Plastic lampshade injection molding device and mold assembly thereof

Abstract

The utility model relates to a plastic lampshade injection molding device and a mold assembly thereof, and belongs to the field of lampshade production equipment.The mold assembly comprises a mold base, a lower mold is fixedly arranged on the mold base, an upper mold is arranged above the lower mold, a protruding mold core is arranged on the upper surface of the lower mold, and a groove is formed in the lower surface of the upper mold; a cavity is defined by the mold core and the groove, and an injection molding opening communicated with the cavity is formed in the top of the upper mold; a positioning groove is formed in the upper surface of the lower die, a lifting seat in sliding fit with the positioning groove is arranged in the positioning groove, the upper end of the lifting seat is fixedly connected with the die core, and the lower end of the lifting seat is connected with a lifting mechanism. According to the utility model, the resistance during injection can be reduced, molten plastic is extruded by utilizing the mold core, the cavity is quickly filled with the molten plastic, the injection molding efficiency is improved, and the quality of a lampshade is ensured.

Description

Technical Field

[0001] The utility model belongs to the field of lampshade production equipment, in particular to a plastic lampshade injection molding device and a mold assembly thereof. Background Art

[0002] Plastic lampshades are currently very common and are typically produced using injection molding. Different shapes and sizes of lampshades require corresponding injection molds. Existing injection molds typically consist of a fixed mold and a movable mold, which define a molding cavity. The movable mold is equipped with an injection port. Cooling and ejection mechanisms can also be incorporated into the mold to accelerate cooling and solidification of the lampshade and facilitate demolding. Due to the typically thin thickness of lampshades, the molten plastic has difficulty quickly and evenly filling the mold cavity, impacting production efficiency and quality. Utility Model Content

[0003] The technical problem to be solved by the utility model is to provide a plastic lampshade injection molding device and a mold assembly thereof, which can enable the molten plastic to quickly and evenly fill the mold cavity.

[0004] In order to solve the above problems, the technical solution adopted by the present invention is as follows: a mold assembly includes a mold base, a lower mold is fixedly provided on the mold base, an upper mold is provided above the lower mold, a raised mold core is provided on the upper surface of the lower mold, a groove is provided on the lower surface of the upper mold, the mold core and the groove enclose a molding cavity, and an injection port connected to the molding cavity is provided on the top of the upper mold;

[0005] The upper surface of the lower mold is provided with a positioning groove, and a lifting seat is provided in the positioning groove and slidably cooperates with the positioning groove. The upper end of the lifting seat is fixedly connected to the mold core, and the lower end of the lifting seat is connected to the lifting mechanism.

[0006] Furthermore, a vertical guide column is provided on the mold base, and the guide column passes through the upper mold and is slidably engaged with the upper mold.

[0007] Furthermore, a detachable one-way valve is provided in the injection port.

[0008] Furthermore, the lifting mechanism is a hydraulic cylinder.

[0009] Furthermore, an exhaust groove is provided on the inner wall of the injection port or on the parting surface between the lower mold and the upper mold.

[0010] Furthermore, a cooling cavity is provided in the mold core, and a cooling medium inlet and a cooling medium outlet connected to the cooling cavity are provided on the bottom surface of the lifting seat. The cooling medium inlet is connected to a cooling medium supply mechanism through a first hose, and the cooling medium outlet is connected to a second hose.

[0011] Furthermore, the cooling medium supply mechanism includes a water tank, the water tank is connected to the first hose via a water pump, and the second hose is connected to the water tank.

[0012] Furthermore, a valve is provided on the second hose; a plurality of vertical ejection holes are provided on the upper surface of the mold core, a push rod that slides with the ejection hole is provided on the upper part of the ejection hole, a support block is fixedly provided on the lower part of the ejection hole, the upper surface of the support block contacts the lower surface of the push rod, and a medium through hole connected to the cooling chamber is provided on the support block.

[0013] A plastic lampshade injection molding device comprises the above-mentioned mold assembly.

