CN113290789A

CN113290789A - Thick workpiece injection mold and operation method

Info

Publication number: CN113290789A
Application number: CN202110724003.XA
Authority: CN
Inventors: 苏良瑶; 张志宏; 赵栋杰; 陈炳奎; 张光辉
Original assignee: Hangzhou Bensong New Materials Technology Co ltd
Current assignee: Hangzhou Bensong New Materials Technology Co ltd
Priority date: 2021-06-29
Filing date: 2021-06-29
Publication date: 2021-08-24

Abstract

The application belongs to the technical field of plastic processing, and particularly relates to an injection mold and an operation method. Disclosed is a thick article injection mold, including: the push rod, the push block is connected to the one end of push rod, and is located the die cavity outside, the thimble board is connected with the other end of push rod, buffer structure and/or die cavity compression structure. The design of the push block, the push rod, the ejector plate, the buffer structure and/or the cavity compression structure can obviously reduce the layering and air hole defects of the plastic part in the cooling process, and provides a reliable technical scheme for processing the plastic-aluminum-substituted thick part.

Description

Thick workpiece injection mold and operation method

Technical Field

The application belongs to the technical field of plastic processing, and particularly relates to an injection mold and an operation method.

Background

The plastic has the advantages of light weight, low raw material cost, low processing cost, easy molding, high production efficiency and the like, and gradually replaces the traditional metal structural part. However, in the alternative process, one important factor to consider is the mechanical properties of the plastic structure. Due to the limitation of the characteristics of plastic materials, the mechanical properties of products can be reduced for a plurality of reasons, but the defects of layering, air holes and the like of the internal structure of a finished piece can be caused by shrinkage in the processing and cooling process, particularly for thick finished pieces, the defects are particularly obvious, so that the appearance of the plastic finished piece is poor, the mechanical properties are reduced, the requirements of the original metal structural part are difficult to meet, and the pain point which is difficult to solve in the industry is always the current.

Due to the particularity of the plastic material in the processing process, the manufacturing of the plastic sample block is difficult along with the increase of the thickness of the plastic sample block, the shrinkage deformation is difficult to control as the thickness of a workpiece is thicker, and the defects of layering, air holes and the like are difficult to solve. The thickness of the product in the prior art is usually below 7mm, and the product with the thickness above 7mm is a thick product, which is difficult to realize by the conventional technology. The 3D printing technology can directly print out thicker parts, however, is limited by the mechanical properties of special plastic materials, cannot add high-content reinforcing filler (such as glass fibers), cannot realize 3D printing due to the properties of flowability, rapid cooling forming and the like, and has the defects of layering, air holes and the like easily appearing between different printing layers due to the material nozzle structure and process setting in the printing process. The double-shot molding process can increase the thickness of a finished piece, but the double-shot molding can generate obvious layering, has poor mechanical property and easily causes the layering and falling off in the milling process. The compression molding process has high requirement on the thickness of the product, and when the thickness is thick, the product is easy to cause fast shrinkage deformation, and small products are difficult to mold by compression molding. For materials with poor flowability (e.g., high proportion of reinforcing filler), the samples prepared by the molding process are very prone to delamination and porosity inside the sample block due to outgassing problems.

In addition, for thick plastic products with higher mechanical property requirements, plastic sample blocks meeting the requirements of the product thickness can be prepared first, and then required samples are milled. However, the internal structure of the product has the defects of delamination and air holes due to shrinkage in the process of processing and cooling.

Disclosure of Invention

In view of the layering and the air vent problem that the thick part processing that prior art exists produced, the application provides an injection mold who reduces the layering and the air vent problem that thick part processing produced. The method is realized by the following technical scheme:

a thick article injection mold comprising:

one side wall of the cavity is a movable push block, the volume of the cavity can be changed by moving the push block,

one end of the push rod is connected with the push block and is positioned outside the cavity,

the ejector pin plate is connected with the other end of the push rod,

the buffer structure and/or the cavity compression structure,

the distance between the initial working position of the buffer structure and the ejector plate is more than or equal to 0, and the ejector plate is in a contact state when the distance between the ejector plate and the buffer structure is 0; the buffer structure can drive the ejector plate to move when the push block moves towards the push rod direction, and can apply buffer thrust in the opposite direction of the movement of the ejector plate to the ejector plate, so that the push block has buffer resistance in the process of moving towards the push rod direction;

the distance between the initial working position of the cavity compression structure and the ejector plate is larger than or equal to 0, when the distance between the ejector plate and the cavity compression structure is 0, the cavity compression structure is in a contact state, and the cavity compression structure can apply thrust in the direction opposite to the moving direction of the ejector plate to the ejector plate through contact with the ejector plate, so that the push block moves towards the inside of the cavity.

