WO2017183647A1 - Gas-discharging structure and injection molding die - Google Patents

Abstract

[Problem] To provide: a gas discharge structure, which has a high opening area ratio efficiently allowing gas inside a cavity to be discharged easily, is an integrated structure that does not require work such as assembly or alignment, and is a structure with reinforcing crosspieces that can withstand molding pressure, and which has a gas discharge passage that is linear and does not have level differences; and an injection molding die obtained using same. [Solution] In a mode in which the flat apical surfaces 7 of protruding parts 5 are abutted against the flat surfaces 6 opposite flat surfaces 3 on one side of unit thin plates 2, the directions of rectangular grooves 4 and protruding parts 5 are made to coincide and matched and multiple unit thin plates are stacked. By bonding and integrating the flat surfaces 6 with the flat apical surfaces 7 of the protruding parts 5 in said configuration, a gas-discharging structure 1 according to an embodiment that is made of multiple rectangular holes 3 and reinforcing crosspieces 4 is obtained. Said gas-discharging structure 1 can be formed with: a unit thin plate thickness of 1 mm or less; a rectangular groove 4 depth of 0.03 mm or less; a width/depth ratio, which is the ratio of the width to depth thereof, of at least 50; a length between the rectangular grooves 4 of 1 mm or less; end-processed portions at the two ends of at least 0.5 mm; and the number of stacked plates being at least five.

Description

Gas exhaust structure and injection mold

The present invention relates to a gas discharge structure and an injection mold.

In the injection molding of resin molded products, it is necessary to discharge the air in the molding die to the outside as the resin is injected into the molding die, so a gas discharge structure with a fine gap is arranged in the molding die. ing. This gas discharge structure has a slit that forms a gas flow path, and the rectangular groove serving as the slit has a groove width and length so that the resin does not flow into the gas discharge structure on the product surface. A structure in which a plate provided with a plurality of rectangular grooves having a wide cross section at the far back is provided with a structure fastened using a bolt or a pin. As described above, since the fastening portion bolt and the positioning pin are provided, the laminated structure has a longer interval between adjacent rectangular grooves, and as a result, the ratio of the rectangular groove length / plate length has been reduced (Patent Document 1). ).
Further, the thickness of the plate forming the gas discharge structure is set to be thick in consideration of deformation of the rectangular groove constituting plate due to machining or molding pressure. As a result, there is a commercial product that has a laminated structure in which the ratio of the rectangular groove width / plate thickness is reduced to reduce the number of laminated plates at a constant thickness.

JP 2004-167714 A

In the gas exhaust structure and the commercial product shown in the above-mentioned Patent Document 1, since the total length of the slit grooves is short with respect to the structure length, and the number of laminated plates is small with respect to the structure thickness, the aperture ratio is low. Low gas emission efficiency. For this reason, as the resin is filled into the mold cavity, the ability to discharge out of the mold cavity through the slit groove is lower than the amount of gas that needs to be discharged per unit time. In other words, the quality of the obtained resin product deteriorated.

Since the distribution of the slit grooves in the stacking direction is rough, the position of the resin merging and the position of the gas discharge path do not coincide with each other, and it is necessary to change the stack thickness in order to adjust this.
Furthermore, because of the structure having bolt fastening and positioning pins, when assembling the structure into the mold, assembly work or positioning work of the structure itself is required.
In addition, since the rectangular groove extends deeper than the product surface, it is easy for gas residue to accumulate, and it is difficult to remove the gas residue even after cleaning, requiring disassembly and cleaning / assembly.

In view of the problems in the prior art described above, the present invention is an integral structure that has an efficient and high opening ratio that can easily discharge the gas in the cavity and does not require assembly or positioning, and can be used for molding pressure. An object of the present invention is to provide a gas discharge structure that has a gas discharge path that is straight and has no steps, and an injection mold using the same, in order to prevent gas residue from being provided with a structure that can withstand reinforcing bars.

In order to solve the above-described problems, a gas discharge structure according to the present invention includes one flow path cross section derived from a pressure loss equation, a reinforcing flow beam derived from a flow channel total area satisfying a gas discharge rate, and a strength calculation equation. In consideration of the above, a gas discharge structure with a flow path plane having a checkerboard pattern and a depth is formed, and a change in the cross section of the gas flow path is eliminated, gas residue accumulation is prevented, and assembly bolts and positioning pins are not used. It was constructed in consideration of preventing the road from decreasing.

