JP2001179750A - Die clamping device, pressurizing device for die clamping device, and method for manufacturing resin molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform operations to open/close a die at high speed and clamp the die finally under high pressure with a high positional precision, using a simply structured and low-cost device instead of a large-scale device for molding /fabricating a resin. SOLUTION: A pressurizing device 3 equipped with a ball-screw mechanism 34 which moves back and forth a molding die 2 connected to either of molding die members 21, 22 and a motor 33 for the ball-screw mechanism 34, is installed between the molding die member 21 and a movable platen 12. The rapid opening/closing operation of the molding die 2 is performed by moving the movable platen 12 back and forth, and on the other hand, the final die clamping operation of the molding die 2 is performed by driving the motor 33 to move the ball-screw mechanism 34 back and forth as a discrete action from the rapid opening/closing operation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to the technical field of resin molding such as injection molding, injection compression molding or compression molding, and more particularly to a high-speed opening / closing operation of a pair of mold members and a high-pressure final mold. The present invention relates to a device for easily and inexpensively realizing a tightening operation and a method for manufacturing a resin molded body using the device.

[0002]

2. Description of the Related Art A mold clamping device used for injection molding, injection compression molding, compression molding or the like is for opening and closing a pair of molding die members. This mold clamping device requires not only a high-speed mold opening / closing operation requiring almost no load, but also a high-pressure final mold clamping operation for preventing a gap between a pair of molding mold members from being opened by injection pressure of molten resin. You. Further, in the case of molding accompanied by compression, a final mold clamping operation at an appropriate speed and high pressure is required to shape and pressurize the molten resin.

As a mold clamping device for realizing such high-speed mold opening and closing and high-pressure final mold clamping, for example, Japanese Patent Publication No.
No. 828 is known. FIG. 7 shows a mold clamping device described in this publication. The mold clamping device includes a coarse movement converting means including a coarse movement ball screw 380 and a coarse movement ball nut 370, a fine movement ball screw 320 and a fine movement ball nut. And a motor 440 for driving the converter for coarse movement and the converter for fine movement.

According to this, when performing high-speed opening / closing operations of the molding dies 300 and 400, the motor 44 is operated while the clutch 480 is disengaged by operating the fine movement side brake 470.
0 is driven to rotate the coarse movement ball screw 380 via the gears 450 and 420. Then, the movable platen 100 and the molding die member 300 advance and retreat via the coarse movement ball nut 370, whereby the high-speed opening and closing operation of the molding dies 300 and 400 is performed. On the other hand, when performing high-pressure final mold clamping of the molding dies 300 and 400, the coarse movement brake 400 is operated and the motor 440 is driven with the clutch 410 being disengaged to drive the gears 450 and 500 and the spline shaft 49.
The ball screw 320 for fine movement is rotated through 0. Then, the movable platen 100 and the molding die member 300 advance and retreat via the fine movement ball nut 310, whereby the molding die 30
A final clamping at a high pressure of 0,400 is performed.

[0005] As described above, the mold clamping device moves the molding die member 300 at a high speed by rotating the coarse movement ball screw 380 at a high speed when the mold is opened and closed with almost no need for a load. At the time of the required final mold clamping, the rotation of the spline shaft 490 is decelerated relative to the rotation of the motor 440 to generate a large force, thereby realizing high-pressure final mold clamping.

[0006]

However, since the high-speed mold opening / closing operation and the high-pressure final mold clamping operation are performed by the same driving source (motor 440) as in the mold clamping device,
The mechanism for switching the driving force and moving the mold is large and complicated, and the cost of the apparatus is high. Further, it is difficult to perform a long clamping stroke at a high speed and a high pressure with good positional accuracy at the time of final clamping at a high pressure. The object of the present invention has been made in view of the above circumstances, and is a mold for performing ultra-high-speed mold opening / closing and high-pressure final mold clamping with high positional accuracy without the need for a large-scale device, simply and at low cost. An object of the present invention is to provide a clamping device, a pressurizing device used in the mold clamping device, and a method for manufacturing a resin molded body using the mold clamping device.