[0014] The beneficial effects of the present invention are as follows: the mold core is mounted on a lifting seat, which can be used to move the mold core up and down, adjusting its position and thereby changing the size of the cavity formed by the mold core and the groove of the upper mold. During injection molding, the mold core is first moved downward to enlarge the cavity and reduce injection resistance. Molten plastic is then injected into the cavity through the injection port. When the injection volume reaches the volume of the lampshade, injection is stopped. The lifting mechanism then drives the lifting seat and mold core upward, allowing the mold core to squeeze the plastic, prompting the plastic to quickly and evenly fill the entire cavity. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a cross-sectional schematic diagram of the utility model;

[0016] Figure 2 It is an enlarged schematic diagram of the ejection structure;

[0017] Figure markings: 1—mold base; 2—lower mold; 3—upper mold; 4—mold core; 5—mold cavity; 6—injection port; 7—lifting seat; 8—lifting mechanism; 9—guide column; 10—one-way valve; 11—cooling chamber; 12—cooling medium inlet; 13—cooling medium outlet; 14—first hose; 15—cooling medium supply mechanism; 16—second hose; 17—water pump; 18—valve; 19—push rod; 20—support block; 21—medium through hole. DETAILED DESCRIPTION

[0018] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0019] The mold assembly of the present utility model, such as Figure 1As shown, it includes a mold base 1, which is made of a thick metal plate, which can be a rectangular plate or a circular plate. A lower mold 2 is fixedly provided on the mold base 1, and the lower mold 2 can be welded to the mold base 1. As a preferred embodiment, the lower mold 2 is connected to the mold base 1 by bolts to facilitate the replacement of lower molds 2 of different models and specifications, thereby improving the utilization rate of the mold base 1. An upper mold 3 is provided above the lower mold 2, and a raised mold core 4 is provided on the upper surface of the lower mold 2, and a groove is provided on the lower surface of the upper mold 3. After the upper mold 3 and the lower mold 2 are combined, the mold core 4 and the groove enclose a molding cavity 5. The shape and size of the molding cavity 5 are adapted to the shape and size of the lampshade to be processed. An injection port 6 connected to the molding cavity 5 is provided at the top of the upper mold 3. The injection port 6 is used to inject molten plastic into the molding cavity 5.

[0020] A positioning groove is provided on the upper surface of the lower mold 2, and a lifting seat 7 is provided in the positioning groove to slide with the positioning groove. The upper end of the lifting seat 7 is fixedly connected to the mold core 4, and the lower end of the lifting seat 7 is connected to the lifting mechanism 8.

[0021] The core 4 can be connected to the lift base 7 via screws or integrally formed with the lift base 7. The lift mechanism 8 drives the lift base 7 and the core 4 to rise and fall synchronously. After the upper mold 3 and lower mold 2 are closed, if the core 4 moves upward, the distance between the core 4 and the upper mold 3 decreases, reducing the volume of the cavity 5. If the core 4 moves downward, the distance between the core 4 and the upper mold 3 increases, increasing the volume of the cavity 5. The increased volume of the cavity 5 reduces injection resistance, allowing the molten plastic to be injected into the cavity 5 more quickly.

[0022] When using the present utility model, the lifting mechanism 8 is first used to drive the lifting seat 7 and the core mold 4 to move downward an appropriate distance, so that the volume of the cavity 5 increases, and then the molten plastic is injected into the cavity 5 through the injection port 6. When the injection volume is the same as the volume of the lampshade, the injection is stopped. At this time, since the volume of the cavity 5 is greater than the volume of the injected molten plastic, the molten plastic cannot fill the cavity 5. Then, the lifting mechanism 8 is used to drive the lifting seat 7 and the core mold 4 to gradually move upward, and the volume of the cavity 5 gradually decreases. The core mold 4 can then squeeze the molten plastic in the cavity 5, prompting the molten plastic to quickly fill the entire cavity 5. Under the extrusion of the core mold 4, it can be ensured that the molten plastic fills the cavity 5 more evenly, thereby ensuring that the thickness and strength of the lampshade are uniform.

[0023] It can be seen that the utility model can reduce the resistance during injection, and at the same time utilize the mold core 4 to extrude the molten plastic, so as to quickly fill the mold cavity with the molten plastic, thereby improving the injection molding efficiency and ensuring the quality of the lampshade.

