JPH04185413A - Injection and compression molding device - Google Patents

Abstract

PURPOSE:To achieve the molding stable in long time, while a resin path is not blocked by providing the sweeping rod which is retracted from the resin path and opens the resin path in the injection process of resin and which enters the resin path and pushes out the resin in the resin path outside of the path in the molding process of resin. CONSTITUTION:A first sweeping rod 40 is retracted to halfway position, and the lower valve body 28a of a direction-switching valve 28 is changed to closing position, and then the molten resin extruded from an extruding machine 32 is stored in an accumulator 24 through the upper valve body 28b of the direction-switching valve 28. When the prescribed amount of molten resin is stored, the lower valve body 28a is changed to opening position. whereby molten resin is by-passed outside. During this process, a mold is opened, and a molded object is ejected by operating an ejector pin 26. Both sweeping rods 40, 44 are returned to retracted position and lower position. The preparation for injection is completed by turning the upper valve body 28b of the direction-switching valve 28 from the opening position to the closing position. By repeating this operation, molded objects may be repeatedly produced.

Description

[Detailed description of the invention] (b) Industrial application fields The present invention relates to an injection compression molding apparatus.

(b) Prior Art An example of a conventional injection compression molding apparatus is shown in FIG. 9. The molten resin extruded from the extruder 50 passes through the vibrator 52, the directional control valve 54, and flows into the accumulator 56. The piston 56a in the accumulator 56 is pushed down by the pressure of the resin, and the resin is stored until a predetermined amount is reached. When a predetermined amount of resin is stored in the accumulator 56, the directional control valve 54 is switched and the extruder 50
The communication with the accumulator 56 is cut off, and the molten resin extruded from the extruder 50 is bypassed to the outside. In this state, the injection process is started.

That is, the mold 60 disposed between the fixed platen 62 and the movable platen 64 of the molding device 58 is opened, and the nozzle touch cylinder 66 is operated to move the frame 68 upward in the figure. The nozzle 70 is pressed against the mold 60 to be in a touch state. Next, the piston 56a is raised. As a result, the resin in the accumulator 56 is injected into the cavity of the mold 60 through the horizontal resin flow path 72 and the vertical resin flow path 74 in the figure. After the mold is closed and clamped to compress and solidify the molten resin in the cavity, the mold 60 is opened and the solidified molded product 74 is taken out. Meanwhile, during the resin solidification process, the directional switching valve 54 is returned to the initial switching position. Thereby, the process of storing resin from the extruder 50 in the accumulator 56, the process of injecting the resin into the cavity, the process of solidifying and taking out the molded product, etc. are repeated in order, and the molded product can be continuously molded.

(c) Problems to be Solved by the Invention However, in the conventional injection compression molding apparatus, the resin flow path 7 connecting the accumulator 56 and the cavity
Resin is always present in the resin channels 2 and 74, and the resin remains in the resin flow paths 72 and 74 from the end of injection to the start of the next injection. Therefore, when a thermosetting resin or a reaction-curing resin is used as the resin material, a curing reaction occurs and solidifies while the resin remains in the resin channels 72 and 74. There is a problem that 74 may become clogged. That is, extruder 5
0, the vibrator 52, the accumulator 56 and the mold 60,
In order to ensure fluidity of the resin, the resin is heated to maintain its temperature within a predetermined range. Resin flow path 72/7
When the heating temperature rises above a predetermined level or when a relatively high temperature state is maintained for a long time, the thermosetting resin or reaction-curing resin in the resin flow path 72 causes a curing reaction and solidifies. 74 will be stuck. Causes of the above situation include errors in setting the temperature of the heater, errors in adding too much of the curing agent for the reaction-curing resin, and cases in which the injection compression molding machine remains heated for a long time and does not inject due to a malfunction. and so on.

The present invention aims to solve these problems.

(d) Means for Solving the Problems The present invention solves the above problems by preventing the presence of resin in the resin flow path from the end of injection to the start of the next injection. That is, the injection compression molding apparatus of the present invention stores the molten resin extruded from the extruder (32) in the accumulator (24), passes the resin flow path (25, 27) from the accumulator (24), and opens the mold. mold (1
6, 18), and then closes the mold to form the mold. When the resin is injected, it exits from the resin flow path (25, 27) and the resin flow Road (2
5, 27), while the resin flow path (2) is opened during resin molding.
Cleaning rods (40, 44) that enter the resin flow path (25, 27) and push the resin out of the flow path, and a drive device that moves the cleaning rods (40, 44) back and forth! (42・46). Note that the symbols in parentheses indicate corresponding members in the embodiment.

