame. The drive cylinder is used to push the rectangular frame to move along the length direction of the fixed mold and the moving mold, and to remove the burrs from the mold closing gap by means of each of the straight blades.

[0010] In some possible implementations, the rectangular frame consists of four straight tubes and four right-angle connectors, with the four straight tubes and the right-angle connectors connected by a threaded seal to form a square frame; each straight tube has a right-angle connecting plate fixedly connected to the surface of the fixed mold, and the right-angle connecting plate is fixedly connected to the straight blade.

[0011] Each of the right-angle connecting plates has a positioning hole reserved along the thickness direction, and each of the straight blades has multiple through holes along the thickness direction. An external hexagonal bolt is inserted through the positioning hole and the through hole. The end of the external hexagonal bolt is used to fix the straight blade to the inner surface of the right-angle connecting plate by a fastening nut.

[0012] In some possible implementations, each of the through holes is a straight slot hole that extends along the width direction of the straight blade and is used to adjust the length by which the cutting edge of the straight blade extends outward relative to the right-angle connecting plate.

[0013] In some possible implementations, a return spring is also fitted around the stud of the external hexagonal bolt. The return spring is located between the right-angle connecting plate and the straight blade, and is used to buffer the impact force when the straight blade removes burrs.

[0014] In some possible implementations, one end of the cutting edge of each of the straight blades is bent to form a right-angled bend, which is used to avoid the external hexagonal bolt so that its cutting edge is in clearance fit with the surface of the fixed mold.

[0015] In some possible implementations, a dry ice-assisted cleaning unit is also included, which includes a dry ice cleaner, a gas supply line, and multiple nozzles. The gas supply pipeline is integrated inside the straight pipe of the rectangular frame, and the nozzles are evenly distributed on the side of the straight pipe facing the mold gap and are connected to the gas supply pipeline.

[0016] In some possible implementations, the axes of each nozzle are inclined toward the mold gap, and their axes form a predetermined angle with the axis of the straight tube.

[0017] The technical effects achieved by this invention are as follows: This invention features a circumferential cutting component mounted on the outer sleeve of a mold-closing assembly, surrounding the mold-closing gap. Furthermore, the circumferential cutting component is equipped with circumferential cutting blades around the mold-closing assembly and the mold-closing gap. The circumferential cutting component can move along the mold-closing gap and automatically remove burrs present during its movement. Thus, after the plastic part is injection molded, the circumferential cutting component can immediately remove the burrs generated in the mold-closing gap. This structural design not only overcomes the inefficiencies of traditional manual removal methods but also avoids scratching the injection-molded part. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of a hot runner injection mold with adjustable flow channel size provided in an embodiment of the present invention; Figure 2 yes Figure 1 A schematic diagram of the side structure; Figure 3 yes Figure 1 Assembly diagram of the fixed mold and the moving mold; Figure 4 yes Figure 3 A schematic diagram of the side structure; Figure 5 yes Figure 3 Assembly diagram of the rectangular frame with the fixed mold and the moving mold; Figure 6 yes Figure 1 Assembly diagram of the rectangular frame, fixed mold, and fixed template; Figure 7 for Figure 1 Assembly diagram of the central drive cylinder and the rectangular frame; Figure 8An exploded view of the assembly of a rectangular frame and a straight blade in a hot runner injection mold with adjustable runner size, provided for another embodiment of the present invention. Figure 9 for Figure 8 Assembly diagram of the straight blade and the right-angle connecting plate; Figure 10 for Figure 9 A schematic diagram of the side structure; Figure 11 A schematic diagram of the back structure of a straight blade of a hot runner injection mold with adjustable flow channel size, provided for another embodiment of the present invention.

[0019] Figure 12 A schematic diagram of the assembly of a ring-cutting component and a dry ice jet blocking frame for a hot runner injection mold with adjustable runner size, provided for another embodiment of the present invention. Figure 13 for Figure 12 Assembly diagram of the central ring cutting component, dry ice spray blocking frame, and waste collection channel.