[0007]

The technical means of the mold clamping device of the present invention taken to solve the above problems are as follows. A mold clamping apparatus comprising: a movable plate and a fixed plate for separately attaching a pair of molding members, and a moving mechanism for reciprocating the movable plate with respect to the fixed plate to open and close the molding members at a high speed. In the above, "a linear motion mechanism for moving one of the pair of molding die members forward and backward with respect to the other molding die member, and a pressurizing device having a drive source for the linear motion mechanism, the one molding die member and Provided between the movable platen or the fixed platen, and the moving mechanism has a function of preventing the movable platen from retreating when the pressurizing device pressurizes.
It is characterized by.

The above technical means works as follows.
The movable plate is moved forward and backward by the moving mechanism to open and close the pair of forming mold members at a high speed, while the driving source of the pressurizing device moves the linear motion mechanism back and forth to separate the one molding separately from the high speed opening and closing operation. The mold members are advanced and retracted to perform a final mold clamping operation of the pair of molding mold members. At the time of final mold clamping by the pressurizing device, a reaction force against the pressing force of the pressurizing device acts on the movable platen and the moving mechanism via the molten resin supplied between the molding die members. The movable platen is held at a predetermined position without retreating by the retreat preventing function.
At this time, since the final mold clamping operation is performed by the pressurizing device separately from the moving mechanism of the movable plate, the moving mechanism of the movable plate has a simple configuration only for the high-speed opening and closing operation of the molding die member. In addition, the pressurizing device can be simply configured by a linear motion mechanism and its driving source. Also,
Since the advancing and retreating of the molding die member by the pressing device is performed separately from the case of the movable plate, the positioning of the molding die member can be performed with high accuracy. Furthermore, since the pressurizing device is disposed between one of the molding die members and the movable platen or the fixed platen,
This pressurizing device can be configured to be detachable from the mold clamping device.

The pressurizing device for the mold clamping device may be a pressurizing device for clamping the pair of forming mold members, wherein the fixing device includes a fixing plate attached to the movable platen or the fixed platen; A movable plate attached to one of the molding die members of the pair of molding die members, a linear motion mechanism supported by the fixed plate and connected to the movable plate to move the movable plate forward and backward, and the linear motion mechanism. And a driving source for driving ”.

According to this, when the drive source is driven to move the linear motion mechanism forward and backward, the movable plate connected to the linear motion mechanism is driven forward and backward, whereby the one mold member attached to the movable plate is moved. Drives forward and backward. Then, the distance between the pair of molding die members can be changed by the final clamping force by adjusting the driving amount of the driving source. Further, in the pressurizing device, “the area S [cm ² ] of the movable plate and the maximum pressing force F [kN] applied to the movable plate by the linear motion mechanism satisfy a relationship of 2.5 <S / F. According to the “satisfy”, a molded body having a large projected area can be molded.

On the other hand, as a method of manufacturing a resin molded body by reciprocating a movable platen with respect to a fixed platen by a moving mechanism of a mold clamping device to open and close a pair of molding die members,
A pressurizing device comprising a linear motion mechanism for moving one of the pair of molding die members back and forth with respect to the other molding die member, and a drive source for the linear motion mechanism, the one molding die member and the movable Using a mold clamping device provided between the board or the fixed board,
A mold closing step by moving the movable platen of the mold clamping device, a resin supply step of supplying molten resin between the pair of molding die members, and advancing one molding die member by the pressurizing device to melt the molten resin. And a pressurizing step of applying pressure.

[0012] In this case, since the pressurizing step narrows the interval between the molding die members, a uniform pressing force is applied to the molten resin between the molding die members. A resin molded body with less distortion and deformation can be obtained. Here, by allowing the amount of advance of the molding die member to be within the range of 0.1 mm to 50 mm so that the mold can be clamped, a uniform pressing force is applied to the entire molten resin, and the molten resin is spread evenly in the cavity. However, if the pressure is less than 0.1 mm, it is difficult to apply a uniform pressing force to the entire molten resin unless the supply pressure of the molten resin is further increased. Otherwise, it is difficult to apply a uniform pressing force to the entire molten resin.

[0013] In the method for manufacturing a resin molded article, the method further comprises the step of: "after the pressurizing step, increasing the distance between the pair of molding die members by retracting one molding die member by the pressing device. Performing a process to form an air layer in the molded article ", the gap between the mold members is further widened by the gap increasing step. An expansion pressure due to the pressurized fluid is applied to the entire resin. Thereby, a resin molded article having an air layer such as a foam layer and a hollow layer is obtained.

