Injection mold clamping pressure forming apparatus and method

Abstract

The application belongs to the technical field of injection mold and provides an injection mold pressure forming device and method, which comprises, from top to bottom, a front mold bottom plate, a front mold hot runner plate, a front mold fixed plate, a rear mold fixed plate, a rear mold core fixed plate and a rear mold bottom plate; further comprising an oil cylinder fixing seat arranged at the middle part of the outer wall of the injection mold pressure forming device; the front mold fixed plate and the rear mold fixed plate are provided with an injection cavity; the middle part of the rear mold core fixed plate is provided with a rear mold core, the rear mold core penetrates through the rear mold fixed plate and extends to the injection cavity, and springs are connected between the two ends of the rear mold fixed plate and the rear mold core fixed plate. The injection mold pressure forming device and method can replace the first injection molding and then the pressure forming by injection compression, can improve the uniformity of the overall density of the injection molded product, can make the pressure received by each position of the injection molded product more uniform, and can further avoid the warping deformation of the injection molded product during high-temperature baking.

Description

Technical Field

[0001] The invention belongs to the technical field of injection molds, and in particular relates to an injection mold clamping pressure molding device and method. Background Art

[0002] Injection molding machines are the main molding equipment that uses plastic molding molds to make plastic products of various shapes from thermoplastics or thermosetting plastics. During plastic injection molding, the filled plastic melt shrinks due to cooling, so a pressure holding device is often used to hold the plastic melt under pressure. Since the distance between the inlet and each position of the product is different, the density of each position of the product after injection molding is different, such as Figure 1 As shown in the figure, the glue inlet is at different positions A, B, and C of the product, so the density of the three positions A, B, and C is also different, and the holding pressure is also different. Therefore, during the holding pressure process, the filling pressure compaction degree of each structural position is different, resulting in different stress release at each position after high-temperature baking, and the product will warp and deform.

[0003] For example, patent document CN206501397U discloses an injection molding pressure holding control device, which includes an injection molding machine base, an electrical control box mounted on the injection molding machine base, a display screen mounted on the control box, buttons mounted on one side of the display screen, a PLC controller and memory mounted inside the electrical control box, the display screen, buttons, and memory being electrically connected to the PLC controller, a screw mounted on the top of the injection molding machine base, a fixed plate mounted on the screw, a shot cylinder mounted at the center of the fixed plate, an electric push rod mounted above the shot cylinder, the electric push rod and the shot cylinder connected by a screw, the bottom end of the screw mounted inside the shot cylinder, a transmitting transducer mounted on one side of the shot cylinder, a receiving transducer mounted on the other side of the shot cylinder, and a heating plate mounted on the inner wall of the shot cylinder, the heating plate consisting of an upper aluminum plate, a heating wire, thermally conductive silicone, and a lower aluminum plate. Although this technology can control pressure more accurately and control the operation of the heating plate through a PLC controller, it can reduce shrinkage caused by melt cooling, thereby improving the quality of plastic products. However, this patent document discloses that during melt injection, the density of the product at different locations is different, which results in different holding pressures at different locations of the product during the holding process, thereby affecting the shape of the product. Summary of the Invention

[0004] The present invention aims to address the deficiencies of the existing technology and provide an injection molding pressure molding device and method that uses injection compression instead of injection molding followed by pressure holding molding, which can improve the uniformity of the overall density of the injection molded product, make the pressure at each position of the injection molded product more uniform, and thus avoid warping and deformation of the injection molded product during high-temperature baking.

[0005] In order to achieve the above technical objectives, the present invention adopts the following technical solutions:

[0006] An injection mold clamping pressure molding device comprises a front mold base plate, a front mold hot runner plate, a front mold fixing plate, a rear mold fixing plate, a rear mold core fixing plate and a rear mold base plate which are sequentially arranged from top to bottom;

[0007] It also includes an oil cylinder fixing seat, which is arranged in the middle of the outer wall of the injection mold pressure molding device;

[0008] An injection cavity is provided between the front mold fixing plate and the rear mold fixing plate;

[0009] A rear mold core is provided in the middle of the rear mold core fixing plate, and the rear mold core passes through the rear mold fixing plate and extends to the injection cavity. Springs are connected between the two ends of the rear mold fixing plate and the rear mold core fixing plate.

[0010] Preferably, a front mold cavity is provided on the front mold fixing plate, a rear mold cavity is provided on the rear mold fixing plate, and the injection cavity is arranged between the front mold cavity and the rear mold cavity.

