Injection mold closing pressure forming device and method

Abstract

The invention belongs to the technical field of injection molds, and provides an injection mold closing pressure forming device and method.The injection mold closing pressure forming device comprises a front mold bottom 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 bottom plate which are sequentially arranged from top to bottom; the oil cylinder fixing seat is arranged in the middle of the outer wall of the injection mold closing pressure forming device; an injection molding cavity is formed between the front mold fixing plate and the rear mold fixing plate; a rear mold core is arranged in the middle of the rear mold core fixing plate, the rear mold core penetrates through the rear mold fixing plate and extends to the injection molding cavity, and springs are connected between the two ends of the rear mold fixing plate and the rear mold core fixing plate. According to the injection molding mold closing pressure forming device and method, injection molding and pressure maintaining forming are replaced with injection molding compression, the uniformity of the overall density of an injection molding product can be improved, the pressure borne by each position of the injection molding product is more uniform, and then buckling deformation of the injection molding product during high-temperature baking is avoided.

Description

Technical Field

[0001] The invention belongs to the technical field of injection molds, and in particular relates to an injection mold 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. Therefore, 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, 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, including an injection molding machine base, an electric control box installed on the injection molding machine base, a display screen installed on the control box, a button installed on one side of the display screen, a PLC controller and a memory installed inside the electric control box, the display screen, the button and the memory are all electrically connected to the PLC controller, a screw is installed on the top of the injection molding machine base, a fixed plate is installed on the screw, a shot cylinder is installed at the center of the fixed plate, an electric push rod is installed above the shot cylinder, the electric push rod is connected to the shot cylinder through a screw, the bottom end of the screw is installed inside the shot cylinder, a transmitting transducer is installed on one side of the shot cylinder, a receiving transducer is installed on the other side of the shot cylinder, a heating plate is installed on the inner wall of the shot cylinder, and the heating plate is composed of an upper aluminum plate, a heating wire, a thermal conductive silica gel and a lower aluminum plate. Although this technology can control the pressure more accurately and control the operation of the heating plate through the PLC controller, it can reduce the shrinkage caused by melt cooling, so that the quality of plastic products is improved. However, this patent document discloses that during melt injection, the density of different positions of the product is different, which results in different holding pressures at different positions of the product during the holding pressure process, thereby affecting the shape of the product. Summary of the invention

[0004] The present invention aims to address the deficiencies in the prior art and to provide an injection molding pressure molding device and method that uses injection molding compression instead of injection molding followed by pressure holding molding, thereby improving the uniformity of the overall density of the injection molded product, making the pressure on each position of the injection molded product more uniform, and thereby avoiding 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 bottom 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 bottom plate which are arranged in sequence 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, 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.

[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 cylinder fixing seat includes a cylinder movable insert, which is slidably connected to the cylinder fixing seat and is located between the front mold fixing plate and the rear mold fixing plate. When the injection molding is completed, the 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 pressure molding device comprises the following steps:

[0016] S1, the injection mold clamping pressure molding device is in a tightened state, the front mold fixing plate and the rear mold fixing plate are in a tightened state, the injection cavity space volume is a fixed value, 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, 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 synchronously, and then the rear mold core also moves downward by the same distance synchronously, and the injection cavity increases the spatial volume by the same distance synchronously;

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

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

[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 cylinder fixing seat includes a cylinder movable insert, which is slidably connected to the cylinder fixing seat and 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 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 beneficial effects of the present invention are:

[0026] (1) By arranging springs between the two ends of the rear mold fixing plate and the rear mold core fixing plate, elastic force is generated between the rear mold fixing plate and the rear mold core fixing plate. When the rear mold fixing plate moves downward, the rear mold core fixing plate is driven to move downward synchronously, so that the spatial volume of the injection cavity increases by the same distance from the original fixed value. After the molten plastic fluid is injected into the injection cavity, the high-pressure clamping mold is tightened to close the injection mold pressure molding device, and the spatial volume of the injection cavity is restored to the fixed value. The plastic fluid in the injection cavity is compressed and filled. Compared with injection molding first and then pressure holding, the injection compression replaces the pressure holding molding, so that the overall density of the injection molded product is more uniform, and the pressure at each position of the injection molded product is more uniform. In the subsequent high-temperature baking process of the injection molded product, the problems of warping and deformation of the injection molded product are avoided;

[0027] (2) By replacing injection molding with compression molding, the process and working time are saved, and the injection molding efficiency is improved;

[0028] (3) By setting up a movable oil cylinder insert, after the injection mold is completed and the injection mold pressure molding device is opened, the movable oil cylinder insert can prevent the rear mold fixing plate and the rear mold core fixing plate from moving relative to each other, so that the spring will not have an elastic effect. Therefore, when the inclined pin insert moves upward to eject the injection molded product, the inclined pin insert will not damage the injection molded product due to the relative movement between the rear mold fixing plate and the rear mold core fixing plate, thereby better protecting the injection molded product. By setting up the inclined pin insert, it is more convenient to take out the injection molded product. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 A three-dimensional diagram of the injection mold pressure molding device of the present invention;

[0030] Figure 2 It is a cross-sectional view of the injection mold pressure molding device of the present invention;

[0031] Figure 3 For the present invention Figure 2 A partial enlarged view of the middle A;

[0032] Figure 4 A cross-sectional view of a portion of the internal structure of the present invention including a spring and an oblique pin insert;

[0033] Figure 5 It is a schematic diagram of the internal structure of the present invention from a top view.

