CN111907004A

CN111907004A - Prevent injection mold of weld line production

Info

Publication number: CN111907004A
Application number: CN202010751361.5A
Authority: CN
Inventors: 李成林
Original assignee: Chongqing Wanbang Precision Die Co ltd
Current assignee: Chongqing Wanbang Precision Die Co ltd
Priority date: 2020-07-30
Filing date: 2020-07-30
Publication date: 2020-11-10

Abstract

The invention relates to the technical field of injection molds, and particularly discloses an injection mold for preventing a weld line from being generated, which comprises a movable mold and a fixed mold, wherein a mold cavity is formed between the movable mold and the fixed mold, an injection hole is formed in the movable mold, the movable mold is positioned above the fixed mold, a molding column is integrally formed on the fixed mold, the molding column is of a hollow structure, a transition hole is formed in the top of the molding column, an air hole communicated with the mold cavity is formed in the side wall of the molding column, a hydrophobic filter membrane is fixed on the air hole, an air flow channel is formed in the movable mold, the air flow channel is communicated with the transition hole after the movable mold and the fixed mold are closed, the aperture of the air flow channel is smaller than that of the transition hole, and the. Adopt the technical scheme in this patent to solve the problem that the hole department of injection moulding shell can form the weld line in prior art.

Description

Prevent injection mold of weld line production

Technical Field

The invention relates to the technical field of injection molds, in particular to an injection mold capable of preventing a weld line from being generated.

Background

The shell of electronic products such as mobile phones, flat plates and the like is usually produced by adopting an injection molding process, in addition, the hole opening treatment is required during production, the hole opening mode with the highest efficiency is that according to the design of the product, the hole forming position is completed by arranging bulges such as a modeling column on a mold, because the injection mold comprises a fixed mold and a movable mold, the modeling column can be arranged on the fixed mold and also can be arranged on the movable mold, no matter which mold is arranged, a small gap can exist between the end surface of the modeling column and the other mold, because the shell of the electronic products such as mobile phones, flat plates and the like has higher requirements on the appearance, the obvious weld line cannot exist on the appearance surface of the product, and the weld line can be generated due to the existence of the gap, so that the appearance quality of the product does not reach the.

Disclosure of Invention

The invention provides an injection mold capable of preventing a weld line from being generated, and aims to solve the problem that the weld line can be formed at a hole of an injection casing in the prior art.

In order to achieve the purpose, the technical scheme of the invention is as follows:

the utility model provides an injection mold who prevents weld line production, includes movable mould and cover half, form the die cavity between movable mould and the cover half, seted up the hole of moulding plastics on the movable mould, the movable mould is located the top of cover half, integrated into one piece has the molding post on the cover half, the molding post is hollow structure, and the top of molding post is equipped with the transition hole, is equipped with the gas pocket of intercommunication die cavity on the lateral wall of molding post, is fixed with hydrophobic filter membrane on the gas pocket, has seted up the air current way on the movable mould, behind movable mould and the cover half compound die, air current way and transition hole intercommunication, the aperture of air current way is less than the aperture of transition hole, and the air current way has air feed pump and aspirator.

The technical principle and the effect of the technical scheme are as follows:

1. in the scheme, the die cavity is formed after the movable die and the fixed die are assembled, the air suction pump is started, the air in the die cavity is sucked out through the filter membrane and is in a vacuum state, the air suction pump is closed after the air suction pump is closed, the air supply pump is started when the injection molding is started, the air generated by the air supply pump enters the molding column through the air flow channel, and due to the fact that in the injection molding process, the molten colloid generates extrusion force towards the inside of the molding column on the filter membrane, the air generated by the air supply pump can be offset with the extrusion force at the filter membrane, and the filter membrane. The arrangement can prevent the problem that the surface of a formed product has air holes due to the fact that gas in the die cavity is difficult to discharge in the injection molding process.

