JP2010089327A - Molding device and method of manufacturing molding using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a molding device capable of manufacturing a molding of high quality. <P>SOLUTION: Cooling pipes 50 and 70 are arranged in the center in the thickness direction of a cavity mold 45 of an upper mold 41 and a cavity mold 65 of a lower mold 61 respectively. Heaters 51 and 71 for heating the molds are mounted on object surfaces 48 and 68 of the cooling pipes 50 and 70 and on the opposite object surfaces of the same respectively. The cooling pipes 50 and 70 and the heaters 51 and 71 for heating the molds are mounted in the cavity molds 45 and 65 symmetrically respectively in the direction parallel to the object surfaces 48 and 68 and in the direction vertical to the object surfaces 48 and 68. It is possible to prevent warps of the cavity molds 45 and 65 even when the temperatures of the cavity molds 45 and 65 are increased or decreased. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a mold apparatus and a method of manufacturing a molded body using the mold apparatus, and more particularly, a mold for manufacturing a molded body by press molding or the like by pressing a pair of opposing molds together. The present invention relates to an apparatus and method for obtaining a body.

Currently, a resin molded body having an ultra-fine concavo-convex shape of several tens of nm to several hundred μm on the surface and a three-dimensional, thin, and large-area shape is an optical component for an electronic display such as a microlens array. There is a demand for optical information communication components such as multimode optical waveguides.
In the resin molding technique disclosed in Patent Document 1, the resin is directly applied to fine irregularities in a molten state with a short relaxation time of residual stress, thereby forming a shape close to the final shape, and then during pressure forming (At this point, the resin temperature has dropped to the mold temperature.) By keeping the corners of the fine irregularities at the minimum pressure that can be filled with resin to prevent excessive filling, optical information communication This is a method of obtaining a resin-made ultrafine structure molding having low residual stress, low birefringence, high light transmittance, and excellent mechanical strength required for parts and the like.

  However, if the mold is thermally deformed at the time of resin coating or pressurizing with an approximately molded body shape, deformation or residual stress occurs in the molded product, which is a problem. Also, in this method, the mold temperature is cooled to below the temperature at which the mold temperature can be taken out from the melting temperature of the resin (flow stop temperature, glass transition temperature, crystallization temperature, etc.), so the residual stress is reduced during molding. However, if there is a difference in the cooling time inside the molded body during cooling, thermal stress is generated, and an external force exceeding the relaxation limit at that temperature was applied due to temporary thermal deformation of the mold. In some cases, residual stress is generated, and residual stress and distortion due to these remain in the molded body at the completion of the molding process.

  FIG. 5 shows the configuration of this type of conventional mold apparatus disclosed in Patent Document 2. In FIG. The mold apparatus includes an upper mold 11 and a lower mold 21, and the upper mold 11 is attached to the main mold 13 fixed to the mold mounting plate 12 and to the main mold 13 via a heat insulating plate 14. The cavity mold 15 is provided. Similarly, the lower mold 21 has a main mold 23 fixed to the mold attachment plate 22 and a cavity mold 25 attached to the main mold 23 via a heat insulating plate 24.

Opposite surfaces of both cavity molds 15 and 25 constitute a target surface from which a molded body is obtained, and these cavity molds 15 and 25 are respectively provided with heaters 16 and 26 for heating the mold on the target surface side, and on the opposite target surface side. The cooling pipes 17 and 27 are arranged on the side. On the other hand, both main molds 13 and 23 are provided with cooling pipes 18 and 28, respectively.
A mirror finish is applied to the target surface of the upper mold 11, and a stamper 30 having fine irregularities is disposed on the target surface of the lower mold 21. The stamper 30 is sucked and fixed through a suction groove 31 formed in the cavity mold 25, and a stamper presser 32 for mechanical fixing is disposed around the stamper 30.

As shown in FIG. 6, both cavity molds 15 and 25 are respectively provided by a plurality of support bolts 19 and 29 penetrating from the corresponding mold mounting plates 12 and 22 through the main molds 13 and 23 and the heat insulating plates 14 and 24. It is fixed. By these support bolts 19 and 29, the upper mold 11 and the lower mold 21 are each in the form of an integral structure.
The cavity mold 25 of the lower mold 21 is provided with a vacuum suction circuit 33 communicating with the suction groove 31.