In one embodiment, the buffer structure is one or more elastic elements, and the elastic elements are in a pre-pressing state during operation. In the prepressing state, the elastic element can give reverse elasticity to a part for compressing the elastic element, so that resistance to the movement process is formed, but the elastic element is controlled not to completely block the cavity movement to influence the injection molding process, and the elastic element is preferably selected.

In one embodiment, the damping structure is one or more first pressure transmission devices. By controlling the operation of the first pressure transmission device (such as the stretching of the oil cylinder), resistance to the movement process is formed.

In one embodiment, the buffer structure is one or more elastic elements and one or more first pressure transmission devices, the elastic elements are in a pre-pressing state during operation, the first pressure transmission devices can apply pushing force or pulling force to the ejector pin plate, and the pushing force or the pulling force can apply buffer pushing force to the ejector pin plate in the direction opposite to the movement direction of the ejector pin plate, so that the push block has buffer resistance in the process of moving towards the push rod; one of the elastic element and the first pressure transmission device is in contact connection with the ejector plate and is in a series superposition state, or the elastic element and the first pressure transmission device are both in contact connection with the ejector plate and are in a parallel state. The series-connection superposition state and the parallel-connection state are two different installation modes, and the series connection can be selected according to requirements, and if the compression amount of a single elastic element and the stroke of an oil cylinder are smaller than the requirements, the maximum stroke for providing resistance can be enhanced.

In one embodiment, the elastic element is one or more of a compression spring, a disc spring and a nitrogen spring.

In one embodiment, a guide structure is provided in the compression spring. The offset direction of the compression spring during working is favorably controlled.

In one embodiment, the guide structure is a guide rod or a shock absorber. The compression spring may constitute a damping spring with the shock absorber.

In one embodiment, the cavity compression structure is one or more second pressure transmission devices.

In one embodiment, the initial position of the cavity compression structure is not in direct contact with the ejector plate.

In one embodiment, the initial position of the cavity compression structure is in direct contact with the ejector plate. If the oil cylinder is fixed with the ejector plate, the installation mode of the oil cylinder ejector base plate can be realized.

In one embodiment, the cavity compression structure is one or more of a second pressure transmission device and a pressure transmission structure, the pressure transmission structure is driven by the second pressure transmission device, and through contact connection with the ejector plate, pushing force in the direction opposite to the movement direction of the ejector plate is applied to the ejector plate, so that the push block moves towards the inside of the cavity.

In one embodiment, the pressure transmission structure is one of a seesaw transmission structure or a skew shovel transmission structure.

In one embodiment, the first pressure transmission device or the second pressure transmission device is a hydraulic device, a pneumatic device or a gas-liquid mixing pressure device. Specifically, an oil cylinder, an air cylinder or a gas-liquid pressure cylinder and the like can be selected according to requirements.

In one embodiment, a heating device is arranged outside the cavity and used for preventing the cavity from being layered due to the temperature difference of the cavity in the moving process of the push plate caused by too low temperature of the cavity.

The application also provides an operation method of the thick part injection mold, which corresponds to the buffer structure and/or the cavity compression structure, and comprises the buffer structure working step and/or the cavity compression structure working step:

the buffer structure comprises the following working steps: when the cavity is filled with melt, the buffer structure applies buffer thrust in the direction opposite to the movement direction of the ejector plate to the ejector plate in the partial or whole process that the ejector plate moves towards the direction of the push rod, and the buffer thrust is transmitted to the ejector plate through the push rod, so that the ejector plate has buffer resistance in the process of moving towards the direction of the push rod;

the working steps of the cavity compression structure are as follows: and after the process of filling the melt into the cavity is finished, the cavity compression structure applies pushing force or pulling force to the ejector plate, and the pushing force or pulling force is transmitted to the push block through the push rod to push the push block to move towards the inside of the cavity. Preferably, the buffer structure and the cavity compression structure exist at the same time, the two steps are implemented together, the compression amount of the melt in the cavity is further controlled, and the layering and air hole defects in the cooling process are reduced.

