KR100970361B1 - Thermal press forming device and mold system for the device - Google Patents

Abstract

(assignment)

In hot press molding for transferring the uneven pattern to the surface of the thermoplastic plate, the contact state between the thermoplastic plate and the stamper is uniformized.

(Solution)

Cylinder mechanisms 112 and 114 are mounted on the slide 104 and bolster 102 of the press apparatus. Each cylinder mechanism has a cylinder 120 in which a pressure chamber 126 filled with a heat fluid is located. The cylinder 120 has a flexible top plate 124, and the flexible top plate 124 has an inner surface in contact with the pressure chamber 126 and an outer surface for supporting the stamper 128. A plurality of heat exchange pipes 134 for cooling the heat fluid in the pressure chamber 126 are disposed in the pressure chamber 126. The preload device 160 applies a bias pressure to the pressure chamber 126 to inflate the top plate 124 outward.

Description

PRESSURE DEVICE AND MOLD SYSTEM FOR THE DEVICE

The present invention relates to a heat press forming apparatus for pressing a stamper to transfer a finely shaped pattern onto the surface of a thermoplastic plate, and a mold system for the apparatus.

This kind of hot press molding apparatus is used for molding an optical component or a highly decorative panel having a fine shape pattern on the surface, such as a light guide plate or a diffusion plate for a backlight of a liquid crystal display and a lens or an optical disk substrate, for example. The structure of the metal mold | die for this kind of hot press molding is disclosed by patent document 1, for example. According to this disclosure, a plate-shaped stamper is attached to a heating cooling plate having heating cooling means, the stamper is heated and cooled by the heating cooling plate, and the stamper is pressed against the surface of the thermoplastic resin plate via the heating cooling plate. do.

Patent Document 1: Japanese Unexamined Patent Publication No. 2004-74769

The height of the unevenness of the shape pattern transferred by this kind of hot press molding is typically several micrometers to several tens of micrometers. On the other hand, the thickness of the thermoplastic resin plate which is a workpiece has a variation of about 0.1 mm. In addition, there is a variation of about 0.01 to 0.05 mm in the size of the mold to which the stamper is attached and the thickness and plan view of the stamper itself.

In addition, in the hot press molding disclosed in Patent Document 1, the stamper is pressurized onto the surface of the workpiece in a state where the stamper is heated with a heating cold plate, and the stamper is cooled to the workpiece after cooling the stamper with the heating cooling plate. End pressurization. For this reason, the curvature by heat distortion at the time of heat cooling generate | occur | produces in a heating cooling plate.

Due to these events, the pressure distribution on the contact surface of the stamper and the workpiece is uneven at the time of molding, so that a part of the stamper is not pressurized by the required pressure to the workpiece. As a result, a defect occurs in which the pattern is not partially transferred completely to the surface of the workpiece.

Several measures can be taken to solve this problem. For example, a large pressing force more than the pressing force necessary for transferring is loaded. Or raise the heating temperature of a stamper, and lower the surface pressure required for transcription | transfer. Alternatively, the pressurization time of the heated stamper to the workpiece is lengthened, and the softening layer of the workpiece is increased to lower the surface pressure necessary for transfer.

However, such measures are not preferable in terms of equipment cost and operating cost, and because they load more than necessary temperature and surface pressure on the workpiece, the expansion of the material side at the time of molding becomes large, and the bulging of the material side at the end of molding Post processing is necessary.

Therefore, an object of the present invention is to uniformize the contact state between the thermoplastic plate and the stamper in hot press molding for transferring the uneven pattern to the surface of the thermoplastic plate.

The hot press forming apparatus for pressurizing the stamper according to the present invention and transferring the shape pattern onto the surface of the thermoplastic plate comprises a press device having a bolster, a slide, and a driving device for driving the slide, and mounted on the slide or bolster. It is provided with a cylinder mechanism. The cylinder mechanism has a cylinder in which a pressure chamber filled with a heat fluid is inside. The cylinder has a flexible top plate. The flexible top plate has an inner surface in contact with the pressure chamber and an outer surface for supporting the stamper. The hot press forming apparatus further includes a heating and cooling device for heating and cooling the heat medium in the pressure chamber, and a preloading device for applying a bias pressure to the pressure chamber.

