Injection molding pressure maintaining device, injection molding system and application method

Abstract

The invention provides an injection molding pressure maintaining device, an injection molding system and an application method, a glue injection body part comprises a first end, a second end and an outlet end, the first end is used for being connected with an injection molding machine and receiving inlet glue, the second end is connected with the outlet end through a second flow channel, the first end is communicated with the side face of the second flow channel through a first flow channel, and the second end is communicated with the outlet end through a second flow channel. An injection nozzle is arranged at the outlet end; the pressure maintaining driving part controls the pressure maintaining rod to extend into the second end in a linear reciprocating motion mode, and the pressure maintaining rod can switch the communicating state and the blocking state of the first flow channel and the second flow channel. The communicating state and the blocking state of the first flow channel and the second flow channel are switched through the pressure maintaining rod, so that after pressure maintaining is finished, negative pressure is formed when the pressure maintaining rod is drawn back, and a sizing material is prevented from overflowing from the injection nozzle after pressure maintaining is finished; therefore, the problem of glue leakage is effectively prevented, material waste is reduced, pollution of a production line is reduced, and the yield and the product quality are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of plastic injection molding, and particularly relates to an injection pressure holding device, an injection molding system and an application method thereof. Background Art

[0002] In the existing injection molding process, especially in the injection molding process of PET materials, pressure holding is a crucial link. When traditional injection molding machines perform pressure holding for PET materials, they face many challenges and problems, mainly including the following aspects:

[0003] 1. Glue leakage problem: When the traditional injection molding machine finishes pressure holding, the nozzle separates from the mold gate. Due to the pressure difference, glue is likely to overflow at the nozzle, causing material waste and equipment pollution;

[0004] 2. Pressure holding difficulty: The volume stroke in the pressure holding cylinder of the pressure holding device of the traditional injection molding machine is relatively long, while the actual required pressure holding stroke is relatively short. As a result, each time the pressure holding action is completed, there will be a relatively large amount of plasticized and molten PET colloid remaining in the pressure holding cylinder. The PET fluid under long-term high-temperature heating will turn yellow, black or even carbonize, seriously affecting the appearance quality of the product;

[0005] 3. Pressure holding efficiency problem: After the injection molding machine finishes injecting glue, the screw in the injection molding machine barrel still needs to continue to perform pressure holding in place for a certain period of time to ensure that the appearance size of the product meets the standard before retreating for material storage and plasticization, preparing for the next injection molding cycle. In this way, the time of each injection molding cycle is long and the production efficiency is low.

[0006] Therefore, the existing technology urgently needs an injection pressure holding device with a simple structure, convenient operation and capable of effectively solving the above problems, so as to improve the quality and production efficiency of PET products, reduce material waste and equipment pollution, and reduce production costs. Summary of the Invention

[0007] In order to overcome the deficiencies of the prior art, the purpose of the present invention is to provide an injection pressure holding device, an injection molding system and an application method thereof, which are mainly used to solve defects such as low pressure holding efficiency, serious glue leakage problem, residual colloid problem, etc.

[0008] To solve the above problems, the technical solutions adopted by the present invention are as follows:

[0009] In the first aspect, the present invention provides an injection pressure holding device, including:

[0010] An injection glue body part, including a first end, a second end and an outlet end. The first end is used to connect to an injection molding machine and receive incoming glue. The second end is connected to the outlet end through a second flow channel. The first end is connected to the side of the second flow channel through a first flow channel. An injection nozzle is provided at the outlet end;

[0011] A pressure-holding driving part controls a pressure-holding rod to extend into the second end in a linear reciprocating manner, and the pressure-holding rod can switch the communication state and blocking state between the first flow channel and the second flow channel.

[0012] In some embodiments, it further includes a heat management module. When the first flow channel and the second flow channel are in a communication state, the pressure-holding rod is located in the initial area of the second flow channel, and the area of the second flow channel other than the initial area is the pressure-holding area. The heat management module is used to form a first heat field and a second heat field in the injection body part. The first heat field includes the pressure-holding area and the first flow channel, and the second heat field includes the initial area, and the temperature of the first heat field is greater than that of the second heat field.