[0014]

As described above, according to the mold clamping device and the pressurizing device according to the present invention, the pressurizing device is formed separately from the moving mechanism of the movable platen. Can be simplified and the apparatus can be reduced in size and at a low cost. On the other hand, according to the method of manufacturing a resin molded product according to the present invention, a substantially uniform pressure is applied to the molten resin to be supplied between the molding die members by the pressurizing step by the pressurizing device, so that the residual distortion and deformation are reduced and the appearance is reduced. A beautiful resin molding can be obtained. In addition, since the interval between the mold members is increased after pressurizing the molten resin by the interval increasing step, an expansion pressure due to a foaming agent or a pressurized fluid in the molten resin is applied to the entire resin, and a foamed layer or a hollow layer is formed. A resin molding having an air layer is obtained.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic view of a mold clamping device according to an embodiment of the present invention. The mold clamping device 1 shown in FIG. 1 has a movable plate 12 and a fixed plate to which a pair of molding members 21 and 22 are respectively attached. 11, a moving mechanism (not shown) for reciprocating the movable platen 12 with respect to the fixed platen 11, the movable platen 12 and the one mold member 21
And a pressurizing device 3 provided between them.

The fixed platen 11 and the movable platen 12 have substantially the same rectangular plate shape, and are supported by four tie bars 51 and 52 arranged at the four corners thereof so as to be opposed to each other so as to be freely movable. ing. A male mold member 22 is directly attached to the fixed platen 11, while a female mold member 21 is attached to the movable plate 12 via the pressurizing device 3. The molding die member 22 attached to the fixed platen 11 has a resin passage 221 connected to an injection nozzle of an injection machine (not shown) for supplying molten resin between the molding die members 21 and 22. The movable platen 12 is connected to a drive shaft 41 of a moving mechanism (not shown), and is slidably inserted through the tie bars 51 and 52. 51,5
2, the high-speed opening and closing operation of the pair of molding die members 21 and 22 is performed. The moving mechanism has a drive source such as a hydraulic cylinder or an electric motor connected to the drive shaft 41. The moving mechanism has a function of preventing the movable platen 12 from retreating when the pressurizing device 3 described later is operated. For example, the drive shaft 41 is formed of a ball screw as the function of preventing the retreat movement. When a screw mechanism itself or a hydraulic cylinder is used as a driving source, the driving force may be based on the hydraulic pressure of the driving mechanism, or may be a separate locking mechanism such as a lock pin.

The pressurizing device 3 comprises: a fixed plate 31;
Movable plate 32, support base 35, ball screw mechanism 3
4 (linear motion mechanism) and a motor 33 (drive source) for driving a ball screw mechanism 34. The molding die members 21 and 22 are separated from the movable platen 12 by the final clamping force. It is something to move forward and backward. The fixed plate 3
1 is attached to the movable platen 12, and the movable plate 32 is attached to the rear end of the molding member 21.
The attachment to the movable platen 12 and the molding members 21 and 22 may be performed by bolts or a hydraulic clamp mechanism, and is preferably detachably attached. In this case, if the sizes of the fixed plate 31 and the movable plate 32 are determined, they can be shared with other mold clamping devices.

