CN216032253U

CN216032253U - Ejection structure of low-pressure injection molding mold

Info

Publication number: CN216032253U
Application number: CN202122437972.5U
Authority: CN
Inventors: 丁传超; 舒友祥; 蔺福志
Original assignee: Jiaxing Xinyuan Precision Mould Technology Co Ltd
Current assignee: Jiaxing Xinyuan Precision Mould Technology Co Ltd
Priority date: 2021-10-11
Filing date: 2021-10-11
Publication date: 2022-03-15
Anticipated expiration: 2031-10-11

Abstract

The utility model relates to the field of injection molds, in particular to an ejection structure of a low-pressure injection molding mold, which comprises a second male mold plate, a second ejector plate and a second lower fixing plate, wherein the ejection structure comprises a guide post vertically arranged at the top of the second lower fixing plate, and the second ejector plate is provided with a first through hole for the guide post to pass through; the injection molding pressure is less than the resilience force of the elastic part and less than the mold closing force; in the compression stage, the second male template is abutted with the guide column, the second ejector plate is abutted with the elastic piece, and the elastic piece is in a compression state; during the stage of moulding plastics, second public template and guide post butt, second thimble board and elastic component butt, the elastic component is in resilience state. The ejection structure of the novel overlapped spring is applied to a low-pressure injection molding die, the oil cylinder is replaced to complete prepressing ejection action, the oil cylinder is cancelled, oil leakage is avoided, and pressure maintaining and maintenance are not needed.

Description

Ejection structure of low-pressure injection molding mold

Technical Field

The utility model relates to the field of injection molds, in particular to an ejection structure of a low-pressure injection molding mold.

Background

Corresponding to products of large-scale PC transparent parts, the products are easy to have defects of shrinkage marks, flow marks, welding lines and the like due to uncontrollable warping deformation and easy appearance generation in the injection molding process, and low-pressure injection molding is needed. Compared with the traditional injection molding, the low-pressure injection molding has the following advantages:

1. the number of gates is small, and the trimming cost is low;

2. the warping deformation of the product is small;

3. the product has uniform appearance wall thickness;

4. the product surface has no shrinkage, no flow mark and no welding line;

5. the injection molding pressure is small, and the internal stress of the product is small.

In the prior art, the mold opening sequence of a low-pressure injection molding mold is shown in fig. 1, and the mold opening, mold closing, edge top opening, injection molding, instantaneous compression, edge top opening, and mold opening to take out a part are sequentially performed from left to right, wherein:

opening the mold refers to opening a male mold plate and a female mold plate of the injection molding machine;

the mold closing means that the male mold plate and the female mold plate of the injection molding machine are closed;

the opening of the top edge of the edge refers to that the mold is ejected out of the injection molding machine and the mold is opened to the preset wall thickness;

injection molding means filling the inside of a mold cavity by injection molding;

instantaneous compression means that a preset wall thickness is instantaneously compressed to a fixed wall thickness;

the opening and the ejection at the same time mean that the mold opening and the ejection are synchronously carried out;

the mold opening and part taking means that the male mold and the female mold are opened and the sucking disc takes the parts.

The existing low-pressure injection molding die cylinder ejection layout is shown in fig. 2, and all cylinders need to be combined into one cylinder for one cylinder to be ejected out in order to balance ejection.

Specifically, as shown in fig. 3 and 4, fig. 3 is a schematic diagram of ejection of an oil cylinder in a return stage of the existing low-pressure injection molding process, fig. 4 is a schematic diagram of ejection stage of an oil cylinder in the existing low-pressure injection molding process, and the principle of low-pressure injection molding is that a cavity is opened by a distance S when a mold is closed, so that the space of the cavity is enlarged, a solution can be rapidly filled, and after the solution is filled to 70% -95%, the solution is compressed and molded by using high mold closing force of an injection molding machine.

The action sequence is as follows: oil cylinder ejection → distance of driving ejector plate and straight ejection → injection filling → filling when 70% -95% is filled → high pressure die assembly compression → cooling of die waterway → die opening → product ejection → taking part → die assembly.