JP 2007-76178 A JP 2007-30432 A

  In such a conventional mold apparatus, when the temperature of the cavity molds 15 and 25 is raised by energizing the heaters 16 and 26 for heating the molds, as shown in FIG. The thermal expansion of the cavity molds 15 and 25 is constrained in the vicinity of the heat insulating plates 14 and 24 due to the presence, while the expansion due to the thermal expansion of the cavity molds 15 and 25 is performed on the target surface side where the heaters 16 and 26 for mold heating are located. Will occur. As a result, the upper and lower cavity molds 15 and 25 are deformed into a convex shape. That is, the target surfaces of the cavity molds 15 and 25 are warped and the convex shapes are opposed to each other. When the upper mold 11 and the lower mold 21 are put together in this state, as shown in FIG. 8, only the central portion A of the target surface comes into contact, non-uniform pressure distribution occurs, and pressurization of the outer peripheral portion is performed. Becomes incomplete.

  The cavity molds 15 and 25 are generally made of a stainless steel material in consideration of corrosion resistance and the like, but the stainless steel material has a relatively low thermal conductivity, and the heat generated by the heaters 16 and 26 for heating the molds. Is difficult to propagate quickly and uniformly throughout the cavity molds 15 and 25 and forms a non-uniform temperature distribution. As a result, the deformation phenomenon of the cavity molds 15 and 25 is increasingly increased.

  Further, when energization to the heaters 16 and 26 for mold heating is stopped and water is passed through the cooling pipes 17 and 27 in the cavity molds 15 and 25, as shown in FIG. 9, support bolts 19 and 29 are present. The thermal expansion of the cavity molds 15 and 25 is restricted on the heat insulating plates 14 and 24 side, and shrinkage due to thermal contraction occurs in the vicinity of the cooling pipes 17 and 27. At this time, on the target surface side where the heaters 16 and 26 for mold heating are present, the elongation due to heat at the time of heating still remains, and the cavity molds 15 and 25 are made of stainless steel materials having poor heat conduction. Thus, there is a difference in thermal deformation (elongation and shrinkage) between the opposite surface side and the upper surface side. As a result, the cavity molds 15 and 25 are deformed into a convex shape. That is, the target surfaces of the cavity molds 15 and 25 warp and the convex shapes are opposed to each other. As a result, as shown in FIG. 10, only the central portion B of the target surface comes into contact, and non-uniform pressure distribution occurs.

  Moreover, since rapid cooling is applied to the cavity molds 15 and 25 by passing water through the cooling pipes 17 and 27, the thermal deformation (elongation and contraction) that occurs between the anti-target surface side and the target surface side, There is a greater difference than during heating. As a result, the opposing convex shapes are deformed more greatly. Since the molded body is constrained to the mold by the fine irregularities, if the shape changes such that the mold further warps, it will stretch macroscopically inside the molded body and locally the bottom of the fine irregularities. Stress due to compressive deformation or shear deformation. In addition, since the contact thermal resistance between the cavity mold and the molded body is affected by the pressure on each part of the molded body surface, if the cavity mold is further warped and the pressure distribution becomes more uneven, , There is a difference in the time to reach the glass transition temperature. If it does so, the part which has not yet cooled to the glass transition temperature will be extended | stretched by the thermal contraction of the part cooled previously. Further, when the heat conduction of the cavity mold itself is insufficient, a temperature distribution corresponding to the arrangement of the cooling pipe is generated, and the same problem occurs. Since the relaxation time of the resin has already become longer due to the temperature drop, it is difficult to remove the strain generated at this point in the subsequent process.

As for the crystalline resin, if the cooling rate when passing through the crystallization temperature varies in each part of the molded body, the degree of crystallinity will be different, resulting in a difference in shrinkage rate, warping of the molded body, Causes undulation deformation.
Furthermore, the adhesive force between the molded body and the mold surface is governed by the temperature of both, and if there is a variation in temperature within these planes, the mold will be released smoothly due to uneven adhesion. become unable.

