JP5286471B2 - Transfer mold manufacturing method - Google Patents

Description

The present invention relates to a transfer mold manufacturing method for manufacturing a mold used for molding small articles such as a small resin lens and a small glass lens and for semiconductor encapsulation.

Currently, in many electronic devices and digital home appliances as represented by mobile phones, the direction of development is suitable for high functionality, high accuracy, and miniaturization. And if these products are highly accurate and miniaturized, it is necessary to increase the precision, miniaturization, and miniaturization of the components constituting them. On the other hand, in the production of mass-produced parts, molds are generally used, and if the parts are highly accurate, downsized, and miniaturized, the molds are also required to be highly accurate, downsized, and miniaturized. In the manufacture of molds, it is required to meet the demands for high precision, miniaturization, and miniaturization while satisfying stabilization of quality, price reduction, and shortening of delivery time.

Here, when mass producing miniaturized and miniaturized parts, a plurality of molds capable of producing several tens to several hundreds of parts simultaneously are used. For this reason, in the case of manufacturing a plurality of molds, a skilled worker manually polishes a plurality of inverted parts using a machine tool (for example, a machining center) in one block made of mold material. Finishing processing is performed. For this reason, if the reversal shape of the part is miniaturized and miniaturized, the shape accuracy of the reversal shape is lowered due to restrictions on the tool shape, and further, there arises a problem of shape error and variation in shape in finishing. When a shape error or shape variation occurs, there arises a problem that the mold quality cannot be stabilized and the delivery time cannot be shortened. Therefore, by accurately producing one prototype with the part shape to be manufactured, pressing this prototype from above and below with a block made of superplastic metal, and transferring the shape of the prototype to the block, mold quality Discloses a method of manufacturing a stable mold (with no shape error and shape variation) with a short delivery time (see, for example, Patent Documents 1 and 2).

JP 52-7326 A Japanese Utility Model Publication No. 49-101023

However, in the inventions described in Patent Documents 1 and 2, in order to produce a split mold in which the inverted shape is transferred by sandwiching the original mold from both sides with a block made of a superplastic metal material, Positioning is very difficult, and it becomes difficult to manufacture a plurality of molds with stable quality by preventing shape error and shape variation. In addition, since the block is heated at a high temperature, the block surface is oxidized, and there is a problem that the surface properties of the mold vary. Furthermore, since superplastic metal is used, the characteristics of the mold are affected by the characteristics of the superplastic metal, and the usage is limited compared to conventional molds, and the life is likely to fluctuate. There is also a problem.

The present invention has been made in view of such circumstances, and a plurality of transfer molds having a stable quality by preventing a shape error and a shape variation even when a product is highly accurate, miniaturized, and miniaturized can be manufactured at low cost and with a short delivery time. An object of the present invention is to provide a method for producing a transfer mold that can be produced by the above method.

The transfer mold manufacturing method according to the first invention that meets the above object has the same shape as a product having releasability using a material that exhibits high strength, high hardness, and hardly deformability at a high temperature exceeding 1200 ° C. A first step of producing a master mold having a prototype formed on a flat plate;
A block having a predetermined shape made of a mold material exhibiting softening properties at high temperature is placed in a heating furnace so as to face the master mold, and the metal material is placed in a vacuum or in an inert gas atmosphere at 900 ° C. or more and 1200 ° C. A second step of heating to the following temperature range and pressing the master mold and the blocks to transfer the inverted shape of the master mold to the block;
The block to which the inverted shape of the master mold is transferred is cooled and released from the master mold, and the reference height position of the inverted shape portion of the flat plate of the master mold formed on the block is the surface of the mold base. And a third step of forming a transfer mold by fixing the block to the mold base so as to coincide with the height position of the mold.

In the transfer mold manufacturing method according to the first invention, a plurality of attachment portions can be formed on the mold base, and the blocks on which the inverted shape of the master mold is transferred can be fixed to the attachment portions.