(e) When the working mold is opened, the cleaning member is pulled out from the resin flow path and waits at the retreated position. As a result, the resin flow path between the accumulator and the mold cavity is brought into communication, and a predetermined amount of molten resin is injected from the accumulator into the mold in the injection process.

After the injection process is completed, the cleaning member enters the resin flow path and pushes out the resin in the resin flow path. As a result, no resin is present in the resin flow path. The mold is closed in this state, and the resin injected into the cavity is compressed and assimilated.
The mold is opened and the product is removed. The cleaning member is pulled out of the resin flow path again and moved to the retracted position. By doing this, the resin passes through the resin flow path only when injecting the resin into the cavity, and during other processes, there is no resin in the resin flow path, which prevents the resin flow path from becoming clogged. disappears. Therefore, even if the injection compression molding machine uses a thermosetting resin or a reaction-curing resin, the molding operation can be performed stably for a long time.

(F) Embodiment Figures 1 to 7 show a first embodiment of the present invention. A fixed platen 10 is fixed to the fixed part, and a movable platen 12 is arranged at a position facing the fixed platen. The movable platen 12 is driven by a drive device (not shown) via a rod 12a, and is guided by four tie bars 14 as shown in FIG.
It is movable between the mold closed position shown in the figure and the mold open position shown in FIG. A movable mold 16 is fixed to the movable platen 12. A fixed side mold 18 is arranged at the lower part of the movable side mold 16 in FIG. Although the lower part of the stationary side mold 18 is not shown, it is fixed to the stationary platen 10. A cavity C is formed by the movable mold 6 and the fixed mold 18. The stationary mold 18 is provided with a protruding pin 26 . The ejection bin 26 can eject the molded product in the cavity C out of the mold by moving upward in the figure in the mold open state. In the figure, a frame 22 is installed in the space between the fixed platen 10 and the fixed mold 18.
is located. Two nozzle touch cylinders 20 are fixed to the fixed platen 10. This piston rod is fixed to the lower surface of the frame 22. A slider 38, which will be described later, is also fixed to the lower surface of the frame 22. A first hydraulic cylinder 42 is fixed to the right end of the frame 22. A first cleaning rod 40, which will be described later, is fixed to the rod 42a.

The first hydraulic cylinder 42 is capable of moving the first cleaning rod 40 from the forward position (cleaning position) shown in the figure to a retracted position to the right (see FIG. 4). frame 22
A second hydraulic cylinder 46 is fixed to the lower convex portion. One end of this rod 46a passes through the frame 22 and is connected to a second cleaning rod 44, which will be described later. Second
The hydraulic cylinder 46 can move the second cleaning rod 44 from the raised position (cleaning position) shown in the first figure to the lowered position below this (see FIG. 4). frame 22
An accumulator 24 is arranged on the left side in the figure. An injection piston 24b and a hydraulic piston 24c are fitted into the accumulator 24, and both pistons 24
b and 24c are integrally connected by a rod 24d.