The present invention has been made to solve such problems, and an object thereof is to provide a mold apparatus capable of obtaining a high-quality molded article.
Another object of the present invention is to provide a method for producing a molded body using such a mold apparatus.

  A mold apparatus according to the present invention manufactures a molded body by arranging a pair of molds each having a target surface for obtaining a molded body facing each other and pressurizing each other, and at least one of the molds is a target. A mold comprising an object surface constituting member for forming an object surface, a cavity mold for holding the object surface constituting member and having both a heating means and a cooling means, and a main mold for holding the cavity mold from the surface side. In the apparatus, the heating means and the cooling means are arranged symmetrically with respect to the cavity mold both in the in-plane direction parallel to the target surface and in the direction perpendicular to the target surface.

Preferably, a support rod for fastening and holding the cavity mold to the main mold at approximately one central portion in a plane parallel to the target surface, and a pressing jig for pressing the peripheral edge of the cavity mold against the main mold are provided. Yes.
Furthermore, it is preferable to provide a fixture for preventing the support bar from falling off the main mold without restricting thermal deformation of the support bar.
At this time, the support bar extends in a direction perpendicular to the target surface, one end is screwed to the cavity mold, and has a tapered portion formed at the other end, and the fixture extends in a direction parallel to the target surface. In addition, a taper portion formed at the tip portion can be provided, and the taper portion of the support bar and the taper portion of the fixture can be configured to engage with each other.

Moreover, it is preferable that the holding jig has an elastic body that comes into contact with the peripheral edge of the cavity mold in order to hold the cavity mold without restraining thermal deformation of the cavity mold.
As the cavity-type constituent material, a material having better thermal conductivity than a conventionally used stainless steel material (thermal conductivity: about 20 W / m · K) is used. The range of thermal conductivity of the desired material is at least 70 W / m · K or more, preferably 100 W / m · K or more, taking into account other characteristics such as rigidity and specific heat, such as beryllium copper alloy Be a candidate.
Furthermore, it is preferable to provide a heat insulating plate sandwiched between the cavity mold and the main mold.
As the target surface constituent member, a stamper having a target surface on which fine irregularities are formed or a flat plate having a flat target surface can be used.

  The method for producing a molded body according to the present invention includes a step of increasing the temperature of the cavity mold by a heating means using the mold apparatus as described above, and a step of obtaining a molded body by pressurizing a pair of molds to each other. The method includes a step of lowering the temperature of the cavity mold by the cooling means and a step of taking out the obtained molded body from the mold apparatus.

  According to this invention, the heating means and the cooling means are arranged symmetrically with respect to the cavity mold both in the in-plane direction parallel to the target surface and in the direction perpendicular to the target surface. Also, the occurrence of warpage of the cavity mold is prevented, and a high-quality molded product can be obtained.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
FIG. 1 shows a configuration of a mold apparatus according to the embodiment. The mold apparatus includes an upper mold 41 and a lower mold 61. The upper mold 41 is detachably held by a main mold 43 fixed to the mold mounting plate 42, a cavity mold 45 attached to the main mold 43 via a heat insulating plate 44, and a pressing member 46 on the cavity mold 45. And a flat plate 47. The flat plate 47 has a trapezoidal cross section, and a flat target surface 48 for obtaining a molded body is formed on the short side. The flat plate 47 is sucked and fixed through a suction groove 49 formed in the cavity mold 45, and the target surface 48 is mirror-finished.

  Similarly, the lower die 61 is held by a main die 63 fixed to the die attaching plate 62, a cavity die 65 attached to the main die 63 via a heat insulating plate 64, and a holding member 66 on the cavity die 65. A target surface 68 for obtaining a molded body is formed on the stamper 67. The stamper 67 is sucked and fixed through a suction groove 69 formed in the cavity mold 65, and fine unevenness for transferring a fine shape to the molded body is formed on the target surface 68.