In the transfer mold manufacturing method according to the first invention, the block is inserted into a recess formed in a holding member made of a high temperature material exhibiting high strength, high hardness, and hardly deformability at high temperature, It is preferable that only the surface facing the master mold is exposed from the holding member.
Here, the holding member is formed with a space communicating with the concave portion that can accommodate the mold material that is excluded when the inverted shape of the master mold is transferred to the block. preferable.

In the transfer mold manufacturing method according to the first aspect of the present invention, it is preferable that a rough reversal shape smaller than the reversal shape of the master mold is formed in advance on the side of the block facing the master mold.

In the transfer mold manufacturing method according to the first aspect of the present invention, an inert gas is supplied into the heating furnace to adjust the cooling rate of the block on which the inverted shape of the master mold is transferred and to heat-treat the block. Is preferred.

The transfer mold according to the second invention that meets the above object is manufactured by the transfer mold manufacturing method according to the first invention.

In the transfer mold manufacturing method according to any one of claims 1 to 6, since the master mold in which the original mold having the same shape as the product is formed on the flat plate is used, the master flat plate and the inverted shape of the original mold are simultaneously formed on the block. By fixing the block to the mold base with the inverted shape portion of the flat plate as a reference, the block can be accurately positioned, and a highly accurate transfer mold can be manufactured at a low cost and with a short delivery time.
Further, since the heating is performed in a vacuum or in an inert gas atmosphere, it is possible to prevent the block from being oxidized and to manufacture a transfer mold having excellent surface properties.

In particular, in the transfer mold manufacturing method according to claim 2, when fixing a plurality of blocks to the mold base, each block can be positioned accurately and easily, and there is no shape error and shape variation, and the same. It is possible to manufacture a multi-cavity transfer mold that can form a product with surface properties at a low cost and with a short delivery time.

In the transfer mold manufacturing method according to claim 3, since the outer shape of the holding member does not change even when the master die and the block are pressed, the block can be easily fixed to the mold base via the holding member. .
In the transfer mold manufacturing method according to claim 4, when the inverted shape of the master mold is transferred to the block, the block is inserted into the concave portion of the holding member and the exposed surface is pressed by the master mold to be in a sealed state. Since the holding member is formed with a space portion having a volume corresponding to the volume of the mold material to be removed when the inverted shape of the master mold is transferred to the block, the inverted shape of the master mold is formed. The mold material that is excluded when transferring to the block can enter the space, and the inverted shape of the master mold can be reliably transferred to the block.
In the transfer mold manufacturing method according to the fifth aspect, since the master mold is roughly inverted in shape in advance in the block, the master mold inversion can be quickly transferred to the block.

In the transfer mold manufacturing method according to claim 6 , by supplying an inert gas into the heating furnace, a heat transfer (quenching) of the block on which the inverted shape of the master mold is transferred can be performed. The mold surface hardness can be increased to extend the life of the transfer mold.

Next, embodiments of the present invention will be described with reference to the accompanying drawings for understanding of the present invention.
Here, FIGS. 1A, 1B, and 1C are explanatory diagrams of a transfer mold manufacturing method according to the first embodiment of the present invention, and FIG. 2 is a block master in the transfer mold manufacturing method. FIG. 3 is an explanatory diagram of a block according to a modification, and FIG. 4 is an explanatory diagram of a block used in a transfer mold manufacturing method according to the second embodiment of the present invention. is there.

As shown in FIGS. 1 (A), (B), and (C), the transfer mold manufacturing method according to the first embodiment of the present invention has high strength, high hardness, and difficulty at a high temperature exceeding 1200 ° C. A first step of producing a master mold 12 in which a prototype 10 having the same shape as a product having releasability is formed on a circular flat plate 11 in plan view, using a deformable material, A predetermined shape made of a mold material, for example, a cylindrical block 13 having the same diameter as the flat plate 11 in plan view is disposed in the heating furnace so as to face the master mold 12, and the mold material exhibits softening properties. Heating to a temperature range of 900 ° C. or more and 1200 ° C. or less, pressing the master mold 12 and the block 13 together to transfer the inverted shape of the master mold 12 to the block 13, and the inverted shape of the master mold 12 are transferred. The master block 12 is cooled Demolded, and a third step of forming a transfer mold 15 is fixed to the mold base 14. In addition, in the master mold | type 12, a dent does not exist in the side part. Details will be described below.