When the buffer structure and the cavity compression structure exist simultaneously, the working steps are executed according to the corresponding sequence, when the cavity compression structure works, the buffer structure (including an elastic element) is in a compressed state, and when the cavity compression structure works, the buffer structure also provides the thrust of the push block in the same direction as the cavity compression structure, so that the elastic deformation process is recovered.

In one embodiment, the step of operating the cavity compression structure further includes a gate cooling process, where the gate cooling process is performed after the cavity is filled with the melt and before the cavity compression structure operates. The sprue bushing or the needle valve type hot runner is adopted to fill the melt into the cavity, and when the sprue bushing is adopted, the melt in the sprue bushing needs to be cooled, so that the phenomenon that the melt overflows from the sprue bushing or is extruded out of the injection molding machine when the cavity compression structure works is prevented.

Compared with the prior art, one side wall of the cavity is provided with the movable push block, the volume of the cavity is controlled, and the cavity is adjusted to be a variable-volume cavity from a fixed cavity of an original injection mold and is also used as a necessary condition for matching with a buffer structure and/or a cavity compression structure; the structural design of push rod and thimble board for with the atress of thimble board, transmit the ejector pad for through the push rod, avoided establishing buffer structure and die cavity compression structure inside die holder (A board or B board), the following problem of existence includes: 1) the working state of the part of the structure is difficult to monitor, and the maintenance and the replacement of accessories are complicated; 2) when a buffer structure and a cavity compression structure need to provide larger thrust to the push plate, the push plate is easy to deform due to the limitation of the design thickness of the push plate, the matching of the push plate and the inner wall of the cavity is influenced, and the service life is greatly shortened; 3) the buffer structure and the cavity compression structure are designed in the die holder and limited by the thickness of the die holder and the height size of the cavity, and the size and the stroke of the selected buffer structure and the cavity compression structure are shorter, so that the injection molding requirement of a thicker workpiece is difficult to meet. According to the scheme, the ejector pin plate is arranged outside the die holder, the required thickness can be designed and adjusted according to the pressure requirement, and deformation caused by overlarge pressure is avoided; still can set up the thimble board support column to the thimble board and be used for strict restriction thimble board moving direction, avoid appearing because of the inhomogeneous emergence deformation that leads to the push pedal atress of thimble board atress, the life of extension mould.

According to the technical scheme, the situation that the buffer structure and the cavity compression structure exist simultaneously or one of two selection is adopted, the melt is extruded, gas between the melts is further removed, the density of the melt is improved, the needed surrounding loose space is reduced in the cooling process layering and the air hole, and therefore the layering and the air hole are extruded. In addition, the melt density increases, the melt at the preformed delamination and porosity during cooling needs to move elsewhere to form delamination and porosity, and the increase in density impedes the melt from moving, thereby reducing the delamination and porosity formation. The application selects the buffer structure, so that the melt can be extruded by utilizing the combined action of injection pressure and the buffer structure in the process of filling the melt in the cavity; the selection die cavity compression structure can extrude the melt through extruding the push block towards the inside of the die cavity after the melt filling process of the die cavity, and the die cavity compression structure is an active compression structure, and the compression ratio of the melt in the die cavity is controlled by controlling the compression distance (such as the ejection distance of an oil cylinder to an ejector plate), so that the optimum compression ratio can be adjusted according to the experiment of a plurality of workpieces for the same material. Preferably, buffer structure and die cavity compression structure exist simultaneously, and the effect is better, and further compression fuse-element improves fuse-element density, and when buffer structure exists, die cavity compression structure can not contact the thimble board in advance, is supported by buffer structure, shortens die cavity compression structure's operating time, increase of service life.