As shown in FIG. 3, a resin storage chamber 24g is formed in the upper part of the injection piston 24b in the drawing. Both pistons 24b
- The volume of the resin storage chamber 24g is maximized when the rod 24c and the rod 24d are lowered. A channel section 24a extends rightward from the upper right end of the accumulator 24 in FIG. 1 along the upper surface of the frame 22 in the drawing, and a nozzle section 24e is formed at the tip thereof. A cooling medium flow path 24f for preventing hardening of the molten resin is formed in the nozzle portion 24, e. The flow path portion 24a of the accumulator 24 is fixed to the upper surface of the frame 22 in the drawing. A rod-shaped guide 36 is fixed to fixed portions (two locations) outside the two nozzle touch cylinders 20, and a cylindrical slider 38 is fitted to this. The slider 38 is fixed to the lower surface of the frame 22 in the figure as described above. The nozzle touch cylinder 20 moves the frame 22 to the illustrated nozzle touch position (the state in which the nozzle part 24e of the accumulator 24 is pressed against the stationary mold 18) while guiding the frame 22 by the guide 36 and the slider 38.
It is movable between this and the nozzle retracted position below in the figure. A directional control valve 28 is fixed to the upper left end of the accumulator 24 in the figure. The directional switching valve 28 is rotatably provided with two valve bodies 28a and 28b. The left end side of the resin flow path in the horizontal direction in the figure of the directional switching valve 28 is connected to the extruder 32 via a flexible vibrator 30, and the right end side is connected to a first resin flow path of the accumulator 24, which will be described later. It is connected to 25. A bypass resin flow path on the lower side in the figure of the directional switching valve 28 communicates with an external resin pool. The inner periphery of the vibrator 30 is lined with Teflon to prevent resin from sticking. Further, a heat insulating material 34 is provided on the outer circumference of the vibrator 30 to maintain the molten resin inside at a predetermined temperature. In FIG. 1, a first resin flow path 25 is formed in the flow path portion 24a of the accumulator 24 in the horizontal direction. In addition, a second tube is provided in the vertical direction that communicates with the cavity C through the nozzle portion 24e of the accumulator 24 and the stationary mold 18.
A resin flow path 27 is formed. The first resin flow path 25 and the second resin flow path 27 communicate with each other via a connecting resin flow path 29 formed in the vertical direction in FIG. Each resin channel 25
・27 and 29 are formed in the shape of cylindrical holes as shown in FIGS. 6 and 7. In addition, in FIGS. 6 and 7, the dimension of the connecting resin flow path 29 is shown as long for ease of understanding, but the actual dimension is extremely short. The first cleaning rod 40 has a cylindrical shape and is disposed within the first resin flow path 25 of the accumulator 24 . The tip of this extends through the flow path of the valve body 28b above the directional control valve 28 to near the flow path branch point (fifth
(see figure). As described above, the first cleaning rod 40 is movable between the forward position (cleaning position) shown in FIG. 1 and the retreated position shown in FIG. 4. Further, a cylindrical second cleaning rod 44 is arranged within the second resin flow path 27 . The tip of this reaches cavity C. As described above, the second cleaning rod 44 is movable between the raised position (cleaning position) shown in FIG. 1 and the lowered position shown in FIG. 4. In the arrangement shown in FIG. 1, no resin exists in the resin channels 25 and 27 except for a small amount of resin in the resin channel 29.

In addition, each valve body 28a and 28b of the direction switching valve 28 in the figure
are in a communicating state, but the tip of the first cleaning rod 40 extends through the resin flow path of the upper valve body 28b to near the flow path branching point, blocking the resin flow path connected to the accumulator 24. ing.

Therefore, the resin extruded from the extruder 32 through the vibrator 30 into the directional switching valve 28 passes through the lower valve body 28a and is bypassed to the outside from the bypass resin flow path.

Next, the operation of this first embodiment will be explained.

In FIG. 4, the movable mold 16 is in the mold open position, and the first cleaning rod 40 and the second cleaning rod 44 are in the illustrated positions (retracted position and lowered position), respectively. As a result, the first resin flow path 25 is connected to the connecting resin flow path 29 and the second resin flow path 27.
It communicates with cavity C via. Nozzle part 24
e is located at the nozzle touch position pressed against the stationary mold 18. Injection piston 2 of accumulator 24
4b has been lowered to the position shown by the imaginary line, and the resin storage chamber 2
The maximum capacity of molten resin is stored in 4g. The upper valve body 28b of the directional control valve 28 is located in the closed position and ready for injection.