[0020] The attached diagram lists the components represented by each number as follows: 100. Base; 110. Material cylinder; 120. Hopper; 130. Rotary drive device; 200. Determine the mold; 210. Determine the template; 300. Moving mold; 310. Moving template; 320. Guide rod; 330. Mold closing drive device; 400. Rectangular frame; 410. Straight pipe; 420. Right-angle connector; 430. Right-angle connecting plate; 431. Positioning hole; 500, straight blade; 510, through hole; 520, right-angle bent blade; 600, Drive cylinder; 610, Drive end; 700. External hex bolt; 710. Fastening nut; 720. Return spring; 800, Nozzle; 900. Dry ice spray blocking frame; 910. Square groove; 920. Waste collection channel. Detailed Implementation

[0021] To make the objectives and advantages of this invention clearer, the invention will be specifically described below with reference to embodiments. It should be understood that the following text is merely used to describe one or more specific embodiments of the invention and does not strictly limit the scope of protection specifically claimed by the invention.

[0022] like Figure 1-7As shown, this embodiment of the invention provides a hot runner injection mold with adjustable runner size. The hot runner injection mold includes a base 100, a horizontal injection assembly, a mold closing assembly, a ring cutting assembly, and a drive cylinder 600. The base 100 is the load-bearing structure of the injection mold and can be integrally cast from ductile iron. A horizontal injection assembly is horizontally positioned on the top of the base 100, located on one side of the top of the base 100. The horizontal injection assembly includes a barrel 110, a hopper 120, and a screw. The barrel 110 is a cylindrical structure horizontally positioned on top of the base 100. A heating jacket is wound around the outside of the barrel 110 to heat and melt the plastic granules placed inside. Simultaneously, the barrel wall of the barrel 110 is also provided with a rock wool insulation layer to ensure that the temperature of the molten plastic does not escape.

[0023] A hopper 120 is vertically mounted on a barrel 110, serving to receive granular plastic and continuously feed the granules into the barrel 110. A feed valve may also be installed at the bottom of the hopper 120, allowing control over the speed at which the plastic granules enter the barrel 110. A screw is rotatably mounted inside the barrel 110, with one end connected to a rotary drive device 130 via a coupling, and a check ring at the end to prevent backflow of molten plastic. Driven by the rotary drive device 130, the screw shears and crushes the plastic granules within the barrel 110, melting them under the high temperature of the heating jacket for subsequent injection molding.

[0024] The mold clamping assembly consists of a fixed mold unit, a moving mold unit, and a mold clamping drive device 330. The fixed mold unit includes a fixed template 210 and a fixed mold 200. The fixed template 210 can be made of tempered 45# steel and is fixedly mounted on the top of the base 100 with anchor bolts. The fixed mold 200 is fixedly mounted on the side of the fixed template 210 facing the moving template 310 with hex socket head cap screws. The surface of the fixed mold 200 can be nitrided, and the size of its inwardly recessed cavity is customized according to the target injection molded part.

[0025] Similarly, the moving mold unit includes a moving template 310, a moving mold 300, and guide rods 320. The moving mold 300 is fixedly installed on the corresponding side of the moving template 310 by hexagonal socket head cap screws. The size of the moving template 310 is exactly the same as that of the fixed template 210. It achieves sliding engagement with the fixed template 210 through the guide rods 320 at the four corners to ensure that the moving mold 300 moves smoothly without deviation during the lateral movement.

[0026] The surface of the moving template 310 away from the moving mold 300 is fixedly connected to the drive end 610 of the mold closing drive device 330 fixed to the top of the base 100. The mold closing drive device 330 can drive the moving template 310 and the moving mold 300 to move towards the fixed mold 200 and achieve tight mold closing. The opposite sides of the fixed mold 200 and the moving mold 300 can jointly enclose to form an injection cavity. Furthermore, the surface of the fixed template 210 away from the moving template 310 is also connected to the end of the barrel 110 through the nozzle 800 to ensure that the molten plastic in the barrel 110 can be smoothly injected into the injection cavity.

