JP2000343568A - Injection mold structure fitted with gate cutting mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize automatic gate cutting imparting a good finish surface without using a rotary mechanism or a slider mechanism when a gate is arranged to the wall thickness cross-sectional part of a product such as the hole part side surface of the product. SOLUTION: A mold is equipped with a submarine gate having a structure wherein a gate piece G is formed so as to be projected in the AA direction on the fixed side of a mold parting surface PL to reach the wall thickness cross section of a product part F. By providing the submarine gate formed to the gate piece G and the edge part generating cutting action in the boundary surface of the product part F when a runner part E and the product part F are ejected, the runner part E and the product part F are cut to be divided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold structure for injection molding, and more particularly, to use a protrusion of a molded product when a gate is provided in a thick section of a product such as a side surface of a hole of a product. The present invention relates to a mold structure for injection molding for automatically cutting a gate and a product part.

[0002]

2. Description of the Related Art Conventionally, this type of injection mold having a gate cut mechanism is disclosed in, for example, Japanese Patent Application Laid-Open No. 03-03831.
As shown in Japanese Patent Publication No. 6 (1994), in a mold structure for injection molding, it is used for the purpose of automatically and reliably performing a gate cut to produce a high quality molded product.

FIG. 7 is a configuration diagram showing an example of a conventional injection molding die structure with a gate cut mechanism using a rotating mechanism. The fixed-side template 2 is in contact with the fixed-side mounting plate 1 (auxiliary plate 9), the rotation operating member 8 is fitted in the receiving hole 2b of the fixed-side template 2, and the rotary sable piece 10 is twisted. In state. In this mold closed state, the molten resin is filled into the cavity C through the resin passage. When the resin filled in the cavity C is solidified, the fixed mold plate 2 and the movable mold plate 3 are moved in a direction in which the fixed mold plate 2 and the movable mold plate 3 are separated from the fixed mounting plate 1. As a result, while the rotation operating member 8 comes out of the receiving hole 2b of the fixed-side mold plate 2, the rotary swivel piece 10 is rotated to return to the initial state.
At this time, the rotation of the rotary stubble piece 10 causes the pin gate 15 provided on the rotary splay piece 10 to undergo angular rotation and displacement, so that the solidified resin reaching the cavity C from the cavity C via the gate is cut at the pin gate 15 portion.

As another means for achieving the same object, there is a mold structure for injection molding disclosed in JP-A-6-114894.

FIG. 8 is a cross-sectional view showing an example of a conventional injection mold having a gate cut mechanism using a slider mechanism. The gate cut block 10 is provided with a tunnel gate portion 1B which communicates with the inner edge of the molded product on the edge end surface 1Aa of the product cavity 1A in a state where the gate cut block 10 occupies the filling work position. When the gate cut block 10 is slid from the filling operation position to the gate cut position, the gate cut block 10 is moved to the edge end surface 1 of the product cavity 1A.
The object is achieved by a configuration in which the molded product is moved from the outside of the molded product in Aa toward the inside of the molded product.

The position of the gate in the injection molding mold is compared with a mold structure in which the gate is disposed on the side surface of the hole when the product has a hole shape having an area where the runner and the gate can be inscribed. Often used. This is because the gate marks do not appear on the external surface of the product, so it is easy to maintain the appearance quality of the product, and in the mold structure, it is necessary to take out the product without making the mold extremely eccentric or large Mold dividing surface and the mold dividing surface for taking out the runner and gate can be made the same surface, so the mold structure is simplified,
This is because the number of mold parts can be reduced.

[0007]

In the above gate arrangement, when applying a mold structure for injection molding as disclosed in Japanese Patent Application Laid-Open No. 03-338316, parts are provided by providing a rotating mechanism. There was a problem that the number of points increased and the mechanism became complicated.