The support 35 is provided with the fixing plate 31.
The ball screw mechanism 34 and the electric motor 33 are mounted on the support 35.
A guide bar 36,
The movable plate 32 is slidably inserted into the guide bars 36 and 37. As the electric motor 33, a servomotor is preferably used in order to improve the positioning accuracy of the molding members 21 and 22. The ball screw mechanism 34 includes a ball screw 341 having one end connected to the movable plate 32, a ball nut 342 for passing the ball screw 341, and a gear 343 meshing with the ball nut 342. The gear 34
Reference numeral 3 is connected to the rotating shaft of the electric motor 33. When the electric motor 33 is rotated, the ball nut 342 is rotated via the gear 343, whereby the ball screw 341 is driven forward and backward. Then, the movable plate 32 and the molding member 21 attached to the ball screw 341 are
1 is driven forward or backward in accordance with the forward or backward movement of 1. At this time, since the movable plate 32 is inserted into the guide bars 36 and 37 and is prevented from rotating, the positioning of the molding members 21 and 22 in the rotational direction does not come. This mold member 21
The rotation of the electric motor 33 is controlled by the rotation of the electric motor 33. The rotation speed of the electric motor 33 is determined based on a predetermined set value or in accordance with the amount of advance and retreat of the molding die member 21 and the pressing force. Further, at the time of clamping by the pressurizing device 3, a reaction force against the pressing force of the pressurizing device 3 is applied to the movable plate 12 and the moving mechanism via the molten resin R supplied between the molding die members 21 and 22. Although it works, the movable plate 12 is held at a predetermined position without retreating by the retreating movement preventing function of the moving mechanism. Thereby, the ball screw mechanism 3
4 is efficiently transmitted to the molding member 21. The pressure applied to the movable plate 32 by the ball screw mechanism 34 is equal to the area S of the movable plate 32.
[Cm ² ] and the maximum pressing force F [kN] applied to the movable plate 32 by the ball screw mechanism 34 are 2.5 <S / F.
It is preferable to satisfy the following relationship. That is, 2.5
By satisfying the <S / F relationship, a compact having a large projected area can be formed, and it is possible to cope with a so-called large machine.

The pressurizing device 3 is disposed between the movable platen 12 and one of the molding die members 21.
It moves with the movement of. In this case, the movement of the molding die member 21 by the movable platen 12 and the movement of the molding die member 21 by the pressurizing device 3 are performed separately, but a part or all of the operations may be performed simultaneously. The control of the movement of the movable plate 12 and the movement of the movable plate 32 may be performed individually or in synchronization.

The pressurizing device 3 is provided between the movable platen 12 and one of the molding members 21.
1 may be attached to the fixed platen 11 and provided between the fixed platen 11 and the other mold member 22. Further, the rotational movement of the electric motor 33 is transmitted to the ball screw 341 via the gear 343.
, But may be transmitted via a belt. Further, the ball nut 342 is rotated, but the rotating shaft of the electric motor 33 is transmitted to the ball screw 341 to rotate the ball screw 341.
May be rotated. Further, the mold clamping device 1 provided with the pressurizing device 3 can be used as a mold clamping device 1 of a general molding machine such as an injection molding machine, an injection compression molding machine, a compression molding machine, a thermoforming machine, a blow molding machine and the like. . In this case, the mold clamping direction of the mold clamping device 1 is appropriately selected depending on the situation, such as an accurate vertical direction, a substantial vertical direction, an accurate horizontal direction, and a substantial horizontal direction.

Next, a method of manufacturing a resin molded body using the mold clamping device 1 will be described. FIG. 2 to FIG. 4 show a series of the molding steps, and FIG.
The mold closing step (B) shown in FIG. 3 and the pressurizing step (C) shown in FIG.
Are sequentially performed. First, as shown in FIG. 2, the mold members 21, 22 are not closed between the mold members 21, 22.
Is placed at a predetermined position, and a molten resin R is supplied between the molding surfaces defined by the molding die members 21 and 22 (resin supply step (A)). As a method of supplying the molten resin R into the molding die 2, an injection machine (not shown) directly injects and supplies the molten resin R into the cavity via a resin passage 221 provided in the molding die member 22. The resin passage 221 includes a check valve (not shown) for preventing the molten resin R from flowing backward. As a method of supplying the molten resin R, the molten resin R supplied into the cavity between the molding die members 21 and 22 is used.
In order to prevent unnecessary cooling, the method of injecting and supplying via the resin passage 221 as described above is preferable. However, for example, a method of supplying the resin into the cavity by an external supply unit having a resin supply nozzle or the like may be used. Well, an appropriate method is adopted.