This hot press forming apparatus heats the stamper by heating the heat medium in the pressure chamber. When the temperature of the stamper is heated above the material softening temperature of the thermoplastic plate, the slide of the press device is lowered, and the stamper is applied to the thermoplastic plate. Pressurize. At this time, the stamper is pressurized to the surface of the thermoplastic plate via the flexible top plate by the internal pressure of the pressure chamber, so that the pressure distribution to the surface of the thermoplastic plate of the stamper becomes more uniform. Thereafter, the heat medium in the pressure chamber is cooled in this pressurized state. When the temperature of the stamper is cooled to below the material softening temperature of the thermoplastic plate, the slide rises.

In a preferred embodiment, the cylinder mechanism is configured such that when the press force applied to the cylinder mechanism from the press device increases, the internal pressure of the pressure chamber increases. For example, the cylinder mechanism further has a piston slidably inserted into the cylinder to vary the volume of the pressure chamber, the piston being connected to the slide or bolster, thereby increasing the press force applied to the piston from the slide or bolster. In other words, the pressure chamber slides in the cylinder so as to reduce the volume.

In a preferred embodiment, the heating cooling device has a heat exchange pipe formed in the pressure chamber and a heating cooling fluid supply device for supplying heating fluid and cooling fluid into the heat exchange pipe. Alternatively, the heating and cooling device may have an electric heater formed in the pressure chamber, a heat exchange pipe formed in the pressure chamber, a heater power source for driving the electric heater, and a cooling fluid supply device for supplying a cooling fluid into the heat exchange pipe. do.

In a preferred embodiment, when the slide is raised to end the pressurization of the stamper against the thermoplastic plate, the bias of the size necessary for the top plate to bulge outward and become convex by the internal pressure of the pressure chamber. The pressure is applied to the pressure chamber.

In a preferred embodiment, a pressure sensor for detecting the internal pressure of the pressure chamber is further formed. Then, the drive device is configured to control the movement of the slide so that the internal pressure of the pressure chamber becomes a preset set pressure based on the detected pressure from the pressure sensor.

In a preferred embodiment, a temperature sensor for detecting the temperature of the heat fluid in the pressure chamber is further formed. The heating and cooling device is configured to control the temperature of the heat medium in the pressure chamber to be a preset set temperature based on the detected temperature from the temperature sensor.

The mold system for the heat press molding apparatus for pressurizing the stamper according to another aspect of the present invention to transfer the uneven pattern to the surface of the thermoplastic plate includes the above-described cylinder mechanism, a heating cooling device, and a preloading device. .

According to the present invention, it is to uniformize the contact state between the thermoplastic plate and the stamper during molding.

EMBODIMENT OF THE INVENTION Hereinafter, the heat press molding apparatus which concerns on one Embodiment of this invention is demonstrated, referring drawings.

BRIEF DESCRIPTION OF THE DRAWINGS The whole structure of the heat press molding apparatus which concerns on one Embodiment of this invention is shown.

The hot press forming apparatus 100 is composed of a combination of a general-purpose press apparatus and a mold system for hot press molding. The general-purpose press apparatus is provided with the bolster 102 fixed to the floor, the slide 104 arrange | positioned above this bolster 102, and the drive device 106 which drives the slide 104. FIG. The slide 104 is driven by the drive device 106 to move up and down along a post not shown so as to be approached and separated from the bolster 102. The drive device 106 has, for example, a servo motor 108 for driving the slide 104 and a motor controller 110 for driving and controlling the servo motor 108. Instead of using the servo motor as shown as the drive device 106, one using a hydraulic actuator may be used.