That is, in the gas discharge structure according to the present invention, a unit thin plate in which a plurality of rectangular grooves are provided on one side plane of the thin piece and a plurality of protrusions are provided through the plurality of rectangular grooves is formed in the direction of the rectangular grooves and the protrusions. And a plurality of rectangular holes and reinforcing bars are formed by joining and integrating a plane opposite to the surface having the rectangular groove and the protruding portion and a top plane of the protruding portion. Features.

A unit thin plate comprising a plurality of rectangular grooves having a certain width and a certain depth and penetrating through the plurality of rectangular grooves and arranged in parallel through the plurality of rectangular grooves is formed into a rectangular shape on one side plane of the thin piece. The top surface of the protrusion of the surface having the groove and the protrusion and the flat surface opposite to the surface having the rectangular groove and the protrusion are aligned and joined together by aligning the directions of the rectangular groove and the protrusion. It can be made up of a rectangular hole and a reinforcing bar.

The rectangular groove of the unit thin plate and the protruding portion arranged in parallel through the rectangular groove are formed by one or more of photoetching, milling, grinding, die-sinking electric discharge machining, and wire cut electric discharge machining. Further, a rectangular groove penetrating through the unit thin plate with a certain width and a certain depth, and a plurality of protrusions having a certain height projecting in parallel from the plane portion through the plurality of rectangular grooves are formed by photoetching and It can be formed by one or more of milling, grinding, die-sinking electric discharge machining, and wire cut electric discharge machining.

This makes it possible to eliminate changes in the gas channel cross section precisely and prevent gas residue accumulation. In particular, since the rectangular grooves are formed by etching without processing pressure, thinner plates can be used as necessary, and the number of stacked layers per unit thickness can be increased. Further, the ratio of the thickness of the rectangular groove to the thickness of the thin plate can be increased, and a high aperture ratio can be realized during lamination.

The plane opposite to the surface having the rectangular groove and the protruding portion and the top plane of the protruding portion can be joined by diffusion bonding. As described above, the entire surface excluding the rectangular groove is diffusion bonded, so that an integrated gas discharge structure that does not require the use of assembly bolts or positioning pins can be obtained. At the same time, the flow path can be prevented from decreasing. In addition, it was possible to set the reinforcing bars to be thin, and a high aperture ratio was achieved.

Further, the injection mold of the present invention comprises a unit thin plate having a plurality of rectangular grooves provided on one side plane of a thin piece, and a plurality of protrusions arranged in parallel via the plurality of rectangular grooves. The top flat surface of the projecting portion of the surface having the rectangular groove and the surface opposite to the surface having the projecting portion are joined and integrated by aligning the directions of the rectangular groove and the projecting portion, and a plurality of layers are laminated to form a rectangular hole and a reinforcing bar. The gas discharge structure is fitted into the mold body so as to constitute a part of the molding surface.

In the gas discharge structure, a plurality of rectangular grooves having a certain width and a certain depth are provided on one side plane of the thin piece, and a plurality of protrusions having a certain height are arranged in parallel through the plurality of rectangular grooves. A plurality of unit thin plates are stacked with the top flat surface of the protruding portion of the surface having the rectangular groove and the protruding portion and the plane opposite to the surface having the rectangular groove and the protruding portion aligned in the direction of the rectangular groove and the protruding portion. They may be joined and integrated to form a plurality of rectangular holes and reinforcing bars.

According to the gas discharge structure and the injection mold of the present invention, the gas discharge structure incorporated in the injection mold has a strength that can withstand the resin pressure and the vicinity of the end of the one-way flow of the resin over the entire mass production period. In the vicinity of the merging position of the counterflow and the counterflow, it has a high opening ratio from the inlet to the outlet in order to easily discharge the gas in the cavity, and there are fastening bolts and positioning pins to eliminate the need for operations such as assembly and positioning. In addition, it is possible to simultaneously satisfy the fact that the gas flow path is straight and has no steps in order to prevent gas residue accumulation.