The lower valve body 28a is located in the open position. This prevents the resin stored in the accumulator 24 from flowing backward into the directional control valve 28, and also prevents the molten resin extruded from the extruder 32 from flowing into the valve body 28 below the directional control valve 28.
a and is bypassed to the outside from the bypass resin flow path. When the resin used is a thermosetting resin, both molds 16 and 18 are usually heated to maintain a temperature of about 160°C. Furthermore, the inside of the vibrator 3°, each resin flow path 25, 27, 29, and the accumulator 24 are maintained at about 100°C. A cooling medium flows through the cooling medium flow path 24f to cool the nozzle portion 24e. From this state, the injection piston 24b of the accumulator 24 is moved from the accumulation position shown by the imaginary line to the #f ratio position shown by the solid line, and passes through each resin flow path 25, 29, 27 and enters the cavity C.
The molten resin 48 is injected in the form of a lump. Next, the second hydraulic cylinder 46 is operated to raise the second cleaning rod 44 to the raised position shown in FIG. As a result, the molten resin in the second resin flow path 27 is forced into the cavity C. Next, the upper valve body 28b of the directional control valve 28 is rotated from the closed position to the open position, the first hydraulic cylinder 42 is operated, and the first cleaning rod 40 is moved to the forward position (cleaning position) shown in FIG.
At the same time, the movable platen 12 is moved to the mold closing position shown in FIG. 1 to close the mold. As a result, the molten resin in the first resin flow path 25 is pushed out into the directional switching valve 28, merges with the molten resin pushed out from the extruder 32, and is bypassed through the lower valve body 28a. By doing this, the first resin flow path 25 and the second resin flow path 2
No resin exists in the connecting resin flow path 2.
(A small amount of molten resin remains in the container). The movable mold 16 is further lowered and clamped, and the molten resin in the cavity C is compressed and solidified to form a molded product. During this time, the first cleaning rod 40 is moved back to the halfway position shown in FIG. It accumulates in the accumulator 24 through the upper valve body 28b. When a predetermined amount of molten resin is accumulated in the accumulator 24,
The lower valve body 28a in FIG. 1 is switched to the open position again, and the molten resin is again bypassed to the outside. During this time, the mold is opened and the ejection bin 26 is operated to eject the molded product. Both cleaning bars 40 and 44 are returned to the positions shown in FIG. 4 (retracted position and lowered position). The upper valve body 28b of the directional control valve 28 in FIG. 4 is in the open position! By rotating it from the position to the closed position, preparations for injection are completed. By repeating the above operations, molded products can be repeatedly molded.

Next, FIG. 8 shows a second embodiment of the present invention. Fixed side mold 1
A cylindrical nozzle receiver 86 with one step is disposed between the nozzle portion 84e and the nozzle portion 84e. The accumulator 84 has a first
The arrangement is upside down from that of the embodiment, and the molten resin pushes up the injection piston 84b and flows into the resin storage chamber 84.
It is designed to be stored in g. Further, a directional switching valve section is formed at the lower center of the accumulator 84, and one valve element 88 is rotatably supported by this. The direction switching valve part has an inlet resin flow path 84c that opens on the left side in the figure.
An outlet resin flow path 84d opening upward in FIG. 1 and a bypass resin flow path 84h opening downward in the figure are formed.

The outlet resin flow path 84d communicates with the first resin flow path 83. When the valve body 88 is in the illustrated inflow position, the molten resin that has flowed into the inlet resin flow path 84c from the extruder (not shown) (similar to the presser 32 in the first embodiment) flows through the outlet resin flow path 84d. The injection piston 84b is pushed up to the position shown in the figure, and the molten resin is stored in the resin storage chamber 84g. When the valve body 88 is located in the bypass position, which is rotated 90 degrees counterclockwise from the position shown in the figure, the bypass resin flow path is opened. The molten resin is bypassed to the outside through 84h.

Note that the diameter of the outlet resin flow path 84d is the same as that of the first resin flow path 83.
It is said to be larger than the diameter of As a result, when the valve body 88 is in the illustrated inflow position, even if the first cleaning rod 80 has entered the first flow path 83 as described later, the resin flow from the inlet resin flow path 84c to the outlet resin flow path 84c. It is possible to store resin in the resin storage chamber 84g through the outer periphery of the passage 84d. The first dipping rod 80 is disposed in the first resin flow path 83 and is driven by a hydraulic cylinder device (not shown) (same as the first hydraulic cylinder 42 in the first embodiment) to move backward as shown. position, and the forward position (cleaning position) where the second cleaning rod 82 located in the second resin flow path 85 contacts the cylindrical surface.
It is possible to move between That is, the first resin flow path 83 and the second resin flow path 85 are directly connected, so that there is no need to provide the connecting resin flow path 29 as in the first embodiment. The other configurations are similar to those of the first embodiment.