According to the technical problems of layering and air holes generated by processing of thick parts, and for the sample requirements of the thick parts in the prior art, when plastic materials are used for replacement, technicians in the field can conventionally choose to avoid the structural design of the thick parts in terms of structural design, for example, the structural design of material stealing or the air-assisted forming process is adopted to control the wall thickness, so that the defect caused by uneven shrinkage is avoided, and the mechanical property of the thick parts is enhanced by designing reinforcing ribs and the like so as to meet the requirements; other ways to avoid layering and air holes are adjustment of technological parameters such as mold temperature and pressure and structure, and no problem of solving the problem of the angle of the thick part is found. Therefore, the technical solution of the present application is not directed to solving the technical problems, but is not a routine choice for those skilled in the art. Furthermore, the core part of the mould to solve this problem, which is not a simple combination of the structures of the prior art, requires innovative design (i.e. overcoming the prejudice of the prior art: by controlling the wall thickness) and easy combination of practice.

The technical scheme is particularly suitable for workpieces (including sample blocks) with the required sample thickness being more than or equal to 10 mm. For a workpiece with a small sample thickness, the probability of generating delamination and air holes is small, except the condition of high requirement on the mechanical property of the product, or except the condition that the delamination and the air holes are easy to appear on the surface of the sample when the sample is milled from a sample block.

Drawings

Fig. 1 is a disassembled structural schematic diagram of a thick part mold according to embodiment 1;

FIG. 2 is a schematic structural diagram of a control component of the related push block of FIG. 1;

FIG. 3 is a schematic structural view of a control part of a push block according to embodiment 2;

FIG. 4 is a schematic structural view of a control part of a push block according to embodiment 3;

FIG. 5 is a schematic structural view of a control part of a push block according to embodiment 4;

FIG. 6 is a schematic structural view of a control part of a push block according to embodiment 5;

FIG. 7 is a photograph of a cross section of a sample block prepared in comparative example;

FIG. 8 is a photograph of a cross-section of a sample block prepared in example 5.

In fig. 1, some of the mounting members, connecting members, and the like, which are well known to those skilled in the art, are omitted, and another module leg is hidden for easy viewing.

The reference numbers in the figures are: 1 bottom plate, 2 compression springs, 201 push plate guide pillars, 202 limiting blocks, 3 oil cylinders, 301 shovel parts, 302 inclined blocks, 303 fixing shaft assemblies, 304 rocker assemblies, 4 ejector plates, 5 push rods, 6 push blocks, 7 mold feet, 8 backing plates, 9 water channels, 10B plates, 1001 cavities, 11A plates, 12 sprue gates and 13 panels.

Detailed Description

The technical solutions of the present application are further described below with reference to specific examples, and it should be noted that the following descriptions are not intended to limit the claims of the present application.

A thick article injection mold comprising:

the ejector pin plate is connected with the other end of the push rod,

the buffer structure and/or the cavity compression structure,

The technical scheme of the application omits the selection of other components of the injection mold, such as a base, a filling port (a sprue bushing or a needle valve structure), a pressure maintaining structure and the like, which are well known to a person skilled in the art; the cavity can be formed by combining an A plate (a fixed die holder) and a B plate (a movable die holder), also called as an upper die holder and a lower die holder, wherein the upper and the lower are only one embodiment and can also be transversely placed; the cavity can be a regular cube or a cylinder, such as a thick block cavity, or an irregular structure, wherein one direction needs a thicker wall thickness, and the 'one side wall' preferably corresponds to the thick wall; the push block can be flat, or can be arc or other complex structures; one end of the push rod is connected with the push block, and the push block can be fixedly connected or in any supporting mode which can support and promote the push block to move along the cavity, such as non-contact connection and the like, and can also be connected at intervals by adding a gasket and other structures in the middle, the connection mode of the push rod and the ejector plate is not limited, and the requirement that the ejector plate controls the push rod to move is met, and the push rod is preferably fixedly connected;

