JPS63179722A - Injection compression molding method and molding machine - Google Patents

Abstract

PURPOSE:To mold a product of high quality by extruding a melt into between a movable mold and a fixed mold after the melt is poured into a groove section formed in the center of the movable mold and then compressing the melt while the movable mold is actuated. CONSTITUTION:The distance between a moving platen 26 and a floating platen 30 is adjusted as l1 by driving cylinders 32a and 32b in a mold. Next, the distance between the joining faces of a movable mold 38 and a fixed mold 40 is adjusted as l2. Then, a melt A is injected from a gate 49 of a fixed platen 22 into a cavity 46 and stored in a groove section 50. A mold clamping cylinder 14 is driven while the cylinders 32a and 32b in the mold are open, and when the moving platen 26 is displaced by the distance l1, the melt A stored in the groove section 50 is flowed into the cavity 46. Said melt A is compressed by a male mold 42 of the movable mold 38 and a movable core 52 by moving the movable plate 26 toward the fixed platen 22 while the cylinder 14 is actuated and further displacing the movable plate, and the peripheral end of the cavity 46 corresponding to a side face section Wb of a product W is filled with molten hot water.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an injection compression molding method and a molding machine. The present invention relates to an injection compression molding method and a molding machine that make it possible to mold a high-quality product by extruding the molten metal between molds and then compressing it under the action of the movable mold.

Generally, in an injection molding machine, a cavity is defined between a movable mold and a fixed mold, a molten metal made of a thermoplastic resin material such as plastics is injected into the cavity, and the mold is opened after the molten metal has hardened. By doing so, the desired product is obtained.

In this case, injection molding machines are used in various manufacturing fields because they can form products with complex shapes in large quantities.

By the way, in such injection molding machines, molten metal is injected into the cavity through a gate defined in a fixed mold.
There is a concern that molding defects may occur depending on the shape of the product to be molded or the position of the gate relative to the cavity.

That is, when the molten metal 4 is injected into the rectangular cavity 2 from the center as shown in FIGS. 1a to 1C, the molten metal 4 spreads concentrically around the center (see FIG.
, abuts against the side wall of the cavity 2 (FIG. 1b). The molten metal 4 then flows along each side wall toward each corner portion 6a to 6d of the cavity 2 (FIG. 1C).

Therefore, since there is a temperature difference between the molten metal 4 that has reached each of the corner portions 6a to 6d and the molten metal 4 at the intermediate portion of each side wall, product defects such as warping due to the difference in the amount of shrinkage of the molten metal 4 can occur. will occur.

In particular, when the molten metal 4 contains a fibrous filler 8 for reinforcement, an orientation phenomenon occurs in which the fibrous filler 8 is arranged according to the internal pressure distribution or flow direction of the molten metal 4. In this case, since the fibrous filler 8 is arranged to be oriented in the flow direction of the molten metal 4, the orientation of the fibrous filler 8 is different for each side wall of the cavity 2, and therefore each corner portion 6a to 6d In this case, the orientation state of the fibrous filler 8 changes rapidly (FIG. 1C).

As a result of the second result, internal stress due to orientation occurs in the molded product, causing warping, cranking, etc.

Therefore, in order to solve this inconvenience, for example,
There is a method in which the position of the gate relative to the cavity, the size of the gate, the number of gates, etc. are selected depending on the shape of the product, and the thickness of the product is adjusted to prevent molding defects from occurring. However, in this case, the structure of the cavity becomes extremely complicated, and the shape of the product is restricted.

On the other hand, since thermoplastic resin materials shrink considerably as they harden, the injection molding machine cannot mold a product that accurately follows the cavity.Therefore, it is necessary to compensate for the deformation of the product due to such shrinkage. As a method, a cavity is defined in advance with allowance for shrinkage of the molten metal, and after filling this cavity with the molten metal, the movable mold is displaced toward the fixed mold as the molten metal hardens and contracts. There is an injection compression molding method that compresses molten metal. In this case, the occurrence of shrinkage and distortion in the product is effectively suppressed, making it possible to obtain a highly accurate product. However, nothing can be done about the molecular orientation of the molten metal or the fiber orientation of the fibrous filler, and as in the case described above, concerns about the occurrence of cranks and the like due to internal stress cannot be eliminated.

