JPH0657415B2 - Stack Molding Machine - Google Patents

Description

TECHNICAL FIELD The present invention relates to a plastic injection molding machine. More specifically, by arranging a cavity block having cavities on both sides of a runner block having a gate through which molten plastic is injected, it is possible to inject molten plastic from each gate to each cavity at the same time. The present invention relates to a stack mold molding machine that dramatically improves the number of molds (mold area) with respect to mold clamping force.

[Prior Art] Conventionally, the following is known as a stack molding machine.

As shown in FIG. 7 (a), when the mold is opened and closed, the runner block 2 remains in a fixed position and both cavity blocks 5 are held.
A and 5b moved in opposite directions [Japanese Patent Publication No. 51-25408, Kunststoffe 7
0 (1980) 11, 742-746]. In FIG. 7, 1 is a sprue, 4 is an injection unit, and 3 is an injection nozzle.

Injection unit, arranged in the direction perpendicular to the mold opening / closing direction (Japanese Patent Publication No. 45-3951 and Japanese Patent Publication No. 43-7454).

As shown in FIG. 7 (b), when the mold is opened and closed, the injection unit 4 and the cavity block 5b on the injection unit 4 side remain in the same position, and the runner block 2 and the cavity block 5a on the mold clamping side are in the same direction. To be moved to [Kunststoffe 71 (198
1) 5, pages 274-278].

[Problems to be Solved by the Invention] By the way, in a general horizontal injection molding machine, the injection unit is arranged in the mold opening / closing direction, and only one mold opening / closing mechanism for opening / closing the mold is provided. If a stack molding machine can be constructed using this general horizontal injection molding machine, the existing equipment can be effectively used.

However, in the stack molding machine described above,
In order to move the two cavity blocks in opposite directions, two mold opening / closing mechanisms are required, and there is a problem that a special injection molding machine must be prepared. In addition, the above-mentioned stack mold molding machine has a problem that it is necessary to prepare a special injection molding machine in which the injection unit is arranged at right angles to the mold opening / closing direction.

On the other hand, in the stack molding machine described above, when the mold is opened, the relative positions of the injection unit and the runner block change, and the injection nozzle and the sprue are cut off.
Then, the molten plastic remaining in the injection nozzle or the sprue leaks out and leaks, which significantly hinders the work. Therefore, in this type of stack molding machine, a valve for preventing leakage (valve nozzle) is provided in the injection nozzle, and a valve mechanism is also provided in the sprue. However, such an injection nozzle or sprue has a problem that the structure is complicated and the flow resistance of the molten plastic becomes large, which makes injection difficult. Further, depending on the plastic to be injected, there is also a problem that molten plastic accumulates in the dead space of the valve mechanism and deteriorates.

As described above, in the stack molding machine, there is a problem that a special injection molding machine is required or that molten plastic leaks when the injection nozzle is cut off from the sprue. When using a general injection molding machine to perform leak-free molding, it becomes necessary to install a leak prevention valve mechanism on the injection nozzle and sprue, which complicates the device and makes it impossible to maintain the injection pressure or dead space. Deterioration of the molten plastic due to is a problem.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a stack molding machine which uses a general injection molding machine and is capable of molding while preventing leakage of molten plastic without providing a leak preventing valve mechanism.

[Means for Solving Problems] Means taken in the present invention for solving the above problems will be described with reference to FIG. 1 corresponding to one embodiment of the present invention.
Through hole 7 fixed in a fixed position and formed in the mold opening / closing direction
A cavity block 5b on the nozzle side having a spline, and a runner block 2 having a sprue 1 extending toward the cavity block 5b on the nozzle side through a through hole 7 and movable in the die opening / closing direction. Then, the injection unit 4 for pressing the injection nozzle 3 with the sprue 1 by the moving force in the mold opening direction
And a mold clamping side cavity block 5a which is movable in the mold opening / closing direction and is located on the opposite side of the injection unit 4 with the runner block 2 interposed therebetween. The mold clamping side cavity block 5a is arranged in the mold opening direction. By moving the mold, the runner block 2 is moved in the mold opening direction together with the injection unit 4 by the pressing force of the injection nozzle 3 against the sprue 1 to perform mold opening, and the cavity block 5a on the mold clamping side is closed. The runner block 2 by pushing the runner block 2 with the moving force of the mold clamping side cavity block 5a in the mold closing direction, the runner block 2 resists the pressing force of the injection nozzle 3 against the sprue 1. In addition, the stack mold forming machine is characterized in that the mold is closed by moving in the mold closing direction.