  Both the cavity molds 45 and 65 are provided with cooling pipes 50 and 70 constituting cooling means at the center in the thickness direction, respectively, and the target surface side and the anti-target surface of the cooling pipes 50 and 70 are disposed. On both sides, heaters 51 and 71 for mold heating that constitute heating means are disposed. The cooling pipes 50 and 70 and the mold heaters 51 and 71 are in the in-plane direction parallel to the target surfaces 48 and 68 with respect to the cavity molds 45 and 65, respectively, and in the direction perpendicular to the target surfaces 48 and 68. That is, they are also arranged symmetrically in the thickness direction.

On the other hand, both main molds 43 and 63 are provided with cooling pipes 52 and 72, respectively.
Furthermore, holding jigs 53 and 73 extending to the sides of the cavity molds 45 and 65 are attached to the mold mounting plates 42 and 62, respectively. The peripheral portions of the cavity molds 45 and 65 are pressed against the main molds 43 and 63 through the elastic bodies 54 and 74.

As shown in FIG. 2, one end portions of the support rods 55 and 75 are screwed to one place in a substantially central portion in the surface of the cavity molds 45 and 65 on the heat insulating plates 44 and 64 side. The support rods 55 and 75 extend in a direction perpendicular to the target surfaces 48 and 68 and pass through the main molds 43 and 63, and the other ends engage with grooves formed in the mold mounting plates 42 and 62. Concave taper portions 56 and 76 are formed at the other end.
Also, fixtures 57 and 77 are inserted into the grooves formed in the mold attachment plates 42 and 62 from the side, and convex taper portions 58 and 78 formed at the tip portions of the fixtures 57 and 77 are support rods. Thus, the support rods 55 and 75 are prevented from falling off from the main molds 43 and 63 without restricting the thermal deformation of the support rods 55 and 75.
With such a configuration, the cavity molds 45 and 65 are held and fixed at a substantially central point, and are released from thermal deformation restraint by the pressing jigs 53 and 73 and the elastic bodies 54 and 74.

The cavity molds 45 and 65 are provided with vacuum suction circuits 59 and 79 communicating with the suction grooves 49 and 69.
Note that the cavity molds 45 and 65 are made of a good thermal conductive material having excellent thermal conductivity, for example, beryllium copper.
The mold mounting plates 42 and 62 are for mounting the upper mold 41 and the lower mold 61 on a mold mounting board of a press apparatus (not shown), and cooling pipes 52 and 72 disposed on the main molds 43 and 63. Is for reducing heat conduction to the mold mounting plate of the press apparatus.

Next, a method for producing a molded body using the mold apparatus according to this embodiment will be described.
First, the mold heating heaters 51 and 71 are energized to increase the temperature of the cavity molds 45 and 65, for example, a molten resin is applied onto the stamper 67, and the upper mold 41 and the lower mold 61 are pressurized together. To obtain a molded body. Thereafter, water is passed through the cooling pipes 50 and 70 to lower the temperatures of the cavity molds 45 and 65, and the obtained molded body is taken out from the mold apparatus.

  Here, when the heaters 51 and 71 for mold heating are energized to raise the temperature of the cavity molds 45 and 65, as shown in FIG. Due to the fixing method of 65, no force is generated to restrain the thermal expansion of the cavity molds 45 and 65. In addition, the mold heating heaters 51 and 71 and the cooling pipes 50 and 70 disposed in the cavity molds 45 and 65 are similar in symmetry to the in-plane direction and the thickness direction of the cavity molds 45 and 65, respectively. Warping of the cavity molds 45 and 65 is prevented by having the mold arrangement form. That is, by adopting a similar piping configuration, the expansion due to the thermal expansion of the cavity molds 45 and 65 occurs uniformly in the cavity molds 45 and 65, and as a result, warpage of the cavity molds 45 and 65 occurs. Occurrence is prevented. In this state, when the upper mold 41 and the lower mold 61 are aligned with each other, the entire target surfaces 48 and 68 are in uniform contact, and a uniform pressure distribution can be obtained.

