JPH10244542A - Mold moving apparatus and molding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mold moving apparatus capable of performing both of the compression and expansion of the molten resin injected into a mold and excellent in mechanical efficiency and a molding method using this apparatus. SOLUTION: Two piston plates 35, 36 different in size integrated through a rod 37 within a hydraulic cylinder 34 internally partitioned into two pressure chambers 31, 32 arranged along a moving direction in order not only to apply compression force to the molten resin in a mold 10 but also to expand a cavity to expand the molten resin are provided in a mold moving apparatus 20. By this constitution, strong drive force can be directly and uniformly transmitted to a moving mold and mechanical efficiency becomes excellent and, when oil pressure is applied in such a state that the pressure chambers 31, 32 communicate mutually, oil also flows in the pressure chamber 31 from the pressure chamber 32 and a moving speed increases.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for compressing a resin in a mold when performing injection molding, injection compression molding, press molding, large hollow gas injection molding, multilayer molding, foam molding and GF expansion molding. Or a mold moving device for moving the moving mold of the mold forward and backward to change the volume of a cavity provided in the mold in order to perform expansion (expansion), and the like. The present invention relates to a molding method using a moving device.

[0002]

2. Description of the Related Art In injection compression molding, a molten resin is filled in a slightly opened mold, and then the mold is closed.
The molding is performed by applying a compressive force to the molten resin filled in the mold. According to such injection compression molding, molding is performed with a low resin injection pressure, and since the pressure in the mold becomes uniform, no warping or distortion occurs in the molded product, and even if the molded product is thin, the shape can be reduced. There is an advantage that a good molded product can be manufactured, and further, there is an advantage that the skin material is less damaged in the integral molding of the skin material. As a molding machine for performing injection compression molding, a mold clamping device for advancing a movable mold movably provided in the molding machine among molds toward a fixed mold fixed to the molding machine; and a mold. It generally has a compression device for compressing the molten resin filled therein.

A conventional compression device is disclosed in Japanese Patent Laid-Open No. 57-9 / 1982.
As shown in Japanese Patent No. 5429 and Japanese Patent Application Laid-Open No. 60-122128, a movable part for increasing or decreasing the volume of the cavity of the mold is provided inside the mold, and the movable part is moved forward through a pin abutting the movable part. There is known a method in which the volume of a cavity is reduced to compress a molten resin filled in a mold. Further, as a mechanism for driving the movable portion to move forward, a pair of inclined members in which inclined surfaces inclined with respect to the moving direction of the movable portion are brought into surface contact with each other, are arranged along the moving direction. A mechanism that generates a compressive force by moving one of the inclined members in a direction orthogonal to the forward direction of the movable portion is employed. In such a compression apparatus, there is a problem that versatility is lacking because injection compression molding cannot be performed for a normal mold having no movable part therein.

In order to solve this problem, as shown in FIG. 9, the present applicant has unitized a mechanism for pressing the movable mold 71 toward the fixed mold 72 and united the mechanism with the movable mold 71 and the fixed mold 72. A compression device 75 that can be attached and detached between a mold 73 and a mold clamping device 74 constituted by
164500). The compression device 75 includes a pair of inclined members 77 and 78 having an inclined surface 76 inclined with respect to the compression direction along the compression direction. Side inclined member 78
Is advanced toward the inclined member 77 to generate a compressive force. According to such a compression device 75, the overall thickness is reduced, and can be mounted on a normal injection molding machine together with the mold, and the injection compression molding can be performed on a normal mold having no built-in movable part. The advantage is that the versatility of can be improved.

[0005]

However, in the above-described compression device 75, the inclined members 77, 7 which relatively move are provided.
Since the directions of the driving force of the cylinder device 79 are changed by sliding the inclined surfaces 76 of each other, the friction loss is large and the mechanical efficiency of the device is low (50 to 70).
%). In addition, during or after injection, in the case of molding involving retraction of a movable mold during molding, such as foam molding in which it is necessary to promote the foaming of a foaming agent by expanding the volume of the cavity, the resin pressure injected into the mold is , The sliding resistance of the inclined members 77 and 78 is increased,
Since the frictional force between 78 is the static frictional force, a strong force is required to resist the static frictional force at the time of starting the retreat of the inclined member 78. On the other hand, once it starts moving, the frictional force between the inclined members 77 and 78 replaces the static frictional force with the dynamic frictional force,
The sliding resistance rapidly decreases. For this reason, the moving speed is not stable, and it is difficult to smoothly perform the relative movement of the inclined members 77 and 78, and the moving speed and the position of the movable mold cannot be finely adjusted. However, there is also a problem that molding is not always sufficient.

An object of the present invention is to perform both compression and expansion on a molten resin injected into a mold,
An object of the present invention is to provide a molding die moving device excellent in mechanical efficiency and a molding method using the molding die moving device.

[0007]

The first invention of the present invention is a molding die moving apparatus for moving a movable die relatively to a fixed die of a die filled with a molten resin. The pressure chambers are respectively provided in a hydraulic cylinder partitioned into two so that two pressure chambers arranged along the moving direction of the movable type are formed, and are formed via rods. It is characterized in that it comprises two integrated piston plates having different pressure receiving surfaces. Here, the movable mold of the mold refers to a portion of the mold that is filled with a molten resin and is moved during molding for molding the molten resin, and is not necessarily a movement that is driven by a mold clamping device. It is not always attached to the die plate, and may be attached to a fixed die plate fixed at a position adjacent to the injection device. In addition, the fixed mold of the mold refers to a part of the mold that is fixed at a predetermined position and is not moved at the time of the above-described molding, and is not necessarily attached to the fixed die plate, and is not necessarily attached to the movable die plate. May be attached. According to the first aspect of the present invention, when the size of the piston plate is set to be approximately the same as the projected area of the mold cavity, a large mechanical output can be obtained, and the compression and expansion of the cavity volume can be obtained. Since the moving distance of the movable type required for the above is short, the stroke of the piston plate does not need to be set long as in a normal cylinder device. For this reason, the double-acting cylinder device composed of the above-mentioned hydraulic cylinder and two piston plates is a thin large-diameter cylinder device having a large mechanical output, and can be mounted on a normal injection molding machine together with a mold. Become.
Therefore, the driving force can be directly transmitted to the movable mold of the mold, and the mechanical efficiency is improved. In addition, the volume of the cavity provided in the mold is reduced by both compression and expansion. Will be able to do it.

In addition, since the large-diameter piston plate drives the entire movable mold, the movable mold moves while maintaining the parallel state with the fixed mold, and moves from the start to the completion of the molding. Since the parallelism between the fixed dies is ensured, the uniformity of the force applied to the entire molten resin is ensured. Here, since the two piston plates have different sizes of the pressure receiving surfaces, when the hydraulic pressure is applied to the pressure chamber on the side of the large-diameter piston plate to drive the large-diameter piston plate, two pressures are generated. By communicating the chambers, the small-diameter piston plate is pulled by the large-diameter piston plate, and oil flows from the small-diameter piston plate-side pressure chamber to the large-diameter piston plate-side pressure chamber,
A large-diameter piston plate reduces the driving force but increases the moving speed. For this reason, even if a large driving force is not required, when the large-diameter piston plate must be driven at a high speed, the two pressure chambers are connected to accelerate the moving speed of the large-diameter piston plate, so that the cycle in molding can be improved. The time can be shortened, and even with a small hydraulic unit having a small oil discharge amount, the movable type can be driven at a speed higher than the pump discharge amount.

In the above, the pressure supply path for applying pressure to the inside of the pressure chamber, the discharge pressure path for releasing the internal pressure of the pressure chamber and the communication path for communicating the two pressure chambers, and these pressure supply paths, A hydraulic circuit provided with a switching means for switching the connection between the pressure chamber and the exhaust path and the communication path is usually provided. If such a hydraulic circuit is provided, it is possible to automatically perform a hydraulic pressure switching operation to two pressure chambers and an opening / closing operation of a communication passage communicating these pressure chambers. In addition, it is possible to perform sequence control for automatically switching the speed of the piston plate in a predetermined procedure, thereby enabling the molding operation to be fully automated. Further, an opening / closing means for opening and closing a communication passage communicating the two pressure chambers is provided, and the opening / closing means and the communication passage are provided near the cylinder. For example, the communication passage and the opening / closing means are connected to the moving device. It is desirable to incorporate it in the main body. With this configuration, the length of the communication passage that communicates the two pressure chambers is reduced, and the speed of the piston plate changes rapidly with respect to the opening and closing operation of the communication passage. Pressure loss is minimized, and also from this point, an excellent mechanical effect can be obtained.

[0010] Further, it is desirable that the two piston plates and rods are provided with openings penetrating therethrough. With this configuration, the nozzle, the ejector pin, and the ejector rod of the injection device can be inserted into the opening of the molding die moving device.
For this reason, when installing the molding die moving device in a molding machine having a fixed die plate and a moving die plate in order to attach the fixed die and the moving die, the molding die moving device includes the moving die plate and the moving die. In this case, not only the protrusion mechanism of the molding machine can be used, but also the movable die can be interposed between the fixed die plate through which the nozzle of the injection device is inserted.

