JP4169664B2 - Injection mold - Google Patents

Description

  The present invention relates to an injection mold used in an injection molding machine, and more particularly to a three-plate type injection molding having a divided surface for taking out resin waste material formed by sprues and runners in addition to a divided surface for taking out a molded product. It relates to molds.

In general, a three-plate type injection molding die used in an injection molding machine has a divided surface for taking out a resin waste material formed by a sprue and a runner in addition to a divided surface for taking out a molded product. In such a mold, a runner strip plate for removing sprues and runners is provided between the fixed side mounting plate and the fixed side mold plate constituting the mold, and the mold is opened after the product is injection molded. Remove the sprue and runner resin waste sticking to the plate with a dedicated take-out machine, or operate the eject pin provided on the fixed side mounting plate when opening the mold to push out the sprue and runner resin waste (For example, refer nonpatent literature 1).
“Injection molding” 8th edition p. 102, p. 109-112 Issuer Plastic Age Co., Ltd. July 10, 1980 Revised 8th edition, 2nd edition issued

  However, in the mold for molding using a dedicated take-out machine as described above, the take-out machine is operated after the mold is opened to take out the sprue and runner resin waste. As a result, there is a problem that the molding cycle becomes longer, the productivity is lowered, the product cost is increased, and a dedicated take-out machine needs to be provided separately from the mold part. There is a problem that the molding equipment including the machine becomes complicated.

  In addition, in the molding die using the eject pin, there is almost no problem when ejecting each resin waste formed with sprue and runner separately, but the resin waste formed with sprue and runner is connected to each other. In this case, even if this is ejected by the eject pin that is linked to the mold opening operation, part of the resin waste material for sprue or the resin waste material for runners is caught in the mold, and the resin waste material does not fall. In addition, it is necessary to constantly monitor whether or not the resin waste material has fallen and dropped, and if the resin waste material does not fall, it must be removed, which makes the work cumbersome and increases productivity and product cost. Has the problem of adverse effects.

  The invention according to claim 1 of the present invention is an injection mold having a fixed mold and a movable mold, wherein the fixed mold includes a fixed mold plate and a fixed mounting plate, and the fixed mold plate and the fixed mold. A runner stripper plate interposed between the side mounting plate and movably provided in a direction to be separated from the fixed side mounting plate, and penetrating the runner stripper plate in the plate thickness direction. A sprue bush attached to the fixed-side mounting plate, and the movable mold includes a movable-side mold plate and a movable-side mounting plate that are opposed to the fixed-side mold plate via a split surface. A cavity for forming a molded product is formed on the splittable mating surface of the fixed side mold plate and the movable side mold plate, and on the splittable mating surface of the runner stripper plate and the fixed side mold plate, Communicates with the first sprue on the sprue bush A runner is formed, and a second sprue is formed on the stationary side template through the gate between the runner and the cavity, and the first sprue is formed from a molten resin injection port of the first sprue. A block for forming a space for dropping the sprue is formed at the outer peripheral portion of the sprue bushing so as to exhibit an elliptical cross section whose major axis length is enlarged toward the runner side. The runner stripper plate is provided with a sprue drop space that extends on an extension line of the shaft and matches the outer peripheral shape of the block.

  According to a second aspect of the present invention, in the injection mold according to the first aspect, the opening amount of the runner stripper plate when the mold is opened is from the fixed side mounting plate to the fixed side mold plate. It is configured to be set by a plastic bolt extending so as to face.

  According to a third aspect of the present invention, in the injection mold according to the first aspect, the block is fixed to the fixed-side mounting plate so as to be in close contact with the outer periphery of the sprue bush.

  In the injection mold according to the present invention, the cross-sectional shape in the direction perpendicular to the longitudinal direction of the first sprue of the sprue bush is aligned with the runner stripper plate and the fixed side die plate from the molten resin injection port of the first sprue. By adopting an elliptical shape whose major axis length increases as it goes to the runner side formed on the surface, it is easy to automatically drop the sprue and resin waste material formed by the runner when the mold is opened, and outside the block By forming a space for dropping the sprue that matches the surrounding shape in the runner stripper plate, even if the resin waste material formed by the sprue and the runner is connected to each other, the resin waste material is weighted from the mold in conjunction with the mold opening. Can automatically drop automatically.

  In the best mode of the embodiment of the present invention, the first sprue of the sprue bush is moved from the molten resin injection port of the first sprue to the runner side formed on the mating surface of the runner stripper plate and the fixed side mold plate. It is configured to have an elliptical cross section in which the long axis length is enlarged, and a block for forming a sprue drop space is extended on the extended line of the long axis of the first sprue at the outer peripheral portion of the sprue bush. And a sprue drop space that matches the outer peripheral shape of the block is formed in the runner stripper plate. Thereby, the resin waste material formed by the sprue and the runner can be surely and automatically dropped from the mold by its own weight in conjunction with the mold opening.