In addition, there is a problem that it is difficult to cope with a mold requiring a plurality of gates. The reasons are divided into the following two cases. First, when increasing the number of gates and increasing the number of independent rotation mechanisms for each gate, not only does the number of parts increase accordingly, but the mold structure must not interfere with each part. This is because some cases cannot be realized depending on the shape. Next, a case in which one component corresponds to a plurality of gates will be described. This is because the rotation mechanism component becomes large, so that the rotation operation becomes inefficient and the degree of freedom in designing other components of the mold is reduced. . Furthermore, since the rotating sprue piece 10 is circular, the gate position must circumscribe the circle of the rotating sprue piece 10, which limits the gate position and the number of gate points.

Furthermore, a rotating sprue piece 10 that rotates.
However, there is a problem that the end face in contact with the mold movable side must be perpendicular to the mold opening and closing direction. The reason is,
If the above condition is not satisfied, the rotating sprue piece 10 cannot rotate because it interferes with the part on the movable side of the mold when rotating. For this reason, restrictions are imposed on the mold design.

In the above gate arrangement, Japanese Patent Laid-Open No.
In applying an injection molding die structure as disclosed in JP-A-114894, a product in which a slide mechanism can be provided without interfering with a product shape portion, for example, all slide components are arranged in a hole of the product. Possible product shapes,
There was a problem that it could not be applied except in special cases.

Further, the provision of the slide mechanism has a problem that the number of parts increases and the mechanism becomes complicated.

Furthermore, since the tunnel gate portion 10B cannot be cut unless the gate cut block 10 is divided into two or more parts, the number of parts increases, and after further dividing parts are combined, they are firmly fixed. There was a problem that action was required.

[0013] Therefore, an object of the present invention is to solve the above-mentioned problems and to provide a mold for injection molding, and particularly to cutting a gate and a product when the gate is provided in a product thick section such as a hole of the product. Without using a slider mechanism or a rotating mechanism to perform the cutting operation, the gate and the product part are automatically and reliably cut with a simple structure using only the protruding operation of the molded product at the time of molding. An object of the present invention is to provide a mold structure for injection molding capable of manufacturing a product.

Another object of the present invention is to provide an injection molding die structure in which a gate portion cut from a product is automatically dropped, thereby reducing the time and labor required for disposal processing. is there.

[0015]

In order to achieve the above object, an injection molding die structure according to the present invention comprises an injection molding die having a fixed side and a movable side with a mold division surface as a boundary. In the structure, a gate piece provided on the movable side gate portion, and a submarine gate formed on the gate piece and protruding in the fixed side direction of the mold dividing surface, the submarine gate is a product It is a structure that reaches the thick section of the part,
The gate piece is characterized in that after the movable side is opened, a cutting action is performed on a boundary surface between the submarine gate and the product when the molded product is ejected.

Further, it is preferable that the gate piece has a nested structure divided from the other mold parts on the movable side.

Further, it is preferable that the mold dividing surface is provided with a runner portion serving as a flow path of the molten resin during injection molding.

Further, it is preferable that the fixed side is provided with a sprue bush provided with a sprue which becomes a part of the runner portion.

It is preferable that the fixed side and the movable side include a fixed side mold plate and a movable side mold plate which are mounted via a fixed side mounting plate and a movable side mounting plate, respectively.

Further, it is preferable that the movable side includes a spacer block and a movable-side receiving plate which are mounted between the movable-side mounting plate and the movable-side mold plate to form a space.

Furthermore, it is preferable that a protrusion plate provided in a space formed by the spacer block and mounted on the movable-side mounting plate, and a protrusion guide pin for positioning the protrusion plate be provided.

Further, it is preferable to provide a protruding pin extending from the protruding plate to the mold dividing surface.

Further, the submarine gate provided in the projection is inclined at a predetermined angle by utilizing a difference in height relationship between the projection on the mold dividing surface of the gate piece and the side surface of the hole of the product part. Is preferred.

The mold structure for injection molding with a gate cut mechanism according to the present invention is a means for generating a cutting action at the boundary between the submarine gate and the product when the molded product is ejected after the movable side of the mold is opened. By having G) in FIG. 3,
The above objective has been achieved. Specifically, in the mold division surface for taking out the product and the gate, the gate piece provided on the movable side gate portion projects the mold division surface gate portion in the fixed side direction within a range where a submarine gate can be formed. And
The submarine gate formed in the gate piece has a structure reaching the thick section of the product part. With this structure, when the resin solidified in the product part is protruded by the protruding pin during the injection molding, a cutting action is generated at the boundary surface between the submarine gate and the product part thick section.