In the injection molding stage, the condition of low-pressure molding can be met only by ensuring that the force for ejecting the distance S is greater than the injection molding pressure and less than the injection molding pressure, and ejection is usually completed by arranging a plurality of oil cylinders with balanced force on an ejector plate. It can be seen from fig. 2 that the number of oil passages connected to the mold is very large, the problem of oil leakage often occurs during installation and use, the period of pressure maintaining and maintenance is very short, the cost is very high, and the yield is not stable.

SUMMERY OF THE UTILITY MODEL

In view of the above, it is necessary to provide an ejection structure of a low-pressure injection mold in order to solve the problems in the prior art.

In order to solve the problems of the prior art, the utility model adopts the technical scheme that:

the ejection structure of the low-pressure injection molding mold comprises a second male mold plate, a second ejector plate and a second lower fixing plate, the ejection structure comprises a guide post vertically arranged at the top of the second lower fixing plate, and a first through hole for the guide post to pass through is formed in the second ejector plate; the injection molding pressure is less than the resilience force of the elastic part and less than the mold closing force; in the compression stage, the second male template is abutted with the guide column, the second ejector plate is abutted with the elastic piece, and the elastic piece is in a compression state; during the stage of moulding plastics, second public template and guide post butt, second thimble board and elastic component butt, the elastic component is in resilience state.

Furthermore, the top of guide post is provided with the radial outside convex first ring flange, and when the elastic component was in the resilience state, the both ends of elastic component supported with first ring flange and second bottom plate respectively and leaned on.

Further, ejecting structure still includes the vertical third spacing post that sets up in second formboard bottom, and the spacing post of third passes first through-hole and guide post butt.

Furthermore, a second annular flange extending inwards from the inner wall of the top end of the first through hole is arranged on the second ejector plate, a second through hole is formed inside the second annular flange, and the outer diameter of the third limiting column is smaller than the inner diameter of the second through hole and smaller than the outer diameter of the first annular flange.

Further, the resilience of the elastic member is larger than the injection molding pressure × 1.5, and the mold clamping force is larger than the resilience of the elastic member × 1.5.

Furthermore, the elastic piece comprises a first cushion block, a spring and a second cushion block, the first cushion block and the second cushion block are respectively arranged at two ends of the spring,

furthermore, the clearance between the spring and the guide post is 0.5-1.0 mm.

Furthermore, the spring adopts a stack spring.

Compared with the prior art, the beneficial effect of this application is:

the ejection structure of the novel overlapped spring is applied to a low-pressure injection molding die, the oil cylinder is replaced to complete prepressing ejection action, the oil cylinder is cancelled, oil leakage is avoided, and pressure maintaining and maintenance are not needed.

Drawings

FIG. 1 is a sequence diagram of mold opening of a low pressure injection molding mold in the prior art;

FIG. 2 is a layout diagram of a cylinder ejection of a conventional low-pressure injection molding mold;

FIG. 3 is a schematic diagram of the ejection of an oil cylinder in the return stage of the existing low-pressure injection molding process;

FIG. 4 is a schematic diagram of a cylinder ejection stage of a conventional low-pressure injection molding process;

FIG. 5 is a schematic view of the compression stage of the new ejection structure pattern of the low pressure injection molding process of the embodiment;

FIG. 6 is a schematic diagram of the injection molding stage of the novel ejection structure pattern of the low-pressure injection molding process of the embodiment;

the reference numbers in the figures are:

1 a-a first master template; 2 a-a first product; 3 a-a first wear block; 4 a-a first straight top block; 5 a-a first top dead man; 6 a-a first core plate; 7 a-a first limit post; 8 a-a first ejector plate; 9 a-a first cylinder; 10 a-a first oil cylinder connecting screw; 11 a-a first cylinder block; 12 a-a first cylinder support block; 13 a-a first lower fixed plate;

1 b-a second master template; 2 b-a second product; 3 b-a second wear block; 4 b-a second straight top block; 5 b-a second straight ejector rod; 6 b-a second core plate; 7 b-a second limit post; 8 b-a third limit post; 9 b-a second ejector plate; 10 b-a guide post; 11 b-a first head block; 12 b-a spring; 13 b-a second head block; 14 b-a second lower fixation plate;

w-product wall thickness; s-distance of cavity opening.