[0027] Continue as Figures 5-7 As shown, surrounding the outside of the fixed mold 200, the present invention also includes a circumferential cutting component for automatically removing burrs at the mold closing gap. The circumferential cutting component consists of a rectangular frame 400 and multiple straight blades 500. The rectangular frame 400 is fitted around the outside of the fixed mold 200, with its inner diameter larger than the outer diameter of the fixed mold 200, forming a clearance fit. Straight blades 500 are fixedly mounted on the four surfaces of the rectangular frame 400 near the fixed mold 200, with the cutting edges of each blade 500 facing the mold closing gap between the fixed mold 200 and the moving mold 300.

[0028] In addition, a drive cylinder 600 is provided inside the fixed mold plate 210. The drive cylinder 600 is vertically disposed on the inner surface of the fixed mold plate 210, and the traveling direction of its drive end 610 is consistent with the length direction of the moving mold 300. The drive cylinder 600 is used to push the rectangular frame 400 to move along the length direction of the fixed mold 200 and the moving mold 300, and to remove the burrs in the mold closing gap through each straight blade 500.

[0029] To achieve precise adjustment of the hot runner size, an adjustable flow channel mechanism can be integrated inside the fixed template 210. This adjustable flow channel mechanism includes a needle valve assembly, a temperature control unit, and a drive assembly. The needle valve assembly includes a needle valve rod and a valve sleeve. The valve sleeve is fitted into a mounting hole in the middle of the fixed template 210 via an interference fit and communicates with the nozzle 800. The needle valve rod slides through the valve sleeve, and its end is connected to the drive assembly. The temperature control unit includes heating elements and temperature sensors distributed along the axial direction of the valve sleeve. Preferably, the heating elements can be electric heating wires. The valve sleeve has multiple equally spaced heating grooves along the axial direction. Resistance temperature sensors are embedded in the heating grooves to monitor the hot runner temperature in real time and provide feedback to the temperature controller. The drive assembly can be a servo motor to drive the needle valve rod to move axially and adjust the gap between the needle valve rod and the valve sleeve, thereby achieving adjustable hot runner size.

[0030] The adjustable flow channel mechanism described above is well known to those skilled in the art, and will not be described in detail here.

[0031] The following is combined Figures 1-7 The working principle and working process of the hot runner injection mold with adjustable flow channel size provided by the invention are described.

[0032] Working principle: After injection molding, the drive cylinder 600 can push the rectangular frame 400 and simultaneously drive multiple straight blades 500 to move along the mold closing direction. The blades of the straight blades 500 slide against the mold closing gap, thereby removing the burrs from the product surface.

[0033] Work process: The mold closing drive device 330 is activated, which pushes the moving mold plate 310 along the guide rod 320 toward the fixed mold plate 210 until the moving mold 300 and the fixed mold 200 are tightly fitted to form a closed injection cavity. At this time, the rectangular frame 400 of the ring cutting assembly is in its initial position, that is, located outside the fixed mold 200, and the cutting edges of the multiple straight blades 500 are all away from the mold closing gap.

[0034] After adding ABS plastic granules to the hopper 120, the feed valve is opened, and the plastic granules immediately enter the barrel 110. The heating jacket installed on the barrel 110 is activated to raise the temperature of the barrel 110 to the melting temperature of the plastic granules. The rotary drive device 130 drives the screw to rotate, and during the rotation, it shears and crushes the plastic granules to ultimately process them into molten plastic. The servo motor can drive the needle valve rod to move to a preset opening degree, and the molten plastic enters the injection cavity through the adjustable flow channel and nozzle 800 under the thrust of the screw.

[0035] After injection molding is completed, the screw maintains pressure for a certain period of time. Then the needle valve rod is closed to allow the injection cavity to enter the cooling stage. The temperature sensor can monitor the hot runner temperature in real time and maintain it at the holding temperature through the heating element.

[0036] After cooling, the rectangular frame 400 is moved towards the mold closing gap by the drive cylinder 600. The cutting edges of each straight blade 500 slide against the mold closing gap and cut off the exposed burrs. Then, the mold closing drive device 330 drives the mold 300 to move in the opposite direction until the mold is opened. The injection molded part is then removed manually or by a robot, thus completing one injection molding cycle.