  Next, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a longitudinal side view showing a first embodiment of an injection mold according to the present invention, FIG. 2 is an enlarged plan view taken along line 2-2 in FIG. 1, and FIG. 3 is taken along line 3-3 in FIG. FIG. 4 is a cross-sectional view, FIG. 4 is a vertical side view of a block forming a sprue bush and a sprue drop space in this embodiment, and FIG. 5 is a bottom view of FIG.

  As shown in FIG. 1, the injection mold 10 in this embodiment constitutes a three-plate mold, and includes a fixed mold 12 and a movable mold 13.

  As shown in FIGS. 1 to 3, the fixed mold 12 includes a fixed mold plate 121 and a fixed mounting plate 122. One end of the fixed mold plate 121 is coupled to the fixed mounting plate 122. The end side is supported by a plurality of support pins 123 slidably engaged with the movable mold 13 so as to be movable toward and away from the fixed side mounting plate 122. In addition, a runner stripper plate 124 is disposed between the fixed side mold plate 121 and the fixed side mounting plate 122, and the runner stripper plate 124 can move in a direction to be in contact with and away from the fixed side mounting plate 122. 123. Further, a sprue bush 125 is attached to the fixed side mounting plate 122 so as to penetrate the runner stripper plate 124 in the plate thickness direction.

  As shown in FIGS. 1 to 3, a sprue bush is provided on the mating surface of the runner stripper plate 124 and the stationary mold plate 121 on the stationary mold plate 121 side, which is a splitting mating surface (parting line) PL1. A runner 126 that communicates with the first sprue 125 a provided in 125 is formed, and a second sprue 128 that communicates between the runner 126 and a cavity described later via a gate 127 is formed on the fixed-side template 121. Is formed.

  As shown in FIGS. 4 and 5, the cross-sectional shape in the direction perpendicular to the longitudinal direction of the first sprue 125a is such that the long axis length increases from the molten resin injection port 125b of the first sprue 125a toward the runner 126 side. It is comprised so that the ellipse shape expanded may be exhibited.

  Further, as shown in FIGS. 1 to 3, a block 129 for forming a sprue drop space extends on the extended line of the long axis of the first sprue 125a at the outer periphery of the sprue bush 125. The runner stripper plate 124 is formed with a sprue drop space 124 a that matches the outer peripheral shape of the block 129.

  The block 129 is attached to the fixed side mounting plate 122 by a bolt 129a.

  As shown in FIGS. 1 and 3, the movable mold 13 includes a movable mold plate 131 and a movable mounting plate 132 which are opposed to the fixed mold plate 121 via a mating surface (parting line) PL <b> 2 that can be divided. As shown in FIG. 1, the movable side mold plate 131 is configured to be fixed to the movable side mounting plate 132 via a receiving plate 133 and an ejecting spacer block 134.

  In addition, a cavity 135 for forming a molded product is formed on a splitting surface (parting line) PL2 between the movable side template 131 and the fixed side template 121 that can be divided.

  In FIG. 1 to FIG. 3, a runner lock pin 136 that penetrates the runner stripper plate 124 and reaches the runner 126 is provided on the fixed side mounting plate 122. The movable mold plate 131 is slidably provided with an eject pin 137 that penetrates the receiving plate 133 and the movable mold plate 131 and reaches the cavity 135. One end of the eject pin 137 is a spacer block. 134 is connected to an eject plate 138 that is movably disposed in a space surrounded by the space 134.

  Next, a product molding operation using the injection mold 10 configured as described above will be described with reference to FIGS.

  When molding the resin product, the injection mold 10 is clamped by a mold clamping mechanism (not shown), and then a mating surface PL2 between the movable mold plate 131 and the fixed mold plate 121 as shown in FIG. In addition, the mating surface PL1 between the runner stripper plate 124 and the stationary side mold plate 121 is held in close contact with each other. In this state, an injection mechanism (not shown) is driven, and the thermoplastic molten resin material injected from this injection mechanism is cavityd through the first sprue 125a, the runner 126, the second sprue 128 and the gate 127 of the sprue bush 125. 135 is pressurized and injected at an optimal injection pressure, injection speed, and injection time.

  After pressure injection of the molten resin material, a pressure holding process for compensating for shrinkage caused by cooling and solidification is allowed to pass, and thereafter, the mold opening operation is started. At the time of opening the mold, first, the mating surface PL2 between the movable mold plate 131 and the fixed mold plate 121 and the mating surface PL1 between the runner stripper plate 124 and the fixed mold plate 121 are shown in FIG. So that they are opened in directions away from each other. At this time, the resin molded product 20 molded in the cavity 135 is held on the movable mold plate 131 side, and the resin waste material 21 molded in the runner 126 and the second sprue 128 is the tip of the sprue bush 125 and the runner lock pin. The tip of 136 is held on the runner stripper plate 124 side.

  In this state, when the runner stripper plate 124 is moved in a direction away from the fixed side mounting plate 122 as shown in FIG. 6B, it is held at the tip of the sprue bush 125 and the tip of the runner lock pin 136. At the same time that the resin waste material 21 is removed from these tips, the resin waste material portion 21a formed by the first sprue 125a of the sprue bush 125 comes out of the first sprue 125a as the runner stripper plate 124 moves. In this case, the first sprue 125a has an elliptical shape in which the major axis length is increased from the molten resin injection port 125b toward the runner 126 side, and the resin waste material portion molded by the first sprue 125a. Since 21a also has an elliptical shape, the posture of the resin waste material 21 when the resin waste material portion 21a comes out of the first sprue 125a becomes constant due to this elliptical shape. As a result, the resin waste material 21 including the resin waste material portion 21a becomes There is no rotation around the first sprue 125a. In addition, when the runner stripper plate 124 moves in a direction away from the fixed side mounting plate 122, the runner stripper plate 124 extends in the dropping direction of the resin waste material 21 including the resin waste material portion 21a (the arrow X direction in FIG. 6B). Since the existing space 124a for dropping the sprue is formed, even if the resin waste material portion 21a formed by the first sprue 125a protrudes toward the runner stripper plate 124, it is caught in the runner stripper plate 124. This can be avoided by the use space 124a. For this reason, the resin waste material 21 formed of the sprue and the runner can be surely and automatically dropped from the mold 10 by its own weight in conjunction with the mold opening.

  In the mold open state, when the eject plate 138 operates, the resin molded product 20 in which the eject pin 137 is molded in the cavity 135 protrudes from the movable side mold plate 131 and is discharged out of the mold 10.

  According to the injection molding die 10 shown in the first embodiment, the first sprue 125a of the sprue bush 125 is moved from the molten resin inlet 125b of the first sprue 125a to the runner stripper plate 124 and the fixed side mold plate 121. The spur bushing 125 is formed with an elliptical cross section whose major axis length is increased toward the runner 126 side formed on the mating surface PL1, and a sprue drop space is formed at the outer peripheral portion of the sprue bush 125. Because the block 129 for extending is provided on the extended line of the long axis of the first sprue 125a, the sprue dropping space 124a that matches the outer peripheral shape of the block 129 is formed in the runner stripper plate 124. Even if the resin waste material formed by sprue and runner is connected to each other, these resin waste materials 21 and 21a are linked to the mold opening. Reliably, and it is possible to automatically fall by their own weight from the die 10 Te. Thereby, the molding cycle of the resin product can be shortened to improve productivity, and the product cost can be reduced.

It is a vertical side view which shows Example 1 of the metal mold | die for injection molding concerning this invention. FIG. 2 is an enlarged plan view taken along line 2-2 of FIG. It is sectional drawing which follows the 3-3 line of FIG. It is a vertical side view of the block which forms the sprue bush and the space for sprue fall in the present Example 1. FIG. 5 is a bottom view of FIG. 4. It is operation | movement explanatory drawing in the present Example 1. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Injection mold 12 Fixed mold 121 Fixed side mold plate 122 Fixed side mounting plate 124 Runner stripper plate 124a Sprue drop space 125 Sprue bush 125
125a First sprue 125b Molten resin inlet 126 Runner 128 Second sprue 129 Block 13 Movable type 131 Movable side mold plate 132 Movable side mounting plate

Claims (3)

An injection mold having a fixed mold and a movable mold,
The fixed mold is provided between the fixed side mold plate and the fixed side mounting plate, and is interposed between the fixed side mold plate and the fixed side mounting plate, and is movable in a direction in which the fixed mold is separated from the fixed side mounting plate. A runner stripper plate, and a sprue bush attached to the fixed side mounting plate so as to penetrate the runner stripper plate in the plate thickness direction,
The movable mold includes a movable mold plate and a movable mounting plate that are opposed to the fixed mold plate via a split surface that can be divided.
A cavity for forming a molded product is formed on the splittable mating surface of the fixed side mold plate and the movable side mold plate,
A runner communicating with the first sprue provided on the sprue bush is formed on the splittable mating surface of the runner stripper plate and the fixed-side template.
A second sprue is formed in the fixed-side template to communicate between the runner and the cavity via a gate,
The first sprue is configured to exhibit an elliptical cross section whose major axis length is increased from the molten resin injection port of the first sprue toward the runner side,
A block for forming a sprue drop space is provided on an outer peripheral portion of the sprue bush so as to extend on an extended line of the long axis of the first sprue, and the sprue drop space matches the outer peripheral shape of the block. Is formed on the runner stripper plate.   The opening amount of the runner stripper plate at the time of mold opening is configured to be set by a plastic bolt provided on the fixed side mounting plate so as to extend from the fixed side mounting plate to the fixed side mold plate. The injection mold according to claim 1, wherein:   2. The injection mold according to claim 1, wherein the block is fixed to the fixed-side mounting plate so as to be in close contact with the outer periphery of the sprue bush.

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