Detailed Description

For further understanding of the features and technical means of the present invention, as well as the specific objects and functions attained by the present invention, the present invention will be described in further detail with reference to the accompanying drawings and detailed description.

As shown in fig. 5 and 6:

the ejection structure of the low-pressure injection molding mold comprises a second male mold plate 6b, a second ejector plate 9b and a second lower fixing plate 14b, the ejection structure comprises a guide post 10b vertically arranged at the top of the second lower fixing plate 14b, and a first through hole for the guide post 10b to pass through is formed in the second ejector plate 9 b; and the elastic member is sleeved on the guide post 10b, and the injection molding pressure is smaller than the resilience force of the elastic member and smaller than the mold closing force; in the compression stage, the second male die plate 6b is abutted with the guide post 10b, the second ejector plate 9b is abutted with the elastic piece, and the elastic piece is in a compression state; in the injection molding stage, the second core plate 6b abuts against the guide post 10b, the second ejector plate 9b abuts against the elastic member, and the elastic member is in a rebound state.

Based on the above embodiment, because the second straight ejector block 4b is connected with the second ejector plate 9b through the second straight ejector rod 5b, during the injection molding stage, the second ejector plate 9b is acted by the resilience force of the elastic member, so that the second straight ejector block 4b is ejected from the second male mold plate 6b, during the compression stage, under the action of the mold clamping force, the second female mold plate 1b downwardly extrudes the second straight ejector block 4b to drive the second straight ejector rod 5b and the second ejector plate 9b to extrude the elastic member, the elastic member is compressed, the second straight ejector block 4b returns to the inside of the second male mold plate 6b, and in the two stages, the second male mold plate 6b does not move all the time.

With reference to fig. 1, the sequence of actions of the above embodiment is: mold closing → reopening distance S → second straight top block 4b ejecting distance S under the action of resilience force of elastic member → injection filling → filling to 70% -95% >, high pressure mold closing compression → mold waterway cooling → mold opening → second straight top block 4b ejecting distance S → product ejection → mold taking → mold closing.

Further, the top of the guide post 10b is provided with a first annular flange 10b1 protruding radially outward, and when the elastic member is in a rebound state, two ends of the elastic member abut against the first annular flange 10b1 and the second lower fixing plate 14b respectively.

Based on the above embodiment, the first elastic flange is used to limit the maximum length of the elastic member, so that the distance S that the second straight top block 4b is ejected is controllable.

Further, ejecting structure still includes the vertical third spacing post 8b that sets up in second formboard 6b bottom, and the first through-hole of third spacing post 8b passing is propped against with guide post 10 b.

Based on the above embodiment, the third limiting column 8b can shorten the length of the guide column 10b, and reduce the difficulty in processing the guide column 10 b.

Further, the second ejector plate 9b is provided with a second annular flange 9b1 extending radially inward from the inner wall of the top end of the first through hole, a second through hole is formed inside the second annular flange 9b1, and the outer diameter of the third stopper post 8b < the inner diameter of the second through hole < the outer diameter of the first annular flange 10b 1.

Based on the above embodiment, in the compression stage, the third limiting post 8b can pass through the second through hole to abut against the guiding post 10b, so that the second core plate 6b stops moving, and the second ejector plate 9b can continue to move downwards until the second annular flange 9b1 abuts against the first annular flange 10b 1; during the injection molding stage, the second female mold plate 1b is moved away from the second lower fixing plate 14b under the action of the injection molding machine, the second male mold plate 6b is stopped, and the second ejector plate 9b is moved away from the second lower fixing plate 14b under the action of the elastic member until one end of the elastic member abuts against the first annular flange 10b 1. Then, the second straight top block 4b is moved by a distance S equal to the axial length of the first through hole minus the axial length of the first annular flange 10b1, thereby making the distance S further controllable.