[0037] This invention features a rectangular frame 400 for a circumferential cutting component fitted over the fixed mold 200 of the mold-closing assembly. Straight blades 500 are fixedly connected to the four inner sides of the rectangular frame 400 near the fixed mold 200, with the cutting edges of each blade 500 facing the joint between the fixed mold 200 and the moving mold 300. Furthermore, a drive cylinder 600 is vertically fixedly connected inside the fixed mold plate 210. The drive end 610 of the drive cylinder 600 is fixedly connected to the rectangular frame 400, allowing it to drive the rectangular frame 400 and each straight blade 500 to move towards the joint between the fixed mold 200 and the moving mold 300. Thus, after the plastic part is injection molded, the drive cylinder 600 can immediately drive the circumferential cutting component to move along the length of the fixed mold 200 and the moving mold 300, removing the burrs generated in the mold-closing gap. This structural design not only eliminates the inefficiencies of traditional manual cutting methods, but also avoids scratching the injection molded part, thus effectively reducing the scrap rate of injection molded parts.

[0038] In some embodiments, such as Figure 8 As shown, the rectangular frame 400 consists of four straight tubes 410 and four right-angle connectors 420. The four straight tubes 410 and the right-angle connectors 420 are connected by threads to form a square frame, which is fitted onto the outside of the fixed mold 200. The inner diameter of the rectangular frame 400 is larger than the outer diameter of the fixed mold 200 to ensure that it will not interfere with the fixed mold 200 when it moves. Each straight tube 410 is fixedly connected to a right-angle connecting plate 430 near the surface of the fixed mold 200, and the right-angle connecting plate 430 is fixedly connected to the straight blade 500.

[0039] Preferably, such as Figure 9 As shown, each right-angle connecting plate 430 has a positioning hole 431 pre-drilled along its thickness direction, and each straight blade 500 has multiple through holes 510 along its thickness direction. External hexagonal bolts 700 are inserted through the positioning holes 431 and through holes 510. The ends of the external hexagonal bolts 700 are used to fix the straight blade 500 to the inner surface of the right-angle connecting plate 430 via fastening nuts 710. In actual use, the corresponding through hole 510 on the straight blade 500 can be selected according to the mold closing gap between the fixed mold 200 and the moving mold 300. The through hole 510 is then aligned with the positioning hole 431 of the right-angle connecting plate 430, and the external hexagonal bolt 700 is inserted and the fastening nut 710 is tightened to complete the fixing of the straight blade 500.

[0040] The detachable structure allows for quick replacement of multiple straight blades 500. When a straight blade 500 wears out or needs to be adapted to different burr types, it can be replaced without disassembling the entire rectangular frame 400; simply unscrew the external hex bolts 700, greatly reducing replacement time. Furthermore, multiple through holes 510 provide multiple mounting positions for initial adjustment of the straight blade 500's mounting height, thus adapting to molds with different parting gaps.

[0041] Specifically, each through hole 510 is a straight slot hole, which extends along the width direction of the straight blade 500. These slot holes are used to adjust the outward extension length of the blade of the straight blade 500 relative to the right-angle connecting plate 430. The straight slot hole design allows for stepless adjustment of the outward extension length of each straight blade 500, precisely adapting to burrs of different thicknesses, thus solving the problem that the fixed blade cannot adapt to changes in burr thickness.

[0042] Preferably, the length of each straight blade 500 is greater than the length of one side of the fixed mold 200, and adjacent vertical straight blades 500 abut against each other, so that each straight blade 500 can be connected to form a complete rectangular structure to prevent the omission of corners during the burr removal process.

[0043] In some embodiments, such as Figure 10 As shown, a return spring 720 is also fitted around the stud of the external hexagonal bolt 700. The return spring 720 is located between the right-angle connecting plate 430 and the straight blade 500, with its two ends slightly in contact with the surface of the right-angle connecting plate 430 and the back of the straight blade 500, respectively. Preferably, a shallow groove can be provided at the contact position between the return spring 720 and the straight blade 500 to prevent the return spring 720 from shifting during compression deformation.