[0024] During demolding, the upper mold 3 needs to be moved upward to separate it from the lower mold 2. This separation can be done manually, or a hydraulic cylinder or other device can be used to push the upper mold 3 up and down, achieving automatic mold closing and parting. To ensure precise alignment of the upper mold 3 and the lower mold 2 during mold closing, the mold base 1 is equipped with vertical guide posts 9. These posts extend through the upper mold 3 and slide in contact with it. These guide posts 9 provide guidance and positioning, ensuring vertical upward and downward movement of the upper mold 3 and preventing horizontal deviation.

[0025] The mold core 4 moves upward, exerting a certain pressure when squeezing the molten plastic. To prevent the plastic in the cavity 5 from being discharged from the cavity 5 through the injection port 6, the present invention provides a detachable one-way valve 10 within the injection port 6. The one-way valve 10 is oriented from outside the cavity 5 to inside the cavity 5. During injection, the injection head of the injection molding machine can dock with the one-way valve 10, injecting the molten plastic into the cavity 5 through the one-way valve 10. When the mold core 4 squeezes the molten plastic, the plastic cannot be discharged through the one-way valve 10, ensuring that the plastic fills the cavity 5. The one-way valve 10 can be connected to the injection port 6 via a thread, or connected to the upper mold 3 via a screw, so that the one-way valve 10 can be removed and the solidified plastic inside can be cleaned.

[0026] In the present invention, the lifting mechanism 8 is a hydraulic cylinder, but an air cylinder or other device may also be used.

[0027] During the process of injecting molten plastic into the mold cavity 5 and extruding the molten plastic by the mold core 4, it is necessary to exhaust the air in the mold cavity 5 to reduce the injection and extrusion resistance and prevent defects such as bubbles and holes from appearing inside the lampshade. To exhaust the air, an exhaust groove is provided on the inner wall of the injection port 6 or on the parting surface between the lower mold 2 and the upper mold 3. Exhaust grooves can also be provided on both the injection port 6 and the parting surface to ensure effective exhaust. The exhaust groove is typically 2 to 5 mm wide and about 0.02 to 0.04 mm deep, connecting the mold cavity 5 to the external space.

[0028] After the lampshade is formed, in order to promote the rapid cooling and solidification of the plastic, the utility model is provided with a cooling cavity 11 in the mold core 4. The mold core 4 is made of heat-conducting materials, such as stainless steel, which can quickly dissipate heat. The bottom surface of the lifting seat 7 is provided with a cooling medium inlet 12 and a cooling medium outlet 13 connected to the cooling cavity 11. The cooling medium inlet 12 is connected to a cooling medium supply mechanism 15 through a first hose 14, and the cooling medium outlet 13 is connected to a second hose 16. The cooling medium supply mechanism 15 can supply a low-temperature cooling medium. The cooling medium enters the cooling cavity 11 through the first hose 14 and the cooling medium inlet 12, cools the mold core 4, and promotes the cooling of the plastic in the cavity 5. After the cooling medium in the cooling cavity 11 absorbs heat, it is discharged from the cooling medium outlet 13 and the second hose 16.

[0029] In the present invention, the cooling medium can be cold air from outside the mold, the cooling medium supply mechanism 15 is an air pump, and the second hose 16 can directly exhaust the air. In order to improve the cooling effect, the cooling medium supply mechanism 15 includes a water tank, which stores cooling water. The water tank is connected to the first hose 14 via a water pump 17, and the second hose 16 is connected to the water tank. Under the action of the water pump 17, the cooling water in the water tank enters the cooling chamber 11 through the first hose 14 and the cooling medium inlet 12. After absorbing heat, it returns to the water tank through the second hose 16 to achieve recycling. The water tank can be open to promote heat dissipation of the water in the water tank. The water level in the water tank can be monitored in real time, and cooling water can be replenished in time when the water level is low.

[0030] After cooling, in order to facilitate the demoulding of the lampshade, an ejection mechanism can be set. The ejection mechanism of the utility model is as follows: Figure 2 As shown, the upper surface of the mold core 4 is provided with multiple vertical ejection holes, which can be evenly distributed around the center of the mold core 4 to ensure that the lampshade is evenly stressed during ejection. A push rod 19 is provided above the ejection hole, which slides in engagement with the hole. A support block 20 is fixedly disposed below the hole, with the upper surface of the support block 20 contacting the lower surface of the push rod 19. The upper surface of the push rod 19 is shaped to match the upper surface of the mold core 4. When the lower surface of the push rod 19 contacts the upper surface of the support block 20, the upper surface of the push rod 19 and the upper surface of the mold core 4 form a molding surface that matches the inner wall of the lampshade. A medium through hole 21 is provided on the support block 20, communicating with the cooling chamber 11. Cooling water in the cooling chamber 11 can enter the medium through hole 21. A valve 18 is provided on the second hose 16. Closing the valve 18 stops the discharge of cooling water from the cooling chamber 11.