It is a front view of one embodiment of a gas discharge structure concerning the present invention. It is a partial front view of one embodiment of a gas discharge structure concerning the present invention. It is a top view of the part shown in FIG. It is a side view of the gas exhaust structure shown in FIG. It is the elements on larger scale of the gas exhaust structure shown in FIG. It is explanatory drawing which shows the manufacturing process of the gas exhaustion structure which concerns on this invention. It is a cross-sectional schematic diagram of one embodiment of an injection mold according to the present invention. It is a perspective view of the gas exhaust structure created in the Example of this invention. It is a photograph of the product created in the Example of the injection mold concerning the present invention. It is a photograph of the product created by the comparative example with respect to the Example of the injection mold which concerns on this invention. It is explanatory drawing which shows the other aspect of the manufacturing process of the gas exhaustion structure which concerns on this invention. It is explanatory drawing which shows another aspect of the manufacturing process of the gas exhaustion structure which concerns on this invention. It is explanatory drawing which shows the other aspect of the manufacturing process of the gas exhaustion structure which concerns on this invention. It is explanatory drawing which shows another aspect of the manufacturing process of the gas exhaust structure which concerns on this invention, (a) is the top view, (b) is the front view. It is a perspective view of the gas exhaust structure of other embodiment of this invention. It is a right view of the gas exhaust structure shown in FIG. It is a perspective view of the gas exhaust structure of further another embodiment of the present invention. FIG. 18 is a partially enlarged perspective view of the gas discharge structure shown in FIG. 17.

A gas discharge structure according to an embodiment of the present invention will be described below with reference to the drawings.
As shown in FIGS. 1 to 5, the gas discharge structure 1 of the present embodiment is formed by laminating a plurality of unit thin plates 2 and joining them together. A plurality of rectangular grooves 4 having a constant width and a predetermined depth are provided on one side plane 3 of the unit thin plate 2. A plurality of projecting portions 5 having a certain height projecting from the one-side plane 3 through the plurality of rectangular grooves 4 are provided.
The rectangular grooves 4 and the protrusions 5 are aligned in a manner in which the top flat surface 7 of the protruding portion 5 is brought into contact with the flat surface 6 opposite to the one-side flat surface 3 of the unit thin plate 2, and a plurality of layers are laminated together.
In this state, the gas discharge structure 1 of the present embodiment including a large number of rectangular holes 8 and reinforcing bars 9 is obtained by joining and integrating the flat surface 6 and the top flat surface 7 of the protruding portion 5.
The gas discharge structure 1 has a unit thin plate thickness of 1 mm or less, a depth of the rectangular groove 4 of 0.03 mm or less, a width / depth ratio which is a ratio of the width to the depth of 50 or more, and the rectangular groove 4 It can be formed by setting the gap length to 1 mm or less, the end processed portions at both ends to 0.5 mm or more, and the number of stacked layers to 5 or more.

A rectangular groove 4 passing through the unit thin plate 2 having a certain width and a certain depth and a plurality of protrusions 5 having a certain height projecting from the planar portion through the plurality of rectangular grooves 4 are formed by a photoetching process. be able to.
As shown in FIG. 6, the photo-etching removes and cleans the front and back surfaces of the material flakes, and after applying a photosensitive resin (resist), the groove pattern film prepared in advance is applied to the photosensitive resin (resist). The groove pattern is formed by attaching and generally baking by UV irradiation. After etching this to form a groove in the material, the photosensitive resin is removed by peeling, washing and drying. By forming by etching in this way, the thinner unit thin plate 2 can be used as necessary, and the number of stacked layers per unit thickness can be increased. In addition, the ratio of the depth of the rectangular groove 4 to the thickness of the unit thin plate 2 can be increased, and a high aperture ratio of the rectangular hole 8 can be realized during lamination.

Bonding and integration of the flat surface 6 and the top flat surface 7 of the protrusion 5 can be performed by diffusion bonding.
Diffusion bonding is performed by bringing the flat surface 6 and the top flat surface 7 of the protruding portion 5 into close contact and pressurizing and heating in a controlled atmosphere such as a vacuum or an inert gas. As a result, bonding can be performed using diffusion of atoms generated on the bonding surface. Thus, in the case of diffusion bonding, an integrated gas discharge structure 1 that does not require the use of assembly bolts or positioning pins is obtained. At the same time, the flow path can be prevented from decreasing. Further, the reinforcing bar 9 can be set to be thin, and a high opening ratio of the rectangular hole 8 can be realized.

FIG. 7 shows an injection mold 10 according to an embodiment of the present invention to which the gas discharge structure 1 according to the present embodiment is applied.
The injection mold 10 includes a fixed mold 11 and a movable mold 12. A cavity 13 is formed between the fixed mold 11 and the movable mold 12. The cavity 13 is provided with a rib forming region 13a, a boss forming region 13b, a protrusion forming region 13c, and the like according to the design based on the attributes of the target product.
On the other hand, the movable mold 12 is configured by combining the main body 14 and the cavity forming portion 15, and the cooling hole 16 is disposed in the cavity forming portion 15. The main body portion 14 is provided with a gas flow path 17 connected to the rib forming region 13a, the boss forming region 13b, and the protrusion forming region 13c.
The gas flow path 17 has a connecting portion for each of the rib forming region 13a, the boss forming region 13b, and the protrusion forming region 13c in the cavity forming portion 15, and the gas discharge structure 1 is disposed in each of the connecting portions.