[Operation] According to the stack molding machine of the present invention, when the cavity block 5a on the mold clamping side is moved in the mold opening direction and the injection unit 4 is moved in the mold opening direction, The runner block 2 is also moved in the mold opening direction by the pressing force of the injection nozzle 3 applied to the sprue 1 by the moving force, so that the parting surface 6b on the nozzle side can be opened. During this time, since the injection nozzle 3 is pressed against the sprue 1 in order to push the sprue 1 to move the runner block 2, there is no fear of leakage of the molten plastic in the injection nozzle 3 or the sprue 1. After fully opening the parting surface 6b on the nozzle side,
If the movements of the injection unit 4 and the runner block 2 are stopped, they both stop the movement while maintaining the pressure contact between the injection nozzle 3 and the sprue 1, and after that, if the cavity block 5a on the mold clamping side is further moved, Parting surface 6a on the mold clamping side
Can be opened. Further, when the cavity block 5a on the mold clamping side is moved in the mold closing direction and the runner block 2 is pushed by the moving force in the mold closing direction, the sprue 1
The injection unit 4 and the runner block 2 are moved in the mold closing direction against the pressing force of the injection nozzle 3 against the mold, and the mold can be closed while maintaining the pressure contact between the sprue 1 and the injection nozzle 3. Therefore, the pressure contact between the sprue 1 and the injection nozzle 3 can be maintained throughout the entire process of opening and closing the mold, and leakage of molten plastic can be prevented without providing a valve mechanism.

On the other hand, in the stack molding machine of the present invention, the injection unit 4 is located in the mold opening / closing direction, and also in a general injection molding machine, the injection unit 4 is movable in the mold opening / closing direction. The only member to be used is the cavity block 5a on the mold clamping side. Therefore, the mold opening / closing mechanism is one set, and can be configured using a general injection molding machine.

[Embodiment] As shown in FIGS. 1 and 2, a tightening side cavity block 5a is provided on one side of a runner block 2 having a sprue 1, and a nozzle side cavity block 5b is provided on the other side. It is provided to form the mold. Sprue 1
Is extended through a through hole 7 provided in the cavity block 5b on the nozzle side. Also, the runner block 2 and the cavity block 5a on the tightening side are
The cavity block 5a on the tightening side is movable in the mold opening / closing direction (left and right direction in the figure), and is moved by a mold opening / closing mechanism (not shown).

An injection unit 4 is provided in the mold opening / closing direction on the extension side of the sprue 1 from the runner block 2. The injection unit 4 is movable in the mold opening / closing direction, and the injection nozzle 3 is pressed against the extending sprue 1.

Further explaining the mold with reference to FIGS. 3 and 4, the runner block 2 has a gate 8 disposed on the surface facing the cavity blocks 5a, 5b on the mold clamping side and the nozzle side. The runner block 2 serves to receive the molding material melt-plasticized by the injection unit 4 from the sprue inlet 9 and reach the gate 8 through the runner 10.
Therefore, most of the sprue 1, the manifold 11, and the hot runner nozzle 12 in which the runner 10 is provided are insulated from other parts of the mold through a heat insulating layer, and at the same time, the heater is used to remove the plastic It is maintained at a temperature suitable for flow.

The tightening side and nozzle side cavity blocks 5a and 5b are
Each has a cavity 13 at a position corresponding to the gate 8. In such a mold, the molten plastic received from the sprue inlet 9 passes through the runner 10 and is drawn to the gate 8 and flows into the cavity 13. Since the cavity 13 is maintained at a predetermined temperature, the molten plastic is cooled and solidified to complete the molded product. At this stage, the mold is opened from the parting surfaces 6a and 6b, and the molds shown in FIGS.
The mold is opened as shown in the figure. Cavity 13 here
If the molded product inside is taken out, the molding is completed, and if the mold is closed again and the state shown in FIGS. 1 and 3 is reached, the next molding can be started. Since the sprue 1 is integrated with the runner block 2 when the mold is opened, the sprue 1 slides in the through hole 7 of the nozzle side cavity block 5b.

A mold as shown in FIGS. 3 and 4 is mounted on a normal injection molding machine 14 as shown in FIGS. That is, a mold is attached and the sprue inlet 9 and the injection nozzle 3 are connected to allow the plastic melted by the injection unit 4 to flow into the mold.

