CN110884020A

CN110884020A - Thin-wall high-pressure foaming forming process and die

Info

Publication number: CN110884020A
Application number: CN201911235371.7A
Authority: CN
Inventors: 陈买桃
Original assignee: SHENZHEN YIHE MOLD MANUFACTURING CO LTD
Current assignee: SHENZHEN YIHE MOLD MANUFACTURING CO LTD
Priority date: 2019-12-05
Filing date: 2019-12-05
Publication date: 2020-03-17

Abstract

The invention relates to a thin-wall high-pressure foaming forming process, which comprises the following steps: before injection molding, high-pressure gas is injected into a mold cavity to form a pressure space with a set pressure intensity in the mold cavity, then the injection molding is carried out in the mold cavity, in the injection molding process, as the space of the mold cavity is a space with air pressure, so that despite the addition of foaming agents to the compound, the compound is not foamed at this stage because there is no space and there is extrusion of gas, when a certain amount of glue is injected, the injection molding machine stops injecting the glue, the space of the mold cavity is increased to a set value, the mold cavity is vacuumized, the sizing material begins to foam in the vacuumizing process, a plurality of foaming holes are formed in the middle layer of the sizing material, but the surface layer is compact, the mold is opened after the foaming is finished, the product is taken out, the strength of the product can be guaranteed by adopting the mode of the application, the thickness is thin, the surface layer is very compact and beautiful, and the method is particularly suitable for the production of automobile products.

Description

Thin-wall high-pressure foaming forming process and die

Technical Field

The invention relates to the technical field of molds, in particular to a thin-wall high-pressure foaming forming process and a mold.

Background

In the traditional foaming injection mold, for a complex plastic product with the wall thickness lower than 3MM, the traditional foaming technology is used, although the complex plastic product can be foamed, the appearance is rough, and the surface layer of the product cannot be very compact and beautiful; especially for the first-class appearance surface of an automobile product, the plastic product of the automobile is often complex and has extremely high appearance requirement, the wall thickness of the plastic product is directly reduced mostly in the prior art, but with higher and higher test requirements, the strength of the plastic product cannot meet the requirement, and the traditional foaming technology is only limited to products with thicker wall thickness and without high requirement on appearance.

Disclosure of Invention

The technical problem to be solved by the present invention is to provide a thin-wall high-pressure foaming molding process and a mold, aiming at the above-mentioned defects in the prior art.

The technical scheme adopted by the invention for solving the technical problems is as follows:

a thin-wall high-pressure foaming forming process is constructed, and the implementation method comprises the following steps:

the first step is as follows: injecting high-pressure gas into a mold cavity before injection molding to form a pressure space with a set pressure intensity in the mold cavity;

the second step is that: injecting the plastic into a mold cavity;

the third step: after the injection molding is finished, increasing the space of the mold cavity to a set value, and vacuumizing the mold cavity;

the fourth step: and opening the mold after the injected plastic foaming is finished.

The thin-wall high-pressure foaming forming process is characterized in that the pressure intensity in the pressure space is 0.5-1.5 MPa.

The thin-wall high-pressure foaming forming process is characterized in that the high-pressure gas is inert gas.

In the third step, the space of the die cavity of the die is enlarged and the die cavity is simultaneously vacuumized.

In the third step, the increased space value is based on the thickness value required by the product.

A thin-wall high-pressure foaming forming die is based on the thin-wall high-pressure foaming forming process, and comprises an A plate, a B plate and a supporting plate; a cavity is arranged on the lower surface of the plate A, and an injection molding port communicated with the cavity is arranged on the plate A; a mold core matched with the cavity is arranged on the supporting plate; a through hole matched with the mold core is formed in the plate B; the upper surface of the core and the cavity form the mold cavity;

the plate A or the plate B is provided with an inflating device for inflating high-pressure gas into the die cavity;

a vacuumizing device for vacuumizing the cavity of the mold is arranged on the plate A or the plate B;

the thin-wall high-pressure foaming forming die further comprises a driving device for driving the mold core to move longitudinally.