In addition, since the cavity molds 45 and 65 are made of a material having excellent thermal conductivity, for example, beryllium copper, the heat generated by the heaters 51 and 71 for the mold heating is quickly transmitted to the entire cavity molds 45 and 65. And it is easy to transmit uniformly and uniform temperature distribution is achieved. As a result, the possibility that the cavity molds 45 and 65 are warped is further reduced.
Here, Table 1 and FIG. 11 show the analysis conditions and results simulating the warpage that occurs when heating the molds of the conventional structure (Comparative Examples 1 and 2) and the molds of the present invention (Examples) of different materials. .

  It has already been described that the warpage is reduced if the thermal conductivity of the material is improved. However, when compared with the same conventional structure, the warp displacement difference in the analysis range of 150 mm is the same as that of Comparative Example 1 in which the thermal conductivity is poor. The comparative example 2 of the material having a thermal conductivity of 5 times or more compared to 5 μm was about half of 2.5 μm. On the other hand, when the mold structure of the present invention is used, it can be seen that the displacement difference is drastically reduced to 1/5 compared with Comparative Example 2 which is the same material as 0.5 μm. From this simulation result, it was confirmed that it is possible to suppress the displacement difference to be extremely small by using the structure of the present invention in addition to using the high thermal conductive material.

  When energization of the heaters 51 and 71 for mold heating is stopped and water is passed through the cooling pipes 50 and 70 in the cavity molds 45 and 65, the heater 51 for mold heating disposed in the cavity molds 45 and 65 is used. And 71 and the cooling pipes 50 and 70 have a similar arrangement form symmetrical in the in-plane direction and thickness direction of the cavity molds 45 and 65, respectively, and the cavity molds 45 and 65 have excellent thermal conductivity. As shown in FIG. 4, the cavity molds 45 and 65 contract between the object surface side and the anti-target surface side sandwiching the cooling pipes 50 and 70 inside the cavity molds 45 and 65. The shrinkage due to is generated uniformly and in a balanced manner, and as a result, warpage in the cavity molds 45 and 65 is prevented. Thereby, the whole object surface 48 and 68 contacts uniformly, and uniform pressure distribution can be obtained.

  Here, FIG. 12 shows temperature profiles in the mold surface in the example and the comparative example 1. As shown in FIG. 13, on the surface (approximately 160 mm square) in contact with the flat plate 47 of the cavity mold 45 (or 15), there are a total of nine points of the four corners and the center of the 100 mm square in the center, and the midpoint of each side. The temperature was measured by installing a thermocouple. In Comparative Example 1, the temperature change at each point during cooling varies, but in the example of the present invention, a profile in which each measurement point substantially matches even during cooling is drawn. Comparing both at the time of passing 90 ° C., it can be seen that the temperature difference, time difference, and cooling rate difference are all improved by the implementation of the present invention, and uniform cooling is obtained.

  In addition, rotation by supporting only one central point is achieved by pressing the peripheral edges of the cavity dies 45 and 65 against the main dies 43 and 63 by the holding jigs 53 and 73 arranged on the sides of the cavity dies 45 and 65. Unstable support, such as the fear of Further, since the elastic bodies 54 and 74 are arranged at the contact portions between the holding jigs 53 and 73 and the cavity molds 45 and 65 so as not to completely restrain the cavity molds 45 and 65, the cavity molds 45 and 65 are disposed. The occurrence of warping is avoided.

Further, since the flat plate 47 forming the target surface 48 of the upper die 41 is detachably held by the cavity mold 45 by the pressing member 46, only the flat plate 47 is replaced even when the target surface 48 is damaged. This eliminates the risk of long-term interruption of the molding operation due to damage to the target surface.
Further, the flat plate 47 has a trapezoidal cross section, and since the target surface 48 from which the molded body is obtained is formed on the short side and has a tapered shape, the molded body is flat plate by heat shrinkage at the time of mold release. It is avoided that it becomes difficult to release the mold because it hugs 47, and it is possible to secure a good release condition.

  In the above embodiment, each of the upper mold 41 and the lower mold 61 is a cavity mold that includes both the flat plate 47 and the stamper 67 and both the heating means and the cooling means from the target surfaces 48 and 68 side. 45 and 65, the heat insulating plates 44 and 64, and the main molds 43 and 63. However, the present invention is not limited to this, and at least one of the upper mold 41 and the lower mold 61 is like this. The present invention can be applied to a mold apparatus having such a configuration.