According to the injection mold 10, the gas discharge structure 1 incorporated in the injection mold 10 has a strength that can withstand the resin pressure, and the end of the one-way flow of the resin and the confluence of the counter flow over the entire mass production period. In the vicinity of the position, it has a high opening ratio that allows the gas in the cavity to be easily discharged, and it is an integrated structure that does not have fastening bolts or positioning pins to eliminate work such as assembly and positioning. In addition, in order to prevent gas residue accumulation, it is possible to simultaneously satisfy that the gas flow path 17 is linear and has no step.
That is, the gas in the cavity 13 including the rib forming region 13a, the boss forming region 13b, and the protrusion forming region 13c is smoothly filled with the resin through the gas discharge structure 1 and the gas flow path 17 connected to each forming region. Thus, the rib forming region 13a, the boss forming region 13b, and the protrusion forming region 13c can be filled with 100% resin.

Resins for injection molding using the above molds are polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polybutylene-ethylene terephthalate (PBT-PET copolymer resin), polyether ether ketone (PEEK resin), polyphenylene. Sulfide (PPS), polyetherimide (PEI), 6 nylon (PA6), 6-6 nylon (PA66), 6T nylon (PA6T), polyphthalamide (PPA), polystyrene (PS), ABS resin (ABS), Thermoplastic resins such as vinyl chloride resin (PVC), polyacetal (POM), liquid crystal polymer (LCP), polysulfone (PSU), polypropylene (PP), and polycarbonate (PC). These can be used alone or in combination. Thermosetting resins such as phenol resin (PF), epoxy resin (EP), diallyl phthalate resin (PDAP), silicone resin (SI), polyimide resin (PI), melamine resin (MF), urea resin (UF) It is. In order to improve heat resistance and dimensional stability, inorganic fillers such as carbon fibers, glass fibers, glass beads, and talc may be appropriately blended with these thermoplastic resins and thermosetting resins. Moreover, you may mix | blend organic fillers, such as a cellulose nanofiber suitably.

The gas discharge structure 1 shown in FIG. 8 was prepared as follows, and resin molding was performed with an injection mold 10 using the gas discharge structure 1.
L21.6mm × W10.1mm × t0.2mm SUS plate L21.6mm, W10.1mm on one surface, 1.0mm away from both ends of L21.6mm, and the groove spacing is set to L0.4mm at equal intervals. A rectangular groove 4 of 6 mm × D 0.025 mm was repeatedly provided at five locations by etching. Similarly, 45 unit thin plates 2 having the same groove shape and outer shape are overlapped, and L21.6 mm × W10.1 mm × t0.5 mm reinforcing SUS plates are overlapped on both longitudinal sides of the unit thin plate 2. A thin plate laminate, which is a laminate consisting of a single thin plate, was constructed. After that, 47 thin plate laminates were made into an integral component of L21.6 mm × W10.1 mm × H10 mm using diffusion bonding. The gas discharge structure 1 as an integrated component is L21.6 mm × H10.
When viewed from the direction of mm, the rectangular groove 4 of L3.6 mm × D0.025 mm penetrates the back surface of L21.6 mm × H10 mm at equal intervals of H10 mm direction pitch 0.2 mm and L21.6 mm direction pitch 4.0 mm. 225 pieces were formed. As a result, it has a high opening ratio of about 9.4%, a gas vent rectangular hole 8 with no step in the depth direction, a reinforcing bar 9 for molding pressure resistance, etc., and an integrated structure that eliminates the need for bolt fastening or positioning pins The gas discharge structure 1 which forms can be realized.

FIG. 9 shows a molded product obtained by resin molding with the injection mold 10 using the gas discharge structure 1. FIG. 10 shows a molded product obtained by an injection mold without using the gas discharge structure 1 as a comparative example.
The obtained molded product was an automobile exterior part, and the molded product weight was 580 gr. Polypropylene (black coloring) was used as the resin material, and a molding machine having a clamping force of 1250 tons was used.
A three-point hot runner gate was used as the mold. The molding conditions were a resin temperature of 220 ° C., a mold temperature of 30 ° C., and an injection speed of 25% (screw diameter φ105 mm).
In the comparative example shown in FIG. 10, the gas vent groove range A provided on the end face of the insert piece wire was 0.03 mm × 60 mm in size, but the resin merging position and the degassing die insert piece position are different. The gas was collected at this position and the filling failure occurred.
On the other hand, in the embodiment shown in FIG. 9, as a result of arranging two gas discharge structures 1 (W10 × L21.6), the resin joining position C fluctuated in the range of 4 mm during molding, but it fits in the gas discharge block. The gas escaped and the resin filling defect was solved.