A second invention of the present invention is a molding method using the molding die moving device of the second invention. That is, in the second invention, in order to move the movable mold relative to the fixed mold of the mold filled with the molten resin, two pressure chambers arranged along the moving direction of the movable mold are formed. As described above, inside the hydraulic cylinder divided into two, the pressure chambers are provided respectively, and two piston plates having different sizes of pressure receiving surfaces integrated via rods are provided. A molding method using a molding die moving device, wherein after starting injection of the molten resin into the mold, the molding die moving device is operated to move the movable die to the fixed die. The volume of the cavity provided in the mold is changed by moving relative to the mold. In the second aspect of the present invention, since the large-diameter piston plate allows the movable mold to move forward and backward with respect to the fixed mold with a large driving force,
In order to apply a sufficient compressive force to the molten resin filled in the mold or to expand the resin, the cavity of the mold can be expanded. In addition, since the movable mold moves while maintaining the parallel state with the fixed mold, the parallelism between the movable mold and the fixed mold of the mold is secured from the start to the completion of molding, so that the mold is filled. The uniformity of the force applied to the entire molten resin is ensured, and furthermore, it is possible to manufacture a molded article having excellent shape and dimensional accuracy including the case where the resin is expanded by expanding the cavity.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. In the following description, the same members as those already described are denoted by the same reference numerals, and description thereof will be omitted or simplified. FIG. 1 shows an injection molding machine 1 according to a first embodiment of the present invention. This injection molding machine 1 has a mold divided into a fixed mold 10A and a movable mold 10B.
Molding is performed at 10. The mold 10 is closed with the moving distance of the movable mold 10B left by the dimension a with respect to the fixed mold 10A, and the inside thereof is filled with the molten resin 2 injected from the injection device 1A. Then, by pressing the movable mold 10B with the mold moving device 20 disposed behind the movable mold 10B, molding is performed while compressing the filled molten resin 2. The injection molding machine 1 includes a fixed die plate 3 on which a fixed die 10A is fixed, a movable die plate 4 provided with a movable die 10B, and a moving die plate 4 for moving the movable die plate 4 toward the fixed die plate 3. Mold clamping device 5
And are provided. The movable die plate 4 is slidably provided along a tie bar 8 bridged between a fixed plate 7 to which a hydraulic cylinder device 6 for mold clamping is fixed and a fixed die plate 3.

The mold clamping device 5 has a toggle mechanism 9 to which a piston rod 6A of a hydraulic cylinder device 6 is connected. The pressing force of the hydraulic cylinder device 6 is increased by the toggle mechanism 9 to move the movable die plate 4 forward. Thus, the mold 10 is clamped. Here, between the movable die plate 4 and the fixed die plate 3, a mold clamping pressure receiving block 3A,
3B is provided. When the movable die plate 4 is advanced, the mold clamping pressure receiving block 3A provided on the fixed die plate 3 abuts against the pressure receiving block 3B provided on the movable die plate 4 side. It receives the clamping force. This mold clamping pressure receiving block
The parallelism between the die plates 3 and 4 is ensured by 3A and 3B.

The mold moving device 20 has a fixed substrate 22 attached to the movable die plate 4 and a movable substrate 21 which moves forward and backward with respect to the fixed substrate 22. The movable die plate 4 and the movable die 10B are provided. It is interposed between. The movable substrate 21 has a movable die 10B mounted on the front surface thereof, and is slidably provided along a guide bar 23 implanted on the fixed substrate 22. Between the fixed substrate 22 and the movable substrate 21, there is provided a thin hydraulic cylinder device 30 whose dimension in the moving direction of the movable die 10B is smaller than its diameter. As shown in FIG. 2, the hydraulic cylinder device 30 has two pressure chambers 31, 32 arranged along the direction of movement of the movable mold 10B indicated by the arrow in the figure.
It has a cylinder 34 whose interior is divided into two by a partition wall 33. Two piston plates 35, 36 are provided in each of the pressure chambers 31, 32 of the cylinder 34, respectively.
The diameter D1 of the pressure receiving surface 35A of the piston plate 35 is set to be larger than the diameter D2 of the pressure receiving surface 36A of the piston plate 36. These piston plates 35 and 36 are integrated via a rod 37 having a diameter D3, and have an H-shaped cross section as a whole. Piston plates 35, 36 and rod 37
Are provided with openings 38 penetrating these centers. The cylinder 34 has a pressure introduction passage for introducing hydraulic pressure for driving the piston plates 35 and 36 into the pressure chambers 31 and 32.
31A and 32A are provided.

In order to supply hydraulic pressure to the mold moving device 20,
A hydraulic unit 11 is provided, and a control device 12 is provided for controlling the mold moving device 20. Between the hydraulic cylinder device 30 and the hydraulic unit 11, pipes 41 to 44 for circulating oil between the hydraulic unit 11 and a two-position solenoid valve 45 for switching connection of the pipes 41 to 44 are provided. Have been. Among them, the two-position solenoid valve 45 is attached to the side surface of the hydraulic cylinder device 30. That is, in each of the pressure introduction paths 31A and 32A of the hydraulic cylinder device 30, a pipe 41,
One end of 42 is connected. On the other hand, one end of each of the pipes 43 and 44 is connected to each of the pipe connection portions 13 and 14 of the hydraulic unit 11. The other end of the pipe 41 is connected to an intermediate portion of the pipe 43, and the other end of the pipe 42 is connected to a first port 46 of a two-position solenoid valve 45. The other end of the pipe 43 is connected to the second port 47 of the two-position solenoid valve 45, and the other end of the pipe 44 is connected to the two-position solenoid valve.
45 is connected to the third port 48. Two-position solenoid valve 45
Connects the first port 46 and the third port 48 when the solenoid 45A is excited, and connects the first port 46 and the second port 47 when the solenoid 45A is demagnetized. .