[0044] In practical use, the straight blade 500 can be moved into the mold closing gap by the drive cylinder 600. When the cutting edge of the straight blade 500 contacts the burr, the reaction force of the burr will force the return spring 720 to compress. At this time, the impact force will be absorbed by the return spring 720, and the cutting edge will smoothly cut into the burr and slide along the mold closing gap to remove it. In this way, the return spring 720 can buffer the instantaneous impact force on the cutting edge when removing the burr, avoiding problems such as blade breakage caused by hard contact between the cutting edge and the burr in the mold closing gap, thereby greatly extending the service life of the cutting edge.

[0045] In some embodiments, such as Figure 11As shown, each straight blade 500 has a right-angled bend 520 at one end, with the bend potentially featuring a rounded transition. The blade of the right-angled bend 520 faces the mold-closing gap of the fixed mold 200, and its bending direction is perpendicular to the axis of the external hexagonal bolt 700. This design avoids the external hexagonal bolt 700 and ensures a clearance fit between the blade and the surface of the fixed mold 200. This design solves the interference problem caused by bolt obstruction in traditional straight blades 500, thus ensuring both easy disassembly of the straight blade 500 and high coverage of burr removal.

[0046] In some embodiments, a dry ice-assisted cleaning unit is further included, comprising a dry ice cleaner, an air supply pipeline, and multiple nozzles 800. The dry ice cleaner is connected to the straight pipe 410 of the rectangular frame 400 via the air supply pipeline, which is concealed within the straight pipe 410 of the rectangular frame 400, thus not occupying additional space and avoiding interference with other components. The nozzles 800 are evenly distributed on the side of the straight pipe 410 facing the mold closing gap and are connected to the air supply pipeline. Furthermore, the axis of each nozzle 800 is inclined towards the mold closing gap, forming a predetermined angle with the axis of the straight pipe 410.

[0047] In practical use, after removing burrs from the mold closing gap using the ring-cutting component, the dry ice cleaning machine can be started immediately. The dry ice cleaning machine delivers dry ice particles to each nozzle 80° via the gas pipeline, and then sprays them at a specific angle onto the mold closing gap. At this time, the remaining burrs will become brittle at low temperature and be washed off by the high-speed airflow, thereby improving the precision of burr removal.

[0048] In some embodiments, such as Figure 12 and Figure 13 As shown, it also includes a waste collection unit, which includes a dry ice spray blocking frame 900. The dry ice spray blocking frame 900 is sleeved on the outside of the moving mold 300 and fixedly connected to the moving template 310. Its surface near the ring cutting assembly is recessed inward to form a square groove 910, which is used to accommodate the straight blade 500 and block dry ice splashes.

[0049] During the mold closing stage, the dry ice spray blocking frame 900 moves with the moving template 310 to the mold closing position and aligns with the rectangular frame 400, with the square groove 910 positioned on the movement trajectory of the straight blade 500. When the straight blade 500 reaches its maximum stroke, the cutting edge of the straight blade 500 enters the square groove 910. During dry ice spraying, the dry ice particles impact the inner wall of the square groove 910 and bounce back, further flushing away any remaining burrs in the gaps, while also preventing dry ice particles from splashing outwards.

[0050] Preferably, the waste collection unit further includes a waste collection channel 920, the top of which is connected to the dry ice spray blocking frame 900. This channel is located below the fixed mold 200 and the moving mold 300 and is used to collect waste material cut from the mold closing gap. This structural design enables automatic waste collection, eliminating the need for manual cleaning and thus reducing labor intensity and improving production efficiency.

[0051] The above description is merely a preferred embodiment of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention. Structures, devices, and operating methods not specifically described or explained in this invention are implemented according to conventional methods in the art unless otherwise specified or limited.

