JP5385099B2 - Injection molding equipment - Google Patents

Description

  The present invention relates to an injection molding apparatus of a type in which a molten resin is injected into a plurality of molds through a manifold from one injection machine to individually form a molded product.

As for this type of injection molding apparatus, for example, the technique disclosed in Patent Document 1 is already known. In this technique, a plurality of branch blocks are provided in a manifold into which molten resin is fed from an injection machine. Each of these branch blocks supplies molten resin into a plurality of molds corresponding to each through a switching valve device.
Each switching valve device is controlled so as to supply the molten resin only to one certain mold and not supply the resin to the other mold. That is, when the filling of the molten resin into one mold is finished, the supply of the molten resin to another mold is started and injection molding is performed one after another.

JP-A-8-323800

In the technique of Patent Document 1, since it is necessary to sequentially fill a plurality of molds with molten resin under the control of the switching valve device, the capacities of the respective molds must be equal to each other. There are restrictions on the molds that can be used.
The present invention is intended to solve such a problem, and its object is to fill the molten resin to be used if the total volume is the same when injection molding is performed using a plurality of molds. It is possible to replace the mold by using a mold having a double molten resin capacity or a mold having a quadruple molten resin capacity to be filled, thereby expanding the flexibility of the mold to be used.

The present invention is for achieving the above object, and is configured as follows.
An injection molding apparatus of a type that molds a molded product in each mold by injecting molten resin into a plurality of molds from an injection machine through a manifold, and the manifold is a plurality of valve gates connected to the mold. It has. The plurality of molds can be fixed at predetermined positions by a fastening mechanism provided corresponding to each mold. These fastening mechanisms are configured to be able to replace a mold that can be connected to one valve gate of the manifold and a mold that can be connected to two or more valve gates.

  In this configuration, in addition to the case where a mold is connected to each valve gate of the manifold, molding can be performed using a large mold connected to two or more valve gates. For example, if the manifold has four valve gates, it can be molded with four molds individually connected to each valve gate, and the total volume of molten resin used is the same. For example, it is possible to mold with two molds having a double capacity of the molten resin to be filled, or one mold having a quadruple capacity of the molten resin to be filled. As a result, the degree of freedom of molds that can be used in one injection molding apparatus can be expanded.

The front view of an injection molding apparatus. The top view of an injection molding apparatus. The left view of an injection molding apparatus. Sectional drawing of the AA arrow direction of FIG.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.
The injection molding apparatus shown in the drawing injects molten resin from a single injection machine 12 provided on the gantry 10 into a plurality of molds 28 through a single manifold 22 in a molding unit 20, and each mold 28. In this configuration, the molded product is molded.
The injection machine 12 includes a heating cylinder 12a and a screw 12b that rotates around an axis within the heating cylinder 12a. An electric heater (not shown) is built in the heating cylinder 12a, and the pellet-shaped resin material supplied into the heating cylinder 12a can be heated to make a molten resin. The base end portion of the heating cylinder 12a is supported by the slide plate 16a of the slide mechanism 16, and a cooling jacket 12c is provided on the outer periphery of the heating cylinder 12a near the support portion. Further, a mixing nozzle 12d (filter nozzle) having high kneading performance is attached to the tip of the heating cylinder 12a.

The slide plate 16a of the slide mechanism 16 can slide in the left-right direction in FIG. 1 or FIG. The slide plate 16a is assembled with a supply hopper 18 for supplying a pellet-shaped resin material into the heating cylinder 12a of the injection machine 12 and a motor 14a in the drive mechanism 14 described later. As a result, the slide of the slide plate 16a causes the injector 12, the supply hopper 18 and the motor 14a to slide in the same direction.
The slide plate 16a of the slide mechanism 16 slides in the left-right direction by rotating the pair of ball screws 16b supported on the gantry 10 side forward and backward around the axis. A motor 16c, which is a drive source of the slide mechanism 16, is assembled on the gantry 10 side, and a drive pulley 16d is fixed to the main shaft (FIG. 1). A driven pulley 16e is fixed to the left end of each ball screw 16b (FIG. 2). A drive belt 16f is placed between the driven pulley 16e and the drive pulley 16d in the state shown in FIG. 4, and both the ball screws 16b rotate in synchronization with each other by the rotational drive of the motor 16c.