Next, as shown in FIG. 3, after the supply of the molten resin R is completed, the movable platen 12 is moved by the drive shaft 41 to close the mold at a high speed (mold closing step (B)). At this time, the mold members 21 and 22 are held at a predetermined position by a predetermined mold clamping force or mechanically, but the gap between the mold members 21 and 22 may be slightly widened by the supply pressure of the molten resin R, The space between the molding members 21 and 22 may not be changed at all. However, in the next pressurizing step (C), the movable platen 12 is held so as not to retreat by the retreating movement preventing function of the moving mechanism. Here, the molding members 21, 22
The distance between the mold members 21 and 22 when the molten resin R is spread into the cavity in the next pressing step (C)
It is preferable to keep the gap larger than 0.1 mm to 50 mm than the gap between the two, but it is particularly easy to keep the molten resin R
Can be supplied, and in order to easily perform shaping and pressing later, within 0.5 mm to 30 mm, and more preferably 1 mm to 30 m
It is preferable that the distance is maintained at a large distance within m. That is, the molten resin can be evenly spread in the cavity within the range of 0.1 mm to 50 mm, but the supply pressure at the time of resin supply becomes high when it is smaller than 0.1 mm. The movable platen 12 requires a higher final clamping force. On the other hand, if it is larger than 50 mm, the amount of movement of the movable plate 32 by the pressurizing device 3 when the molten resin R is pushed and spread in the cavity becomes large. This is because 3 becomes large.

Although the molding die members 21 and 22 may be slightly pushed back by the supply pressure at the time of supplying the resin, it is preferable that the molding die members 21 and 22 be changed within the above range. Further, the mold closing is performed by moving the movable plate 12, but the movable plate 32 may be moved by the pressing device 3 together with the movement of the movable plate 12. Further, the mold closing step (B) is performed after the supply of the molten resin R is completed, but may be performed during the supply of the molten resin R. That is, during the mold closing operation, the molten resin R
The supply of the molten resin R is performed in parallel with the operation of starting the supply of the molten resin R and the supply of the molten resin R, and the supply of the molten resin R is completed simultaneously with or before the completion of the mold closing. Is also good.

Next, as shown in FIG. 4, the mold 21 is moved by moving the movable plate 32 provided on the pressurizing device 3 to remove the molten resin R between the molds 21 and 22. The cavity is pressurized and spread, and the inside of the cavity is evenly filled with the molten resin R (pressing step (C)). The movement of the movable plate 32 is performed by rotating the electric motor 33 of the pressurizing device 3. In other words, the rotational movement of the electric motor 33 is converted into the linear movement of the ball screw 341 via the gear 343 and the ball nut 342, whereby the movable plate 32 connected to the ball screw 341 moves forward. At this time, since the movable plate 32 is inserted into the guide bars 36 and 37 and is prevented from rotating, the positioning of the molding members 21 and 22 in the rotational direction does not come. The moving speed of the movable plate 32 includes the size and shape of the target molded body,
The temperature is determined in consideration of conditions such as the temperature of the first and second substrates, the type of resin, the temperature of the supplied resin, the size of the movable plate 32, and the amount of movement of the movable plate 32.
sec to 100 mm / sec, more preferably 3 mm
/ Sec to 50 mm / sec. That is, 1
If the speed is lower than mm / sec, it takes a long time to shape and pressurize the molten resin R, and the molten resin R may start to harden and become difficult to shape. This is because the pressurizing device 3 becomes large, for example, a motor 33 having a large force is required. In addition, ball screw 3
The pressure applied to the movable plate 32 by 41 is such that the area S [cm ² ] of the movable plate 32 and the maximum pressure F [kN] applied to the movable plate 32 by the ball screw 341 are 2.5 <S /
It is preferable to satisfy the relationship of F. 2.5 <S / F
Is satisfied, the flow distance of the molten resin R can be extended to every corner in the cavity.

The pressurizing step (C) by the pressurizing device 3 includes the mold closing step (B) by moving the movable platen 12.
The mold closing step (B) is preferably completed at least before the pressurizing step (C) is completed. The mold closing step (B) may be performed during or after completion of the resin supply step (A), but preferably during or after completion of the resin supply step (A). Performing only the pressurizing step (C) without performing B) may be a point of controlling the mold closing operation.
Then, after the molten resin R shaped and pressed in the pressing step (C) is cooled and hardened, the drive shaft 41 is driven to retreat the movable platen 12 and open the mold. Is obtained.

