CN112936789A

CN112936789A - Mold utilizing principle of expansion with heat and contraction with cold and injection molding process

Info

Publication number: CN112936789A
Application number: CN202110135953.9A
Authority: CN
Inventors: 王珂; 王雄辉
Original assignee: Ruikangnuo Shenzhen Innovation Development Co ltd
Current assignee: Ruikangnuo Shenzhen Innovation Development Co ltd
Priority date: 2021-02-01
Filing date: 2021-02-01
Publication date: 2021-06-11

Abstract

The invention relates to the technical field of injection molding processes of power adapter shells, in particular to a mold utilizing a principle of expansion with heat and contraction with cold, wherein a mold cavity is arranged on a female mold side plate, a male mold comprises a male mold, the male mold is connected in the mold cavity in a sliding manner, a plurality of through holes are arranged on the periphery of the male mold at equal intervals, an ejector plate comprises ejector pins, the ejector pins are connected in the through holes in a sealing manner in a sliding manner, an externally-hung cold air cooling system is used for blowing cold air into the mold cavity of the female mold side plate, and a hot runner glue inlet plate is used; the injection mold provided by the invention does not need to design a mold-stripping angle, and the sizes of the top and the bottom of an injection product are the same; compared with a left-right split-position structure die, the invention solves the defect that a die joint line is required to be arranged on the opposite angle of the surface of the product when the product has no die stripping angle; in addition, under the condition of the same size of the die, the number of the die cavities of the invention is twice of that of the die cavities of the left-right opposite-open-position structure.

Description

Mold utilizing principle of expansion with heat and contraction with cold and injection molding process

Technical Field

The invention relates to the technical field of injection molding processes of power adapter shells, in particular to a mold utilizing the principle of expansion with heat and contraction with cold and an injection molding process.

Background

The conventional injection mold needs more than 2 degrees of demolding inclination, and a plastic product can be smoothly taken out of the mold during production. Because of the mold stripping angle, the sizes of the top and the bottom of the product are different; when the product design requires the top and bottom dimensions to be consistent, the demolding approach typically employed is a left-right split bit structure, including module a and module b, as shown in fig. 1. This demolding method has several disadvantages: the mold cavity is formed by butt joint of a module a and a module b, a parting line c inevitably occurs on the surface of a plastic product, so that the product has appearance defects, the production efficiency is very low, the utilization rate of the mold space is very low, more than half of the space can not be utilized, areas d and e shown in figure 2 are wasted, the mold is easy to damage and can not be normally produced due to long-time production butt joint collision, and the mold processing requirements of the module a and the module b are very precise, and the mold can be scrapped due to slight dislocation.

Along with the improvement of living standard of people, the requirements on the surface performance of various workpieces are higher and higher, the appearance attractiveness of the product is reduced due to the existence of the parting line c, and the market competitiveness is influenced to a certain extent; the cell-phone, power adapter is all used to the computer etc. and power adapter shell injection moulding market demand is huge, because control to open the position structure mould space waste very big about, mould acupuncture point quantity is half of conventional mould only, and the factory of moulding plastics need open a lot of sets of replication mould and match very many injection molding machines and just can satisfy the production demand usually, need drop into huge mould expense and human cost, and not only production efficiency is low has still caused the very big waste of resource. This has been a long-standing unsolved technical problem.

Disclosure of Invention

The invention aims to solve the defects in the prior art and provides a mold utilizing the principle of expansion with heat and contraction with cold and an injection molding process.

In order to achieve the purpose, the invention adopts the following technical scheme:

a mold utilizing the principle of expansion with heat and contraction with cold is designed, the traditional demolding mode of a male mold core of a plastic product is changed into the traditional demolding mode that the plastic product is reserved in a female mold cavity, and the plastic product generates a contraction space and a cold air injection space.

The mould major structure includes that master model roof, master model curb plate, external cold wind cooling system, public template, liftout plate and hot runner advance the offset plate, be equipped with the die cavity on the master model curb plate, public template includes the terrace die, terrace die slidable connects in the die cavity, a plurality of through-holes have been seted up to the terrace die equidistant all around, the liftout plate includes the thimble, thimble slidable sealing connection be in the through-hole, external cold wind cooling system be used for to master model curb plate die cavity blows in air conditioning, the hot runner advances the offset plate and is used for moulding plastics.