The mold system includes two upper and lower cylinder mechanisms 112 and 114 mounted on the bolster 102 and the slide 104 so as to face each other. 2 enlarges and shows the part of these two cylinder mechanisms 112 and 114. As shown in FIG. Since the two cylinder mechanisms 112 and 114 are substantially the same structure, the upper cylinder mechanism 112 is taken as an example and the structure is demonstrated with reference to FIG. 1 and FIG.

The upper cylinder mechanism 112 has a dieset 116, a piston 118, a cylinder 120, and a holder 122. The die set 116 is approximately rectangular plate-shaped and is fixed on the slide 104. The piston 118 is a substantially rectangular mold and is fixed on the center portion of the die set 116. The cylinder 120 is a substantially rectangular cylindrical shape, and its bottom is open. The piston 118 is inserted into the cylinder 120 from the opening of the bottom of the cylinder 120. With the inner side of the cylinder 120 and the outer side of the piston 118 in close contact, the cylinder 120 can slide up and down relative to the piston 118 (in other words, the piston 118 is a cylinder ( 120) in the up and down direction). The holder 122 is a substantially rectangular circular shape and is fixed on the die set 116 and fitted to the outer circumference of the cylinder 120. The cylinder 120 can slide also about the holder 122 in an up-down direction. The holder 122 restrains the cylinder 120 from the outside so that it does not tilt when the cylinder 120 slides.

A ring-shaped sealing frame 144 having a vacuum packing on the head surface of the holder 122 is attached via a spring 146. The sealing frame 144 is slidable relative to the holder 122 and is elastically supported downward by the spring 146. When the slide 104 descends and the sealing frame 144 abuts the lower cylinder mechanism 114, a vacuum chamber is formed inside the sealing frame 144. In addition, when the slide 104 is lowered, the sealing frame 144 slides upward with respect to the holder 122 in a state of being in contact with the lower cylinder mechanism 114 by the pressing force from the spring 146. By the vacuum pump and air open valve which are not shown in figure, the vacuum suction and air open of this vacuum chamber can be made free.

The cylinder 120 has a top plate 124 in its head portion. Top plate 124 is a flexible thin metal plate. In the cylinder 120, the pressure chamber 126 is partitioned by the top plate 124, the piston 118, and the side walls of the cylinder 120. The pressure chamber 126 is filled with a heat fluid having a high thermal conductivity (for example, a liquid such as oil or GALDEN®) that can be heated to a high temperature even under atmospheric pressure. The pressure chamber 126 is substantially sealed, and the heat fluid does not leak out from the pressure chamber 126 even when the internal pressure of the pressure chamber 126 increases.

The volume of the sealed pressure chamber 126 can be changed by sliding the piston 118 relative to the cylinder 120. When the press force applied to the piston 118 from the slide 104 is increased, the pressure chamber 126 because the piston 118 slides toward the head portion of the cylinder 120 to reduce the volume of the pressure chamber 126. ) The internal pressure increases. Except for the flexible top plate 124, all the walls in contact with the pressure chamber 126 are rigid and do not deform in accordance with the internal pressure of the pressure chamber 126. On the other hand, when the internal pressure of the pressure chamber 126 rises, the flexible top plate 124 is deformed to receive the internal pressure on the inner surface and bulge outward.

As shown in FIG. 2, on the outer surface (head surface) of the head part of the cylinder 120, the flexible thin plate-shaped stamper 128 is fixed. As the fixing method of the stamper 128, for example, the vacuum suction by the vacuum suction groove 130 processed on the head surface of the cylinder 120 (the vacuum pump for this is not shown) and the cylinder 120 Combinations of fasteners 132 formed on the head face of the can be used. The stamper 128 fixed to the head portion of the cylinder 120 has its rear face closely in contact with the outer surface of the flexible top plate 124. When the top plate 124 is deformed by the internal pressure of the pressure chamber 126, the stamper 128 is also deformed in the same manner. At the time of hot press molding, upper and lower stampers 128 and 128 are pressed to both upper and lower sides of the workpiece 200 which is a thermoplastic resin plate. At this time, the stamper 128, 128 is deformed in accordance with the increase in the internal pressure of the pressure chamber 126 as described above, whereby the distribution of the molding pressure of the stamper 128, 128 with respect to the surface of the workpiece 200 is increased. It becomes more uniform than before.