As a material that exhibits high strength, high hardness, and hardly deformability at a high temperature exceeding 1200 ° C. used for manufacturing the master mold 12, for example, zirconia having a bending strength at 1000 ° C. of 300 MPa or more and a Vickers hardness of 1300 or more ( An example of ceramic) can be used. The master mold 12 is manufactured by attaching a diamond tool 17 to a machining center 16 which is an example of a machine tool and wet processing a zirconia block. In addition to zirconia, high-temperature structural ceramics such as alumina, silicon nitride, and silicon carbide, refractory metals such as tungsten and molybdenum, cermet, and the like can be used as materials used when manufacturing the master mold 12. .

As a material constituting the block 13 having a predetermined shape, a mold material that exhibits softening properties at a high temperature, such as martensitic stainless steel, can be used. And as shown in FIG. 2, the block 13 is arrange | positioned in a heating furnace with the one surface side facing the master type | mold 12, and the inside of a heating furnace is evacuated and heated. Here, the master die 12 is a hearth member 19 of a heating furnace via a support base 18 made of a material exhibiting high strength, high hardness, and hardly deformability at high temperatures, for example, alumina which is an example of ceramics. It is placed on top. On the other side of the block 13, a cylindrical pressure member 20 made of a material exhibiting high strength, high hardness, and hardly deformability at high temperatures, for example, alumina, which is an example of ceramics, is disposed. Yes. The master mold 12, the block 13, and the front side of the pressure member 20 are made of a material that exhibits high strength, high hardness, and hardly deformability at high temperatures, for example, high temperature structural ceramics such as alumina, silicon nitride, silicon carbide, etc. The inner diameter of the flat plate 11 is the same as the diameter of the flat plate 11 and is housed in a cylindrical housing member 21 placed on the support base 18. The pressure member 20 is connected to a piston of a pressure device provided outside the heating furnace via a load transmission member (not shown), and the hearth member 19 is a frame of the pressure device via a load support member (not shown). It is supported by.

With the above-described configuration, the master mold 12 and the block 13 are heated to a softening temperature range of 900 ° C. or higher and 1200 ° C. or lower where the block 13 exhibits remarkable softening properties, and the pressure member 20 is supported on the support base 18. When moving toward, the master mold 12 and the blocks 13 are pressed. At this time, the master mold 12, the pressure member 20, and the storage member 21 are not deformed, and only the block 13 is deformed. Since the block 13 is pressurized and deformed in a state surrounded by the master mold 12, the pressure member 20, and the storage member 21, the block 13 is deformed so that one surface side of the block 13 is in close contact with the surface of the master mold 12. The inverted shape of the master mold 12 is transferred to one surface side of the block 13. Here, the pressing between the master mold 12 and the block 13 applies a load of, for example, 80 to 180 kg between the master mold 12 and the block 13 and transfers the inverted shape of the master mold 12 to the block 13.

After transferring the inverted shape of the master mold 12 to the surface of the block 13, the cooling of the block 13 is started. The cooling of the block 13 is performed by, for example, stopping heating of the heating furnace and discharging while supplying an inert gas having a low temperature, for example, nitrogen gas at room temperature, into the heating furnace. Thereby, the heat treatment (quenching) by rapid cooling of the block 13 to which the inverted shape of the master mold 12 is transferred can be performed, and the hardness of the block 13 can be improved. In the supply of nitrogen gas into the heating furnace, the nitrogen gas supply amount and the discharge amount are adjusted so that the average temperature drop rate is, for example, 10 to 30 ° C./second. When the cooling of the block 13 is completed, the block 13 is released from the master mold 12 taken out from the heating furnace, and the reference height of the inverted shape portion (flat surface) of the flat plate 11 of the master mold 12 formed in the block 13 is released. The blocks 13 are respectively fixed to the mounting portions 22 formed in the mold base 14 so that the positions coincide with the height positions of the surface of the mold base 14.