An injection molding process utilizing a principle of expansion with heat and contraction with cold comprises the following steps:

s1: the female die top plate, the female die side plate and the male die plate are assembled to form a cavity, and the hot runner glue inlet plate is injected into the cavity through the male die plate hot nozzle;

s2: after the injection molding is finished, removing the top plate of the female die, removing the hot runner, feeding the rubber plate, ejecting the plate and the male die plate, and keeping the plastic product on the side plate of the female die;

s3: opening the external cold air cooling system, blowing cold air into the inner wall of the injection product fixed in the cavity of the female die side plate by the air nozzle in an aligning manner, carrying out extremely rapid cooling, and rapidly shrinking the injection product when meeting cold so as to separate from the female die side plate;

s4: and driving the ejector plate to eject the injection product by the ejector pin.

Preferably, in step S2, after the male mold plate is ejected, the plastic product left on the female mold plate creates a shrinkage space and a cold air injection space.

Preferably, in step S3, the temperature output from the low temperature air duct system is controlled to be less than 10 degrees, and the air is blown against the inner wall of the injection product through the air nozzle to form a cold air vortex in the product, so as to rapidly cool the injection product, reduce the shrinkage of the product and separate the product from the female mold side plate.

The invention provides a die utilizing the principle of expansion with heat and contraction with cold and an injection molding process, which have the beneficial effects that: compared with the traditional injection mold, the injection mold provided by the invention has no mold-stripping angle, and adopts cold air to cool the inner wall of the injection product left on the side plate of the female mold, so that the injection product is cooled and shrunk in the cavity of the side plate of the female mold, the volume of the injection product is reduced after cooling, the outer wall of the injection product is separated from the inside of the cavity, and then the mold is removed, so that the sizes of the top and the bottom of the injection product are the same; compared with a left-right split-position structure, the invention not only solves the defect that a die joint line is required to be arranged on the opposite angle of the surface of a product when the product has no die stripping angle. In addition, under the condition of the same size of the die, the number of the die cavities of the invention is twice of that of the die cavities of the left-right opposite-open-position structure. The production efficiency of the injection molding product is improved by two times and more.

Drawings

Fig. 1 is a schematic structural diagram of a conventional left-right split bit structure demolding manner.

FIG. 2 is a comparison diagram of the space waste of the mold stripping mode of the traditional left-right split-position structure and the reasonable utilization space of the mold structure of the invention.

FIG. 3 is a schematic view of a conventional demolding method, wherein a plastic part is retained in a male mold.

FIG. 4 is a schematic diagram of a mold using the principle of expansion with heat and contraction with cold and a plastic part of an injection molding process of the present invention left on a female mold.

Fig. 5 is a schematic structural diagram of a mold and an injection molding process using the principle of expansion with heat and contraction with cold according to the present invention.

Fig. 6 is a schematic structural diagram of a male mold and a thimble of a mold and an injection molding process based on the principle of expansion with heat and contraction with cold according to the present invention.

Fig. 7 is a structural schematic view of the external cold air cooling system of the mold and the injection molding process based on the principle of expansion with heat and contraction with cold according to the present invention.

FIG. 8 is a schematic view of a mold and an external cold air cooling system for an injection molding process based on the principle of expansion with heat and contraction with cold according to the present invention.

FIG. 9 is an enlarged view of the position B of the mold and the injection molding process using the principle of expansion with heat and contraction with cold according to the present invention, before cooling by blowing air, when the plastic product is not separated from the side plate of the female mold.

FIG. 10 is a schematic diagram of a mold utilizing the principle of expansion with heat and contraction with cold and an external cold air cooling system of an injection molding process according to the present invention.

FIG. 11 is an enlarged view of the position A of the mold and the injection molding process using the principle of expansion with heat and contraction with cold according to the present invention, after cooling by blowing air, when the plastic product is separated from the side plate of the female mold.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments.