In the pressure chamber 126, an apparatus for cooling the fruit fluid filled therein is formed. In this embodiment, a plurality of heat exchange pipes 134 are disposed in the pressure chamber 126 as an example. The inlets of the plurality of heat exchange pipes 134 are connected to a supply pipe 136 installed in the die set 116 via a manifold 138 formed in the cylinder 120. In addition, the outlets of the plurality of heat exchange pipes 134 are connected to the discharge pipe 140 installed in the die set 116 via the manifold 142 formed in the cylinder 120. Moreover, the wall surface in which the temperature sensor 148 for detecting the temperature of the heat fluid in the pressure chamber 126 is in the pressure chamber 126 or the pressure chamber 126 (in this embodiment, the head surface of the piston 118) On the top).

As shown in FIG. 1, the supply pipe 136 and the discharge pipe 140 are connected to the heating cooling fluid supply device 150. The heated cooling fluid supply device 150 has a fluid circulation device 152 and a control device 154. The fluid circulation device 152 supplies the temperature controlled hot heating fluid (eg, steam, hot water, oil, etc.) and the low temperature cooling fluid (eg, cooling water) to the supply pipe 136, and The fluid discharged through the heat exchange pipe 134 to the discharge pipe 140 is absorbed. By alternately flowing the heating fluid and the cooling fluid through the heat exchange pipe 134, the heat fluid in the pressure chamber 126 can be heated and cooled. Receiving an output signal from the control device 154 and the temperature sensor 148, the preset temperature (heating set temperature and cooling set temperature) at which the temperature of the heat medium in the pressure chamber 126 indicated by the output signal is preset Preferably, the temperature and flow rate of the heating fluid and the cooling fluid supplied by the fluid circulation device 152 are controlled.

In addition, as an alternative configuration for heating and cooling the heat medium in the pressure chamber 126, an electric heater (not shown) and a heat exchange pipe 134 are formed in the pressure chamber 126, and an external heater power source ( (Not shown) to energize the electric heater, stop supply of the cooling fluid to the heat exchanger pipe 134, supply air to the heat exchanger pipe 134, and stop power supply to the electric heater during cooling. Together, the cooling fluid may be supplied to the heat exchange pipe 134.

1, the preload device 160 is connected to the pressure chamber 126 via a preload pipe 162. The preload device 160 continuously applies the predetermined bias pressure to the pressure chamber 126 unchanged, and when the internal pressure of the pressure chamber 126 exceeds the predetermined allowable upper limit pressure, the pressure chamber 126. Remove the excess pressure and set the upper limit pressure. Here, the bias pressure is determined by the internal pressure of the pressure chamber 126 when the slide 104 is raised to terminate the pressing of the stamper 128 against the workpiece 200 after the pattern transfer is performed. 124) This is the pressure (e.g., about 1 MPa) of the required size to bulge outward and become convex. This bias pressure is lower than the pressure (for example, about 4-5 MPa) required for pattern transfer. In addition, the allowable upper limit pressure is much higher than the pressure required for pattern transfer (for example, about 4 to 5 MPa).

As shown in FIG. 1, a pressure sensor 164 for detecting the internal pressure of the pressure chamber 126 is formed in the pressure chamber 126 or the preload pipe 162 (in this embodiment, the preload pipe 162). The output signal of the pressure sensor 164 is input to the motor controller 110 of the drive device 106. The motor controller 110 has a preset internal pressure of the pressure chamber 126 indicated by the output signal of the pressure sensor 164. The movement of the slide 104 using the servo motor 108 as a drive source is controlled so as to be a set withstand pressure (a value which varies depending on the machining process), as a result, a press applied to the slide 104 from the servo motor 108. The magnitude of the force is controlled.