2. Because of the limitation of the precision of the existing die manufacturing, a gap is always formed between the top of the modeling column and the bottom of the movable die, although the gap is very small, the colloid has a certain pressure during the injection molding process, so that the colloid tends to flow in the gap, and the welding line can be formed, in the scheme, because the aperture of the air flow channel is smaller than that of the transition hole, a staggered edge is formed between the transition hole and the air flow channel, the air supplied by the air supply pump also has the tendency of flowing to a gap between the transition hole and the air flow channel along the staggered edge, namely, the gap is blocked, and the fluidity of the gas is far higher than that of the colloid in the micro gap, so the gas can block the micro gap, in order to avoid the influence of overlarge gas pressure on the formed shell, the gas supply pump is closed after the gas pressure in the gas flow channel reaches 1.5MPA in the scheme; the product obtained by the scheme is found by trial production that the weld lines are not generated at the holes.

Furthermore, the aperture of the transition hole is more than twice of the aperture of the airflow channel.

Has the advantages that: therefore, the staggered edges between the transition holes and the airflow holes can be prolonged, and gas can be filled into gaps between the top of the modeling column and the bottom of the movable mold better.

Further, the injection molding hole is arranged on one side far away from the airflow channel.

Has the advantages that: this enables the injected gel to gradually flow to the filter membrane instead of directly impacting the filter membrane.

Further, the injection molding hole is an upper stepped hole and a lower stepped hole, and the aperture below the stepped holes is smaller than that above the stepped holes.

Has the advantages that: the arrangement can reduce the backflow of the colloid from the injection molding hole.

Further, the air hole is arranged on one side back to the injection molding hole.

Has the advantages that: therefore, the colloid entering the die cavity from the injection molding hole can not directly impact the filter membrane in the air hole, and the impact force on the surface of the filter membrane is reduced.

Furthermore, the top of the modeling column is matched with the air flow channel through an arc surface.

Has the advantages that: the arrangement improves the sealing performance between the molding column and the movable mold.

Furthermore, the top of the molding column is an upward convex arc surface, and the bottom of the movable mold is provided with a concave surface matched with the arc surface.

Has the advantages that: the downward fluidity of the colloid is higher than the upward fluidity, and the upward flow needs to overcome the self gravity, so the arrangement can further improve the difficulty of the colloid flowing to the gap between the arc surface and the concave surface.

Furthermore, an electromagnet is fixed in the modeling column, an elastic part which is horizontally arranged is fixed on the electromagnet, an arc-shaped plate is fixed at the free end of the elastic part, the arc-shaped plate is a magnetic plate, and the electromagnet is repelled with the arc-shaped plate after being electrified, so that the arc-shaped plate is tightly attached to the air hole.

Has the advantages that: like this when the evacuation, the electro-magnet outage, the arc leaves the gas pocket under the effect of elastic component, this kind of gas in the die cavity can be quick leads to the filtration membrane and is taken away, and the evacuation is accomplished the back, the electro-magnet circular telegram, make it repel mutually with the arc, the arc supports at gas pocket department, the in-process of moulding plastics, the gas is backfilled to the post of modelling to the air feed pump, a small amount of gas can enter into between arc and the filter membrane with the support filter membrane through the small gap between arc and the inner wall of modelling post, reduce the deformation that the colloid produced the filter membrane, make and form smooth hole on the product housing.

Furthermore, a limiting groove located at the air hole is formed in the inner wall of the modeling column, and the limiting groove is matched with the arc-shaped plate in shape.

Has the advantages that: the arc-shaped plate is better attached to the inner wall of the modeling column through the arrangement.

Further, a mounting hole for discharging a wire of the power supply magnet is formed in the fixed die, and the mounting hole is communicated with the inside of the modeling column.

Has the advantages that: this arrangement prevents the wires of the electromagnet from affecting the surface of the housing.

Drawings

FIG. 1 is a schematic view showing a structure of an injection mold in which a fixed mold and a movable mold are not closed according to embodiment 1 of the present invention for preventing a weld line from being generated;

FIG. 2 is a schematic view of a fixed mold and a movable mold of an embodiment 1 of an injection mold for preventing weld lines from being generated after the fixed mold and the movable mold are closed;

FIG. 3 is an enlarged view of portion A of FIG. 2;

FIG. 4 is an enlarged view of the molding pillars in example 2 of the injection mold for preventing the weld line from being generated according to the present invention.