Next, the operation of this second embodiment will be explained. Resin storage chamber 84
When a predetermined amount of molten resin is stored in g, the valve body 88 is rotated 90 degrees counterclockwise from the illustrated inflow position to the bypass position. That is, the outlet resin flow path 84d leading to the resin storage chamber 84g is blocked, and the inlet resin flow path 8
4c and the bypass resin flow path 84h are communicated with each other. As a result, the resin extruded from the extruder (not shown) is bypassed to the outside through the directional control valve section. First cleaning rod 8
0 is located in the illustrated retracted position, and the second cleaning bar 82 is positioned from the illustrated raised position to the lowered position shown by the imaginary line below. As a result, the accumulator 84 and the cavity C are brought into communication via the resin channels 83 and 85. The movable mold 16 is in a mold open position above the illustrated position. The injection piston 84b is lowered to inject the molten resin in the accumulator 84 into the cavity C through the first resin flow path 83 and the second resin flow path 85. Subsequently, the first cleaning rod 80 is moved to the forward position, and the molten resin in the first resin flow path 83 is pushed out into the cavity C. Next, the second cleaning rod 82 is raised from the lowered position shown by the imaginary line to the raised position shown by the solid line to push out the molten resin in the second resin flow path 85 into the cavity C. As a result, the resin flow path 8
There is no molten resin in 3.85. The mold is closed and clamped, and the resin is compression molded to fit the shape of cavity C. After the resin solidifies, the mold is opened and the molded product is molded. Take it out. By returning both cleaning rods 80 and 82 to the retracted position and the lowered position, preparation for injection is completed. By repeating the above operations, molded products can be repeatedly molded.

In the configuration of this second embodiment, all of the molten resin in the channels 83 and 85 where the cleaning rods 80 and 82 are arranged is pushed out into the cavity C, so the molten resin in the accumulator 84 is effectively utilized. Ru. Also, during the solidification process, resin flow paths 83 and 8 passing through the accumulator 84 and the cavity C.
Since the resin flow path can be made completely free of resin, clogging of the resin flow path can be almost completely prevented.

In the above description of the first embodiment, it is assumed that the first resin flow path 25 and the second resin flow path 27 have a circular cross section, and the cleaning rods 40 and 44 that fit therein also have a cylindrical shape. However, if the cross sections of both the resin channels 25 and 27 are square, and the cleaning rods 40 and 44 are also prismatic.

There is no need to provide the connecting resin flow path 29.

Moreover, although thermosetting resin or reaction-curing resin is used as the raw material resin, thermoplastic resin or the like may also be used in the apparatus of the present invention.

(G) As described in detail, according to the present invention, even if the injection compression molding machine uses a thermosetting resin or a reaction-curing resin, after injecting the molten resin into the mold, Since there is no resin in the resin flow path connecting the accumulator and the mold until injection starts, the resin flow path is not clogged and stable molding can be performed for a long time. By arranging the end of the cleaning rod to match the cavity surface, runnerless molding, in which the molded product does not have a runner, becomes possible.

[Brief Description of the Drawings] Figure 1 is a partial sectional view of the first embodiment of the present invention seen from the side, Figure 2 is a plan view of Figure 1, and Figure 3 shows how molten resin is stored in an accumulator. Figure 4 is a diagram illustrating the state in which molten resin is injected into the opened mold, and Figure 5 is a diagram showing the state in which the cleaning rod has penetrated the valve body of the directional control valve. , FIG. 6 is a diagram explaining the connection state of the resin flow path, and FIG.
The drawings are a sectional view taken along the line ■--■ in FIG. 6, FIG. 8 is a partial sectional view showing a second embodiment of the present invention, and FIG. 9 is a partial sectional view showing a conventional injection compression molding machine. 10... Fixed plate, 12... Movable plate, 14... Tie bar, 16... Movable side mold, 18... Fixed side mold,
22...Frame, 24...Accumulator, 24
a...Flow path section, 24e...Nozzle section, 24g...Resin storage chamber, 25...First resin flow path, 27...Second resin flow path, 28...Direction switching valve, 29... Connection resin channel, 32... Extruder, 40... First cleaning rod, 42...
...First hydraulic cylinder, 44...Second cleaning rod, 46.
...Second hydraulic cylinder, 80...First cleaning cylinder, 82.
...First cleaning rod, 84...Accumulator, 84a.
... Channel section, 84e... Nozzle section, 84g... Resin storage chamber, 83... First resin channel, 85... Second resin channel. Figure 3 Figure 4 Figure 5 Figure 6 Figure 7

Claims (1)

[Claims] The molten resin extruded from the extruder (32) is stored in an accumulator (24), and passed from the accumulator (24) through the resin channels (25, 27) to the opened mold (16).・
In an injection compression molding device that injects the molten resin (48) into the resin flow path (18) and then closes the mold for molding, when the resin is injected, the resin exits from the resin flow path (25, 27) and enters the resin flow path (25).・While opening 27), during resin molding, it enters into the resin flow path (25, 27) and closes the resin flow path (25).
・27) Cleaning rod (40.4) that pushes the resin out of the flow path
4) and a drive device (
42 and 46). An injection compression molding apparatus comprising: