JP5210367B2 - Method for producing molded product using wood mold - Google Patents

Description

The present invention uses a wood fiber material having heat resistance, impact resistance, and durability for artificial wood, and is used for vacuum forming a molded product having irregularities from a heated planar thermoplastic resin sheet. In particular, the present invention relates to a method for manufacturing a molded product using a wood mold that can be formed by performing 2-axis or 3-axis simultaneous machining with an NC machine tool after creating a drawing or program by CAD or CAM. .

For example, containers for storing foodstuffs in supermarkets and convenience stores are generally manufactured by vacuum forming a sheet-like plastic. Examples of mold materials used for vacuum forming include wooden molds, plaster molds, resin molds, ceramic molds, aluminum molds, and ZAS molds as described in Non-Patent Document 1 (P52 to P54). Furthermore, the details of the wooden mold are described in, for example, Patent Document 1, and the details of the mold are described in, for example, Patent Document 2 and Non-Patent Document 1 (P62 to P75).

JP 11-48256 A JP 2002-240141 A

Published by Yoichi Yasuda, “Introduction to Thermoforming Technology”, Nikkan Planning & Sales Co., Ltd., September 18, 2000

However, the wood mold, the gypsum mold, and the resin mold for vacuum forming are easy to manufacture, but have a short life, so that it is difficult to manufacture a large number of molded products by repeated molding.
In particular, vacuum molds are weak to heat and easily broken, so they were partially used for high-mix low-volume production, but they are vulnerable to vibration and impact, making precision machining with machine tools extremely difficult. Therefore, most of them were hand-crafted by craftsmen. When a mold is used, the mold has a long life, but a mold for manufacturing the mold is required, resulting in a problem that the manufacturing cost is high.
The present invention has been made in view of such circumstances, and provides a method for manufacturing a molded product using a wooden mold that can be used repeatedly, can be precision machined, and is used for vacuum forming at a low manufacturing cost. Objective.

The method for producing a molded product according to the first aspect of the present invention is characterized in that the mold material main body of the wood fiber material having the mold material main body portion and the bottom plate portion joined to the bottom with a sealing adhesive and having a smooth back surface. NC machining is performed on the surface side from the surface side, and a rough engraved cavity (cavity) with a finishing allowance of 0.2 to 0.6 mm from the finished dimension of the molded product is maintained while maintaining a flat surface on the front edge. A first step of performing, a second step of applying a first thermosetting resin on the rough engraving to cure the resin, and further NC processing the surface of the resin-cured rough engraving to form the mold body A third step of performing a finish engraving of the recessed recess in the portion, a fourth step of applying a second thermosetting resin to the surface of the finish engraving and curing at least the surface thereof, and a bottom portion of the bottom plate portion A peripheral edge with a flat bottom end surface is formed around it. In addition to forming a vacuum chamber, a plurality of vacuum holes having a diameter of 0.1 to 1 mm (preferably 0.5 to 1 mm when formed by a drill) penetrating the hollow and the vacuum chamber are formed. a fifth step of, release promoting resin at least in the recess concave portion (e.g., silicone resin, Teflon (registered trademark) resin) to have a sixth step of coating the prepared wood type, on the wood type A heated planar thermoplastic resin sheet is disposed, the vacuum chamber is depressurized and adsorbed in the recess, and then the thermoplastic resin sheet is cooled by the wood mold.
In addition, an uneven | corrugated pattern may exist in a hollow recessed part inside.

A method of manufacturing a molded article according to the second invention is a method for producing a molded article according to the first invention, the vacuum chamber is divided into first and second chambers up and down by a partition member, the partition A communication hole penetrating vertically is formed in the member.

Method for producing a molded article according to the third invention, in the first method for producing a molded article according to the second invention, the first, second thermosetting resin, two-liquid mixing type urethane resin ( Including polyurethane resin). In addition, as the thermosetting resin, for example, urea resin, melanin urea resin, phenol resin, unsaturated polyester, silicone resin, and the like may be used.