[0013] In some embodiments, the heat management module includes a heating element and a cooling water channel. The heating element is attached to at least a part of the outer wall surface of the pressure-holding area and the first flow channel, and the cooling water channel is arranged inside the wall thickness where the initial area is located.

[0014] In some embodiments, the heat management module further includes a control unit and a temperature measurement unit. The control unit and the temperature measurement unit are signal-connected. The temperature measurement unit is used to detect the real-time temperature of the first heat field, and the control unit is used to control the heating power of the heating element.

[0015] In some embodiments, a guiding inclined surface is formed at the extending end of the pressure-holding rod, and the guiding inclined surface forms a shear stress guiding for the fluid at the connection of the first flow channel and the second flow channel.

[0016] In some embodiments, the connection angle between the first flow channel and the second flow channel is a right angle or an acute angle.

[0017] In some embodiments, the pressure-holding driving part includes a pressure-holding cylinder head and a servo oil cylinder. The pressure-holding cylinder head is fixed to the end face of the second end. The pressure-holding cylinder head is connected to the fixed part of the servo oil cylinder through a support column. The pressure-holding rod is connected to the servo oil cylinder through a locking ring. The servo oil cylinder is used to drive the pressure-holding rod to move reciprocally, and the pressure-holding cylinder head is provided with a relief hole for the movement of the pressure-holding rod.

[0018] In some embodiments, a detachable pressure-holding cylinder sleeve is embedded in the second flow channel, and the pressure-holding cylinder head fixes the pressure-holding cylinder sleeve inside the second flow channel.

[0019] In a second aspect, the present invention provides an injection molding system, including an injection molding machine and an injection molding pressure-holding device as described above. The discharge barrel of the injection molding machine is fixed to the first end of the injection body part.

[0020] In a third aspect, the present invention provides an application method applied to an injection molding system as described above, including:

[0021] Control the pressure-holding rod to be in the initial position so that the first flow channel is in communication with the second flow channel;

[0022] Control the injection molding machine to inject glue and fill the fluid into the first flow channel and the second flow channel;

[0023] Control the pressure-holding rod to push inward to the pressure-holding position so that the first flow channel is in a blocked state with the second flow channel for pressure-holding;

[0024] Control the injection molding machine to perform pre-plasticization work for material storage.

[0025] Compared with the prior art, the present invention has at least the following beneficial effects:

[0026] 1. The injection molding pressure-holding device of the present invention switches the communication state and the blocked state between the first flow channel and the second flow channel through the pressure-holding rod, so that after the pressure-holding is completed, a negative pressure is formed when the pressure-holding rod is retracted, preventing the rubber material from overflowing from the injection nozzle after the pressure-holding is completed; this not only effectively prevents the problem of glue leakage, reduces material waste, but also reduces the pollution of the production line, and helps to improve the yield and product quality;

[0027] 2. By establishing a thermal field with a temperature difference through the heat management module, the first thermal field helps to improve the fluidity of the fluid in the pressure-holding area and the first flow channel, and the second thermal field can provide a cooling function to reduce the temperature, so that the colloid between the clearance of the pressure-holding rod and the cylinder liner is cooled and crystallized and no longer leaks out, preventing glue leakage;

[0028] 3. The injection molding pressure-holding device of the present invention adopts a modular design, and the injection body part and the pressure-holding drive part are separately arranged, which is convenient for installation, disassembly and replacement; moreover, the entire injection molding pressure-holding device can be directly loaded on the discharge barrel of a general-purpose injection molding machine, and can produce PET preforms, with low modification cost and strong adaptability.

[0029] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. Description of the Drawings

[0030] The present invention will be further described with the help of the accompanying drawings, but the embodiments in the drawings do not constitute any limitation to the present invention. For those of ordinary skill in the art, other drawings can also be obtained according to the following drawings without creative efforts.

[0031] Figure 1 It is a schematic diagram of the overall structure of an injection molding pressure-holding device in an embodiment.

[0032] Figure 2 It is a schematic diagram of a half-sectional structure of an injection molding pressure-holding device installed on an injection molding machine in an embodiment.

[0033] Figure 3 It isFigure 2 Schematic enlarged view of the partial structure of part A.