As described above, according to the mold clamping device 1,
In addition to the moving mechanism of the movable platen 12, the final clamping operation of the forming die members 21 and 22 by the final clamping force is performed by the pressing device 3, so that the moving mechanism of the movable platen 12 is formed by the molding die member 21. , 22 can be configured simply for high-speed opening and closing operations, and the pressure device 3 can be simply configured by the ball screw mechanism 34 and the electric motor 33. Therefore, the moving mechanism and the pressurizing device 3 can have a simple configuration, and the mold clamping device 1 can be reduced in size and can be configured at low cost.

On the other hand, in the pressurizing step (C), the molten resin is supplied by the final mold clamping force, and the interval between the molding die members 21 and 22 at a constant interval is narrowed. An even pressure is applied. As a result, the flow distance of the molten resin R is extended, and a resin molded body with less residual distortion and deformation can be obtained. Further, since the final distance between the molding die members 21 and 22 is determined with good positional accuracy by the pressing device 3, a resin molded body with good dimensional accuracy can be obtained. Therefore, by using the mold clamping device 1 according to the present embodiment, a molded article having a beautiful appearance can be easily manufactured.

In the above-mentioned manufacturing method, as shown in FIGS. 2 and 3, so-called injection compression molding in which the mold is closed after the molten resin R is supplied in a state where the mold members 21 and 22 are not closed. However, after the mold closing step (B) shown in FIG. 3, a resin supply step (A) for supplying the molten resin R into the cavity may be performed. (Other Manufacturing Method) Next, a method of manufacturing a resin molded article having a hollow portion using the mold clamping device 1 according to the above embodiment will be described. In this case, as shown in FIG.
One provided with a fluid injection path 211 for supplying a pressurized fluid into the molten resin between 1 and 22 is used.

As shown in FIG. 5, in order to manufacture a resin molded body having a hollow portion, following the pressurizing step (C) (see FIG. 4), the resin molded body is passed through a fluid injection passage 211 provided in the molding die member 21. A pressurized fluid is injected into the molten resin R in the cavity, and the movable plate 32 is moved backward by the pressurizing device 3 to increase the cavity clearance (interval increasing step (D)). That is, when the pressurizing step (C) by the movement of the movable plate 32 by the pressurizing device 3 is completed,
The injection of the pressurized fluid into the molten resin R from the fluid injection passages 211 of the mold members 21 and 22 is started. In order to reliably inject the pressurized fluid into the molten resin R, the injection start timing of the pressurized fluid is relatively short after the supply of the molten resin R into the cavity is completed, usually within about 15 seconds. It is preferable to carry out. The pressurized fluid is such that the molten resin R is
It is supplied continuously or intermittently until it solidifies between 1 and 22. The supply of the pressurized fluid is not limited to the one fluid injection passage 211 shown in FIG. 5, and a plurality of fluid injection passages may be provided according to the shape and size of the target hollow molded body. It may be supplied from a plurality of locations.

The pressurized fluid is not particularly limited, as long as it is pressurized and can flow, and can be supplied into the molten resin R between the molding surfaces to form a hollow space. For example, in addition to gas such as air, nitrogen, and carbon dioxide, a liquid that is easily vaporized by the heat of the molten resin R to which it is supplied, such as liquefied carbon dioxide gas or water, or a foamed bead, It may be a fluid or granular solid which is supplied into the molten resin R and easily generates a gas by the decomposition of the molten resin R by heat or the like. Usually, a compressed gas such as compressed air, compressed nitrogen, or compressed carbon gas is preferably used as the pressurized fluid, but low-cost compressed air is particularly preferred. The injection pressure of the compressed gas is determined in consideration of the molding conditions.
Preferably, it is about 0.1 MPa or more and less than about 1 MPa. The injection pressure of the pressurized fluid may be constant during injection into the molten resin R, or may be changed.

When a compressed gas is used as the pressurized fluid, the compressed gas is released from the molten resin R in parallel with the supply of the compressed gas into the molten resin R to form the compressed gas in the resin R. If the compressed gas is caused to flow in the hollow space, the molding cycle can be shortened by promoting the cooling of the molten resin R. However, when a hollow space is formed in the resin R in an uncured state of the resin, the supply of the pressurized fluid is stopped, and thereafter, the molten resin R is solidified while maintaining the pressure of the pressurized fluid in the hollow space. You may. The method of discharging the pressurized fluid is performed by alternately repeating supply and discharge of the pressurized fluid through the fluid injection passage 211. When the pressurized fluid is supplied from a plurality of fluid injection passages into the resin R, the supply of the pressurized fluid is continued from at least one of the fluid injection passages while the pressurized fluid is supplied from at least one of the remaining fluid injection passages. May release a pressurized fluid,
The pressurized fluid may be discharged through the fluid discharge passage while supplying the pressurized fluid into the resin R from the fluid injection passage by using the molding die 2 having a fluid discharge passage dedicated to discharge the pressurized fluid.