[0034] Description of reference numerals:

[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 be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. 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 creative work are within the scope of protection of the present invention.

[0037] In the description of the present invention, it is necessary to understand that the terms "coaxial", "bottom", "one end", "top", "middle", "the other end", "upper", "one side", "top", "inside", "front", "center", "both ends" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0038] In the present invention, unless otherwise clearly stipulated and limited, the terms such as "installation", "setting", "connection", "fixation" and "screw-on" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral one; 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] Combination 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 which are arranged in sequence from top to bottom, and also comprises 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 model cavity 31, the rear mold fixing plate 4 is provided with a rear model cavity 41, and the injection cavity 8 is arranged between the front model cavity 31 and the rear model 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 model 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 model cavity 31 and the rear model cavity 41, and the injection channel is connected to the injection cavity 8, and springs 9 are 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, 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 used to close the injection mold clamping 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 a preset distance, and then the rear mold core 51 also moves upward synchronously 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 returns to a fixed value, and the plastic fluid in the injection cavity 8 is compressed and filled, and the overall density of the injection molded product is more uniform, and the stress released at each position is the same. Compared with injection molding first and then pressure holding molding, injection molding compression replaces pressure holding molding, so that the density of the injection molded product is more uniform, and the pressure at each position of the injection molded product is more uniform. In the subsequent high-temperature baking process of the injection molded product, the warping and deformation of the injection molded product are avoided.

[0042] Example 2

[0043] Combination 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 and 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 relative 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] The 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 tightened state, the front mold fixing plate 3 and the rear mold fixing plate 4 are in a tightened state, the volume of the injection cavity 8 is a fixed value, 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, 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 synchronously, and then the rear mold core 51 also moves downward by the same distance synchronously, and the injection cavity 8 increases the spatial volume by the same distance synchronously;

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

[0050] S4, after the injection is completed, the high-pressure mold clamping closes the injection mold pressure molding device, the rear mold fixing plate 4 moves upward synchronously 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, and the spatial 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, and the density is uniform;

[0051] S5, the oil cylinder fixing seat 7 comprises an oil cylinder movable insert 71, the oil cylinder movable insert 71 is slidably connected to the oil cylinder fixing seat 7, and the oil cylinder movable insert 71 is 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 due to the elastic force of the spring 9;

[0052] S6. An oblique pin insert 61 is provided on the rear mold bottom plate 6, and the oblique pin insert 61 is slidably connected to the rear mold bottom 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 mold 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 modification, equivalent replacement and improvement made within the application scope of the present invention shall be included in the protection scope of the present invention.

Claims

1. An injection mold pressure molding device, characterized in that: It includes a front mold bottom 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 bottom plate which are arranged in sequence from top to bottom; It also includes a 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.

2. The injection mold clamping pressure molding device according to claim 1, characterized in that: The front mold fixing plate is provided with a front mold cavity, the rear mold fixing plate is provided with a rear mold cavity, 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 4, characterized in that: 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 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.

6. 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 can eject the injection molded product.

7. A method for injection molding using the injection mold clamping pressure molding device according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1, the injection mold clamping pressure molding device is in a tightened state, the front mold fixing plate and the rear mold fixing plate are in a tightened state, the injection cavity space volume is a fixed value, 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, 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 synchronously, and then the rear mold core also moves downward by the same distance synchronously, and the injection cavity increases the spatial volume by the same distance synchronously; S3, injecting molten plastic fluid into the injection cavity; S4, after the injection is completed, the high-pressure mold clamping closes the injection mold pressure molding device, the rear mold fixing plate moves upward synchronously by a preset distance, driving the rear mold core fixing plate to move upward synchronously by a preset distance, and then the rear mold core also moves upward synchronously by the same distance, the injection cavity space volume is restored to a fixed value, the plastic fluid in the injection cavity is compressed and filled, and the density is uniform; 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.

8. The method for injection molding according to claim 7, characterized in that: The preset distance is 0.2mm-0.4mm.

9. The method for injection molding according to claim 7, characterized in that: 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 elastic force of the spring.

10. The method for injection molding according to claim 7, 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 clamping pressure molding device is opened, the oblique pin insert ejects the injection molded product.

Images