As described above, the present invention provides a good and reliable gate cut surface by means of generating a cutting action at the interface between the gate and the product when the molded product is ejected after the mold division surface is opened. We are cutting. Therefore, there is no need to perform gate cutting using a rotating mechanism or a slider mechanism.

[0026]

Next, an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a sectional view showing an embodiment of the mold structure for injection molding of the present invention. This structure includes a fixed side AA and a movable side BB with the mold division plane PL as a boundary. The fixed side AA is composed of a fixed side template B mounted via the fixed side mounting plate A, and a sprue bush D embedded in the fixed side template B. Further, a product portion F on which the surface of the product shape is transferred is formed on the mold division surface PL. Next, with respect to the movable side BB, the spacer block M, the movable side receiving plate I,
The movable mold plates H are mounted in this order. Further, a gate piece G is embedded in the movable mold plate H. The projecting plate K is positioned by the projecting guide pin N, and the projecting pin J extends from the projecting plate K to the runner portion E. Further, a product portion F on which the back surface of the product shape is transferred is formed on the mold division surface PL. The runner portion E and the product portion F are spaces for filling with a molten resin during injection molding.

FIG. 2 is a plan view showing the movable side in the embodiment of the injection mold structure of the present invention. Movable side B
In B, a gate piece G is disposed at a location to be a hole of the product part F, and the gate piece G is provided with a submarine gate Eb.

FIG. 3 is a partially enlarged sectional view showing a main part of the embodiment of the injection mold structure of the present invention shown in FIG. The sprue bush D is provided with a sprue Ea which is a part of a runner portion E which is a flow path of the molten resin. The gate piece G protrudes in the mold division plane PL in the fixed side AA direction in a range in which a submarine gate Eb which becomes a part of the runner portion E can be formed, and the submarine gate provided in this protruding portion is provided. Eb is the gate piece G
Utilizing the difference in the height relationship between the projection on the mold division plane PL and the side surface of the hole of the product part F, the projection is inclined in the range of 20 ° to 45 ° with respect to the horizontal direction in the figure. Further, the submarine gate Eb is provided with a taper in a direction in which the diameter becomes smaller as approaching the product portion within a range of 5 ° to 20 ° with respect to the linear center axis of the submarine gate Eb, Has reached. Further, the cold slag Ec, which is a part of the runner portion E, is not separated from the movable side BB surface until the molten resin filled in the runner portion E is solidified and then protruded by the protruding pin J. Only E
In the case of moving in the direction of protrusion from right to left as shown in FIG. 1, a part of the cold slug Ec is obstructed by the gate piece G or the protrusion pin J. Further, the gate piece G is provided with a flange portion Gb, so that the gate piece G is positioned without moving.

Next, the operation of the embodiment of the present invention will be described in detail with reference to the drawings.

First, the operation of the embodiment of the injection mold structure of the present invention will be described with reference to FIG. The fixed side AA and the movable side BB are attached to the injection molding machine, and the movable side BB is clamped at a predetermined pressure with respect to the fixed side AA by the mold clamping operation of the injection molding machine. After the mold split surface PL comes into contact, the resin melted to a predetermined viscosity is injected from the injection molding machine nozzle in contact with the sprue bush D at a pressure required to fill the space of the runner portion E and the product portion F. You. The injected molten resin is sprue E
After passing through the submarine gate Eb via a, it reaches the product section F. When the filling of the product portion F with the resin is completed, the filled resin is cooled to the fixed side AA and the movable side BB. When the resin solidifies after cooling and becomes ready to be taken out, the fixed side AA and the movable side BB are divided at the mold dividing plane PL by the mold opening operation of the molding machine. At this time, the resin solidified in the runner section E and the product section F is the above-described cold slag Ec
It is in close contact with the movable side BB due to the structure for preventing falling off.
Next, by the ejection operation of the molding machine, the ejection plate K is pushed from the right to the left in the drawing, so that the ejection pin J fixed to the ejection plate K becomes the cold slug Ec which is a part of the runner portion E. Extrude resin.