[0011] Preferably, the rear mold core passes through the rear mold cavity and extends to the edge of the injection cavity.

[0012] Preferably, an injection channel is provided between the front mold cavity and the rear mold cavity, and the injection channel is communicated with the injection cavity.

[0013] Preferably, the oil cylinder fixing seat includes an oil cylinder movable insert, the oil cylinder movable insert is slidably connected to the oil cylinder fixing seat, and the oil cylinder movable insert is located between the front mold fixing plate and the rear mold fixing plate. When the injection molding is completed, the oil cylinder movable insert can be inserted between the front mold fixing plate and the rear mold fixing plate to prevent the rear mold fixing plate and the rear mold core fixing plate from moving relative to each other.

[0014] Preferably, an oblique pin insert is provided on the rear mold bottom plate, and the oblique pin insert is slidably connected to the rear mold bottom plate. The oblique pin insert passes through the rear mold core fixing plate and the rear mold core and extends to the edge of the injection cavity. When the injection molding is completed, the oblique pin insert can eject the injection molded product.

[0015] Preferably, a method for injection molding using the injection mold clamping pressure molding device comprises the following steps:

[0016] S1, the injection mold clamping pressure molding device is in a closed state, the front mold fixing plate and the rear mold fixing plate are in a closed state, the injection cavity space volume is a fixed value, and the spring is compressed, so that elastic force is generated between the rear mold fixing plate and the rear mold core fixing plate;

[0017] S2. The injection mold clamping pressure molding device is opened to a preset distance, the front mold fixing plate remains stationary, and the rear mold fixing plate moves downward by a preset distance. The elastic force of the spring drives the rear mold core fixing plate to move downward by a preset distance, and then the rear mold core also moves downward by the same distance, and the spatial volume of the injection cavity increases by the same distance.

[0018] S3, injecting molten plastic fluid into the injection cavity;

[0019] S4. After the injection is completed, the high-pressure mold clamping device is tightened, and the rear mold fixing plate is synchronously moved upward by a preset distance, driving the rear mold core fixing plate to synchronously move upward by a preset distance, and then the rear mold core also synchronously moves upward by the same distance. The volume of the injection cavity space is restored to a fixed value, and the plastic fluid in the injection cavity is compressed and filled, with uniform density;

[0020] S5, the oil cylinder fixing seat prevents the rear mold fixing plate and the rear mold core fixing plate from moving relative to each other due to the elastic force of the spring;

[0021] S6, opening the injection mold clamping pressure molding device and taking out the injection molded product.

[0022] Preferably, the preset distance is 0.2 mm-0.4 mm.

[0023] Preferably, the oil cylinder fixing seat includes an oil cylinder movable insert, and the oil cylinder movable insert is slidably connected to the oil cylinder fixing seat. The oil cylinder movable insert is inserted between the front mold fixing plate and the rear mold fixing plate to prevent the rear mold fixing plate and the rear mold core fixing plate from moving relative to each other due to the spring force.

[0024] Preferably, an oblique pin insert is provided on the rear mold bottom plate, and the oblique pin insert is slidably connected to the rear mold bottom plate. The oblique pin insert passes through the rear mold core fixing plate and the rear mold core and extends to the edge of the injection cavity. When the injection clamping pressure molding device is opened, the oblique pin insert ejects the injection molded product.

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

[0026] (1) By setting the spring between the two ends of the rear mold fixed plate and the rear mold core fixed plate, the elastic force between the rear mold fixed plate and the rear mold core fixed plate is generated, when the rear mold fixed plate moves downward, the rear mold core fixed plate is driven to move downward synchronously, so that the space volume of the injection cavity is increased by the same distance synchronously, after the molten plastic fluid is injected into the injection cavity, the high-pressure locking mold is tightly closed, the injection cavity space volume returns to the fixed value, the plastic fluid in the injection cavity is compressed and filled, compared with the first injection and then the pressure holding, the injection compression replaces the pressure holding forming, so that the overall density of the injection product is more uniform, the pressure received by each position of the injection product is more uniform, and the subsequent injection product avoids the problems of warping and deformation during high-temperature baking process;

[0027] (2) By injection compression instead of first injection and then pressure holding forming, the process and working time are saved, and the injection efficiency is improved;