Since the inverted shape of the flat plate 11 of the master mold 12 and the original mold 10 is formed in the block 13, if the block 13 is fixed to the mold base 14 with the flat surface of the block 13 as a reference, the height of the surface of the mold base 14 is increased. The height position of the inverted shape portion of the flat plate 11 formed on the block 13 coincides with the vertical position so that the block 13 can be positioned accurately. For this reason, when the plurality of blocks 13 to which the inverted shapes having the same shape, dimensions, and surface properties of the prototype 10 are transferred are fixed to the mold base 14 while being positioned so that their height positions are the same, It is possible to easily manufacture a high-quality multi-piece transfer mold 15 that is free from errors, variations in shape, and variations in surface properties.

As shown in FIG. 3, in the block 23 arranged in the heating furnace so as to face the master mold 12, a roughly inverted shape 23 a of the master mold 12 is previously formed on one surface side of the block 23 facing the master mold 12. ing. By forming the generally inverted shape 23a, the amount of softening deformation in the block 23 when the inverted shape of the master die 12 is formed can be reduced, and the inverted shape of the master die 12 can be quickly transferred to the block 23. Can do. Furthermore, the amount of processing around the block 23 required when the block 23 formed with the inverted shape of the master mold 12 is mounted in the mold base 14 can be reduced.

As shown in FIG. 4, the transfer mold manufacturing method according to the second embodiment of the present invention is different from the transfer mold manufacturing method according to the first embodiment of the present invention. A block 24 in which an inverted shape is formed is formed on a holding member 25 made of a high-temperature material that exhibits high strength, high hardness, and hardly deformability at high temperatures, exposing only the surface facing the master mold 12. The contents of each step in the transfer mold manufacturing method according to the second embodiment are the same as those of the transfer mold manufacturing method according to the first embodiment. The content of the process is the same. Therefore, only the block 24 inserted into the recess 26 of the holding member 25 will be described.

As a material constituting the block 24, a mold material showing softening properties at a high temperature, for example, a martensitic stainless alloy can be used. Further, as a high-temperature material that exhibits high strength, high hardness, and hardly deformability at a high temperature constituting the holding member 25, for example, tungsten, molybdenum, etc. having a tensile strength at 1000 ° C. of 150 MPa or more and a Vickers hardness of 100 or more. Can be used. Furthermore, the holding member 25 is a space that can accommodate the mold material that is excluded from the master 10 portion of the master die 12 that is press-fitted into the block 24 when the inverted shape of the master die 12 is transferred to the block 24. 26 a is formed in communication with the recess 26.
For this reason, when the inverted shape of the master mold 12 is transferred to the block 24, the block 24 is inserted into the recess 26 of the holding member 25 and the exposed surface is pressed against the master mold 12 to be in a sealed state. The mold material that is removed when the inverted shape is transferred to the block 24 can enter the space 26 a, and the inverted shape of the master die 12 can be reliably transferred to the block 24.

Even if the block 24 is deformed, the holding member 25 is not deformed. Therefore, if the outer shape and size of the holding member 25 are formed into a shape and size that can be fitted into the mounting portion 22 formed in the mold base 14, the master die 12. The holding member 25 integrated with the block 24 having the inverted shape can be easily fixed to the mounting portion 22 of the mold base 14. Here, since the inverted shape of the flat plate 11 of the master mold 12 and the original mold 10 is formed in the block 24, the block integrated with the holding member 25 on the basis of the inverted shape portion of the flat plate 11 formed in the block 24. By fixing 24 to the attachment portion 22, the height position of the block 24 with respect to the mold base 14 can be accurately positioned. As a result, even when the plurality of blocks 24 are fixed to the mold base 14, the height position of each block 24 can be accurately and easily determined, and a plurality of transfer molds free from shape error and shape variation can be obtained. Can be formed.