the buffer structure and/or the cavity compression structure comprise three technical schemes, and the problems of layering and air holes generated by processing thick parts can be solved. The distance between the initial working position of the buffer structure and the ejector plate is more than or equal to 0, the buffer structure directly contacts with the ejector plate and does not contact with the ejector plate at the beginning, the ejector plate is contacted with the ejector plate after moving for a short distance (for example, 2mm, because the part with the cavity thickness of 2mm is layered and has less bubble defect, and the influence on the result is less without using the buffer structure control at this time), the distance between the initial working position of the cavity compression structure and the ejector plate is more than or equal to 0, and the situation that the cavity compression structure contacts with the ejector plate is also included, before the process of filling the melt into the cavity is finished, the cavity compression structure can be controlled to move ahead of the push rod, so that the push rod has no resistance or the resistance is less than the injection pressure, the normal operation of the injection molding process is ensured, and the cavity compression structure is preferably not contacted with the ejector plate (namely, the distance between the initial working position of the cavity compression structure and the ejector plate is more than 0), after the process of filling the melt into the cavity is finished, the cavity is contacted with the ejector pin plate, and the volume of the cavity is compressed through the ejector pin plate, the push rod and the push block; when the distance between the initial working position of the cavity compression structure and the ejector plate is equal to 0, namely the initial position of the cavity compression structure is in direct contact with the ejector plate, the bottom of an oil cylinder can be fixed with the ejector plate (the distance is 0), an ejector rod of the oil cylinder props against a base (the initial position can not be in contact), and the function of controlling a push rod to compress the cavity through the ejector plate can be realized by jacking a bottom plate; the buffer structure can be realized by any structure known by the technical personnel in the field, the buffer structure is usually a compression spring buffer and provides resistance by the resilience force of the compression spring, and the buffer structure can also provide resistance for an oil cylinder by controlling the recovery speed of the oil cylinder, wherein the recovery speed is less than the speed of pushing a push block to move by injection molding pressure; the cavity compression structure can be realized by utilizing any structure known by persons skilled in the art, and comprises a pressure transmission device, wherein the common pressure transmission device comprises an oil cylinder, the oil cylinder can be replaced by a common air cylinder, an air-liquid pressure cylinder and the like, and a power structure capable of pushing an ejector plate to compress the cavity is selected according to requirements; in addition, the pressure transmission device (such as an oil cylinder) can also realize the function through a pressure transmission structure (such as a seesaw structure) without directly contacting with the ejector plate.

The following examples are provided to further illustrate the embodiments of the present invention, but should not be construed as limiting the claims of the present application.

Example 1

A thick product injection mold, as shown in fig. 2, relates to a push block control part structure, which comprises a cavity 1001, wherein one side wall of the cavity is a movable push block 6, the volume of the cavity 1001 can be changed by moving the push block 6, the shape of the cavity 1001 is a cube in this embodiment, a push rod 5 is arranged, one end of the push rod 5 is connected with the push block 6 and is positioned outside the cavity 1001, and an ejector plate 4 is arranged, and the ejector plate 4 is connected with the other end of the push rod 5; a buffer structure, which is four compression springs 2 arranged at the four corners of the ejector plate 4 in the embodiment, a push plate guide post 3 is arranged in the compression spring 2, the push plate guide post 3 penetrates through an ejector plate 4, simultaneously, the displacement directions of the compression spring 2 and the ejector plate 4 are limited, the distance between the initial working position of the compression spring 2 and the ejector plate 4 is 0, namely, the cavity compression structure is in contact connection with the ejector plate 4, the distance between the initial working position of the cavity compression structure and the ejector plate is more than 0 in the embodiment, the cavity compression structure comprises a second pressure transmission device and a pressure transmission structure, wherein the second pressure transmission device is an oil cylinder 3, the pressure transmission structure is an inclined shovel transmission structure, the inclined shovel transmission structure is composed of a shovel component 301, and the inclined block 302, the shovel component 301 is driven by the oil cylinder 3 to move along the inclined block 302, and the inclined block 302 is fixed at the lower part of the ejector plate 4.

This embodiment 1 further includes other components of the mold, as shown in fig. 1, further including:

the bottom plate 1, the push plate guide post 201 and the compression spring 2 are arranged on the bottom plate 1; the mould foot 7 is fixed on the bottom plate 1, the oil cylinder 3 and the shovel piece 301 are fixed through the mould foot 7, the backing plate 8 is supported and fixed through two mould feet 7, one of the mould feet 7 is not shown in the figure, the B plate 10 is arranged on the backing plate 8, a cavity 1001 is arranged in the B plate 10, the cavity 1001 is sealed by a push block 6 towards the direction of the backing plate 8, the A plate 11 and the B plate 10 are combined to form the cavity 1001, the sprue bushing 12 is communicated with the cavity 1001 through the A plate 11, a panel 13 is arranged on the A plate 11, the water channel 9 is further included, the water channel 9 is inserted and arranged on the sprue bushing 12, the periphery of the cavity 1001 and the inside of the push block 6, and the heating or cooling function is provided.