[0028] (3) By setting the oil cylinder movable insert, after the injection mold is closed and the injection mold pressure forming device is opened, the oil cylinder movable insert can prevent the rear mold fixed plate and the rear mold core fixed plate from moving relative to each other, so that the spring will not be elastically deformed, so that when the inclined pin insert moves upward to eject the injection product, the inclined pin insert will not damage the injection product due to the movement of the rear mold fixed plate and the rear mold core fixed plate, and the injection product is better protected. By setting the inclined pin insert, the injection product can be taken out more conveniently. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 It is a perspective view of the injection mold pressure forming device of the present application;

[0030] Figure 2 It is a sectional view of the injection mold pressure forming device of the present application;

[0031] Figure 3 It is a partial enlarged view of A in the present application; Figure 2

[0032] Figure 4 It is a partial internal structure sectional view of the present application containing spring and inclined pin insert;

[0033] Figure 5 It is a top view of the internal structure of the present application.

[0034] BRIEF DESCRIPTION OF DRAWINGS:

[0035] ​1. Front mold base plate; 2. Front mold hot runner plate; 3. Front mold fixing plate; 31. Front mold cavity; 4. Rear mold fixing plate; 41. Rear mold cavity; 5. Rear mold core fixing plate; 51. Rear mold core; 6. Rear mold base plate; 61. Oblique pin insert; 7. Cylinder fixing seat; 71. Cylinder movable insert; 8. Injection cavity; 9. Spring. DETAILED DESCRIPTION

[0036] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0037] In the description of the present invention, it should be understood that the terms "coaxial", "bottom", "one end", "top", "middle", "the other end", "upper", "one side", "top", "inside", "front", "center", "both ends", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0038] In the present invention, unless otherwise clearly stipulated and limited, the terms "install", "set", "connect", "fix", "screw" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal connection of two elements or the interaction relationship between two elements. Unless otherwise clearly defined, ordinary technicians in this field can understand the specific meanings of the above terms in the present invention according to the specific circumstances.

[0039] Example 1

[0040] Combine Figure 1-Figure 2As shown, an embodiment of the present invention provides an injection mold pressure molding device, comprising a front mold base plate 1, a front mold hot runner plate 2, a front mold fixing plate 3, a rear mold fixing plate 4, a rear mold core fixing plate 5 and a rear mold base plate 6 arranged in sequence from top to bottom, and also comprising a cylinder fixing seat 7, wherein the cylinder fixing seat 7 is arranged in the middle of the outer wall of the injection mold pressure molding device, the front mold fixing plate 3 is provided with a front mold cavity 31, the rear mold fixing plate 4 is provided with a rear mold cavity 41, and the injection cavity 8 is arranged between the front mold cavity 31 and the rear mold cavity 41; a rear mold core 51 is provided in the middle of the rear mold core fixing plate 5, and the rear mold core 51 passes through the rear mold cavity 41 and extends to the edge of the injection cavity 8; an injection channel (not shown in the figure) is provided between the front mold cavity 31 and the rear mold cavity 41, and the injection channel is connected to the injection cavity 8, and a spring 9 is connected between the two ends of the rear mold fixing plate 4 and the rear mold core fixing plate 5.

[0041] By setting springs 9 between the two ends of the rear mold fixing plate 4 and the rear mold core fixing plate 5, an elastic force is generated between the rear mold fixing plate 4 and the rear mold core fixing plate 5. When the rear mold fixing plate 4 moves downward by a preset distance, the rear mold core fixing plate 5 is driven to move downward by a preset distance synchronously, so that the spatial volume of the injection cavity 8 is increased by the original fixed value and the spatial volume of the injection cavity 8 by the same preset distance is increased synchronously. After the molten plastic fluid is injected into the injection cavity 8, the high-pressure clamping mold is tightened to close the injection mold pressure molding device. Specifically, the clamping force is 400t during high-pressure clamping, and the rear mold fixing plate 4 moves upward by a preset distance. , driving the rear mold core fixing plate 5 to move upward synchronously by a preset distance, and then the rear mold core 51 also moves upward synchronously by the same distance, until the front mold fixing plate 3 and the rear mold fixing plate 4 are tightened, and the spatial volume of the injection cavity 8 is restored to a fixed value. The plastic fluid in the injection cavity 8 is compressed and enriched, and the overall density of the injection molded product is more uniform. The stress released at each position is the same. Compared with injecting first and then holding pressure, the density of the injection molded product is more uniform by replacing holding pressure molding with injection compression. The pressure at each position of the injection molded product is more uniform, and the subsequent injection molded product is avoided from warping and deformation during high-temperature baking.