The timing of discharging the pressurized fluid can be started at an appropriate time after the start of the supply of the pressurized fluid. For example, even if the discharge of the pressurized fluid is started substantially simultaneously with the start of the supply of the pressurized fluid. It may be continued after the supply of the pressurized fluid is completed. After the start of the injection of the pressurized fluid, the motor 33 of the pressurizing device 3 is rotated in the reverse direction, the ball screw 341 is moved backward, and the movable plate 32 and the molding die member 21 are moved backward. The retreat distance of the movable plate 32 is
Is appropriately determined depending on the size, shape, and the like of the target resin molded product within the range of the closed state. Also, the retreat of the movable plate 32 is started within a relatively short time after the completion of the supply of the molten resin R, usually within about 15 seconds, in order to reliably extend the flow distance of the molten resin R in the cavity. Preferably.

As described above, when the movable plate 32 is moved backward to increase the cavity clearance, a spread area of the molten resin R in the cavity is secured. This allows
Since the molten resin R spreads into the cavity due to the expansion force of the pressurized fluid, substantially uniform expansion pressure is applied from the inside of the molten resin R to the entire resin R by the injected pressurized fluid. A hollow molded article having a low appearance and a beautiful appearance can be obtained.

In the above-mentioned manufacturing method, the supply of the pressurized fluid is started after the pressurizing step (C) is completed after the filling of the resin R into the cavity is completed. It can be selected as appropriate after the time when it can be supplied into the resin R and the formation of the hollow space in the resin R is possible. The supply of the pressurized fluid can be started. Further, instead of injecting the pressurized fluid, a molten resin containing a foaming agent is supplied between the pair of mold members, and after the pressurizing step (C), the movable plate 32 of the pressurizing device 3 Is retreated to increase the cavity clearance, a foamed molded article having a myriad of air bubbles, having little residual distortion and deformation and having a beautiful appearance can be obtained.

On the other hand, as the molten resin R in the above-mentioned production method, many thermoplastic resins and thermoplastic elastomers which can be usually used in conventional molding methods such as injection molding, injection compression molding, compression molding, extrusion molding and stamping molding are used. And a resin such as a thermosetting resin. For example, polyolefin resins such as polyethylene and polypropylene, polystyrene, polycarbonate,
Common thermoplastic resins such as acrylonitrile-styrene-butadiene block copolymer, polyamide are used, and thermoplastic elastomers such as ethylene-propylene block copolymer and ethylene-butadiene block copolymer are used. These polymer alloys and the like can be used.

The molten resin R may contain various conventional additives such as pigments, lubricants, antistatic agents and antioxidants. Further, conditions such as the temperature of the supplied molten resin R, the cavity clearance when supplying the molten resin R, the mold clamping speed, and the temperatures of the molding members 21 and 22 are determined by the type of the resin R used, the molding member 21, and the like. , 22 and the type of skin material.

On the other hand, a skin material can be provided on the surface of the molded article for the purpose of decorating the surface of the molded article or imparting cushioning properties to the molded article. That is, in any of the manufacturing methods described above, before the supply of the molten resin R between the molding die members 21 and 22 is started (before the resin supply step (A)).
By supplying the skin material between the mold members 21 and 22 and then performing the above-described steps, a molded body having the skin material adhered to the surface can be easily manufactured. in this case,
The supply of the molten resin R is performed on the back side of the design surface of the skin material.
The skin material is appropriately selected according to the purpose of use, and paper, woven fabric, nonwoven fabric, knitted fabric, a net such as a wire mesh, a sheet or film made of a thermoplastic resin or a thermoplastic elastomer, or the like is used. In addition, the surface of these skin materials may be provided with an uneven pattern such as a grain or decoration such as printing. Further, the skin material may be lined with a thermoplastic elastomer sheet to protect the molten resin R from heat or mold clamping pressure or to improve the adhesiveness with the supplied molten resin R, It may be lined with a foam sheet made of polyethylene, polyvinyl chloride, polyurethane or the like. In the above embodiment, the pressurizing device 3 is disposed between the movable mold member 21 and the movable platen 12. On the contrary, as shown in FIG. The pressurizing device 3 may be arranged between the and the fixed platen 11.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a configuration of a mold clamping device according to an embodiment.