The operation method comprises the following steps: in the initial position, the compression spring 2 is in contact with the ejector plate and is in a prepressing state; the push block 6 can be arranged at the top of the cavity 1001 or at a small interval (such as 3 mm), if the push block is at the top, the whole process that the push block 6 moves towards the push rod 5 is influenced by the buffer resistance of the compression spring 2, and if the interval is small, when the melt runs out of the interval, the push block 6 is influenced by the buffer resistance of the compression spring 2 only by applying thrust, namely the compression spring 2 provides buffer resistance in a part of processes; the shovel component 301 is at the thinnest of the sloping block 302;

during operation, the injection molding machine passes the melt through the panel 13, enters the cavity 1001 through the squirt nozzle 12, and enters the buffer structure: when the die cavity 1001 fills the fuse-element, promote the ejector pad 6 to the direction removal of push rod 5 by injection pressure, push rod 5 transmits injection pressure for ejector plate 4, buffer structure is compression spring 2 and continues to be compressed because of injection pressure removes along with ejector pad 6, compression spring 2 forms the reverse thrust to ejector plate 4, hinder ejector plate 4 to compression spring 2's compression, buffer ejector pad 6's motion promptly, when making die cavity 1001 fill the fuse-element, the fuse-element receives the extrusion of injection pressure and ejector pad 6's reverse resistance simultaneously, melt density in the die cavity 1001 has been improved, reduce layering and the pore defect that the thick goods produced when the cooling.

End when the die cavity fills the fuse-element process, can utilize water route 9 cooling sprue 12 part fuse-element, better prevent that hydro-cylinder 3 during operation, be greater than injection pressure to the thrust of fuse-element compression, avoid the circumstances such as flash to appear, later get into die cavity compression structure work step: the oil cylinder 3 controls the shovel component 301 to move, contacts the inclined block 302, pushes the ejector plate 4 to move towards the direction of the push rod 5 through the inclined block 302, further pushes the push block 6 to further compress the melt in the cavity 1001, further controls the compression amount of the melt in the cavity 1001, improves the density of the melt, and reduces the layering and air hole defects in the cooling process;

the melt in the cavity 1001 is compressed to reach the target thickness and is kept for a certain time, then subsequent cooling and other operations are carried out, and then the A plate is directly removed, so that the workpiece can be ejected out through the resilience force of the compression spring 2.

Example 2

The injection mold for thick parts in this embodiment has the same components as those in embodiment 1, and is different from the pressure transmission structure in the structure of the related push block control component, as shown in fig. 3, the pressure transmission structure is a seesaw transmission structure, the seesaw transmission structure is composed of a fixed shaft assembly 303 and a seesaw assembly 304, one end of the seesaw assembly 304 is driven by an oil cylinder 3, and is transmitted to the other end of the seesaw assembly 304 through the fixed shaft assembly 303, and the other end of the seesaw assembly 304 pushes an ejector plate 4 to move towards the push rod direction, so as to provide power for compressing the cavity 1001.

The working process is similar to that of the embodiment 1, and the difference lies in the working of the teeter-totter transmission structure, the working principle of which is shown, and the operation is known by the person skilled in the art, so the detailed operation method is not described in detail.

Example 3

The injection mold for thick parts in this embodiment is the same as embodiment 1 in other parts, except that the structure of the related push block control part does not include a cavity compression structure, but only includes a buffer structure formed by a compression spring 2, the specific structure is shown in fig. 4, the specific working steps do not include the working steps of the cavity compression structure, the working principle is shown, and a person skilled in the art knows how to operate, so the detailed operation method is not described in detail.

Example 4

The injection mold for thick parts in the embodiment has the same components as those in embodiment 3, and is different in that the structure of the related push block control component does not comprise a buffer structure and only comprises a cavity compression structure, the cavity compression structure is an oil cylinder 3, the oil cylinder 3 does not initially contact with an ejector plate 4, and when the cavity is required to be compressed, the oil cylinder 3 pushes the ejector plate 4 to compress melt in the cavity. Wherein, be equipped with stopper 202 on the push pedal guide pillar 201 for the highest mobile position of injecing thimble board 4 prevents that hydro-cylinder 3 from promoting thimble board 4 and surpassing the biggest position and damaging the mould. The specific structure is shown in fig. 5, the specific working steps do not include the working steps of the buffer structure, the working principle is shown, and a person skilled in the art knows how to operate, so the detailed operation method is not described in detail.