[0042] Example 2

[0043] Combine Figure 1-Figure 2As shown, according to a specific embodiment of the present invention, the cylinder fixing seat 7 includes a cylinder movable insert 71, and the cylinder movable insert 71 is slidably connected to the cylinder fixing seat 7, and the cylinder movable insert 71 is located between the front mold fixing plate 3 and the rear mold fixing plate 4. When the injection molding is completed, the cylinder movable insert 71 can be inserted between the front mold fixing plate 3 and the rear mold fixing plate 4 to prevent the rear mold fixing plate 4 and the rear mold core fixing plate 5 from moving relative to each other. The rear mold bottom plate 6 is provided with an oblique pin insert 61. Specifically, there are 6 oblique pin inserts 61, and the oblique pin inserts 61 are slidably connected to the rear mold bottom plate 6. The oblique pin inserts 61 pass through the rear mold core fixing plate 5 and the rear mold core 51, and extend to the edge of the injection cavity 8. When the injection molding is completed, the oblique pin inserts 61 can eject the injection molded product.

[0044] By setting the movable cylinder insert 71, the movable cylinder insert 71 is located between the front mold fixing plate 3 and the rear mold fixing plate 4. After the injection molding is completed, the movable cylinder insert 71 is inserted between the front mold fixing plate 3 and the rear mold fixing plate 4, so that when the injection molding is completed, after the injection molding pressure molding device is opened, the movable cylinder insert 71 can prevent the rear mold fixing plate 4 and the rear mold core fixing plate 5 from moving relative to each other, so that the spring 9 will not have an elastic effect, so that when the oblique pin insert 61 moves upward to eject the injection molded product, the oblique pin insert 61 will not damage the injection molded product due to the mutual movement between the rear mold fixing plate 4 and the rear mold core fixing plate 5, so the injection molded product is better protected. By setting the oblique pin insert 61, it is also more convenient to take out the injection molded product.

[0045] Example 3

[0046] An embodiment of the present invention further provides a method for performing injection molding using the injection mold clamping pressure molding device of the present invention, comprising the following steps:

[0047] S1, the injection mold clamping pressure molding device is in a closed state, the front mold fixing plate 3 and the rear mold fixing plate 4 are in a closed state, the volume of the injection cavity 8 is fixed, and the spring 9 is compressed, so that elastic force is generated between the rear mold fixing plate 4 and the rear mold core fixing plate 5;

[0048] S2. The injection mold clamping pressure molding device is opened to a preset distance, the front mold fixing plate 3 remains stationary, and the rear mold fixing plate 4 moves downward by a preset distance. The elastic force of the spring 9 drives the rear mold core fixing plate 5 to move downward by a preset distance, and then the rear mold core 51 also moves downward by the same distance, and the injection cavity 8 increases its spatial volume by the same distance.

[0049] S3, injecting molten plastic fluid into the injection cavity 8;

[0050] S4. After the injection is completed, the high-pressure mold clamping device is tightened, and the rear mold fixing plate 4 is synchronously moved upward by a preset distance, driving the rear mold core fixing plate 5 to synchronously move upward by a preset distance, and then the rear mold core 51 is also synchronously moved upward by the same distance. The volume of the injection cavity 8 is restored to a fixed value, and the plastic fluid in the injection cavity 8 is compressed and filled, with uniform density;

[0051] S5, the oil cylinder fixing seat 7 includes an oil cylinder movable insert 71, the oil cylinder movable insert 71 is slidably connected to the oil cylinder fixing seat, and is inserted between the front mold fixing plate 3 and the rear mold fixing plate 4 through the oil cylinder movable insert 71 to prevent the rear mold fixing plate 4 and the rear mold core fixing plate 5 from moving relative to each other due to the elastic force of the spring 9;

[0052] S6. An oblique pin insert 61 is provided on the rear mold base plate 6, and the oblique pin insert 61 is slidably connected to the rear mold base plate 6. The oblique pin insert 61 passes through the rear mold core fixing plate 5 and the rear mold core 51 and extends to the edge of the injection cavity 8. When the injection clamping pressure molding device is opened, the oblique pin insert 61 ejects the injection molded product.

[0053] Furthermore, the preset distance is 0.2 mm-0.4 mm, and in this embodiment, specifically 0.4 mm.