The present invention has been made to overcome the above-mentioned disadvantages, and after pouring the molten metal into a groove defined in the center of a movable mold and having an opening corresponding to the outer peripheral shape of the product, the molten metal is By extruding the molten metal into the cavity, and then compressing the molten metal under the action of the movable mold and filling the cavity corresponding to the shape of the product, the curing time of the molten metal in each part of the cavity is approximately the same, and the molecular orientation of the molten metal, etc. The purpose of the present invention is to provide an injection compression molding method and a molding machine that can make the quality of the product uniform and improve the quality and accuracy of the product.

In order to achieve the above object, the present invention injects molten metal into a groove in the center of a movable mold that has an opening corresponding to the outer circumferential shape of the product, and then injects a movable core disposed in the groove. By displacing the molten metal toward the fixed mold, the molten metal flows into the cavity between the movable mold and the fixed mold, and further by displacing the movable mold toward the fixed mold, the cavity flows into the product. The cavity is characterized by having a shape corresponding to the shape and filling the molten metal into the cavity.

The present invention also provides a fixed mold, a movable mold that cooperates with the fixed mold to define a cavity, and an opening defined in the center of the movable mold that corresponds to the outer peripheral shape of the product. a movable core that is disposed in a groove with a movable core that can be displaced toward the fixed mold, a movable platen that displaces the movable core, and a movable platen that is disposed between the movable platen and the movable mold and within a displacement area of the movable platen. and a floating plate that displaces the movable mold toward the fixed mold under the action of the movable plate.

Next, preferred embodiments of the injection compression molding method and molding machine according to the present invention will be described in detail with reference to the accompanying drawings.

In FIGS. 2a to 2d, reference numeral 10 indicates an injection compression molding machine according to the present invention, and this molding machine 10 molds a product W shown in FIG. 3 (for example, a cylinder head cover constituting an engine part of an automobile). will be held. Here, product W
consists of an upper surface part W having approximately the same wall thickness and four side parts W, and is configured in a box shape.

A clamping cylinder 14 and an injection unit 16 are installed at both ends of a base 12 constituting the injection compression molding machine 10. The injection unit 6 has a hopper 18 to which a thermoplastic resin material containing reinforcing fibrous filler B is supplied, and a nozzle 20 for injecting the molten metal A into a cavity to be described later through a runner 19. , the tip of the nozzle 20 is fitted into a fixed plate 22 fixed on the base 12. in this case,
The mold clamping cylinder 14 and the fixed platen 22 are connected to the tie bar 2.
4a and 24b.

The mold clamping cylinder 14 has a movable platen 26 that is guided by tie bars 24a and 24b and is displaced toward the fixed platen 22. A floating plate 30 guided by tie bars 24a and 24b is disposed between the movable plate 26 and the fixed plate 22. Incidentally, one end of the floating platen 30 is attached to the movable platen 26, and connecting rods 28a and 28b are inserted into the other end of the floating platen 30, into which the hollow plates 27a and 27b are screwed. In-mold cylinders 32a and 32b are attached to the corner portions of the movable platen 26, and cylinder rods 34a and 34b of these in-mold cylinders 32a and 32b are connected to the corner portions of the floating platen 30. There is.

A movable mold 38 is attached to the floating plate 30 facing the fixed plate 22 via a spacer 36. Further, a fixed mold 40 is attached to the fixed platen 22 so as to face the movable mold 38 . In this case, the movable mold 38 has a male mold 42 that partially corresponds to the inner peripheral shape of the product W shown in FIG.
has a female die 44 corresponding to the outer peripheral shape of the product W. A cavity 46 filled with the molten metal A is defined between the male mold 42 and the female mold 44. Note that a gate 49, which is an opening of a sprue 48 bored in the center of the fixed mold 40, opens in the cavity 46.

Here, in the center part of the male mold 42 in the movable mold 38,
As shown in FIG. 4, a groove 50 having an opening having a shape substantially similar to the upper surface W of the product W is defined.
0 includes a movable core 52 that can be displaced toward the fixed mold 40.
are mated. In this case, the movable core 52 has a connecting rod 5.
4 is attached, and the other end of this connecting rod 54 is connected to the movable platen 26 through the movable mold 38, the spacer 36, and the floating platen 30 in a slidable manner.

On the other hand, a hollow part 56 is defined in the movable platen 26, and an extrusion cylinder 58 is mounted in this hollow part 56. The extrusion cylinder 5B has a plate body 61 that is displaced by the cylinder roller 0, and the plate body 61 has extrusion rods 62a, 62.
One end of b is attached. These extrusion rods 62a, 6
2b penetrates the movable platen 26, floating platen 30, and spacer 36 and projects into a hollow portion 64 defined by the spacer 36, and a mounting plate 66 is attached to the other end. The extrusion pins 70a, 7 are attached to the mounting plate 66 by the holding vi68.
One end of 0b is attached, and these extrusion pins 70a, 7
Each other end portion of 0b passes through the movable mold 38 and faces the surface of the male mold 42.