The operation occurring near the runner section E at this time will be described with reference to FIG. Cold slag Ec
Is provided with the above-described prevention structure, but the protrusion pin J operates and is pushed out with a predetermined force, so that the resin of the runner portion E starts to be pushed out. At the same time, the resin of the product portion F also protrudes in the same direction, so that the edge portion Ga of the gate piece G causes a cutting action at the boundary surface between the resin of the submarine gate Eb and the resin of the product portion F, and the runner portion. The resin of E and the resin of the product part F are cut and divided.
Thereafter, the resin of the runner portion E is automatically dropped downward by being protruded by the protruding pins J, and the resin of the product portion F is taken out by a take-out machine and carried to a predetermined place.

Further, as a feature of the present invention, by adjusting the outlet diameter or the height of the outlet reaching the product portion F of the submarine gate Eb, the gate cut mark remaining in the product portion F can be reduced to the product front side or the back side. The size and position can be freely adjusted within the thickness range of the product on the side of the hole. When performing this adjustment work, the adjustment can be performed simply by changing only the gate piece G, so that the adjustment is easy.

Further, when machining the mold of the present invention, since the gate piece G is divided from the mold body, if the gate piece G is machined alone, the product portion is formed when the submarine gate Eb is drilled. There is no fear of damaging F.

Further, as a feature of the present invention, when the edge Ga of the gate piece G is worn out during production and the gate cut is deteriorated, only the gate piece G needs to be replaced, so that maintenance is easy. .

Next, a second embodiment of the present invention will be described with reference to the drawings.

FIG. 4 is a plan view showing the configuration of the second embodiment of the present invention. The injection molding mold structure of the present invention,
Product Department 1F1, Product Department 2F2, Product Department 3F3, Product Department 4
It is a movable side plan view which shows the example applied to the case where four products are molded with one mold like F4. Four submarine gates Eb1 to Eb4 are provided. The gate block G1 is a submarine gate 1E of the product section 1F1.
b1 and the submarine gate 4Eb4 of the product section 4F4. The gate piece 3G3 is an example applied to a circular product part 3F3.

FIG. 5 is a sectional view of FIG. The submarine gate 1Eb1 is protruded by the protruding pin 1J1,
The submarine gate 2Eb2 has a structure protruded by a protruding pin 2J2.

Next, a third embodiment of the present invention will be described with reference to the drawings.

FIG. 6 is a sectional view showing a third embodiment of the injection mold structure of the present invention. In this embodiment,
This is an example in which the third embodiment of the injection mold structure according to the present invention is applied to a mold in which the runner part mold dividing plane PL1 and the product part mold dividing plane PL2 open separately. The operation of this structure will be described. When the product portion F is filled with the molten resin and then cooled and solidified, first, the runner portion mold dividing surface PL1 opens, and the runner R is moved toward the runner stripper plate P by the action of the runner lock pin O. Then, the second sprue Q is cut at the thinnest portion. The resin filled in this example is divided into three parts: a group of sprues Ea, runners R and second sprues Q, a submarine gate Eb, and a product part F.

[0041]

As described above, the injection molding die structure of the present invention is provided with a structure for generating a cutting action at the boundary between the submarine gate and the product part when the molded product is ejected. Therefore, when performing an automatic gate cut,
Since there is no need to use a rotating mechanism or a slider mechanism that has been used conventionally, an effect is obtained that the number of components is reduced.

Further, the simplification of the automatic gate cut mechanism has an effect that the range of application to products is expanded.

Furthermore, since gate cutting is performed reliably and with a good finished surface, there is no need for post-processing, and the effect of improving productivity is achieved.