Furthermore, the resilience force of the elastic part is larger than the injection molding pressure multiplied by 1.5, and the mold closing force is larger than the resilience force of the elastic part multiplied by 1.5;

based on the above embodiment, the resilience of the elastic member cannot be similar to the injection molding pressure or the mold clamping force because the resilience of the elastic member is affected by its own degree of compression and temperature.

Further, the elastic member includes a first pad 11b, a spring 12b and a second pad 13b, the first pad 11b and the second pad 13b are respectively disposed at both ends of the spring 12b,

according to the above embodiment, in order to avoid the spring 12b from crushing the second lower fixing plate 14b or the first annular flange 10b1, the first pad 11b and the second pad 13b need to be cushioned.

Furthermore, the clearance between the spring 12b and the guide post 10b is 0.5-1.0 mm.

Based on the above embodiment, too large clearance between the guide post 10b and the spring 12b affects the ejection stroke.

Further, the spring 12b is a stack spring.

In addition, the hardness of the guide post 10b, the first cushion block 11b and the second cushion block 13b reaches 58-60 HRC, and the guide post, the first cushion block and the second cushion block cannot be damaged in the movement process of the spring 12 b.

Compared with the prior art, the beneficial effect of this application is:

The above examples, which are intended to represent only one or more embodiments of the present invention, are described in greater detail and with greater particularity, and are not to be construed as limiting the scope of the utility model. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims

1. The utility model provides a low pressure injection moulding mould's ejecting structure, low pressure injection moulding mould includes second public template (6b), second thimble board (9b) and second bottom plate (14b), its characterized in that, ejecting structure includes

The guide post (10b) is vertically arranged at the top of the second lower fixing plate (14b), and the second ejector plate (9b) is provided with a first through hole for the guide post (10b) to pass through; and

the elastic piece is sleeved on the guide post (10b), and the injection molding pressure is smaller than the resilience force of the elastic piece and smaller than the mold closing force;

in the compression stage, the second male template (6b) is abutted with the guide post (10b), the second ejector plate (9b) is abutted with the elastic piece, and the elastic piece is in a compression state;

and in the injection molding stage, the second male template (6b) is abutted with the guide post (10b), the second ejector plate (9b) is abutted with the elastic piece, and the elastic piece is in a rebound state.

2. The ejector structure of a low pressure injection mold according to claim 1, wherein the top of the guide post (10b) is provided with a first annular flange (10b1) protruding radially outward, and both ends of the elastic member abut against the first annular flange (10b1) and the second lower fixing plate (14b), respectively, when the elastic member is in a rebound state.

3. The ejection structure of the low-pressure injection mold according to claim 1, wherein the ejection structure further comprises a third limiting column (8b) vertically disposed at the bottom of the second core plate (6b), and the third limiting column (8b) passes through the first through hole and abuts against the guide column (10 b).

4. The ejector structure of a low pressure injection mold according to claim 3, wherein the second ejector plate (9b) is provided with a second annular flange (9b1) extending radially inward from the inner wall of the top end of the first through hole, the second annular flange (9b1) has a second through hole formed therein, and the third stopper post (8b) has an outer diameter < the inner diameter of the second through hole < the outer diameter of the first annular flange (10b 1).

5. The ejection structure of a low-pressure injection mold according to claim 1, wherein the resilient force of the elastic member > injection pressure x 1.5, and the mold clamping force > resilient force of the elastic member x 1.5.

6. The ejector structure of a low pressure injection mold according to claim 1, wherein the elastic member comprises a first pad (11b), a spring (12b), and a second pad (13b), the first pad (11b) and the second pad (13b) being disposed at both ends of the spring (12b), respectively.

7. The ejection structure of a low pressure injection mold according to claim 6, wherein the clearance between the spring (12b) and the guide post (10b) is 0.5 to 1.0 mm.

8. The ejection structure of a low-pressure injection mold according to claim 1, wherein the spring (12b) is a stack spring.