Method for producing a molded article according to the fourth invention, in the method of manufacturing a molded article according to the first to third invention, the wood fiber material medium density fiber board (MDF) or hardboard (hardboard) is there. In addition, it is good to use what has a density of 0.4-0.8 and a bending strength of 150 kg / cm < ² > or more (more preferably 300 kg / cm < ² > or more), for example, as a medium fiber board.

A method of manufacturing a molded article according to the fifth invention is a method for producing a molded article according to the first to fourth invention, a plurality of said recesses recess is formed on one of the wood fiber material .

Since the manufacturing method of the molded product according to claims 1 to 5 uses a wood fiber material as a main material of the wood mold, it can withstand vibration and impact of a cutting machine, and NC processing is performed from the surface side. This makes it possible to produce the required mold directly and inexpensively. And the part that is directly touched by the thermoplastic resin sheet for molding (also called “resin sheet”) is hardened with thermosetting resin, so it can be used for a long time without being worn out even if it is used repeatedly. it can.
In addition, since the bottom plate part is fixed to the bottom of the mold body main body where the resin sheet is molded with a sealing adhesive, the thermosetting resin applied to the inner surface of the mold body main body should be highly permeable. Even if it is used, the resin is not transmitted to the bottom plate.
Further, it is possible to manufacture at a short delivery time and at a low cost as compared with a conventional mold, and it is possible to manufacture a product with improved accuracy and durability as compared with a conventional resin mold or vacuum mold for vacuum forming.

In particular, in the method for manufacturing a molded product according to claim 2, the vacuum chamber formed in the bottom plate portion is separated into a first chamber and a second chamber by a partition member in the vertical direction, and the partition member communicates vertically. Since the holes are formed, vacuum forming can be performed more uniformly, and the resin product can be stably formed.

In the method for producing a molded article according to claim 3, since the first and second thermosetting resins are two-component mixed urethane resins, the permeability of the thermosetting resin to the wood fiber material is low. It is possible to provide a wood mold having a higher strength.

In the method for producing a molded article according to claim 4, since the wood fiber material is a medium fiber board or a hard fiber board, the material can be obtained stably.

In the method for manufacturing a molded product according to claim 5, since a plurality of hollows are formed for one wood fiber material, a plurality of molded products can be molded simultaneously.

(A)-(C) are explanatory drawings of the manufacturing method of the wooden type | mold used for the manufacturing method of the molded article which concerns on the 1st Embodiment of this invention. It is a sectional side view of the wood type | mold used for the manufacturing method of the molded article which concerns on the 2nd Embodiment of this invention. (A) is a plan view of the same wood type, and (B) is a front sectional view. (A)-(C) are the side end view of a wooden type | mold used for the manufacturing method of the molded article which concerns on the 3rd Embodiment of this invention, a top view, and a front end view.

Next, embodiments of the present invention will be described with reference to the accompanying drawings for understanding of the present invention.
With reference to FIGS. 1 (A) to 1 (C), a method for manufacturing a wooden mold used in the method for manufacturing a molded product according to the first embodiment of the present invention will be described.
As shown in FIG. 1 (A), the wood fiber material having a large vertical and horizontal width of, for example, about 10 to 50 mm in plan view from the size of a molded article (product) having irregularities to be actually manufactured by vacuum forming. A wood fiber board 10 as an example is prepared. This wood fiber board 10 has a mold material main body 11 and a bottom plate 12 which are sufficiently thicker than the depth of a molded product (for example, a food pallet), and these are acrylic adhesives which are an example of a sealing adhesive. It is joined using the agent. As a result, a liquid (for example, an uncured thermosetting resin liquid) that permeates the wood fiber board 10 does not enter the bottom plate portion 12.