The injection compression molding machine according to the present invention is basically constructed as described above.Next, a molding method using this molding machine and its effects will be explained.

First, the distance between the movable platen 26 and the floating platen 30 is adjusted to f+ by driving the in-mold cylinders 32a and 32b. That is, when the in-mold cylinders 32a and 32b are driven, the floating platen 30 is displaced along the tie bars 24a and 24b via the cylinder rods 34a and 34b, and the distance between the movable platen 26 and the floating platen 30 is set to 11. in this case,
Since the movable core 52 that fits into the groove 50 of the movable mold 38 is connected to the movable platen 26 via the connecting rod 54,
is displaced relative to the movable mold 38, and as a result,
The groove 500 stroke is also set to 11.

Next, the distance between the joint surfaces of the movable mold 38 and the fixed mold 40 is set to 1! , adjust to. That is, when the mold clamping cylinder 14 is driven, the movable platen 26 is displaced along the tie bars 24a, 24b. Therefore, the movable mold 38 is connected to the cylinder 32 in the mold.
It is displaced via the floating plate 30 and spacer 36 connected to the cylinder rods 34a, 34b and the connecting rods 28a, 28b of a, 32b, and the distance between the joint surfaces with the fixed mold 40 is set to 12.

The state at this time is shown in FIG. 2a.

Next, in the state shown in FIG. 2a, the thermoplastic resin material containing the fibrous filler B is supplied into the hopper 18 of the injection unit 16. Therefore, the thermoplastic resin material is heated and melted and pressurized by the injection unit 1-16, and the molten metal A is passed through the runner 19 of the nozzle 20 to the fixed platen 2.
The liquid is injected into the cavity 46 from a gate 49 of a sprue 48 defined in the center of the sprue 2 . In this case, the molten metal A is stored in a groove 50 defined in the center of the movable mold 38. Here, the groove portion 50 defines a thick space portion whose aspect ratio is not very large compared to the product W. Therefore,
A large thermal gradient or pressure deviation does not occur locally in the molten metal A stored in this space, and no orientation phenomenon occurs in the fibrous filler B contained in the molten metal A. As a result, the thermal or internal pressure equilibrium state of the molten metal A is suitably maintained.

When a predetermined amount of molten metal A is injected into the groove 50, the mold cylinders 32a and 32b are opened and the mold clamping cylinder 1 is opened.
4 is driven. In this case, the movable platen 26 is displaced by a distance i toward the floating platen 30, and the movable platen 26
The movable core 52 is displaced by a distance 2I toward the fixed mold 40 via a connecting rod 54 attached to the movable core 52 . As a result, the movable core 52 and the male mold 42 of the movable mold 38 are flush with each other, and the molten metal A stored in the groove 50 is transferred to the movable mold 38.
and the fixed mold 40 into a cavity 46 . The state at this time is shown in Figure 2. In addition, if the extrusion cylinder 58 installed inside the hollow part 56 of the movable platen 26 is driven and the plate body 61 is retracted to the mold clamping cylinder 14 side in synchronization with the displacement operation of the movable platen 26, the extrusion hinge 70a ,7
The tip of 0b does not protrude into the cavity 46, which is preferable.

Here, the shape of the opening of the groove 50 is formed to be substantially similar to the upper surface W of the product W, as shown in FIG. Therefore, the molten metal A pushed out from the groove 50 reaches the peripheral edge of the cavity 46 corresponding to the upper surface W in approximately the same time. In addition, the width of the cavity 46 in the state shown in FIG. As a result, the molten metal A uniformly spreads into the cavity 46 constituting the upper surface W of the product W.

After the movable platen 26 is displaced by a distance of 1+ and comes into contact with the floating platen 30, the movable platen 26 is further displaced toward the fixed platen 22 under the driving action of the mold clamping cylinder 14. In this case, the movable mold 38 and the movable core 52 are pressed by the movable plate 26 via the floating plate 30 and the spacer 36, and are directed toward the fixed mold 40 at a distance i%il! Displace by a large amount.

Therefore, the molten metal A is pressed by the male mold 42 and the movable core 52 of the movable mold 38, and is filled up to the peripheral end of the cavity 46 corresponding to the side surface W of the product W. The state at this time is shown in FIG. 2C.