  The drive mechanism 14 is for rotating the screw 12b of the injection machine 12 about its axis, and the main shaft of the motor 14a which is the drive source is located on the right side of FIG. 1 or FIG. 14b is fixed. On the other hand, one end of the screw 12b passes through the slide plate 16a and is located on the same side as the main shaft of the motor 14a, and a driven pulley 14c is fixed on the shaft. A driving belt 14d is hung between these pulleys 14b and 14c, and a rotational force is transmitted from the motor 14a to the screw 12b. As the screw 12b continuously rotates around the axis, the molten resin in the heating cylinder 12a is continuously fed toward the mixing nozzle 12d.

The cooling jacket 12c of the injection machine 12 is provided adjacent to the outlet 18a of the supply hopper 18 so as to surround the outer periphery of the heating cylinder 12a, and the cooling water is circulated therein to suppress the ambient temperature. Yes. Thereby, the heat of the heating cylinder 12a is prevented from being transmitted to the supply hopper 18, and the pellet-like resin material is melted at the outlet 18a of the supply hopper 18 so as not to cause a bridge phenomenon.
In addition, the cooling jacket 12c is positioned between the driving belt 16f of the slide mechanism 16 and the heating cylinder 12a (FIG. 4), and a compact design in which the driving belt 16f is disposed close to the heating cylinder 12a is possible. .

In the molding unit 20, a manifold 22 is installed on the extension axis of the injection machine 12, and two molds 28 are arranged on each side of the manifold 22, two in total. One end of the manifold 22 is joined to the tip of a mixing nozzle 12d in the injection machine 12, whereby the inside of the manifold 22 communicates with the inside of the injection machine 12. The manifold 22 is provided with valve gates 24 at four locations corresponding to the molds 28, and the tips of the valve gates 24 communicate with cavities in the corresponding molds 28.
As described above, by providing each valve gate 24 in the manifold 22, when a plurality of molds 28 are replaced in the molding unit 20, the valve gates are individually provided in all the molds 28. Cost can be reduced.

A total of four molds 28 arranged two on each side of the manifold 22 are unevenly distributed in one direction on both sides of the manifold 22 (FIG. 2). This is because the resin injection port (gate) of the mold 28 is shifted from the center, it can be used no matter how the four molds 28 are replaced, and the length of the manifold 22 is reduced as much as possible. This is due to three points. For example, if the gate of the mold 28 is in the center, the pitch of the two valve gates 24 on both sides of the manifold 22 becomes longer, and the valve gate 24 becomes longer accordingly. If the replacement of the molds 28 is not taken into consideration, the molds 28 can be aligned and the length of the manifold 22 can be suppressed.
The replacement of the mold 28 is to operate a fastening mechanism (toggle clamp 30) described later to detach the mold 28 from the gantry 10, and when replacing the troubled mold or a different molding. This is done when changing to a metal mold.

Each mold 28 includes a mold clamping mechanism 26. In each mold clamping mechanism 26, a fixed side die plate 26b and a movable side die plate 26c are vertically opposed to each other on the upper surface of a horizontally disposed substrate 26a. The movable side die plate 26c moves toward or away from the fixed side die plate 26b by driving control of the mold clamping cylinder 26d. The mold 28 is assembled between the die plates 26b and 26c, and the mold 28 is clamped and opened by the drive control of the mold clamping cylinder 26d.
The substrate 26a of each mold clamping mechanism 26 slides in a direction toward or away from the manifold 22 with respect to the gantry 10. By adjusting the slide position, the tip of each valve gate 24 can be inserted into the resin injection port of the corresponding mold 28 in a prescribed state (nozzle touch state).

Each mold clamping mechanism 26 includes an ejector cylinder 29 for each mold 28 (FIG. 2). Thereby, each metal mold | die 28 has a taking-out function of a molded product, respectively, and the taking-out mechanism as incidental equipment can be abolished.
Further, a connector connected to the electronic control unit is attached to each mold 28, and the mold number is identified by this connector so that necessary information such as injection time and cooling time is automatically input to the electronic control unit. It is also possible to make it. This eliminates the need for the operator to input the information every time the mold 28 provided with the mold clamping mechanism 26 is replaced.

The toggle clamps 30 are respectively attached to the gantry 10 at locations where the mold clamping mechanisms 26 (that is, the molds 28) are disposed. These toggle clamps 30 can fasten the substrate 26a of the mold clamping mechanism 26 to the gantry 10 side by determining the slide position by operating each lever 30a as shown by the solid line in FIG. By operating the lever 30a as indicated by the phantom line in FIG. 3, the fastening can be released.
The toggle clamp 30 may be a fastening means having another structure, but at present, the toggle clamp 30 having the structure shown in FIG. 2 or FIG. 3 is optimal. 2 steps such as tightening are required, and the work is not as simple as the toggle clamp 30.