[0034] Figure 4 Schematic diagram of the structure of the pressure-holding cylinder sleeve and the pressure-holding rod. Specific implementation manners

[0035] The applicant has found that:

[0036] In the field of PET preform injection molding technology, especially in the production of plastic preforms, it is difficult to hold the pressure of injecting PET material with traditional injection molding machines and leakage of glue is likely to occur. The disadvantage of traditional pressure-holding devices is that when the pressure-holding ends and the nozzle is separated from the mold gate, due to the existence of the pressure difference, the nozzle at the outlet of the main runner will have glue overflow, resulting in waste and pollution of plastics.

[0037] In addition, the volume stroke in the pressure-holding cylinder of traditional injection molding machines is relatively long. When the barrel injection is completed and enters the pressure-holding stage, because its stroke is long while the stroke that needs to be pressure-held is short, there will be a relatively large amount of plasticized and molten PET colloid remaining in the pressure-holding cylinder every time the pressure-holding action is completed. The PET fluid will turn yellow, black and carbonize after being heated at high temperature for a long time, which will affect the appearance quality once it is pressure-held into the injection-molded product.

[0038] In view of this, referring to Figures 1 to 4 , on the one hand, the present embodiment provides an injection pressure-holding device, including:

[0039] The glue injection main body part 10 includes a first end 11, a second end 12 and an outlet end 13. The first end 11 is used to connect to the injection molding machine 30 and receive incoming glue. Among them, the first end 11 and the second end 12 are located on one side of the glue injection main body part 10, the outlet end 13 is located on the other side of the glue injection main body part 10. There is a certain distance between the first end 11 and the second end 12. The second end 12 is connected to the outlet end 13 through a second runner 15. The first end 11 is communicated with the side surface of the second runner 15 through a first runner 14. The outlet end 13 is provided with an injection nozzle 16;

[0040] The pressure-holding driving part 20 controls the pressure-holding rod 21 to extend into the second end 12 in a straight line and reciprocally. The pressure-holding rod 21 can switch the communication state and the blocking state between the first runner 14 and the second runner 15.

[0041] It should be noted that a first flow channel 14 is provided inside the glue injection body portion 10 and is connected to the flow channel of the discharge barrel 31 of the injection molding machine 30. Specifically, the upper right part of the glue injection body portion 10 is the first end 11, and a circular flange is provided at the first end 11. A circular boss at the top of the flange is assembled into the notch of the discharge barrel 31 of the injection molding machine 30 and is fixed to the mouth of the discharge barrel 31 of the injection molding machine 30 with a nut. The upper left part of the glue injection body portion 10 is the second end 12, and an injection nozzle 16 is provided at the second end 12. Through threaded connection, the PET glue material passes from the mouth of the discharge barrel 31 through the inner cavity of the flow channel, passes through the pressure holding cylinder, and reaches the injection nozzle 16. The glue material then reaches the mold cavity of the mold from the spray holes of the injection nozzle 16;

[0042] During the glue feeding stage, the pressure holding rod 21 is controlled to move to the initial position, so that the first flow channel 14 and the second flow channel 15 are in a connected state. The glue material flows from the first end 11 through the first flow channel 14 and converges into the second flow channel 15, and flows from the second flow channel 15 to the outlet end 13 and is ejected from the injection nozzle 16 to complete the injection molding;

[0043] During the pressure holding stage, the pressure holding rod 21 is controlled to push inward and move to the pressure holding position, so that the first flow channel 14 and the second flow channel 15 are in a blocked state for pressure holding; at this time, the first flow channel 14 is blocked by the pressure holding rod 21. The inward push of the pressure holding rod 21 increases the pressure of the colloid in the flow channel at the front end of the head of the pressure holding rod 21 towards the spray port of the injection nozzle 16, and the glue material is densified into the mold cavity, thus completing the pressure holding work; while during the pressure holding, that is, when the head of the pressure holding rod 21 moves completely beyond the outlet of the first flow channel 14 to the left, the screw of the injection molding machine 30 can correspondingly carry out the plasticizing work of storing and plasticizing PET plastic, preparing for the next injection molding cycle. Pressure holding and material storage can be carried out simultaneously, shortening the product molding cycle and improving work efficiency;

[0044] When the injection nozzle 16 is separated from the mold after the pressure holding is completed, the pressure holding rod 21 returns to the initial position under the drive of the servo oil cylinder 24. A certain negative pressure will be formed in the flow channel at the front end of the head of the pressure holding rod 21. Under the action of the internal and external pressure difference, the glue material at the orifice of the spray hole of the injection nozzle 16 will flow back to the flow channel, achieving the purpose of preventing overflow and dripping, reducing the generation of waste glue at the glue head, and avoiding pollution.

[0045] In some possible embodiments, a plurality of diversion ports are designed at the second end 12 of the glue injection body portion 10, and each diversion port is connected to an outlet end 13, that is, there are a plurality of injection nozzles 16, forming a one-time multi-cavity injection structure. The head of the pressure holding rod 21 is designed into a fan shape adapted to the diversion ports, and the diversion ports are synchronously pressure held during movement. By simultaneously injecting and pressure holding multiple cavities within one injection molding cycle, the production efficiency can be greatly improved and the manufacturing cost can be reduced. The design of the fan-shaped pressure holding rod head can ensure the pressure consistency of each cavity and improve the stability and repeatability of multi-cavity molding.

[0046] Combined Figure 2 andFigure 3 As an implementation, it further includes a heat management module. When the first flow channel 14 and the second flow channel 15 are in a connected state, the pressure holding rod 21 is located in the initial area 43 in the second flow channel 15. The area of the second flow channel 15 outside the initial area 43 is the pressure holding area 44. The pressure holding rod 21 in the initial position divides the second flow channel 15 into the initial area 43 and the pressure holding area 44;

[0047] The heat management module is used to form a first heat field and a second heat field in the injection body part 10. The first heat field includes the pressure holding area 44 and the first flow channel 14, and the second heat field includes the initial area 43. The temperature of the first heat field is higher than that of the second heat field;

[0048] It should be noted that the first heat field and the second heat field represent that the temperatures of the two heat fields are different, and it does not limit that both heat fields need to be heated. Among them, the pressure holding area 44 and the first flow channel 14 included in the first heat field are the areas where the rubber material flows. Therefore, it requires a higher temperature to improve the fluidity of the rubber material; while the second heat field includes the initial area 43, that is, the area where the pressure holding rod 21 is in the initial position. By cooling the initial area 43 and reducing the temperature, the colloid in the clearance between the pressure holding rod 21 and the cylinder sleeve in the second flow channel is cooled and crystallized and no longer leaks outwards, preventing glue leakage. It can be said that the setting of the second heat field is generated in a specific application scenario. Only when this injection pressure holding device is used on a traditional injection molding machine will there be a problem of colloid oozing out from the mating clearance due to the reciprocating movement of the pressure holding rod in the second flow channel. Therefore, it is thought to prevent the flow of colloid in a specific area by establishing a heat field with a temperature difference.

[0049] Specifically, the heat management module includes a heating element 41 and a cooling water channel 42. The heating element 41 is attached to at least a part of the outer wall surface of the pressure holding area 44 and the first flow channel 14. By arranging it on the outer wall surface of a specific area of the injection body part 10, it provides heat for the rubber material in its flow channel to maintain its molten state and improve fluidity;

[0050] The cooling water channel 42 is arranged inside the wall thickness where the initial area 43 is located. A cooling water channel 42 is formed in the wall thickness of the injection body part 10. By injecting flowing cooling water, heat is carried away, the temperature of the initial area 43 is reduced, the fluidity is reduced, and glue leakage is prevented.

[0051] Furthermore, the heat management module further includes a control unit and a temperature measuring unit. The control unit and the temperature measuring unit are signal-connected. The temperature measuring unit is used to detect the real-time temperature of the first heat field and detect the temperature of the injection body part 10 in real time. The control unit is used to control the heating power of the heating element 41 and adjust the thermal effect of the first heat field according to the detected temperature.

[0052] Additionally, during the injection stage, a corresponding first temperature threshold is set; during the holding pressure stage, a corresponding second temperature threshold is set; during the end of the holding pressure stage, a corresponding third temperature threshold is set. Among them, the first temperature threshold is greater than the second temperature threshold, and the second temperature threshold is greater than the third temperature threshold. By controlling different first thermal field temperatures in a gradient manner at different stages, the fluidity of the rubber material can be increased during the injection stage, the temperature can be reduced during the holding pressure stage to complete pressurized solidification, and then the temperature can be further reduced during the end of the holding pressure stage to reduce the fluidity of the rubber material, prevent overflow and dripping, and better remain in the second flow channel 15 under the negative pressure environment formed after the head of the holding pressure rod 21 moves.