Here, the molten metal A flows substantially simultaneously from the cavity 46 corresponding to the upper surface portion W1 of the product W to the portion corresponding to the side surface portion Wb. Therefore, the fibrous filler B contained in the molten metal A
are oriented substantially parallel to the flow direction of the molten metal A, as shown in FIG. In this case, the adjacent side surface W,
The fibrous filler B is also oriented substantially parallel.

Finally, after the molten metal A has hardened by maintaining the state shown in FIG. 2C for a predetermined time, the mold is opened. Therefore, the mold clamping cylinder 14
is driven to move the movable platen 26 away from the floating platen 30. In this case, the distance between the movable platen 26 and the floating platen 30 is 2. Then, the connecting rods 28a, 2 connected to the movable platen 26
8b, the floating plate 30, spacer 36, and movable mold 38 begin to move toward the mold clamping cylinder 14 along the tie bars 24a, 24b. In addition, mold clamping cylinder 1
If the extrusion cylinder 58 is driven in synchronization with the operation of step 4 and the cylinder rod 60 is displaced toward the fixed platen 22, the extrusion rods 62a and 62b connected to the cylinder rod 60 are moved through the mounting plate 66 and the holding plate 68. Extrusion pins 70a, 70
Press b. As a result, the extrusion pins 70a, 70b
protrudes from the movable mold 38 toward the fixed mold 40, and the product W is taken out from between the movable mold 38 and the fixed mold 40.

The state at this time is shown in FIG. 2d.

Here, the fibrous filler B contained in the product W molded as described above is oriented in the thermoplastic resin material as shown in FIG. 3.

That is, the upper surface W of the product W is formed by compressing the molten metal A once stored in the groove 50 under the action of the movable core 52 and the movable mold 38, so that the upper surface W of the product W is not affected by the position of the gate 49 and is formed into a fibrous shape. Filler B has a relatively random orientation. Further, in the side surface portion W of the product W, the fibrous filler B is oriented substantially parallel to the adjacent side surface portion W5.
No sudden change in orientation occurs between the two.

Therefore, there is no internal stress due to the orientation state of the fibrous filler B, and as a result, the occurrence of warpage and distortion is suitably suppressed. Furthermore, after flowing the molten metal A substantially simultaneously to the periphery of the upper surface Wb using a movable core 52 having a cross-sectional shape substantially similar to the outer peripheral shape of the upper surface Wb of the product W, Since the molten metal A is filled up to the terminal end, the curing time of the molten metal A is approximately the same at the terminal end.

As a result, there is no deformation due to the difference in the amount of shrinkage of the molten metal A, and an extremely accurate product can be molded.

Note that the injection compression molding machine according to the present invention can also be configured as shown in FIGS. 5a to 5C. That is, the female mold 88 of the fixed mold 86 engages with the male mold 84 of the movable mold 82 fixed on the base 80, and there is a space between the male mold 84 and the female mold 88 for molding the product W. cavity 90
is defined. On the other hand, in the center part of the male mold 84 in the movable mold 82, as shown in FIG.
A groove portion 92 having a substantially similar shape to the outer circumferential shape of the groove portion 92 is defined, and a movable core 9 movable core 9 displaceable toward the fixed mold 86 under the driving action of a hydraulic cylinder 94 is defined in the center portion of the groove portion 92.
6 is arranged. Furthermore, fence cores 98a and 98b are disposed facing each other between the movable core 96 and the long side wall of the groove portion 92. In this case, the fence core 98a, the movable core 96, and the fence core 98b each have a bin 10.
0a to 100c are planted, and the bottles 100a and 1
00b and pins 100b and 100c are connected by link members 102a and 102b that engage through elongated holes, respectively. And these link members 102a,
The middle part of 102b is the support shaft 10 fixed to the movable mold 82.
4a and 104b for rotation. Note that the runner 10 of the nozzle 106 is located in the center of the fixed mold 86.
The gate 11 is the opening of the sprue 110 that communicates with the gate 8.
2 opens.

Therefore, in the state shown in FIG. 5a, molten metal A is injected into the cavity 90 from the gate 112 in the sprue 110 of the stationary mold 86 via the runner 108 of the nozzle 106.