Hereinafter, various aspects of the manufacturing process of the gas discharge structure of the present invention will be described with reference to the drawings. A rectangular groove 4 that penetrates the unit thin plate 2 with a certain width and a certain depth and a plurality of protruding parts 5 that protrude from the flat surface through the plurality of rectangular grooves 4 are photo-etched, milled and ground. It can be formed by one or more processes of machining, die-sinking electric discharge machining, and wire cut electric discharge machining.

When applying milling, as shown in FIG. 11, the one side plane 3 of the unit thin plate 2 is cut using a milling drill 18 that rotates at high speed. The unit thin plate 2 is fixed on a table (not shown), and the milling drill 18 moves in the Z direction (up and down), and moves the table in the XY direction (front and rear, left and right) for processing.

When applying the grinding process, as shown in FIG. 12, a grinding wheel 19 rotating at a high speed is used, and the unit thin plate 2 is scraped off by extremely hard and fine abrasive grains constituting the grinding wheel 19. Mold to the shape of

When applying the die-sinking electric discharge machining, as shown in FIG. 13, 1000 to 100,000 sparks are intermittently blown in the machining liquid 20 between the electrode 21 and the unit thin plate 2 per second. Then, the metal is melted by the heat so that the shape of the electrode 21 is carved into the unit thin plate 2.

When applying the wire electric discharge machining, as shown in FIG. 14, the metal is melted in the machining liquid 20 by the electric spark discharge heat between the wire electrode 22 and the unit thin plate 2 to form the wire electrode 22 on the unit thin plate 2. It is processed so as to be carved into a shape corresponding to the movement locus 23.

The gas discharge structure according to another embodiment of the present invention will be described below with reference to the drawings.
The gas discharge structure 1 shown in FIGS. 15 and 16 has a flange 1a on the upper surface. By having this flange 1a, it is possible to prevent the product from coming off after being assembled into the injection mold 10. The collar 1a is formed, for example, by performing processing for removing the upper surface portion of the gas discharge structure 1 shown in FIG. 8 by wire-cut electric discharge machining, milling, grinding, or the like.
The gas discharge structure 1 shown in FIGS. 17 and 18 has flanges 1b on both sides. The flange 1b can also be prevented from coming off after being incorporated into the injection mold 10, and is formed by performing a process of removing a required portion by wire-cut electric discharge machining, milling, grinding, or the like.

DESCRIPTION OF SYMBOLS 1 ... Gas discharge structure, 2 ... Unit thin plate, 4 ... Rectangular groove, 5 ... Projection part, 8 ...
-Rectangular hole, 6 ... plane, 7 ... top plane.

Claims (4)

1. A plurality of unit thin plates in which a plurality of rectangular grooves are provided on one side plane of the thin piece and a plurality of projecting portions are provided through the plurality of rectangular grooves are laminated in a direction in which the directions of the rectangular grooves and the projecting portions are aligned. A gas discharge structure comprising a plurality of rectangular holes and reinforcing bars formed by joining and integrating a plane opposite to the surface having the projections and a top plane of the projections.
2. 2. The rectangular groove of the unit thin plate and the protruding portion arranged in parallel through the rectangular groove are formed by one or more of photoetching, milling, grinding, die-sinking electric discharge machining, and wire cut electric discharge machining. Gas exhaust structure.
3. The gas discharge structure according to claim 1 or 2, wherein a plane opposite to the surface having the rectangular groove and the protruding portion and a top plane of the protruding portion are joined by diffusion bonding.
4. A unit thin plate formed by providing a plurality of rectangular grooves on one side plane of the thin piece and providing a plurality of projecting portions arranged in parallel through the plurality of rectangular grooves, the top flat surface of the projecting portion of the surface having the rectangular grooves and projecting portions and the rectangular shape A gas discharge structure comprising a rectangular hole and a reinforcing bar is partly formed by laminating and integrating a plurality of flat surfaces on the opposite side of the surface having the grooves and the protrusions by aligning the directions of the rectangular grooves and the protrusions. An injection mold characterized by being fitted into the mold main body so as to constitute.
   
   

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