The gantry 10 is provided with stockers 32 for temporarily stocking the molded products S taken out from the individual dies 28 below the dies 28. Each stocker 32 includes a chute bar 32a that receives an arch-shaped molded product S (assist grip) taken out from each mold 28 opened. The chute bar 32a is inclined so as to become lower outward from the mold opening position of the mold 28, and a stopper 32b that is controlled to advance and retreat by a solenoid or the like is provided at the outer end portion ( FIG. 3). Each stocker 32 is provided with a cooling fan 32c for cooling the molded product S below each chute bar 32a.
The chute bar 32a of each stocker 32 receives the molded product S removed from the corresponding mold 28 and sends the molded product S toward the outer end according to the inclination. For this reason, on the chute bar 32a of each stocker 32, the first molded product S is received by the stopper 32b, and subsequently, the molded products S molded by the respective molds 28 are sequentially stocked.

In this way, the molded products S molded by the respective molds 28 are temporarily stocked by the individual stockers 32, and each molded product S is not dropped until the cooling is completed, thereby suppressing the molded product S from being scratched. be able to. Further, by cooling the molded product S outside the mold 28, the cooling time of the molded product S in the operation cycle of each mold 28 can be shortened.
The number of molded products S that can be stocked in each stocker 32 is determined in advance, the position of the last molded product S that has reached that number is detected by a sensor, and the operation of the stopper 32b is controlled based on this detection signal. This makes it possible to automate the process from “demolding” to “removal”, “cooling”, and “dispensing” of the molded product S. In addition, since each stocker 32 is arranged toward the four sides of the molding portion 20 corresponding to each mold 28, the collection efficiency of the molded product S delivered from each stocker 32 is also improved.

A recovery hopper 34 that receives a spool, a runner, and a gate (hereinafter referred to as “runner etc.”) falling from the mold 28 is provided inside the gantry 10 below the molding unit 20 (FIG. 1). The runner or the like falls by its own weight onto the collection hopper 34 before the molded product S is taken out from each mold 28. The runners and the like received by the recovery hopper 34 are put into a pulverizer 36 disposed under the recovery hopper 34 and pulverized into pellets, and then sent out to a supply pipe 38 shown in FIG. In the supply pipe 38, a new resin material supplied from the direction indicated by the arrow a in FIG. 1 and a pulverized material such as a runner are mixed, conveyed in the direction of the arrow b, and fed into the supply hopper 18. For transporting the mixed resin material, an existing technique using an air flow is used.
In this embodiment, the weight ratio of the runner or the like to one molded product S is “98: 2”, and as a result, the blending ratio of the new resin material and the pulverized material such as the runner becomes the same ratio. Originally, the molded product S is molded only with a new resin material. If a pulverized material such as a runner is mixed, the quality of the molded product S is inevitably deteriorated. Quality can be maintained.

The reason why the runners and the like are dropped from the respective molds 28 before the molded product S is taken out is to prevent the runners and the like from hitting the molded product S when they are removed from the mold at the same time. Even when the molded product S and the runner are not removed from the mold at the same time, it is necessary to avoid contact of the molded product S with the runner or the like. In the present embodiment, the molded product S is stocked in the stocker 32, and the runners and the like are dropped by their own weight toward the collection hopper 34. Therefore, the molded product S is not scratched when the runner is removed first. It is also advantageous in terms of the molding cycle.
Further, since the runners and the like are dropped and collected from the molds 28 arranged toward the four sides of the molding unit 20, the runners are collected efficiently.

In the injection molding apparatus configured as described above, the resin material supplied from the supply hopper 18 to the injection machine 12 is heated and melted in the heating cylinder 12a, and is rotated from the mixing nozzle 12d to the molding unit 20 by the rotation of the screw 12b. It is sent to the manifold 22. In the molding unit 20, the four molds 28 are clamped by the individual mold clamping mechanisms 26. Thereafter, the molten resin fed into the manifold 22 is injected into the respective molds 28 from the four valve gates 24, and the molded product S is molded in each mold 28.
After a predetermined cooling time elapses, each mold 28 is opened by an individual mold clamping mechanism 26, and an ejector cylinder 29 of each mold clamping mechanism 26 is operated, thereby causing various ejector pins (not shown). The runner or the like is removed first, and then the molded product S is removed. The molded products S taken out from the individual molds 28 are temporarily stocked in the stockers 32 provided corresponding to the respective molds 28 as described above, and the molded products S are processed as described above. After cooling outside the mold 28, it is transported to a predetermined location.