[0053] As an implementation manner, a guiding inclined surface 22 is formed at the inserted end of the holding pressure rod 21. The guiding inclined surface 22 forms a shear stress guiding for the fluid at the connection of the first flow channel 14 and the second flow channel 15. When the holding pressure rod 21 is in the initial position, due to the shape of its head conforming to the flow direction of the fluid at the outlet of the first flow channel 14, the shear stress in the longitudinal flow direction of the colloid is reduced, and the risk of plastic decomposition is lowered, making the flow transition of the rubber material in the second flow channel 15 smoother. After the injection is completed, the servo oil cylinder 24 drives the holding pressure rod 21 to move leftward to a suitable position as required, applying pressure to the colloid in the flow channel at the front end of the head of the holding pressure rod 21 in the direction of the nozzle 16 of the injection nozzle, and the rubber material increases in density in the mold cavity to achieve the purpose of holding pressure for injection molding.

[0054] Preferably, the connection angle between the first flow channel 14 and the second flow channel 15 is a right angle, and the guiding inclined surface 22 at the end of the holding pressure rod 21 is a 45° inclined surface, guiding the vertically injected rubber material into the second flow channel 15.

[0055] Preferably, the connection angle between the first flow channel 14 and the second flow channel 15 is an acute angle, and the inclination angle of the guiding inclined surface 22 at the end of the holding pressure rod 21 is half of the above connection angle. For example, if the connection angle between the first flow channel 14 and the second flow channel 15 is 60°, then the inclination angle of the guiding inclined surface 22 is 30°, guiding the obliquely injected rubber material into the second flow channel 15.

[0056] In some possible embodiments, a plurality of pressure sensors are arranged on the holding pressure rod 21 to monitor the pressure changes at different positions in real time during the holding pressure process. According to the pressure feedback data, the output force of the servo oil cylinder is dynamically adjusted to achieve multi-stage pressure gradient control of the holding pressure process. Specifically: in the initial stage of holding pressure, the pressure is rapidly increased to ensure full filling of the rubber material; in the middle stage of holding pressure, the pressure rises steadily to maintain the internal pressure of the plastic part; in the later stage of holding pressure, the pressure slowly decreases to make the plastic part cool and solidify. Through the refined pressure control of the holding pressure process, high-quality plastic parts with more stable dimensions and smaller internal stresses can be obtained.

[0057] Combined with Figure 4, as an implementation manner, the holding pressure driving part 20 includes a holding pressure cylinder head 23 and a servo oil cylinder 24. The holding pressure cylinder head 23 is fixed to the end face of the second end 12. The holding pressure cylinder head 23 is connected to the fixing part of the servo oil cylinder 24 through a support column 25 by thread, so that the holding pressure cylinder sleeve 26, the holding pressure rod 21 and the axis of the servo oil cylinder 24 are horizontally on the same line. The right end of the holding pressure rod 21 is connected to the servo oil cylinder 24 through a locking ring. The servo oil cylinder 24 is used to drive the holding pressure rod 21 to reciprocate. The holding pressure cylinder head 23 is provided with a relief hole for the movement of the holding pressure rod 21. The holding pressure cylinder head 23 is sleeved outside the holding pressure rod 21 and is fixed to the second end 12 of the glue injection body part 10 by screws. The second flow channel 15 is internally embedded with a detachable holding pressure cylinder sleeve 26. The holding pressure cylinder head 23 fixes the holding pressure cylinder sleeve 26 inside the second flow channel 15. Among them, the holding pressure cylinder sleeve 26 is in a straight cylinder shape, and two openings are formed on its side wall for docking the flow channels located in the upper part. A horizontal flow channel is formed inside the holding pressure cylinder sleeve 26 for the horizontal movement of the holding pressure rod 21.