The hydraulic unit 11 is a pump for generating hydraulic pressure.
15 and a tank 16 for storing the oil returned from the hydraulic cylinder device 30. The pump 15 and the tank 16 of the hydraulic unit 11 are connected via a three-position solenoid valve 17 to the piping connection 13,
Connected to 14. The pump 15 is connected to the first port 18 of the three-position solenoid valve 17, and the tank 16 is connected to the second port 19.
The third port 20 is connected to a pipe connection section 13, and the fourth port 21 is connected to a pipe connection section 14. When the solenoid 17A is excited, the three-position solenoid valve 17 guides oil from the first port 18 to the third port 20 and guides oil from the fourth port 21 to the second port 19, so that the solenoid 17B is excited. Then, the oil from the first port 18 is guided to the fourth port 21 and the oil from the third port 20 is guided to the second port 19. In addition, solenoid
When both 17A and solenoid 17B are demagnetized, port 18 is connected to port 19 and is configured to form an unload circuit. The hydraulic unit 11 further includes a pressure control valve for controlling a hydraulic pressure and a flow control valve (both not shown) for controlling a flow rate.

Here, when the solenoid 45A of the two-position solenoid valve 45 and the solenoid 17A of the three-position solenoid valve 17 are excited, the pressure chambers 31, 32 are respectively connected to the pump 15 and the tank by pipes 41-44. A pressure supply path connected to the pressure chamber 16 for applying pressure to the inside of the pressure chamber 31 and an exhaust pressure path for releasing the internal pressure of the pressure chamber 32 are formed. on the other hand,
Solenoid 45B of two-position solenoid valve 45 and three-position solenoid valve 17
When the solenoid 17B is excited, the pressure chambers 31, 32 are respectively connected to the tank 16 and the pump 15 by the pipes 41 to 44.
And a pressure supply path for applying pressure to the inside of the pressure chamber 32 and an exhaust pressure path for releasing the internal pressure of the pressure chamber 31 are formed. When the solenoid 45A of the two-position solenoid valve 45 is demagnetized, the pressure chambers 31 and 32 form a communication path with each other. When the solenoid 45A is excited, the communication path is closed. Here, solenoid valves 45, 17
Are switching means for switching the connection between the pressure supply paths, the exhaust pressure paths and the communication paths and the pressure chambers 31, 32. The two-position solenoid valve 45 also serves as an opening / closing means for opening / closing a communication passage communicating the pressure chambers 31 and 32.

In such a hydraulic cylinder device 30, a mold
In order to give priority to driving speed over driving force when moving the movable mold 10B toward the fixed mold 10A, the solenoid 45A of the two-position solenoid valve 45 is demagnetized and the three-position solenoid valve 17 is demagnetized.
To excite the solenoid 17A. Then, as shown in FIG. 3A, in a state where the pressure chambers 31 and 32 communicate with each other, hydraulic pressure is applied to both the pressure chambers 31 and 32. At this time, the pressure receiving surface 35A of the piston plate 35 is
Since it is larger than A, the piston plate 36 is moved in a direction to narrow the pressure chamber 32 by losing the driving force of the piston plate 35, and the oil in the pressure chamber 32 is pressure-fed to the pressure chamber 31 through the communication passage. Therefore, the amount of oil that is obtained by adding the flow rate Q2 from the pressure chamber to the flow rate Q1 from the pump 15 flows into the pressure chamber 31. Move forward at high speed. However,
A part of the driving force of the piston plate 35 is canceled out by the hydraulic pressure applied to the pressure receiving surface 36A of the piston plate 36, so that sufficient strength may not be secured for compression molding.

On the other hand, when it is desired to prioritize the driving force over the driving speed, the solenoid 45A of the two-position solenoid valve 45 is excited and the solenoid 17A of the three-position solenoid valve 17 is excited. Then, as shown in FIG. 3B, the pressure chamber 31 is connected to the pump 16, the pressure chamber 32 is connected to the tank 16, and the piston plate 35 moves forward slowly. At this time, since the pressure receiving surface 36A of the piston plate 36 is large, the advancing speed is slow, but a sufficient driving force for performing the compression molding is secured. Then, the movable mold 10B of the mold 10 is
To retract from A, the solenoid 45A of the two-position solenoid valve 45
As well as the solenoid 17B of the three-position solenoid valve 17
To excite. Then, as shown in FIG. 3C, the pressure chamber 32 is connected to the pump 16, the pressure chamber 31 is connected to the tank 16, and the piston plate 35 is retracted. In addition, as the switching means for switching the pressure supply path, the exhaust pressure path, and the communication path, in addition to those including the above-described solenoid valves 45 and 17, those including a pilot check valve, a sequence valve, a prefill valve, and the like can also be adopted. The specific configuration of the switching means is not particularly limited to the above configuration.

Next, the molding operation (forming procedure) of the present embodiment
Will be described. First, the mold 10 and the mold moving device 20
Is mounted on a general injection molding machine 1 as shown in FIG. 1 to obtain an injection compression molding machine. At this time, the mold moving device
In the hydraulic cylinder device 30 of 20, the piston plate 35 is retracted. Here, when the injection molding machine 1 is started,
First, the mold clamping device 5 is operated to move the movable die plate 4 toward the fixed die plate 3 and close the mold 10 while leaving the moving distance of the movable mold 10B by the dimension a. At this time, the dimension a can be set in a range of, for example, 0.1 mm to 100 mm. At this time, a mold clamping pressure receiving block 3 is provided between the movable die plate 4 and the fixed die plate 3.
A and 3B are provided. Accordingly, when the toggle mechanism 9 of the mold clamping device 5 is fully extended, the die plates 3 and 4 become parallel, and the parallel state of the die plates 3 and 4 is maintained in a stable state. After this, the injection device
The molten resin is injected into the mold 10 from the injection nozzle of 1A. The molten resin to be injected is a thermoplastic resin, and is a general-purpose resin such as polyethylene, polypropylene, polystyrene, and ABS; an engineering plastic such as polycarbonate, polyamide, and polyacetal;
All other injection-moldable polymer materials such as those containing a reinforcing agent such as glass fiber, carbon fiber and organic fiber, a filler such as talc, and various additives in these resins can be employed. .