According to the thin-wall high-pressure foaming forming die, the plate A and the plate B are kept sealed through the first sealing ring, and the lower end of the injection molding opening and the cavity are both located in the first sealing ring.

According to the thin-wall high-pressure foaming forming die, the plate B and the supporting plate are kept sealed through the second sealing ring, and the mold core and the through hole are located in the second sealing ring.

The thin-wall high-pressure foaming forming die comprises a die cavity, a thin-wall high-pressure foaming forming die body and a gas filling device, wherein the gas filling device comprises a gas filling mechanism for filling gas into the die cavity and a safety valve communicated with the die cavity.

The invention relates to a thin-wall high-pressure foaming forming die, wherein a driving device comprises a driving block, a transverse moving mechanism for driving the driving block to transversely move, and a mounting seat for mounting the transverse moving mechanism; the mounting seat is fixedly connected with the supporting plate;

an upper positioning block and a lower driving block which are distributed up and down are arranged on one side of the driving block, which is far away from the transverse moving mechanism; a first positioning groove matched with the upper positioning block is formed in the surface of one side of the plate B, and a movable distance exists between the upper positioning block and the inner wall of the first positioning groove; a second positioning groove matched with the lower driving block is formed in the surface of one side of the supporting plate and communicated with the upper surface of the supporting plate; and the upper surface of the lower driving block is provided with a jacking inclined surface which is acted with the lower surface of the plate B.

The invention has the beneficial effects that: injecting high-pressure gas into a mold cavity before injection molding to form a pressure space with a set pressure intensity in the mold cavity, then injecting the injection molding into the mold cavity, wherein in the injection molding process, as the cavity space is a space with air pressure, although a foaming agent is added into a rubber material, no space exists and the rubber material is extruded by the gas, the rubber material is not foamed at the stage, after a certain amount of rubber is injected, the injection molding machine stops injection molding, the space of the mold cavity is increased to a set value, the mold cavity is vacuumized, the rubber material can start foaming in the vacuumizing process, a plurality of foaming holes are formed in the middle layer of the rubber material, but the surface layer is compact, and the mold is opened to take out a product after foaming is completed. Is especially suitable for the production of automobile products.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the present invention will be further described with reference to the accompanying drawings and embodiments, wherein the drawings in the following description are only part of the embodiments of the present invention, and for those skilled in the art, other drawings can be obtained without inventive efforts according to the accompanying drawings:

FIG. 1 is a flow chart of a thin-wall high-pressure foaming process according to a preferred embodiment of the present invention;

FIG. 2 is a schematic structural diagram of the thin-wall high-pressure foaming mold according to the preferred embodiment of the invention before injection molding;

FIG. 3 is a structural diagram of the thin-wall high-pressure foaming mold according to the preferred embodiment of the invention;

fig. 4 is a schematic structural diagram of a driving device of a thin-wall high-pressure foaming mold according to a preferred embodiment of the invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention, and it is obvious that the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the present invention without inventive step, are within the scope of the present invention.

The thin-wall high-pressure foaming forming process of the preferred embodiment of the invention, as shown in fig. 1, is realized by the following steps:

s01: injecting high-pressure gas into a mold cavity before injection molding to form a pressure space with a set pressure intensity in the mold cavity;

s02: injecting the plastic into a mold cavity;

s03: after the injection molding is finished, increasing the space of the mold cavity to a set value, and vacuumizing the mold cavity;

s04: opening the mold after the injected plastic foaming is finished;

injecting high-pressure gas into a mold cavity before injection molding to form a pressure space with a set pressure intensity in the mold cavity, then injecting the injection molding into the mold cavity, wherein in the injection molding process, as the cavity space is a space with air pressure, although a foaming agent is added into a rubber material, no space exists and the rubber material is extruded by the gas, the rubber material is not foamed at the stage, after a certain amount of rubber is injected, the injection molding machine stops injection molding, the space of the mold cavity is increased to a set value, the mold cavity is vacuumized, the rubber material can start foaming in the vacuumizing process, a plurality of foaming holes are formed in the middle layer of the rubber material, but the surface layer is compact, and the mold is opened to take out a product after foaming is completed. Is particularly suitable for the production of automobile products;

preferably, the pressure in the pressure space is 0.5-1.5 MPa; the preferred pressure is maintained at 1 MPa.