[0058] In some possible embodiments, the holding pressure rod 21 is made of a composite material with a metal matrix composite ceramic coating. The inside of the holding pressure rod 21 is made of high-strength alloy steel material, and the outer surface is coated with a ceramic coating that is resistant to high temperature and wear. This composite structure can effectively reduce the thermal conductivity of the holding pressure rod, reduce the transfer of heat from the high-temperature rubber material to the direction of the servo oil cylinder, and protect the oil cylinder seals. At the same time, the ceramic coating has excellent anti-wear performance, which can greatly extend the service life of the holding pressure rod and reduce the downtime for maintenance.

[0059] Preferably, the first flow channel 14 and the second flow channel 15 inside the glue injection body part 10 form a U-shaped structure, and the holding pressure rod 21 is coupled at the horizontally extending flow channel below, so that the rubber material flows according to the U-shaped flow channel. Such a setting can save the space for modification and improve the adaptability.

[0060] In a second aspect, the present embodiment provides an injection molding system, including an injection molding machine 30 and an injection molding and holding pressure device as described in the above embodiment. The discharge barrel 31 of the injection molding machine 30 is fixed to the first end 11 of the glue injection body part 10.

[0061] As an implementation manner, at the discharge barrel 31 of the traditional injection molding machine 30, an injection molding and holding pressure device can be directly installed, and by adapting to the circular flange at the first end 11, various different traditional injection molding machines 30 can be adapted.

[0062] As an implementation manner, an in-mold metering device is added between the glue injection body part 10 and the injection molding machine 30. This device includes a metering cylinder, a metering valve, and a driving device. The injection molding machine injects the molten rubber material into the metering cylinder, and then the metering valve precisely controls the dosage of the rubber material injected into the first runner. Through an independent in-mold metering system, the metering error of the injection molding machine itself can be avoided, and high-precision control of the glue injection amount can be achieved. At the same time, the in-mold metering cylinder plays a buffering role, which can reduce the fluctuation of the injection pressure and improve the stability of the injection molding process.

[0063] In a third aspect, the present embodiment provides an application method applied to an injection molding system as described in the above embodiment, including:

[0064] Control the pressure holding rod 21 to be in the initial position, so that the first runner 14 and the second runner 15 are in a communicating state;

[0065] Control the injection molding machine 30 to feed rubber, and fill the fluid in the first runner 14 and the second runner 15;

[0066] Control the pressure holding rod 21 to push inward and be in the pressure holding position, so that the first runner 14 and the second runner 15 are in a blocked state for pressure holding;

[0067] While performing pressure holding, control the injection molding machine 30 to perform pre-plasticization work for material storage.

[0068] When the pressure holding is over, control the pressure holding rod 21 to retract outward, so that the first runner 14 and the second runner 15 are in a communicating state. By forming a negative pressure, the rubber material at the orifice of the injection nozzle 16 will flow back to the runner.

[0069] During the above process, the temperature measurement unit is also used to detect the temperature of the glue injection body part 10 in real time, and the heating power of the heating element 41 is controlled by the control unit. Specifically:

[0070] In the feeding stage, set a first temperature threshold so that the rubber material can improve its fluidity in the feeding stage;

[0071] In the pressure holding stage, set a second temperature threshold to reduce the temperature and complete pressure-induced solidification;

[0072] In the end stage of pressure holding, set a third temperature threshold to further reduce the temperature and reduce the fluidity of the rubber material to prevent overflow and dripping;

[0073] Among them, the first temperature threshold is greater than the second temperature threshold, and the second temperature threshold is greater than the third temperature threshold. By controlling different first heat field temperatures in different stages in a gradient manner, the production efficiency and quality are improved.

[0074] In summary, compared with the prior art, the above embodiments provide an injection molding holding pressure device, an injection molding system and an application method. The injection molding holding pressure device of the present invention switches the communication state and the blocking state between the first flow channel 14 and the second flow channel 15 through the holding pressure rod 21, so that after the holding pressure ends, a negative pressure is formed when the holding pressure rod 21 is retracted, preventing the rubber material from overflowing from the injection nozzle 16 after the holding pressure ends; this not only effectively prevents the problem of glue leakage, reduces material waste, but also reduces the pollution of the production line, and helps to improve the finished product rate and product quality;

[0075] A thermal field with a temperature difference is established through the heat management module. The first thermal field helps to improve the fluidity of the fluid in the holding pressure area 44 and the first flow channel 14, and the second thermal field can provide a cooling function to reduce the temperature, so that the colloid between the fitting clearances of the holding pressure rod 21 and the cylinder liner is cooled and crystallized and no longer leaks out, preventing glue leakage;

[0076] The injection molding holding pressure device of the present invention adopts a modular design, and the injection glue body part 10 and the holding pressure driving part 20 are separately arranged, which is convenient for installation, disassembly and replacement; moreover, the entire injection molding holding pressure device can be directly loaded on the discharge barrel 31 of a general-purpose injection molding machine 30, and can be used to produce PET preform products, with low modification cost and strong adaptability.