In such a device, the pressure (nozzle pressing force) for pressing the injection nozzle 3 of the injection unit 4 against the sprue 1 is
At least the cavity block 5a on the mold clamping side when the mold is closed
FIG. 5 shows an example in which the force is smaller than the force of moving in the mold closing direction (mold closing force). In this example, sequence control is performed so that the nozzle pressing force becomes particularly low when the mold is closed. In addition to this, the mold closing force can be increased, and the level of the nozzle pressing force itself may be adjusted to be smaller by the mold closing force if other operations are not hindered.

Molding is performed by such an apparatus, and when the mold is opened, the entire injection unit 4 moves in the direction of the arrow while moving the runner block 2 by the nozzle pressing force. The amount of movement of the injection unit 4 is preferably set to approximately half of the mold opening / closing stroke from the normal nozzle touch position toward the mold. Then, the state of movement of the cavity block 5a and the runner block 2 on the mold clamping side is as shown in FIG.
That is, when the mold opening operation is performed, the cavity block 5a on the mold clamping side and the runner block 2 move together first, and the parting surface 6b on the nozzle side first opens. After the injection unit 4 has moved a predetermined stroke, the runner block 2 stops, and the cavity block 5a on the mold clamping side is further stopped.
Moves, the parting surface 6a on the mold clamping side opens,
The molded product can be taken out from the cavities 13 on both sides.

Next, when the mold is closed, the cavity block 5a on the mold clamping side is moved by the operation of the mold opening / closing mechanism, and the parting surface 6a on the mold clamping side is closed. Then, since the nozzle pressing force is made smaller than the mold closing force, the runner block 2 cannot fully oppose the mold closing force, moves in the mold closing direction, and eventually the parting surface 6b on the nozzle side also closes and becomes the mold clamping state. Can be molded.

[Effects of the Invention] As described above, in the present invention, since opening and closing of each of the two parting surfaces can be performed by using a set of mold opening and closing mechanism provided in a normal injection molding machine and a nozzle pressing mechanism in combination,
It is not necessary to prepare an injection molding machine with a special configuration, and it is not necessary to equip the mold with a special device such as a link mechanism. Further, since the injection nozzle 3 and the sprue 1 of the mold are not cut off during the entire molding process, there is no fear of leakage of the molten plastic. Further, it is not necessary to provide the injection nozzle 3 and the sprue 1 with a valve mechanism. Therefore, stack molding can be easily performed with an extremely simple injection molding machine and die.

[Brief description of drawings]

FIG. 1 is a schematic view showing a mold closed state of a stack molding machine according to an embodiment of the present invention, FIG. 2 is a schematic view showing the mold open state, and FIG. 3 is a mold in a mold closed state. Sectional view, FIG. 4 is a sectional view of the mold in the mold opening state, FIG. 5 is a graph showing the relationship between the nozzle pressing force and the mold closing force, and FIG. 6 is the mold of the cavity block and runner block on the mold clamping side. 7A and 7B are graphs showing the movement relationship at the time of opening, respectively, and are explanatory views of the conventional stack mold forming machine. 1: Sprue, 2: Runner block, 3: Injection nozzle, 4: Injection unit, 5a: Cavity block on mold clamping side, 5b: Cavity block on nozzle side, 6a: Parting surface on mold clamping side, 6b: Nozzle side Parting surface, 7: through hole, 8: gate, 9: sprue inlet, 10: runner, 11: manifold, 12: runner nozzle, 13: cavity, 14: injection molding machine.

Claims (1)

[Claims] 1. A cavity block 5 on the nozzle side, which is fixed at a fixed position and has a through hole 7 formed in the mold opening / closing direction.
b, a runner block 2 movable in the mold opening / closing direction and having a sprue 1 extending to the nozzle side cavity block 5b side through the through hole 7, and a mold opening / closing direction movable in the mold opening direction. It has an injection unit 4 that presses the injection nozzle 3 against the sprue 1 by a moving force, and a cavity block 5a on the mold clamping side that is movable in the mold opening / closing direction and is located on the opposite side of the injection unit 4 with the runner block 2 interposed therebetween. Then, by moving the cavity block 5a on the mold clamping side in the mold opening direction, the runner block 2 moves in the mold opening direction together with the injection unit 4 by being pressed by the pressing force of the injection nozzle 3 against the sprue 1. Then, the cavity block 5a on the mold clamping side is moved in the mold closing direction, and is moved by the moving force of the cavity block 5a on the mold clamping side in the mold closing direction. A stack molding machine characterized in that the runner block 2 moves in the mold closing direction together with the injection unit 4 against the pressing force of the injection nozzle 3 with respect to the sprue 1 by pressing the nablock 2. .