After a predetermined time has elapsed from the start of injection of the injection device 1A, or when the injection screw provided inside the injection device 1A reaches a predetermined position, the mold moving device 20 is started. Here, the activation of the mold moving device 20 may be performed after or during the injection of the resin, and the injection amount of the resin into the mold 10 can be arbitrarily set. When the mold moving device 20 starts operating, the molten resin inside the mold moving device 20
Since the whole is not full and a large force is not required for moving the movable mold 10B, the driving speed is prioritized over the driving force. That is, with the pressure chambers 31 and 32 in communication with each other, the pressure chamber 3
Hydraulic pressure is applied to both 1 and 32 to advance the piston plate 35 at high speed. When the movable mold 10B moves forward to some extent, the communication between the pressure chamber 32 and the pressure chamber 31 is canceled and the pressure chamber 31
Only while applying hydraulic pressure, the pressure chamber 32 is connected to the tank 16 to release the pressure, and the piston plate 35 is advanced at a low speed. At this time, the hydraulic pressure generated by the pump 15 is received by the large pressure receiving surface 35A of the piston plate 35, so that the mold 1
A strong driving force required for compression molding of the molten resin within 0 is obtained. Further, the piston plate 35 has a large area and is substantially the same as the projected area of the cavity of the mold 10 as shown in FIG. 1, so that when the movable mold 10B moves forward, the movable mold 10B A balanced pressing force can be applied without bias, and the movable 10B
Moves forward while always maintaining accurate parallel accuracy with respect to the fixed mold 10A. As a result, the compressive force applied to the molten resin in the mold 10 is uniform without any bias, and the obtained molded product is free from warpage and distortion, has good shape and dimensional accuracy, and has a good shape and dimensional accuracy. Even if the movable mold 10B and the movable mold 10B have a spigot structure that is slidably fitted to each other, the sliding portions of the movable mold 10B and the movable mold 10B are not damaged by wear. As the switching control method of the forward speed of the piston plate 35, a time control method based on the passage of time from the start of movement, a position control method based on the position of the movable type 10B, a hydraulic control method based on the hydraulic value of the hydraulic unit, Further, a resin pressure control method based on the pressure value of the molten resin in the mold can be adopted.

While pressure is applied to the molten resin by the mold moving device 20, the molten resin is cooled and solidified for a predetermined time. When a predetermined time has elapsed and the molten resin has sufficiently solidified, the mold clamping device 5 operates to move the movable die plate 4 backward and open the mold 10. Then, the molded product is taken out of the mold 10 and the molding is completed. Thereafter, the above-described injection compression molding operation is repeated as necessary. Here, between the time when the moving die plate 4 starts to retract and the time when the next injection molding starts, while applying hydraulic pressure to the pressure chamber 32, the pressure chamber 31 is connected to the tank 16 to release the pressure, and the piston is discharged. The plate 35 is retracted.

According to the above-described embodiment, the following effects can be obtained. That is, since the piston plate 35 is enlarged and the cylinder 34 is enlarged in diameter, a large mechanical output can be obtained, and the hydraulic cylinder device 30 alone can output a sufficient driving force necessary for compression molding, and one Since the entire hydraulic cylinder device 30 is made thinner, the driving force can be directly transmitted to the movable die 10B of the die 10 mounted on the injection molding machine 1, thereby improving the mechanical efficiency. it can.

In addition, the size of the piston plate 35 is
As shown in FIG. 1, it is set slightly smaller than the movable mold 10B, and when the movable mold 10B moves forward,
Since a well-balanced pressing force is applied so as not to be biased to one place, the movable mold 10B moves forward while always maintaining accurate parallel accuracy with respect to the fixed mold 10A. The uniformity of the force applied to the entire molten resin filled in 10 is ensured, and a molded article having excellent shape and dimensional accuracy can be manufactured.

The pressure receiving surfaces 35A and 36A of the two piston plates 35 and 36 are made different in size, and the two pressure chambers 31 and 32 can communicate with each other. Can be switched to a high speed, so when it is desired to give priority to the forward speed over the driving force, the forward speed of the piston plate 35 can be accelerated,
The cycle time in molding can be reduced, and the hydraulic unit can be downsized.

Further, since the two piston plates 35, 36 and the rod 37 are provided with the openings 38 penetrating them, the nozzles of the injection device, the ejector pins, the ejector rods and the like are inserted into the openings 38. Thus, the mold moving device 20 can be attached to any position inside the movable die plate 4, the fixed die plate 3, and the mold 10.