This molten metal A is applied to the groove 92 between the fence cores 98a and 98b.
is stored in In this case, since the fence cores 98a and 98b are disposed in the longitudinal direction of the groove 92, the molten metal A does not flow into the groove 92 in the longitudinal direction.
are uniformly stored in

Next, under the driving action of the hydraulic cylinder 94, the movable member 796 is raised toward the fixed mold 86. At this time, the fence cores 98a and 98b are lowered together with the upward movement of the movable core 96 by the action of the link members 102a and 102b. As a result, the molten metal A stored on the upper surface of the movable core 96 flows simultaneously in the lateral and longitudinal directions of the cavity 90. The state at this time is shown in FIG.

Next, when the movable mold 82 is displaced toward the fixed mold 86 by a driving means (not shown), the molten metal A is almost simultaneously filled up to the peripheral end of the cavity 90 corresponding to the side surface W of the product W. become. In this case, since the fiber filler B mixed into the molten metal A is oriented in the same manner as shown in FIG. 3, the occurrence of warpage, distortion, etc. on the product W is effectively suppressed.

As described above, according to the present invention, after pouring the molten metal into the groove having an opening corresponding to the outer peripheral shape of the product in the center of the movable mold, the molten metal is poured between the movable mold and the fixed mold. The molten metal is compressed and filled into the cavity by extrusion and then by further displacing the movable mold toward the fixed mold. Therefore, the flow characteristics of the molten metal are uniform regardless of the position of the gate with respect to the cavity, so that extremely suitable molecular orientation without internal stress etc. can be obtained. As a result, the molded product will not be warped or distorted, making it possible to obtain a product of extremely high quality. Furthermore, when the molten metal contains a fibrous filler, the effect of improving the orientation characteristics is extremely large.In particular, there is no internal stress caused by orientation at the peripheral edge of the product, and the product is extremely robust and highly accurate without warping or cranking. It becomes possible to obtain a product with a high quality.

Although the present invention has been described above with reference to preferred embodiments, the present invention is not limited to these embodiments, and various improvements and changes in design can be made without departing from the gist of the present invention. Of course.

[Brief explanation of the drawing]

1a to 1C are explanatory diagrams of the flow characteristics of molten metal and the orientation characteristics of fibrous filler in the prior art; FIGS. 2a to d are diagrams illustrating the configuration and operation of an injection compression molding machine according to the present invention; Figure 3 is an explanatory diagram of a product molded by the injection compression molding machine according to the present invention, Figure 4 is an explanatory diagram of the mold configuration in the injection compression molding machine according to the present invention, and Figures 5 a to C are diagrams according to the present invention. FIG. 6 is an explanatory diagram of a mold configuration of another embodiment of the injection compression molding machine according to the present invention. 10... Injection compression molding machine 12... Base 14...
- Mold clamping cylinder 16... Injection unit 22...
・Fixed plate 24a, 24b...tie bar 2
6... Movable plates 28a, 28b... Connecting rod 30... Floating plates 32a, 32b... In-mold cylinder 36... Spacer 3rd... Movable mold 40
...Fixed mold 46...Cavity 49.
...Gate 50...Groove 52...Movable core 54...Connection iron 5
8... Extrusion cylinder 70a, 70b... Extrusion pin 82... Movable mold 86... Fixed mold 90... Cavity 94... Pressing cylinder 96... Movable core 98a, 98b...・Fence core W... Product A... Molten metal B... Fibrous filler FfG, 5b ILI40 1L14DFI
G, 5c 102a 102b 8b

Claims (4)

[Claims] (1) Molten metal is poured into a groove in the center of the movable mold that has an opening corresponding to the outer circumferential shape of the product, and then the movable core disposed in the groove is displaced toward the fixed mold. This causes the molten metal to flow into the cavity between the movable mold and the fixed mold, and further displaces the movable mold toward the fixed mold, thereby shaping the cavity to correspond to the product and flowing the molten metal. An injection compression molding method characterized by filling the cavity with: (2) In the method according to claim 1, molten metal is injected into the groove in which the fence core is disposed on the peripheral side, and then the movable core is displaced toward the fixed mold, and the fence core is An injection compression molding method comprising causing the molten metal to flow through a fence core into a cavity between a movable mold and a fixed mold by retracting the metal mold. (3) a fixed mold, a movable mold that cooperates with the fixed mold to define a cavity, and an opening formed in the center of the movable mold and corresponding to the outer peripheral shape of the product. a movable core disposed in the groove and movable toward the fixed mold; a movable platen for displacing the movable core; An injection compression molding machine characterized by comprising a floating plate that displaces a movable mold toward a fixed mold under the action of the movable plate. (4) The injection compression molding machine according to claim 3, wherein the distance between the movable platen and the floating platen is set equal to the displacement stroke of the movable core with respect to the movable mold.