3A-3D show the flow of the machining operation which the hot press molding apparatus 100 which has the structure mentioned above performs.

As shown to FIG. 3A, the workpiece 200 which is a thermoplastic resin plate before a process is set on the lower stamper 128 in the state in which the slide 104 is in an upper limit position. Thereafter, as shown in FIG. 3B, the slide 104 is lowered, and the sealed frame 144 is in contact with the lower holder 122. The vacuum chamber 170 is formed inside the sealing frame 144, and the slide 104 stops. By the vacuum pump not shown, the vacuum pulling of the vacuum chamber 170 is started, and the supply of a heating medium to the upper and lower heat exchange pipes 134 and 134 is started.

After that, as shown in FIG. 3C, when the temperature of the heat medium in the upper and lower pressure chambers 126, 126 rises to a predetermined set temperature, and the vacuum degree in the vacuum chamber 170 reaches the predetermined vacuum pressure, the slide The 104 starts to drop again, and the upper and lower stampers 128 and 128 press the workpiece 200 with the workpiece 200 interposed therebetween. As a result, the press force applied to the upper and lower cylinder mechanisms 112 and 114 from the slide 104 and the bolster 102 increases. In addition, when the slide 104 continues to descend, the upper and lower pistons 118 and 118 slide with respect to the upper and lower cylinders 120 and 120, thereby reducing the volume of each of the pressure chambers 126 and 126. The internal pressures of 126 and 126 rise higher than the bias pressure. For this reason, since the upper and lower flexible top plates 124 and 124 receive the high internal pressure of the pressure chambers 126 and 126 and try to swell outward, the outer surface of the upper and lower stampers 128 and 128 spreads over the whole area, It is pressurized at high and uniform pressure on both surfaces of the workpiece 200. The internal pressures of the pressure chambers 126 and 126 are detected by the respective pressure sensors 148 and 148, and the movement of the slide 104 is controlled so that each detected internal pressure becomes a set pressure (high pressure sufficient for hot press molding). Adjusted. During the predetermined set time, the upper and lower stampers 128 and 128 are pressed on both surfaces of the workpiece 200 at the set pressure.

Thereafter, as shown in FIG. 3D, the supply of the cooling fluid to the upper and lower heat exchange pipes 134 is started. Pressurization of the workpiece 200 by the stamper 128, 128 at the set pressure is continued until the temperature of the heat medium in the pressure chambers 126, 126 drops to a predetermined low temperature. Thereafter, the slide 104 is raised to return to the state of FIG. 3A and the molding is finished.

In this way, the stamper 128, 128 is pressed against the surface of the workpiece 200 by the internal pressure of the pressure chambers 126, 126 via the flexible top plates 128, 128, thereby processing the workpiece, the stamper, the mold. The stamper can be pressurized with a uniform pressure on the surface of the workpiece 200 without being affected by the dimensional accuracy of the workpiece. As a result, hot press molding can be performed by the minimum press force and heating temperature required, thereby reducing the installation cost and operating cost of the press forming apparatus, and shortening the production time.

Moreover, in the said embodiment, since the heat exchange member (heat exchange pipe, an electric heater, etc.) for heat-cooling a heat fluid is arrange | positioned in a pressure chamber, arrangement | positioning of a heat exchange member, switching of heating, and cooling are easy, and also a stamper is attached. The temperature deviation of the outer surface of the top plate becomes small.

In addition, in the above embodiment, since the pressure chamber is always in a state where bias pressure is applied, when the stamper is dropped from the workpiece after molding, the top plate and the stamper of the pressure chamber have a convex shape in which the center portion thereof is slightly inflated outward. For this reason, the workpiece is easily released from the stamper.