Example 5

The injection mold for thick parts in this embodiment is the same as embodiment 3 in other parts, except that a cavity compression structure part and a limiting block 202 in embodiment 4 are added, the specific structure is shown in fig. 6, the working principle is shown in the foregoing

embodiments

3 and 4, and those skilled in the art know how to operate, so the detailed operation method is not described in detail. The injection molding of this example gave a regular polyhedron block 60mm thick with a cross-section as shown in FIG. 8.

Comparative example

In this comparative example, a conventional injection mold was directly designed to have a cavity of a constant thickness (60 mm in this comparative example), and a schematic cross-sectional view of a sample block as shown in fig. 7 was obtained by injection molding. The structure of the comparative example is a conventional injection mold structure, and a person skilled in the art knows how to implement the structure, and the detailed description is omitted.

The cross section of the sample block with the same specification and size is injected through the comparative example and the example 5, a large amount of air holes and layering defects appear in the comparative example, but the sample block obtained through injection molding of the example 5 has almost no air holes, and the layering condition is improved obviously. The beneficial effects of the technical scheme of the application can be further proved.

It should be noted that the mold in the embodiment of the present application may be placed vertically or horizontally according to the requirement, and the terms of upper and lower directions and the like are used according to the structure in the specific embodiment, but are not intended to limit the scope of the present application.

The examples described in the detailed description of the application are merely illustrative of the technical solutions of the application. Non-inventive changes or equivalent changes made according to the features and principles as contemplated by the present technical solutions are included in the scope of protection of the present application.

Claims

1. A thick article injection mold, comprising:

the ejector pin plate is connected with the other end of the push rod,

the buffer structure and/or the cavity compression structure,

2. A thick item injection mould as claimed in claim 1, wherein the damping means is one or more elastic elements or first pressure actuators, the elastic elements being in a pre-stressed state during operation.

3. The injection mold for thick products according to claim 1, wherein the buffer structure is one or more elastic elements and one or more first pressure transmission devices, the elastic elements are in a pre-pressing state during operation, the first pressure transmission devices can apply pushing force or pulling force to the ejector plate, and the pushing force or the pulling force can apply buffer pushing force to the ejector plate along the direction opposite to the movement direction of the ejector plate, so that the push block has buffer resistance during the movement towards the push rod;

one of the elastic element and the first pressure transmission device is in contact connection with the ejector plate, the elastic element and the first pressure transmission device are in a series superposition state,

or

The elastic element and the first pressure transmission device are in contact connection with the ejector plate, and the elastic element and the first pressure transmission device are in a parallel state.

4. A thick part injection mold according to claim 2 or 3, wherein the elastic element is one or more of a compression spring, a disc spring and a nitrogen spring.

5. A thick article injection mold according to claim 1, wherein the cavity compression structure is one or more second pressure actuators.

6. The injection mold for thick articles of claim 1, wherein the compression structure of the mold cavity is one or more of a second pressure transmission device and a pressure transmission structure, the pressure transmission structure is driven by the second pressure transmission device and is in contact connection with the ejector plate to apply a pushing force to the ejector plate along the direction opposite to the moving direction of the ejector plate, so that the pushing block moves towards the inside of the mold cavity, and the pressure transmission structure is one of a seesaw transmission structure or a slant shovel transmission structure.

7. A thick part injection mold according to any one of claims 2, 3, 5 and 6, wherein the first pressure transmission device or the second pressure transmission device is a hydraulic device, a pneumatic device or a gas-liquid mixing pressure device.

8. A thick part injection mold according to claim 1, wherein a temperature raising device is provided outside the cavity.

9. A method of operating a thick article injection mould according to claim 1, comprising the buffer structure working step and/or the cavity compression structure working step, corresponding to the buffer structure and/or the cavity compression structure:

the working steps of the cavity compression structure are as follows: and after the process of filling the melt into the cavity is finished, the cavity compression structure applies pushing force or pulling force to the ejector plate, and the pushing force or pulling force is transmitted to the push block through the push rod to push the push block to move towards the inside of the cavity.

10. The method of claim 9, wherein the cavity compression step further comprises a gate cooling step performed after the cavity filling step and before the cavity compression step.