As described above, the present invention has been described with reference to the embodiment. However, the present invention is not limited to the configuration described in the above-described embodiment, and the matters described in the scope of claims. Other embodiments and modifications conceivable within the scope are also included.
For example, the block and the master mold are heated in a vacuum, but can be performed in an inert gas atmosphere, for example, in a nitrogen gas atmosphere or an argon gas atmosphere. In addition, when heat treatment (rapid cooling) is performed by adjusting the cooling rate of the block on which the master-type inverted shape is transferred in the heating furnace, it can also be performed by supplying argon gas into the heating furnace.
Furthermore, in the second embodiment, an approximately inverted shape of the master mold may be formed in advance on the side of the block facing the master mold.

(A), (B), (C) is explanatory drawing of the transfer metal mold | die manufacturing method which concerns on the 1st Embodiment of this invention. It is explanatory drawing at the time of transferring the reverse shape of a master type | mold to a block with the transfer mold manufacturing method. It is explanatory drawing of the block which concerns on a modification. It is explanatory drawing of the block used with the transfer die manufacturing method which concerns on the 2nd Embodiment of this invention.

10: prototype, 11: flat plate, 12: master mold, 13: block, 14: mold base, 15: transfer mold, 16: machining center, 17: diamond tool, 18: support base, 19: hearth member, 20: Pressurizing member, 21: storage member, 22: mounting portion, 23, block, 23a: roughly inverted shape, 24: block, 25: holding member, 26: recessed portion, 26a: space portion

Claims (6)

A first step of producing a master mold in which an original mold having the same shape as a product having releasability is formed on a flat plate using a material exhibiting high strength, high hardness and hardly deformability at a high temperature exceeding 1200 ° C .; ,
A block having a predetermined shape made of a mold material exhibiting softening properties at high temperature is placed in a heating furnace so as to face the master mold, and the metal material is placed in a vacuum or in an inert gas atmosphere at 900 ° C. or more and 1200 ° C. A second step of heating to the following temperature range and pressing the master mold and the blocks to transfer the inverted shape of the master mold to the block;
The block to which the inverted shape of the master mold is transferred is cooled and released from the master mold, and the reference height position of the inverted shape portion of the flat plate of the master mold formed on the block is the surface of the mold base. And a third step of forming the transfer mold by fixing the block to the mold base so as to coincide with the height position of the transfer mold. The transfer mold manufacturing method according to claim 1, wherein a plurality of attachment portions are formed on the mold base, and the blocks on which the inverted shape of the master mold is transferred are fixed to the attachment portions, respectively. Transfer mold manufacturing method. In the transfer mold manufacturing method according to claim 1 or 2, the block is inserted into a recess formed in a holding member made of a high temperature material exhibiting high strength, high hardness, and hardly deformability at high temperature, Only the surface facing the master mold is exposed from the holding member. 4. The transfer mold manufacturing method according to claim 3, wherein the holding member has a space in the recess that can accommodate the mold material that is excluded when the inverted shape of the master mold is transferred to the block. A transfer mold manufacturing method characterized by being formed in communication. 5. The transfer mold manufacturing method according to claim 1, wherein a rough reversal shape smaller than the reversal shape of the master die is formed in advance on the side of the block facing the master die. A transfer mold manufacturing method characterized by the above. The transfer mold manufacturing method according to any one of claims 1 to 5 , wherein an inert gas is supplied into the heating furnace to adjust a cooling rate of the block on which the inverted shape of the master mold is transferred. A method for producing a transfer mold, wherein the block is heat-treated.

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