Further, pipes 41 to 44 for transmitting the hydraulic pressure generated by the hydraulic unit 11 are provided, and a two-position solenoid valve 45 and a three-position solenoid valve 17 are provided for switching the interconnection of these pipes 41 to 44. Therefore, it is possible to perform a sequence control for automatically switching the movement of the movable die 10B such as forward and backward movements, and to automatically switch the speed of the piston plate 35 according to a predetermined procedure, so that the molding operation can be fully automated.

Further, a two-position solenoid valve 45 as an opening / closing means for opening / closing a communication passage communicating the pressure chambers 31, 32 is mounted on the side surface of the hydraulic cylinder device 30, so that the communication passage communicating the pressure chambers 31, 32 is provided. The length of the pipes 41 and 42 is shortened, and the speed of the piston plate 35 can be quickly changed for the opening and closing operation of the communication passage. The pressure loss of the pipe 41 into which the amount of oil plus the flow rate Q2 flows is minimized, and the speed of the piston plate 35 during high-speed movement can be sufficiently secured.
From this point, excellent mechanical efficiency can be obtained. Further, the communication path and the opening / closing means can be incorporated in the moving device 20, so that the moving device 20 can be made compact and its handling can be facilitated.

FIG. 4 shows a second embodiment of the present invention. In this embodiment, the mold moving device 20 attached to the movable die plate 4 side in the first embodiment is replaced with a mold moving device 20A attached to the fixed die plate 3 side. That is, in FIG.
The fixed die 10A is provided on the fixed die plate 3 side, the fixed die 10A is provided on the movable die plate 4 side, and the mold moving device 20A is interposed between the fixed die plate 3 and the movable die 10B. The fixed substrate 22 of the mold moving device 20A is fixed to the fixed die plate 3. The fixed substrate 22 and the movable substrate 21 that moves forward and backward with respect to the fixed substrate 22 are provided with openings 21A and 22A that communicate with the opening 38 on the piston plate 35 side, respectively. Through these openings 21A, 38, 22A, the injection nozzle 1B of the injection device 1A is connected to the sprue 10 provided on the movable mold 10B.
C is reachable. Here, when the movable die 10B is advanced toward the fixed die 10A after the injection is completed, the injection nozzle 1B comes off the sprue 10C of the movable die 10B as shown in FIG. For this reason, the injection nozzle 1B is provided with a shut-off valve (not shown) in order to prevent drawing, and the cavity end 10D of the sprue 10C of the mold 10 is provided.
Is provided with a valve gate (not shown) so that the molten resin in the mold 10 does not flow backward. In this embodiment, the same operation and effect as those of the first embodiment can be obtained.

FIG. 6 shows a third embodiment of the present invention. In the present embodiment, the mold moving device 20 provided outside the mold 10 in the first embodiment is a mold moving device 20B built in the mold 10E. That is, in FIG. 6, the movable die 10B provided on the movable die plate 4 side is provided with a movable core 10F as a movable die which can move forward and backward with respect to the fixed die 10A. The moving die 10B is provided with a hollow portion having a predetermined capacity behind the movable core 10F, and a die moving device 20B is provided inside the hollow portion. This mold moving device 20B
In the figure, the fixed substrate 22 and the movable substrate 21 are omitted from the mold moving device 20 in the first embodiment, and the movable core 10F is directly fixed to the piston plate 35. In addition,
In the present embodiment, not only a normal molten resin but also a molten resin having an expandability, such as a resin to which a foaming agent is added or a resin containing glass fiber, can be injected into the mold 10E. It has become. In the case of using an expansive molten resin, as shown in FIG. 6, the movable core 10F is fixed to the fixed mold 10A.
After the molten resin is injected into the mold 10E with the molten resin filling the cavity in the mold 10E, the movable core 10F is fixed to the fixed mold as shown in FIG.
By retracting from 10A, the cavity is expanded to promote the foaming of the foaming agent and the like, and a light molded article can be manufactured by the expansion. In this embodiment, the same operation and effect as those of the first and second embodiments can be obtained, and a compressive force is partially applied to the molten resin injected into the mold 10C. In addition, the effect that the cavity can be expanded.

[0031]

Next, the effects of the present invention will be described based on specific examples. [Example] This example is an experiment in which molding is performed using an injection molding machine, a mold moving device 20, and a molding procedure based on the first embodiment. The mold employed in this embodiment is for molding a rectangular plate-like molded product, and has a side gate provided at the center of one long side of the cavity. Each dimension of the molded product is 1000 mm long × 500 mm wide ×
The thickness is 2 mm. In addition, a general-purpose horizontal injection molding machine having a clamping force of 850 t is used as the injection molding machine. Further, the hydraulic cylinder device 30 has a diameter D1 of the pressure receiving surface 35A and a pressure receiving surface 36A.
And the diameter D3 of the rod 37 (see FIG. 2) are set to 800 mm, 660 mm, and 350 mm, respectively.