Preferably, the high pressure gas is an inert gas; preferably, nitrogen is used as the high pressure gas.

Preferably, in the third step, the space of the die cavity is enlarged and the vacuum pumping is carried out at the same time, so that the appearance of the product is guaranteed.

Preferably, in the third step, the increased space value is based on the thickness value required by the product; if the thickness of the adhesive layer is 1mm before foaming and a product with the thickness of 1.5mm needs to be manufactured, the thickness after increasing is 1.5 mm.

A thin-wall high-pressure foaming forming die is disclosed, according to the thin-wall high-pressure foaming forming process, as shown in fig. 2, and referring to fig. 3 and 4, the die comprises an A plate 1, a B plate 2 and a support plate 3; a cavity 10 is arranged on the lower surface of the A plate 1, and an injection molding port 11 communicated with the cavity 10 is arranged on the A plate 1; a mold core 30 matched with the mold cavity 10 is arranged on the support plate 3; a through hole matched with the core 30 is formed in the B plate 2; the upper surface of the core 30 and the cavity 10 form a mold cavity;

the A plate 1 or the B plate 2 is provided with an inflating device 4 for inflating high-pressure gas into the die cavity;

the A plate 1 or the B plate 2 is provided with a vacuum extractor (not shown in the figure) for extracting vacuum in the mold cavity;

the thin-wall high-pressure foaming forming die also comprises a driving device 5 for driving the mold core 30 to move longitudinally;

in a die assembly state, the inflating device inflates air in a die cavity, after a set air pressure is reached, the injection molding opening 11 performs injection molding, an injection molding completion signal is provided for the driving device 5 and the vacuumizing device after the injection molding is completed, the driving device 5 drives the die core to move downwards to increase the space of the die cavity, the vacuumizing device performs vacuumizing on the die cavity, rubber materials are foamed, and after the completion of die opening, normal ejection is performed, so that the thickness is thinner, the surface layer is very compact and attractive, shrinkage is not easy to occur, the production cost is reduced, and the automobile tire is particularly suitable for production of automobile products;

the vacuumizing device and the inflating device are conventional equipment, and the existing equipment is adopted, so that detailed description is omitted;

by adopting a thin-wall foaming mode, a product with a thinner-wall structure can be designed, and the material cost of the product is reduced; because the stress in the die generated in the processes of die assembly and pressure maintaining in the conventional molding process is reduced or eliminated, the thin-wall foaming injection molding can enable the product to be flatter and straighter and the product to have higher dimensional precision, thereby providing a larger space for improving the quality and the price of the product; by specially designing the die, the thin-wall foaming has advantages for the molding of thick-wall products, and the surface quality of the products is very perfect.

Preferably, the plate A1 and the plate B2 are kept sealed through a first sealing ring 6, and the lower end of the injection port 11 and the cavity 10 are both positioned in the first sealing ring 6; the plate B2 and the support plate 3 are kept sealed through a second sealing ring 7, and the mold core 30 and the through hole are both positioned in the second sealing ring 7; the air tightness during inflation and air exhaust is kept.

Preferably, the inflation device comprises an inflation mechanism for inflating the mold cavity and a safety valve communicated with the mold cavity; the safety valve is arranged, and when the air pressure reaches a certain degree, the air can be exhausted and decompressed, so that the phenomenon that the air pressure is too large is avoided, and the safety is improved.