  The molding steps such as “clamping”, “injection”, “cooling”, “mold opening”, and “removing the molded product S” in the four molds 28 are performed by opening / closing each valve gate 24 in the manifold 22 and molds of each mold clamping mechanism 26. This is performed by controlling the fastening cylinder 26d and the ejector cylinder 29, respectively. In addition, about the timing of a shaping | molding process, it can arrange | equalize so that it may become simultaneously in each metal mold | die 28, or can also make it shift | deviate. In any case, the current state of the molding process in each mold 28 is displayed collectively on the operation panel (not shown) of the injection molding apparatus.

Next, a case where all or a part of each mold 28 is replaced with another mold will be described. In order to remove the mold from the apparatus side in order to replace the mold in a general injection molding apparatus, the mold is clamped by a mold clamping mechanism, the mold is removed from the die plate, and the mold clamping mechanism is opened. A process is required. In addition, the work space for removing the mold is limited by the mold clamping mechanism, and the opening / closing stroke must be increased in order to make room for the work space.
In contrast, in the mold 28 provided with the mold clamping mechanism 26 of the present embodiment, the mold 28 is clamped by the mold clamping mechanism 26, and the mold clamping mechanism 26 ( Each mold 28 can be removed from the gantry 10 side in two steps such as releasing the fastening of the substrate 26a). In addition, since only the individual valve gates 24 exist on the manifold 22 side in the periphery of each mold 28, it is possible to secure a sufficient work space when removing the mold 28.

In the present embodiment, the tip of each valve gate 24 of the manifold 22 is configured to enter the concave portion of the fixed side die plate 26b in the mold clamping mechanism 26 and the resin injection port of the mold 28 (fixed mold) ( 2 or 3). For this reason, when exchanging the mold 28, it is necessary to slide the mold clamping mechanism 26 together with the mold 28 in the direction of separating from the valve gate 24 after releasing the fastening by the respective toggle clamps 30. When the mold 28 equipped with the mold clamping mechanism 26 is mounted again, the individual substrates 26a are placed at positions where the tip of the valve gate 24 properly enters the concave portion of the fixed die plate 26b and the resin injection port of the mold 28. The slide position is determined by fastening the individual toggle clamps 30.
In this way, by sliding the mold 28 provided with the mold clamping mechanism 26 and inserting each valve gate 24 into the mold 28, the runner and the like are shortened accordingly, and this is directed toward the recovery hopper 34. The amount of mold opening for dispensing is small, and the yield of the resin material is improved. These advantages are exhibited for each molding in each mold 28, whereas the frequency of the labor of sliding when replacing (detaching) the mold 28 provided with the mold clamping mechanism 26 is low.

The toggle clamp 30 that individually fastens each mold 28 provided with the mold clamping mechanism 26 to the gantry 10 side not only replaces the four molds 28 as described above, but also includes, for example, two molds. It is also possible to exchange the mold 28 and one mold that can be connected to the two valve gates 24 of the manifold 22. In other words, if the volume of the molten resin sent to the manifold 22 by the injection machine 12 is the same, a mold having a double capacity of the molten resin to be filled can be replaced with two molds 28 and used. . In addition, a mold that can be connected to the four valve gates 24 and has a quadruple capacity of the molten resin to be filled can be replaced with four molds 28 and used. However, in the manifold 22 of the present embodiment, two valve gates 24 are provided on both sides thereof, so that the mold connected to the three or four valve gates 24 straddles the manifold 22. Installed in condition.
If the total volume of the molten resin to be used is the same by the above-mentioned mold exchange, the mold of the molten resin to be filled is doubled to two molds, or the volume of the molten resin to be filled is quadrupled. It becomes possible to perform molding with a single mold. Note that the mold replacement can be performed even during molding. As described above, when the timing of the molding process in each mold 28 is shifted, for the mold 28 for which “the removal of the molded product S” has been completed, the other molds 28 are being molded. Can also be replaced.

12 Injection machine 22 Manifold 24 Valve gate 28 Mold 30 Toggle clamp (fastening mechanism)
S molded product

Claims (1)

An injection molding apparatus of a type that molds a molded product in each mold by injecting molten resin into a plurality of molds through a manifold from an injection machine,
The manifold includes a plurality of valve gates connected to the mold, and the plurality of molds can be fixed at predetermined positions by fastening mechanisms provided corresponding to the individual molds, respectively. The fastening mechanism is an injection molding apparatus configured such that a mold that can be connected to one valve gate of a manifold and a mold that can be connected to two or more valve gates can be replaced.

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