Further, since the gate piece G is divided from the mold body, by adjusting the exit diameter or the height of the exit reaching the product part of the submarine gate, the gate cut marks remaining on the product part can be reduced. It is easy to adjust because the size and position can be freely adjusted within the product thickness cross section such as the front side or back side, and when performing this adjustment work, it is possible to adjust only by changing the gate piece only It works.

Also, when processing the mold, there is an effect that there is no fear of damaging the product part when drilling the submarine gate.

In addition, when the edge of the gate piece is worn during production and the gate is cut poorly, there is an effect that the maintenance is easy.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an embodiment of an injection mold structure of the present invention.

FIG. 2 is a plan view of the movable side of FIG.

FIG. 3 is a partially enlarged view of FIG. 1 showing a main part in the present invention.

FIG. 4 is a movable side plan view showing a second embodiment of the injection mold structure of the present invention.

FIG. 5 is a sectional view of FIG. 4;

FIG. 6 is a sectional view showing an injection molding die structure according to a third embodiment of the present invention.

FIG. 7 is a configuration diagram of an injection mold structure for performing automatic gate cutting by a conventional rotation mechanism.

FIG. 8 is a cross-sectional view of an injection molding die structure that performs automatic gate cutting by a conventional slider mechanism.

[Explanation of symbols]

 A Fixed side mounting plate B Fixed side mold plate D Sprue bush E Runner part Ea Sprue Eb Submarine gate Eb1 Submarine gate 1 Eb2 Submarine gate 2 Eb3 Submarine gate 3 Eb4 Submarine gate 4 Ec Cold slug F Product part F1 Product part 1 F2 Product part 2 F3 Product part 3 F4 Product part 4 G Gate piece G1 Gate piece 1 G2 Gate piece 2 G3 Gate piece 3 Ga Edge portion Gb Flange portion H Movable mold plate I Movable receiving plate J Projection pin J1 Projection pin 1 J2 Projection pin 2 K Projection plate L Movable side mounting plate M Spacer block N Projection guide pin O Runner lock pin P Runner stripper plate Q Second sprue R Runner PL Mold split surface PL1 Runner mold split surface PL2 Product die Mold split surface AA fixed side B movable first fixed-side mounting plate 2 fixed die plate 3 movable side mold plate 8 rotating actuating member 10 rotates Suburu piece

Claims (9)

[Claims] 1. An injection mold structure having a fixed side and a movable side with a mold dividing surface as a boundary, wherein: a gate piece provided at the movable side gate portion; And a submarine gate formed so as to protrude in the fixed side direction of the mold dividing surface, wherein the submarine gate has a structure reaching a thick cross section of a product part, and the gate piece is After the movable side is opened, a cutting operation is performed on a boundary surface between the submarine gate and the product when the molded product is ejected, wherein the mold is used for injection molding. 2. The mold structure for injection molding according to claim 1, wherein said gate piece has a nested structure divided from other mold parts on the movable side. 3. The mold structure for injection molding according to claim 1, wherein said mold dividing surface is provided with a runner portion serving as a flow path of a molten resin during injection molding. 4. The mold structure for injection molding according to claim 3, wherein said fixed side includes a sprue bush provided with a sprue which is a part of said runner portion. 5. The fixed side and the movable side include a fixed side mold plate and a movable side mold plate which are mounted via a fixed side mounting plate and a movable side mounting plate, respectively. Item 5. The mold structure for injection molding according to any one of Items 1 to 4. 6. The movable side includes a spacer block and a movable side receiving plate mounted between the movable side mounting plate and the movable side mold plate to form a space. 6. The mold structure for injection molding according to 5. 7. A protruding plate provided in a space formed by the spacer block and mounted on the movable-side mounting plate, and a protruding guide pin for positioning the protruding plate. 7. The mold structure for injection molding according to 6. 8. A protruding pin extending from the protruding plate to the mold dividing surface.
4. The mold structure for injection molding according to 4. 9. A submarine gate provided in the projection is provided at a predetermined angle by utilizing a difference in height relationship between a projection on a mold division surface of the gate piece and a side surface of a hole of the product part. 9. The method according to claim 1, wherein:
The mold structure for injection molding according to any one of the above.