Referring to fig. 4-11, a mold utilizing the principle of thermal expansion and cold contraction comprises a female mold top plate 1, a female mold side plate 3, an external cold air cooling system 4, a male mold plate 5, an ejector plate 6 and a hot runner inlet rubber plate 7, wherein a mold cavity is arranged on the female mold side plate 3, the male mold plate 5 comprises a male mold core 501, the male mold core 501 is slidably connected in the mold cavity, a plurality of through holes are formed in the periphery of the male mold core 501 at equal intervals, the ejector plate 6 comprises ejector pins which are slidably connected in the through holes, the external cold air cooling system 4 is used for blowing in cold air to the female mold side plate 3, and the hot runner inlet rubber plate 7 is used for.

s1: the female die top plate 1, the female die side plate 3 and the male die plate 5 are closed to form a cavity, and the hot runner glue inlet plate 7 is injected into the cavity through the male die plate hot nozzle;

s2: after injection molding is finished, removing the female mold top plate 1, removing the hot runner rubber inlet plate 7, the ejector plate 6 and the male mold plate 5, and keeping the plastic product on the female mold side plate 3;

s3: the external cold air cooling system 4 is started, the air nozzle aims at the inner wall of the injection product 2 fixed in the cavity of the female die side plate 3 to blow in cold air, the extremely rapid cooling is carried out, and the injection product 2 rapidly shrinks when meeting the cold, so that the injection product is separated from the female die side plate 3;

s4: and driving the ejector plate 6 to eject the injection product 2 by the ejector pin.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered to be within the technical scope of the present invention, and the technical solutions and the inventive concepts thereof according to the present invention should be equivalent or changed within the scope of the present invention.

Claims

1. A mould based on the principle of expansion with heat and contraction with cold features that when the plastic product is released from mould, it is retained in the cavity of female mould to generate a contraction space and a cold air injection space, it is characterized by comprising a female die top plate (1), a female die side plate (3), an externally-hung cold air cooling system (4), a male die plate (5), an ejector plate (6) and a hot runner glue inlet plate (7), the female die side plate (3) is provided with a die cavity, the male die plate (5) comprises a male die (501), the male die (501) is connected in the die cavity in a sliding way, a plurality of through holes are arranged on the periphery of the male die core (501) at equal intervals, the ejector plate (6) comprises ejector pins which are connected in the through holes in a sliding and sealing manner, the external cold air cooling system (4) is used for blowing cold air into the cavity of the female die side plate (3), and the hot runner rubber inlet plate (7) is used for injection molding.

2. An injection molding process using the principle of expansion with heat and contraction with cold according to claim 1, comprising the steps of:

s1: the female die top plate (1), the female die side plate (3) and the male die plate (5) are closed to form a cavity, and the hot runner glue inlet plate (7) is injected into the cavity through the hot nozzle of the male die plate;

s2: after injection molding is finished, removing the female mold top plate (1), removing the hot runner rubber inlet plate (7), the ejector plate (6) and the male mold plate (5), and keeping the plastic product on the female mold side plate (3);

s3: opening the external cold air cooling system (4), blowing cold air into the inner wall of the injection product (2) aligned and fixed in the cavity of the female die side plate (3) by the air nozzle, cooling at the extreme speed, and enabling the injection product (2) to shrink and become small when meeting the cold so as to be separated from the female die side plate (3);

s4: and driving the ejector plate (6) to eject the injection molding product (2) by the ejector pin.

3. The mold and injection molding process using the principle of expansion with heat and contraction with cold as claimed in claim 2, wherein the product left on the female mold side plate (3) creates a shrinkage space and a cold air injection space after the male mold plate (5) is withdrawn in step S2.

4. The mold and the injection molding process using the principle of expansion with heat and contraction with cold according to claim 2, wherein in step S3, the temperature output from the low temperature air pipe system (4) is controlled below 10 degrees, and the air is blown against the inner wall of the injection molded product (2) retained on the female mold side plate (3) through the air nozzle to form a cool air vortex inside the product, so as to rapidly cool the injection molded product and reduce the shrinkage of the product, thereby separating the product from the female mold side plate (3).