Claims

1. A hot runner injection mold with adjustable runner size, characterized in that, include: Base, horizontal injection assembly, mold clamping assembly, adjustable runner mechanism, and ring cutting assembly; Both the horizontal injection assembly and the mold clamping assembly are assembled on the top of the base. The horizontal injection assembly is used to convey molten plastic, and the mold clamping assembly is used to form the injection cavity. The adjustable flow channel mechanism is integrated into the mold clamping assembly and is used to precisely adjust the effective cross-sectional area of ​​the hot flow pipe. The ring-cutting component surrounds the mold-closing gap of the mold-closing component and is used to automatically remove the burrs at the mold-closing gap after injection molding.

2. The hot runner injection mold with adjustable runner size according to claim 1, characterized in that: The mold closing assembly includes a fixed mold unit, a moving mold unit, and a mold closing drive device; The fixed mold unit includes a fixed template and a fixed mold, and the fixed mold is fixedly disposed on the side of the fixed template facing the moving mold unit; The moving mold unit includes a moving template, a moving mold, and a guide rod. The moving mold is fixedly disposed on the side of the moving template facing the fixed mold. One end of the guide rod is fixed to the fixed template, and the other end is slidably engaged with the moving template. The mold closing drive device is fixed to the top of the base, and its drive end is fixedly connected to the moving mold plate, which is used to drive the moving mold to move towards the fixed mold and close the mold to form an injection cavity.

3. The hot runner injection mold with adjustable runner size according to claim 2, characterized in that: The ring-cutting assembly includes a rectangular frame sleeved outside the fixed mold. The inner diameter of the rectangular frame is larger than the outer diameter of the fixed mold. Straight blades are fixedly connected to the four inner surfaces of the frame near the fixed mold. The cutting edge of each straight blade faces the mold-closing gap between the fixed mold and the moving mold.

4. The hot runner injection mold with adjustable runner size according to claim 3, characterized in that: The circumferential cutting assembly also includes a driving cylinder, which is horizontally placed inside the fixed template and its driving end is fixedly connected to the rectangular frame. The driving cylinder is used to push the rectangular frame to move along the length direction of the fixed mold and the moving mold, and to remove the burrs in the mold closing gap by means of each straight blade.

5. The hot runner injection mold with adjustable runner size according to claim 4, characterized in that: The rectangular frame is composed of four straight pipes and four right-angle connectors. The four straight pipes and the four right-angle connectors are connected by threaded sealing to form a square frame. Each straight pipe has a right-angle connecting plate fixedly connected to the surface near the fixed mold. The right-angle connecting plate is fixedly connected to the straight blade. Each of the right-angle connecting plates has a positioning hole reserved along the thickness direction, and each of the straight blades has multiple through holes along the thickness direction. An external hexagonal bolt is inserted through the positioning hole and the through hole. The end of the external hexagonal bolt is used to fix the straight blade to the inner surface of the right-angle connecting plate by a fastening nut.

6. The hot runner injection mold with adjustable runner size according to claim 5, characterized in that: Each of the through holes is a straight slot hole, which extends along the width direction of the straight blade and is used to adjust the length of the blade of the straight blade extending outward relative to the right-angle connecting plate.

7. The hot runner injection mold with adjustable runner size according to claim 6, characterized in that: A return spring is also fitted around the stud of the external hexagonal bolt. The return spring is located between the right-angle connecting plate and the straight blade, and is used to buffer the impact force when the straight blade cuts off the burrs.

8. The hot runner injection mold with adjustable runner size according to claim 7, characterized in that: Each of the straight blades has one end bent to form a right-angle bend, which is used to avoid the external hexagonal bolt so that its cutting edge is in clearance fit with the surface of the fixed mold.

9. The hot runner injection mold with adjustable runner size according to claim 4, characterized in that: It also includes a dry ice-assisted cleaning unit, which includes a dry ice cleaner, a gas pipeline, and multiple nozzles. The gas supply pipeline is integrated inside the straight pipe of the rectangular frame, and the nozzles are evenly distributed on the side of the straight pipe facing the mold gap and are connected to the gas supply pipeline.

10. The hot runner injection mold with adjustable runner size according to claim 9, characterized in that: The axes of each nozzle are inclined toward the mold gap, and their axes form a preset angle with the axis of the straight tube.

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