[0077] The above embodiments are only the preferred embodiments of the present invention, and the scope of protection of the present invention cannot be limited thereby. Any non-substantial changes and substitutions made by those skilled in the art based on the present invention belong to the scope of protection required by the present invention.

Claims

1. An injection molding holding pressure device, characterized in that, Comprising: A glue injection body part, including a first end, a second end and an outlet end. The first end is used to connect to an injection molding machine and receive incoming glue. The second end is connected to the outlet end through a second flow channel. The first end communicates with the side surface of the second flow channel through a first flow channel. The outlet end is provided with an injection nozzle. A pressure holding drive part, controlling a pressure holding rod to extend into the second end in a linearly reciprocating manner. The pressure holding rod can switch the communication state and blocking state between the first flow channel and the second flow channel.

2. The injection molding holding pressure device according to claim 1, characterized in that, It further includes a heat management module. When the first flow channel and the second flow channel are in a communication state, the pressure holding rod is located in an initial area in the second flow channel. The area of the second flow channel other than the initial area is a pressure holding area. The heat management module is used to form a first heat field and a second heat field in the glue injection body part. The first heat field includes the pressure holding area and the first flow channel. The second heat field includes the initial area. The temperature of the first heat field is greater than that of the second heat field.

3. An injection molding holding pressure device as described in claim 2, characterized in that, The heat management module includes a heating element and a cooling water channel. The heating element is attached to at least a part of the outer wall surface of the pressure holding area and the first flow channel. The cooling water channel is internally arranged at the wall thickness where the initial area is located.

4. The injection molding holding pressure device according to claim 3, wherein The heat management module further includes a control unit and a temperature measuring unit. The control unit and the temperature measuring unit are signal-connected. The temperature measuring unit is used to detect the real-time temperature of the first heat field. The control unit is used to control the heating power of the heating element.

5. An injection molding holding pressure device according to claim 1, characterized in that, A guiding inclined surface is formed at the extending end of the pressure holding rod. The guiding inclined surface forms a shear stress guiding for the fluid at the connection of the first flow channel and the second flow channel.

6. The injection molding holding pressure device according to claim 5, characterized in that, The connection angle between the first flow channel and the second flow channel is a right angle or an acute angle.

7. An injection molding pressure holding device according to any one of claims 1 to 6, characterized in that The pressure holding drive part includes a pressure holding cylinder head and a servo oil cylinder. The pressure holding cylinder head is fixed to the end face of the second end. The pressure holding cylinder head is connected to the fixed part of the servo oil cylinder through a support column. The pressure holding rod is connected to the servo oil cylinder through a locking ring. The servo oil cylinder is used to drive the pressure holding rod to reciprocate. The pressure holding cylinder head is provided with a relief hole for the movement of the pressure holding rod.

8. An injection molding pressure holding device according to claim 7, characterized in that A detachable pressure holding cylinder sleeve is embedded in the second flow channel. The pressure holding cylinder head fixes the pressure holding cylinder sleeve inside the second flow channel.

9. An injection molding system, characterized in that, Comprising an injection molding machine and an injection molding pressure holding device according to any one of claims 1 to 8. The discharge barrel of the injection molding machine is fixed to the first end of the glue injection body part.

10. An application method applied to an injection molding system as described in claim 9, characterized in that, Comprising: Controlling the pressure holding rod to be in an initial position, so that the first flow channel and the second flow channel are in a communication state; Controlling the injection molding machine to inject glue, and filling the fluid into the first flow channel and the second flow channel; Controlling the pressure holding rod to push inward and be in a pressure holding position, so that the first flow channel and the second flow channel are in a blocking state for pressure holding; Controlling the injection molding machine to perform pre-plasticization work for material storage.

Images