FIG. 2 is a schematic diagram showing a state where molten resin is supplied in the mold clamping device.

FIG. 3 is a schematic view showing a state in which a mold is closed in the mold clamping device.

FIG. 4 is a schematic diagram showing a state in which the molten resin is pressurized by the pressurizing device in the mold clamping device.

FIG. 5 is a schematic view showing a state in which the interval between molding die members is widened after pressing by a pressing device.

FIG. 6 is a schematic diagram in a case where a pressurizing device is provided between a fixed mold member and a fixed platen;

FIG. 7 is a schematic view showing a configuration of a conventional mold clamping device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 mold clamping device 3 pressurizing device 11 fixed plate 12 movable plate 21, 22 molding die member 31 fixed plate 32 movable plate 33 motor (drive source) 34 ball screw mechanism (linear motion mechanism) 35 support base 36, 37 guide bar 41 drive Shafts 51, 52 Tie bar 211 Fluid injection passage 221 Resin passage 341 Ball screw 342 Ball nut 343 Gear R Melted resin

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Takeo Kitayama 2-10-1 Tsukahara, Takatsuki-shi, Osaka Sumitomo Chemical Industries Co., Ltd. (72) Inventor Akihiro Furuta 2-1-1 Tsukahara, Takatsuki-shi, Osaka Sumitomo Chemical Company F-term (reference) 4F202 AG07 AR02 CA09 CA11 CK19 CL01 CL22 CL39 CL46 4F206 AG07 AR02 JA03 JA05 JA07 JM02 JM05 JN27 JN32 JQ83 JT05 JT32 JT38

Claims (5)

[Claims] 1. A movable plate and a fixed plate for separately mounting a pair of molding die members, respectively, and a moving mechanism for reciprocating the movable plate with respect to the fixed plate to open and close the molding die members at high speed. In a mold clamping device, a linear motion mechanism for moving one of the pair of molding die members back and forth with respect to the other molding die member, and a pressurizing device including a drive source of the linear motion mechanism, A mold clamping device, provided between a molding die member and the movable platen or the fixed platen, wherein the moving mechanism has a function of preventing the movable platen from retreating when the pressurizing device pressurizes. 2. A pressurizing device used for a mold clamping device for reciprocating a movable platen with respect to a fixed platen, for clamping a pair of molding die members, wherein the fixing device is attached to the movable platen or the fixed platen. A plate, a movable plate attached to one of the pair of mold members, a linear motion mechanism supported by the fixed plate and connected to the movable plate to advance and retract the movable plate; A pressurizing device for a mold clamping device, comprising: a driving source for driving a linear motion mechanism. 3. The pressurizing device for a mold clamping device according to claim 2, wherein an area S [cm ² ] of the movable plate and a maximum pressing force F [kN] applied to the movable plate by the linear motion mechanism. But,
A pressurizing device for a mold clamping device, wherein a relationship of 2.5 <S / F is satisfied. 4. A method of manufacturing a resin molded body by reciprocating a movable platen with respect to a fixed platen by a moving mechanism of a mold clamping device to open and close a pair of molding die members. A pressurizing device including a linear motion mechanism for moving one of the mold members back and forth with respect to the other molding die member, and a drive source for the linear motion mechanism is disposed between the one molding die member and the movable platen or the fixed platen. A mold closing step by moving a movable plate of the mold clamping apparatus, a resin supply step of supplying a molten resin between the pair of molding mold members, Pressurizing the molten resin by advancing the mold member to produce a resin molded article. 5. The method for manufacturing a resin molded product according to claim 4, wherein, after the pressing step, one of the molding die members is retracted by the pressing device to reduce a distance between the pair of molding die members. A method for producing a resin molded article, comprising performing an increasing interval increasing step to form an air layer in the molded article.