[0031] During the process of injecting molten plastic into the cavity 5 and extruding the molten plastic by the mold core 4, the lower surface of the push rod 19 contacts the upper surface of the support block 20. During cooling, the valve 18 is opened and the cooling water in the cooling chamber 11 can be discharged smoothly. After cooling is completed, when demolding is required, the valve 18 can be closed to increase the water pressure in the cooling chamber 11. Under the action of the water pressure, the cooling water reaches the lower surface of the push rod 19 through the medium through hole 21. The water pressure is transmitted to the push rod 19, causing the push rod 19 to apply an upward thrust to the lampshade, thereby pushing the lampshade out of the mold core 4. After demolding, the valve 18 is opened and the water pump 17 is turned off. The water pressure in the cooling chamber 11 is reduced, and the push rod 19 moves downward under the action of gravity until its lower end face contacts the support block 20.

[0032] The utility model utilizes cold water as demoulding power, does not require other power, simplifies the structure of the ejection mechanism, and reduces the difficulty of manufacturing the mold core 4.

[0033] The plastic lampshade injection molding device of the utility model comprises Figure 1The mold assembly shown and other components of the injection molding device can be made of any existing technology.

[0034] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that the present invention is susceptible to various modifications and variations. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A mold assembly, comprising a mold base (1), a lower mold (2) fixedly provided on the mold base (1), an upper mold (3) provided above the lower mold (2), a raised mold core (4) provided on the upper surface of the lower mold (2), a groove provided on the lower surface of the upper mold (3), the mold core (4) and the groove enclosing a molding cavity (5), and an injection port (6) communicating with the molding cavity (5) provided on the top of the upper mold (3); characterized in that: A positioning groove is provided on the upper surface of the lower mold (2), and a lifting seat (7) is provided in the positioning groove and is slidably matched with the positioning groove. The upper end of the lifting seat (7) is fixedly connected to the mold core (4), and the lower end of the lifting seat (7) is connected to a lifting mechanism (8).

2. The mold assembly according to claim 1, wherein: A vertical guide column (9) is provided on the mold base (1), and the guide column (9) passes through the upper mold (3) and is slidably engaged with the upper mold (3).

3. The mold assembly according to claim 1, wherein: A detachable one-way valve (10) is provided in the injection port (6).

4. The mold assembly according to claim 1, wherein: The lifting mechanism (8) is a hydraulic cylinder.

5. The mold assembly according to claim 1, wherein: An exhaust groove is provided on the inner wall of the injection port (6) or on the parting surface between the lower mold (2) and the upper mold (3).

6. The mold assembly according to claim 1, wherein: A cooling cavity (11) is provided in the mold core (4), and a cooling medium inlet (12) and a cooling medium outlet (13) communicating with the cooling cavity (11) are provided on the bottom surface of the lifting seat (7). The cooling medium inlet (12) is connected to a cooling medium supply mechanism (15) via a first hose (14), and the cooling medium outlet (13) is connected to a second hose (16).

7. The mold assembly according to claim 6, wherein: The cooling medium supply mechanism (15) comprises a water tank, the water tank is connected to the first hose (14) via a water pump (17), and the second hose (16) is connected to the water tank.

8. The mold assembly according to claim 7, wherein: A valve (18) is provided on the second hose (16); a plurality of vertical ejection holes are provided on the upper surface of the mold core (4); an ejection rod (19) is provided on the upper portion of the ejection hole and is slidably engaged with the ejection hole; a support block (20) is fixedly provided on the lower portion of the ejection hole; the upper surface of the support block (20) contacts the lower surface of the ejection rod (19), and a medium through hole (21) is provided on the support block (20) and is connected to the cooling chamber (11).

9. Plastic lampshade injection molding device, characterized by: The invention comprises the mold assembly according to claim 1.

Images