It is sectional drawing which shows the structure of the metal mold | die apparatus which concerns on embodiment of this invention. It is other sectional drawing which shows the metal mold | die apparatus which concerns on embodiment. It is sectional drawing which shows the mode at the time of the heating of the metal mold | die apparatus which concerns on embodiment. It is sectional drawing which shows the mode at the time of cooling of the metal mold | die apparatus which concerns on embodiment. It is sectional drawing which shows the structure of the conventional metal mold apparatus. It is other sectional drawing which shows the conventional metal mold apparatus. It is sectional drawing which shows the mode at the time of the heating of the conventional metal mold apparatus. It is a figure which shows the mode of the target surface at the time of the heating of the conventional metal mold apparatus. It is sectional drawing which shows the mode at the time of cooling of the conventional metal mold apparatus. It is a figure which shows the mode of the target surface at the time of cooling of the conventional metal mold apparatus. It is a graph which shows the result of having simulated the curvature which generate | occur | produces at the time of the metal mold | die of this invention, and the metal mold | die of a conventional structure. 4 is a graph showing temperature profiles in the mold surface in Examples and Comparative Example 1; It is a figure which shows the measurement position of the temperature profile of FIG.

Explanation of symbols

  41 Upper mold, 42, 62 mold mounting plate, 43, 63 main mold, 44, 64 heat insulation plate, 45, 65 cavity mold, 46, 66 holding member, 47 flat plate, 48, 68 target surface, 49, 69 adsorption Groove, 50, 52, 70, 72 Cooling pipe, 51, 71 Heater for mold heating, 53, 73 Holding jig, 54, 74 Elastic body, 55, 75 Support rod, 56, 58, 76, 78 Taper Part, 57,77 fixture, 59.79 vacuum suction circuit. 61 Lower mold, 67 stamper.

Claims (10)

A pair of molds each having a target surface for obtaining a molded body are placed opposite to each other and pressed together to produce a molded body,
At least one mold includes, from the target surface side, a target surface constituent member that forms the target surface, a cavity mold that holds the target surface constituent member and includes both heating means and cooling means, and the cavity In a mold apparatus having a main mold for holding a mold,
The mold apparatus, wherein the heating means and the cooling means are arranged symmetrically with respect to the cavity mold both in an in-plane direction parallel to the target surface and in a direction perpendicular to the target surface. A support rod that fastens and holds the cavity mold to the main mold at one location in a substantially central portion in a plane parallel to the target surface;
The mold apparatus according to claim 1, further comprising: a pressing jig that presses a peripheral edge of the cavity mold against the main mold.   The mold apparatus according to claim 2, further comprising: a fixture for preventing the support bar from falling off the main mold without restraining thermal deformation of the support bar. The support bar extends in a direction perpendicular to the target surface and has one end screwed to the cavity mold and a tapered portion formed at the other end.
The fixture has a tapered portion that extends in a direction parallel to the target surface and is formed at a tip portion.
The mold apparatus according to claim 3, wherein the taper portion of the support bar and the taper portion of the fixture are fitted to each other.   The said pressing jig has an elastic body which contact | abuts to the peripheral part of the said cavity type | mold in order to hold | suppress the said cavity type | mold, without restraining the thermal deformation of the said cavity type | mold. Mold equipment.   The mold apparatus according to claim 1, wherein the cavity mold is made of a good heat conductive material.   The mold apparatus according to claim 6, wherein the cavity mold is made of beryllium copper.   The mold apparatus according to claim 1, further comprising a heat insulating plate sandwiched between the cavity mold and the main mold.   The mold apparatus according to any one of claims 1 to 8, wherein the target surface constituent member includes a stamper having a target surface on which fine irregularities are formed, or a flat plate having a flat target surface. A method for producing a molded body using the mold apparatus according to any one of claims 1 to 9,
Increasing the temperature of the cavity mold by the heating means;
Obtaining a molded body by pressing the pair of molds together;
Lowering the temperature of the cavity mold by the cooling means;
And a step of taking out the obtained molded body from the mold apparatus.

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