[Comparative Example 1] This comparative example 1 is a conventional multi-cylinder mold-clamping injection compression molding machine which attempts to obtain the same molded product by the same mold and the same procedure as in the previous embodiment. It is an experiment to do. As shown in FIG. 8, a multi-cylinder type injection compression molding machine of Comparative Example 1 has a fixed die plate.
A hydraulic cylinder device 61 provided integrally at four corners of 60 is provided. The piston 62 of the hydraulic cylinder device 61 is
It is connected to one end of the tie bar 63. By hydraulically driving the piston 62, the movable die plate 64 is drawn,
It is possible to apply a compressive force to the molten resin injected into the mold 10. Comparative Example 2 Comparative Example 2 is an experiment in which an injection molding machine and a compression device 75 shown in FIG. 9 are used to obtain the same molded product by the same mold and the same procedure as in the above embodiment. . The compression device used in this comparative example has four hydraulic cylinder devices. Each hydraulic cylinder device is JISB83
This is a general double-acting cylinder specified in 54, and the diameter of the pressure receiving surface of the piston is set to 125 mm. The angle θ of the inclined surface of the inclined member of the compression device is set to 7 degrees.

[Common molding conditions] In the above-described Examples and Comparative Examples 1 and 2, molding is performed using the following common materials and molding conditions. (1) Material: Polypropylene (MI = 24g / 10min; 230 ℃, 2.16
kgf, manufactured by Idemitsu Petrochemical Co., Ltd. Product name: IDEMITSU PP J
(-950HP) (2) Molding conditions Molding temperature: 220 ° C (injection cylinder temperature) Mold temperature: 40 ° C Resin injection time: 3.0 seconds Resin injection pressure: 90 kg / cm ² (gage hydraulic pressure) Cooling time: 30 seconds Compression allowance (dimension a in FIG. 1): 5 mm Compression start timing: 2.8 seconds later (from the start of injection) Compression speed: 10 mm / sec Compression force: 400 t (hold constant until cooling is completed)

[Experimental Results] In the embodiment, the mold has only one side gate, and when the movable mold is advanced,
Although the load was biased to a position off the center of the mold, the movable mold was driven by a large-diameter hydraulic cylinder device, so that the mold could be closed in parallel. For this reason, a molded article having little warpage or deformation and having a substantially uniform thickness was obtained. At this time, the oil discharge pressure of the hydraulic unit is 110 kg
/ cm ² and the discharge flow rate was 0.1 m ³ / min. From these figures, the mechanical efficiency of the mold moving device and the forward speed of the movable mold 10B at high speed will be obtained. Mechanical efficiency η
Is expressed as η = output F1 / input F2. Where output F1
Is measured as the compressive force and F1 = 400t. On the other hand, the input F2 is obtained by appropriately substituting numerical values into the following equation. F2 = A × p = 4064 × 110 (kgw) = 447t where A is the area of the pressure receiving surface 35A of the piston plate 35, and p is the oil discharge pressure of the hydraulic unit. Therefore, the efficiency η is η = 400/447 = 89%. The forward speed v of the movable mold 10B at the time of high speed can be obtained by appropriately substituting numerical values into the following equation. v = Q / (A−B) = 1,000,000 / ｛(4064-
2459) × 60 ° = 10.4 (mm / sec) where B is the area of the pressure receiving surface 36A of the piston plate 36, and Q is the oil discharge flow rate of the hydraulic unit per second.

In Comparative Example 1, the mold had only one side gate, and the load was biased to a position off the center of the mold when the movable mold was advanced, so that the parallel accuracy of the movable mold with respect to the fixed mold was maintained. However, the compression force applied to the molten resin in the mold was biased. As a result, the thickness of the molded product was 2.2 mm on the side gate side and 1.9 mm at the flow end on the opposite side, and it was not possible to obtain a molded product having a uniform thickness. In Comparative Example 2, as in the previous example, the parallel accuracy of the movable type with respect to the fixed type was maintained,
A molded product having a substantially uniform thickness was obtained without any bias in the compressive force applied to the molten resin in the mold, little warpage and deformation. At this time, the oil discharge pressure of the hydraulic unit is 165 kg
/ cm ² and the discharge flow rate was 0.24 m ³ / min. From these numerical values, the mechanical efficiency of the mold moving device and the advance speed of the movable mold will be obtained. The mechanical efficiency η is η = output F
1 / input F2, of which input F2 is F2 = C × n × p / tan θ = 122.7 × 4 × 165 /
0.123 (kgw) = 660t. Here, C is the area of the pressure receiving surface of the hydraulic cylinder device, and n is the number of hydraulic cylinder devices. Here, since the output F1 is 400t, the efficiency η becomes η = 400/660 = 61%. The moving forward speed v is as follows: v = Q × tan θ / (C × n) = 2400000 × 0.1
23 / (122.7 × 4 × 60) = 10.0 (mm / sec) According to such a result, it is understood that the example is superior to the comparative example 2 in mechanical efficiency. In addition, it can be seen that the comparative example 2 requires a discharge flow rate twice or more that of the example in order to achieve the same speed for the movable type. From the above, according to the present invention, it can be seen that the mechanical efficiency can be greatly improved, the cycle time can be reduced, and the hydraulic unit can be downsized.