Detailed Description

The following is further detailed by way of specific embodiments:

reference numerals in the drawings of the specification include: the device comprises a movable die 1, a fixed die 2, a die cavity 3, a modeling column 4, a transition hole 5, an air hole 6, a filter membrane 7, an air flow channel 8, a dislocation edge 9, an injection molding hole 10, an arc surface 11, a concave surface 12, an electromagnet 13, an elastic part 14, an arc plate 15 and a limiting groove 16.

Example 1 is substantially as shown in figures 1 and 2 of the accompanying drawings:

the utility model provides an injection mold who prevents weld line production, including movable mould 1 and cover half 2, form die cavity 3 between movable mould 1 and the cover half 2, wherein movable mould 1 is located the top of cover half 2, integrated into one piece has molding post 4 on cover half 2, combine shown in fig. 3, molding post 4 is hollow structure, and the top is equipped with transition hole 5, be equipped with the gas pocket 6 of intercommunication die cavity 3 on the lateral wall of molding post 4, be fixed with hydrophobic filter membrane 7 on the gas pocket 6, this filter membrane 7 can pass through for the gas, the molten plastic colloid can't pass.

The movable die 1 is provided with an air flow channel 8, wherein the air flow channel 8 is communicated with a transition hole 5 at the top of the modeling column 4, the aperture of the transition hole 5 is more than twice of that of the air flow channel 8, thus a staggered edge 9 is formed between the transition hole 5 and the air flow channel 8, the top end of the air flow channel 8 is connected in parallel with an air supply pump and an air suction pump through pipelines, and the minimum air pressure generated by the air supply pump can be 0.7 MPA.

An injection molding hole 10 is formed in the movable mold 1, the injection molding hole 10 is arranged on the side far away from the airflow channel 8, the injection molding hole 10 is an upper stepped hole and a lower stepped hole of a single step, and the aperture below the stepped hole is smaller than the aperture above the stepped hole; in addition, the air hole 6 on the molding column 4 is arranged opposite to the side of the injection hole 10, namely the injection hole 10 is arranged on the left side of the molding column 4 in the embodiment, and the air hole 6 is arranged on the right side of the molding column 4.

In addition, in this embodiment, the top of the shaped pillar 4 is in arc surface fit with the airflow channel 8, specifically: the top of the molding column 4 is an upward convex arc surface 11, and the bottom of the movable mold 1 is provided with a concave surface 12 matched with the arc surface 11, so that the sealing performance between the molding column 4 and the movable mold 1 is improved, and the length of the dislocation edge 9 is prolonged.

In specific implementation, firstly, according to the figure 2, the movable mold 1 and the fixed mold 2 are matched, after the matching, the arc surface 11 at the top of the modeling column 4 is matched with the concave surface 12 at the bottom of the movable mold 1, the air suction pump is started, so that the air in the mold cavity 3 is sucked out through the filter membrane 7 and is in a vacuum state, the air suction pump is closed, when the injection molding is started, the air supply pump is started, the air generated by the air supply pump enters the modeling column 4 through the air flow channel 8, and because the molten colloid generates extrusion force towards the interior of the modeling column 4 on the filter membrane 7 in the injection molding process, the air generated by the air supply pump can be offset with the extrusion force at the filter membrane 7, and the filter membrane 7 is.

Because of the current precision limit of the die manufacturing, a gap is always formed between the arc surface 11 at the top of the moulding column 4 and the concave surface 12 at the bottom of the moving die 1, although the gap is very small, the colloid has a certain pressure during the injection molding process, so that the colloid tends to flow in the gap, and the welding line can be formed, in the scheme, as the staggered edge 9 is formed between the transition hole 5 and the air flow channel 8, the air supplied by the air supply pump also has the tendency of flowing to the gap between the staggered edge 9 and the air supply pump, namely, the gap is blocked, and the fluidity of the gas is far higher than that of the colloid in the micro gap, so the gas can block the micro gap, in order to avoid the influence of the excessive gas pressure on the formed housing, the gas supply pump is turned off when the gas pressure in the gas flow channel 8 reaches 1.5MPA in the present application.