Preferably, the driving device 5 comprises a driving block 50, a traversing mechanism 51 for driving the driving block 50 to traverse, and a mounting seat 52 for mounting the traversing mechanism 51; the mounting seat 52 is fixedly connected with the support plate 3;

an upper positioning block 500 and a lower driving block 501 which are distributed up and down are arranged on one side of the driving block 50, which is far away from the transverse moving mechanism 51; a first positioning groove 20 matched with the upper positioning block 500 is formed in the surface of one side of the plate B2, and a movable distance exists between the upper positioning block 500 and the inner wall of the first positioning groove 20; a second positioning groove 31 matched with the lower driving block 501 is formed in the surface of one side of the supporting plate 3, and the second positioning groove 31 is communicated with the upper surface of the supporting plate 3; the upper surface of the lower driving block 501 is provided with a jacking inclined plane 5010 which is acted with the lower surface of the B plate 2;

the driving block is driven by the transverse moving mechanism to transversely move, and the jacking inclined plane 5010 on the lower driving block 501 acts on the lower surface of the B plate 2, so that a separating force can be applied to the B plate 2 and the supporting plate 3, and the mold core 30 is further moved downwards to increase the space of a mold cavity; through the matching of the upper positioning block 500 and the first positioning groove 20, the spacing of the separation distance can be performed by adjusting the movable distance between the upper positioning block and the first positioning groove;

the cross sliding mechanism can adopt the existing mechanisms such as an oil cylinder and the like; guide pillars, guide sleeves and the like can be arranged to guide the plate B when the plate B is separated from the supporting plate; when the B plate is separated from the support plate, the second sealing ring needs to be maintained in a compressed state so as to ensure the sealing between the B plate and the support plate.

It should be noted that the scheme of the present application is not limited to the production of automobile products, but is also applicable to the production of other plastic products, and the application of the scheme to other products also belongs to the protection scope of the present application.

It will be understood that modifications and variations can be made by persons skilled in the art in light of the above teachings and all such modifications and variations are intended to be included within the scope of the invention as defined in the appended claims.

Claims

1. A thin-wall high-pressure foaming forming process is characterized by comprising the following steps:

the second step is that: injecting the plastic into a mold cavity;

2. The thin-walled high-pressure foaming process according to claim 1, wherein the pressure in the pressure space is 0.5-1.5 MPa.

3. The thin wall high pressure foaming process of claim 1, wherein the high pressure gas is an inert gas.

4. The thin-walled high-pressure foaming process according to claim 1, wherein in the third step, the vacuum pumping is performed while increasing the space of the mold cavity.

5. The thin-wall high-pressure foaming process according to claim 1, wherein in the third step, the increased space value is determined according to the required thickness value of the product.

6. A thin-wall high-pressure foaming forming die, the thin-wall high-pressure foaming forming process according to any one of claims 1 to 5, characterized by comprising an A plate, a B plate and a supporting plate; a cavity is arranged on the lower surface of the plate A, and an injection molding port communicated with the cavity is arranged on the plate A; a mold core matched with the cavity is arranged on the supporting plate; a through hole matched with the mold core is formed in the plate B; the upper surface of the core and the cavity form the mold cavity;

7. The thin-walled high-pressure foaming mold of claim 6, wherein the plate A and the plate B are sealed by a first sealing ring, and the lower end of the injection port and the cavity are both located in the first sealing ring.

8. The thin-walled high-pressure foaming mold of claim 6, wherein the B plate and the support plate are sealed by a second sealing ring, and the core and the through hole are located in the second sealing ring.

9. The thin-walled high-pressure foaming molding die of claim 6, wherein the inflating device comprises an inflating mechanism for inflating the die cavity and a safety valve communicated with the die cavity.

10. The thin-wall high-pressure foaming mold according to claim 6, wherein the driving device comprises a driving block, a traversing mechanism for driving the driving block to traverse, and a mounting seat for mounting the traversing mechanism; the mounting seat is fixedly connected with the supporting plate;