[0054] The above description is only an embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the scope of the present invention shall be included in the scope of protection of the present invention.

Claims

1. An injection mold clamping pressure molding device, characterized in that, It includes a front mold base plate, a front mold hot runner plate, a front mold fixing plate, a rear mold fixing plate, a rear mold core fixing plate and a rear mold base plate which are arranged in sequence from top to bottom; It also includes an oil cylinder fixing seat, which is arranged in the middle of the outer wall of the injection mold pressure molding device; An injection cavity is provided between the front mold fixing plate and the rear mold fixing plate; A rear mold core is provided in the middle of the rear mold core fixing plate, the rear mold core passes through the rear mold fixing plate and extends to the injection cavity, and springs are connected between the two ends of the rear mold fixing plate and the rear mold core fixing plate; The oil cylinder fixing seat includes an oil cylinder movable insert, and the oil cylinder movable insert is slidably connected to the oil cylinder fixing seat. The oil cylinder movable insert is located between the front mold fixing plate and the rear mold fixing plate. When the injection molding is completed, the oil cylinder movable insert is inserted between the front mold fixing plate and the rear mold fixing plate to prevent the rear mold fixing plate and the rear mold core fixing plate from moving relative to each other.

2. The injection mold clamping pressure molding device according to claim 1, characterized in that: A front mold cavity is provided on the front mold fixing plate, a rear mold cavity is provided on the rear mold fixing plate, and the injection cavity is arranged between the front mold cavity and the rear mold cavity.

3. The injection mold clamping pressure molding device according to claim 2, characterized in that: The rear mold core passes through the rear mold cavity and extends to the edge of the injection cavity.

4. The injection mold clamping pressure molding device according to claim 3, characterized in that: An injection channel is provided between the front mold cavity and the rear mold cavity, and the injection channel is communicated with the injection cavity.

5. The injection mold clamping pressure molding device according to claim 1, characterized in that: An oblique pin insert is provided on the rear mold bottom plate, and the oblique pin insert is slidably connected to the rear mold bottom plate. The oblique pin insert passes through the rear mold core fixing plate and the rear mold core and extends to the edge of the injection cavity. When the injection molding is completed, the oblique pin insert ejects the injection molded product.

6. A method for injection molding using the injection mold clamping pressure molding device according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1, the injection mold clamping pressure molding device is in a closed state, the front mold fixing plate and the rear mold fixing plate are in a closed state, the injection cavity space volume is a fixed value, and the spring is compressed, so that elastic force is generated between the rear mold fixing plate and the rear mold core fixing plate; S2. The injection mold clamping pressure molding device is opened to a preset distance, the front mold fixing plate remains stationary, and the rear mold fixing plate moves downward by a preset distance. The elastic force of the spring drives the rear mold core fixing plate to move downward by a preset distance, and then the rear mold core also moves downward by the same distance, and the spatial volume of the injection cavity increases by the same distance. S3, injecting molten plastic fluid into the injection cavity; S4. After the injection is completed, the high-pressure mold clamping device is tightened, and the rear mold fixing plate is synchronously moved upward by a preset distance, driving the rear mold core fixing plate to synchronously move upward by a preset distance, and then the rear mold core also synchronously moves upward by the same distance. The volume of the injection cavity space is restored to a fixed value, and the plastic fluid in the injection cavity is compressed and filled, with uniform density; S5, the oil cylinder fixing seat prevents the rear mold fixing plate and the rear mold core fixing plate from moving relative to each other due to the elastic force of the spring; S6, opening the injection mold clamping pressure molding device and taking out the injection molded product.

7. The method for injection molding according to claim 6, wherein: The preset distance is 0.2mm-0.4mm.

8. The method for performing injection molding according to claim 6, wherein: The oil cylinder fixing seat includes an oil cylinder movable insert, which is slidably connected to the oil cylinder fixing seat and is inserted between the front mold fixing plate and the rear mold fixing plate through the oil cylinder movable insert to prevent the rear mold fixing plate and the rear mold core fixing plate from moving relative to each other due to the elastic force of the spring.

9. The method for injection molding according to claim 6, wherein: An oblique pin insert is provided on the rear mold bottom plate, and the oblique pin insert is slidably connected to the rear mold bottom plate. The oblique pin insert passes through the rear mold core fixing plate and the rear mold core and extends to the edge of the injection cavity. When the injection clamping pressure molding device is opened, the oblique pin insert ejects the injection molded product.

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