Example 2 is substantially as shown in figure 4:

the difference from example 1 is that: be fixed with electro-magnet 13 in molding post 4, the mounting hole that supplies power magnet 13's wire to discharge is seted up to the cover half 2, the mounting hole communicates with molding post 4 is inside, be fixed with the elastic component 14 that the level set up on electro-magnet 13, the free end of elastic component 14 is fixed with arc 15, the shape of arc 15 is the same with molding post 4 inner wall, arc 15 is the magnetic sheet, set up the spacing groove 16 that is located gas pocket 6 department on the inner wall of molding post 4, spacing groove 16 matches with the shape of arc 15, elastic component 14 is the extension spring in this embodiment, when electro-magnet 13 is not circular telegram, the extension spring leaves spacing groove 16 with arc 15, and after electro-magnet 13 circular telegram, electro-magnet 13 repels with arc 15 for arc 15 supports in spacing groove 16.

Like this when the evacuation, electro-magnet 13 cuts off the power supply, the arc 15 leaves the spacing groove 16 under the effect of elastic component 14, the gaseous filter membrane 7 that passes through that can be quick in the die cavity 3 is taken away like this, and the evacuation is accomplished the back, electro-magnet 13 circular telegram, make it repel mutually with arc 15, arc 15 supports in the spacing groove 16, the in-process of moulding plastics, the gas is backfilled in the gas feed pump to moulding post 4, a small amount of gas can enter into between arc 15 and the filter membrane 7 through the small gap between arc 15 and the spacing groove 16 with supporting filter membrane 7, reduce the deformation that the colloid produced to filter membrane 7, make and form smooth hole on the product shell.

The foregoing is merely an example of the present invention and common general knowledge of known specific structures and features of the embodiments is not described herein in any greater detail. It should be noted that, for those skilled in the art, without departing from the structure of the present invention, several changes and modifications can be made, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicability of the patent. The scope of the claims of the present application shall be determined by the contents of the claims, and the description of the embodiments and the like in the specification shall be used to explain the contents of the claims.

Claims

1. The utility model provides a prevent injection mold of weld line production, includes movable mould and cover half, form the die cavity between movable mould and the cover half, seted up injection hole, its characterized in that on the movable mould: the movable mould is located above the fixed mould, a moulding column is integrally formed on the fixed mould, the moulding column is of a hollow structure, a transition hole is formed in the top of the moulding column, an air hole communicated with the mould cavity is formed in the side wall of the moulding column, a hydrophobic filter membrane is fixed on the air hole, an air flow channel is formed in the movable mould, the air flow channel is communicated with the transition hole after the movable mould and the fixed mould are assembled, the aperture of the air flow channel is smaller than that of the transition hole, and an air supply pump and an air suction pump are connected in parallel to the air flow channel through a pipeline.

2. The injection mold for preventing the generation of the weld line according to claim 1, wherein: the aperture of the transition hole is more than twice of that of the air flow channel.

3. The injection mold for preventing the generation of the weld line according to claim 1, wherein: the injection molding hole is arranged on one side far away from the airflow channel.

4. The injection mold for preventing the generation of the weld line according to claim 1, wherein: the injection molding hole is an upper stepped hole and a lower stepped hole, and the aperture below the stepped holes is smaller than that above the stepped holes.

5. The injection mold for preventing the generation of the weld line according to claim 1, wherein: the air hole is arranged on one side back to the injection molding hole.

6. The injection mold for preventing the generation of the weld line according to claim 1, wherein: the top of the molding column is matched with the air flow channel through an arc surface.

7. The injection mold for preventing the generation of the weld line according to claim 6, wherein: the top of the molding column is an upward convex arc surface, and the bottom of the movable mold is provided with a concave surface matched with the arc surface.

8. The injection mold for preventing the generation of the weld line according to claim 1, wherein: the electromagnetic modeling column is internally fixed with an electromagnet, the electromagnet is fixed with a horizontally arranged elastic piece, the free end of the elastic piece is fixed with an arc-shaped plate, the arc-shaped plate is a magnetic plate, and the electromagnet is repelled with the arc-shaped plate after being electrified, so that the arc-shaped plate is tightly attached to the air hole.

9. The injection mold for preventing the generation of the weld line according to claim 8, wherein: and the inner wall of the modeling column is provided with a limiting groove positioned at the air hole, and the limiting groove is matched with the arc-shaped plate in shape.

10. The injection mold for preventing the generation of the weld line according to claim 9, wherein: and a mounting hole for discharging a wire of the power supply magnet is formed in the fixed die and communicated with the inside of the modeling column.