As mentioned above, although embodiment of this invention was described, the said embodiment is the illustration for description of this invention, and it does not intend to limit the scope of this invention only to the said embodiment. Therefore, this invention can be implemented also in aspects other than the said embodiment.

FIG. 1: is a figure which shows the whole structure of the heat press molding apparatus 100 which concerns on one Embodiment of this invention.

2 is an enlarged view of portions of two cylinder mechanisms 112 and 114.

3 is a diagram illustrating a flow of a machining operation performed by the hot press forming apparatus 100.

Explanation of the sign

100: heat press forming apparatus,

102: bolster

104: slide

106: drive unit

110: motor controller

112, 114: Cylinder mechanism

118: piston

120: cylinder

122: holder

124: top plate

126: pressure chamber

128: stamper

134: heat exchange pipe

148 temperature sensor

150: heating cooling fluid supply device

154: control unit

160: preload device

164: pressure sensor

200: workpiece

Claims (9)

In the heat press molding apparatus 100 for pressing the stamper 128 to transfer the shape pattern to the surface of the thermoplastic plate 200, A press device having a bolster 102, a slide 104, and a drive device 106 for driving the slide, Cylinder mechanisms 112 and 114 mounted on the slide or bolster, each having a cylinder 120 having a pressure chamber 126 filled with a heat fluid, the cylinder having a flexible top plate 124. The flexible top plate includes the cylinder mechanisms 112 and 114 having an inner surface in contact with the pressure chamber and an outer surface for supporting the stamper; A heating and cooling device for heating and cooling the heat medium in the pressure chamber; And a preloading device (160) for applying a bias pressure to said pressure chamber. The method of claim 1, And the cylinder mechanism is configured to increase the internal pressure of the pressure chamber when the press force applied from the press apparatus to the cylinder mechanism increases. The method of claim 2, And further having a piston 118 inserted in the cylinder mechanism to slide in the cylinder to vary the volume of the pressure chamber, the piston being connected to the slide or bolster and being applied to the piston from the slide or bolster. And a press force rises to slide in the cylinder so that the volume of the pressure chamber decreases. 4. The method according to any one of claims 1 to 3, And a heat-exchanging pipe (134) formed in the pressure chamber and a heat-cooling fluid supply device (150) for supplying heating fluid and cooling fluid into the heat-exchange pipe. 4. The method according to any one of claims 1 to 3, A heat press including the electric heater in which the heating and cooling device is formed in the pressure chamber, a heat exchange pipe formed in the pressure chamber, a heater power source for driving the electric heater, and a cooling fluid supply device for supplying a cooling fluid into the heat exchange pipe. Forming device. The method of claim 1, When the slide is raised to end the pressurization of the stamper against the thermoplastic plate by the preload device, the internal pressure of the pressure chamber causes the top plate to bulge outward and become convex. A hot press forming apparatus applied to the pressure chamber as a bias pressure. The method of claim 1, Further provided with a pressure sensor 164 for detecting the internal pressure of the pressure chamber, And the drive device controls the movement of the slide such that the internal pressure of the pressure chamber is a preset set pressure based on the detected pressure from the pressure sensor. The method of claim 1, Further provided with a temperature sensor 148 for detecting the temperature of the heat medium in the pressure chamber, And a control device for controlling the temperature of the heat medium in the pressure chamber to be a preset set temperature based on the detected temperature from the temperature sensor. In the mold system for the heat press forming apparatus for pressing the stamper to transfer the uneven pattern to the surface of the thermoplastic plate, A cylinder mechanism mounted on a slide or bolster of the heat press device, comprising: a cylinder having an inner pressure chamber filled with a heat fluid, the cylinder having a flexible top plate, The flexible top plate includes: the cylinder mechanism having an inner surface in contact with the pressure chamber and an outer surface for supporting the stamper; A heating and cooling device for heating and cooling the heat medium in the pressure chamber; And a preloading device for applying a bias pressure to the pressure chamber.

Images