Although the present invention has been described with reference to preferred embodiments and examples, the present invention is not limited to these embodiments and examples, and various modifications may be made without departing from the spirit of the present invention. And design changes are possible. For example, the following molding methods are used.
Any of the above can be adopted. Normal injection compression molding method. A molding method in which a molten resin is injected into a mold in which a skin material is previously disposed inside to obtain a laminated molded product. A molding method for obtaining a foamed molded product by adding a foaming agent to a molten resin to be injected and filled. A molding method for injecting a molten resin which is ensured expandability by entanglement of mixed fibers, and then expanding a cavity to expand the molten resin in a mold, thereby obtaining a lightweight molded product. While injecting gas into the molten resin filled in the mold,
A molding method for obtaining a molded article in which a cavity is formed by expanding a cavity. In short, any molding method may be used as long as the movable mold is relatively moved when molding the molten resin to freely reduce or enlarge the mold interval during molding.
Therefore, if the molding method includes a step of performing injection while narrowing or expanding the gap at the time of injection, a step of applying a compressive force to the molten resin, or a step of expanding or reducing the gap after the start of injection, The invention can be applied.

[0037]

As described above, according to the present invention, both compression and expansion can be performed on the cavity from which the injection of the molten resin has started, and excellent mechanical efficiency can be obtained. In addition, the molding cycle time can be reduced.

[Brief description of the drawings]

FIG. 1 is a side view showing an entire injection compression molding machine according to a first embodiment of the present invention.

FIG. 2 is an enlarged sectional view showing a main part of the embodiment.

FIG. 3 is a diagram for explaining the operation of the embodiment.

FIG. 4 is a sectional view showing a second embodiment of the present invention.

FIG. 5 is a sectional view showing a different state of the second embodiment.

FIG. 6 is a view similar to FIG. 5, showing a third embodiment of the present invention.

FIG. 7 is a sectional view showing a different state of the third embodiment.

FIG. 8 is a sectional view showing a mold clamping device used in Comparative Example 1.

FIG. 9 is a view similar to FIG. 1 showing a conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Injection molding machine 2 Molten resin 3 Fixed die plate 4 Moving die plate 10,10E Mold 10A Fixed type 10B Moving type 10F Moving core which is a moving part of a moving type 17 Three-position solenoid valve 20,20A, 20B as switching means Mold moving device 31, 32 Pressure chamber 34 Cylinder 35, 36 Piston plate 35A, 36A Pressure receiving surface 37 Rod 38 Opening 41-44 Piping forming pressure supply path, exhaust pressure path and communication path 45 Switching means and opening / closing means Two-position solenoid valve as

Continuing on the front page (72) Inventor, Taki Tamura 2-8-14, Chuo, Yashio, Saitama, Japan Inside Denson Corporation (72) Inventor, Tsuneo Matsui 29, 1 Osasu, Oaza, Sanjo, Niigata Kyowa Kogyo Co., Ltd.

Claims (10)

[Claims] 1. A molding die moving device for relatively moving a movable die with respect to a fixed die of a die filled with molten resin, the molding die moving device being arranged along a moving direction of the movable die. Each of the pressure chambers is provided in a hydraulic cylinder divided into two so that two pressure chambers are formed, and the size of a pressure receiving surface integrated via a rod is different. A molding die moving device comprising: a plurality of piston plates. 2. The molding die moving device according to claim 1, wherein the pressure supply path for applying pressure to the inside of the pressure chamber, the exhaust pressure path for releasing the internal pressure of the pressure chamber, and the two pressure chambers. A molding metal, comprising: a communication path for communication; and a hydraulic circuit provided with a switching unit for switching the connection between the pressure supply path, the exhaust pressure path, and the connection between the communication path and the pressure chamber. Mold moving device. 3. The molding die moving device according to claim 1, wherein the two piston plates and the rod are provided with openings penetrating therethrough. Mold moving device. 4. The molding die moving device according to claim 1, further comprising an opening / closing means for opening and closing a communication passage communicating the two pressure chambers. A molding die moving device, wherein a communication passage is provided near the hydraulic cylinder. 5. The molding die moving device according to claim 1, wherein the molding machine for molding with the die comprises a fixed die plate and a movable die plate movably provided. The fixed die of the mold is attached to the fixed die plate, the movable die is attached to the movable die plate, the molding die moving device,
A molding die moving device interposed between the moving die plate and the moving die. 6. The molding die moving device according to claim 2, wherein the molding machine that performs molding with the die includes a fixed die plate and a movable die plate that is movably provided, and the fixed die is Attached to the moving die plate,
The molding die moving device, wherein the molding die moving device is interposed between the fixed die plate and the moving die. 7. The molding die moving device according to claim 5, wherein the fixed die of the die has a resin passage. 8. The molding die moving device according to claim 6, wherein the moving die of the die has a resin passage. 9. The molding die moving device according to claim 1, wherein said molding die moving device is incorporated in said die. Mold moving device for molding. 10. In order to move the movable mold relative to the fixed mold of the mold filled with the molten resin, two pressure chambers arranged along the moving direction of the movable mold are formed. In a hydraulic cylinder divided into two parts, the pressure chambers are respectively provided, and two piston plates having different sizes of pressure receiving surfaces integrated via rods are used for molding. A molding method using a mold moving device, wherein after starting injection of a molten resin into the mold, the molding mold moving device is operated to move the moving mold with respect to the fixed mold. A molding method characterized by changing the volume of a cavity provided in the mold by relatively moving.