As the sealing adhesive, other adhesives may be used as long as they are heat resistant and stop the penetration of the liquid thermosetting resin before curing that penetrates from above. May be. The mold body 11 is preferably a single medium fiber board (MDF), but a plurality of medium fiber boards may be pasted with a thermosetting adhesive. The bottom plate 12 also uses a medium fiber board having a thickness of 5 to 30 mm, for example. The mold material main body 11 and the bottom plate 12 have smooth and parallel front and back surfaces 13 to 16 respectively.

Next, NC processing is performed from the surface side of the mold body main body 11 of the wood fiber board 10 and a flat surface is maintained on the front side peripheral edge, and a recess that leaves a finishing allowance of 0.2 to 0.6 mm from the finished dimension. Perform rough engraving of the recess. Reference numeral 18 in FIG. 1B denotes a rough carved surface. A two-component mixed urethane resin, which is an example of a first thermosetting resin, is applied on the rough carved surface 18. When this urethane resin is applied, it heats and hardens, and partially penetrates into the rough carved surface 18 to harden the surface. For example, an NC milling machine is used for NC machining.

After the urethane resin is cured, the rough engraved surface 18 is further NC-processed to finish and engrave the recess 19 in the mold body 11. This finishing process engraving can be performed precisely because the rough engraved surface 18 is cured with resin. In addition, if the rough engraved surface 18 is not cured with resin, the medium fiber board is directly cut and the material is partially damaged by the impact or vibration of the blade, so that the precision machining by the blade is not possible. Can not.
In addition, except for the case where the surface 13 of the mold body 11 is smooth and flat, the surface treatment of the mold body 11 is performed. In this case as well, the thermosetting resin is infiltrated into the surface 13 before being processed. It is preferable to leave.

Then, a two-component mixed urethane resin, which is an example of the second thermosetting resin, is applied to the surface of the finish engraving, that is, the recess 19 to cure at least the surface thereof. Also in this case, since the sealing resin agent is applied to the bottom of the mold body 11, the two-component mixed urethane resin does not spread to the bottom plate 12. As a result, the surface of the recessed recess 19 is hardened, and a wood type that can be used repeatedly is obtained.

Then, a plurality of vacuum holes 20 having a diameter of 0.1 to 1 mm (preferably 0.5 to 1 mm) communicating from the bottom plate portion 12 to the recessed portion 19 are formed. In addition, as shown in FIG. 1C, the bottom plate portion 12 is provided with peripheral portions 21 and 22 having a flat bottom end surface in the periphery to form a vacuum chamber 23. The lower side is formed so as to communicate with the vacuum chamber 23. The vacuum holes 20 are preferably formed as evenly as possible.

In this embodiment, a partition plate 25, which is an example of a partition member, is disposed in the middle of the vacuum chamber 23 in the vertical direction, and is separated into a first chamber 26 and a second chamber 27 in the vertical direction. A plurality of communication holes 28 having a large diameter (for example, 5 to 60 mm) are formed in the middle of the partition plate 25. Thereby, the degree of vacuum in the first chamber 26 is kept more uniform, and the amount of air sucked from each vacuum hole 20 is made uniform. In this embodiment, the partition plate 25 and the peripheral portions 21 and 22 are made of a dense material such as a medium fiber board, but may be hard wood.

It is also possible to form a vacuum hole 30 (having the same diameter as that of the vacuum hole 20) leading from the first chamber 26 of the vacuum chamber 23 to the surface 13 of the mold body main body 11.
Thus, the production of the wood mold 32 used for vacuum forming is completed. Therefore, in molding, as shown in FIG. 1 (C), a planar thermoplastic resin sheet (for example, polystyrene, PET, PVC, PPF, PSP, PP foam, 33, such as polypropylene). When the thermoplastic resin sheet 33 is brought into contact with the surface 13 of the wood mold 32 and then sucked from a mold table (not shown) on which the wood mold 32 is placed, and the vacuum chamber 23 is rapidly decompressed, The inside 19 is depressurized, and the thermoplastic resin sheet 33 is sucked by the atmospheric pressure and adsorbed to the recess 19. The thermoplastic resin sheet 33 is cooled by the wood mold 32 and cured to obtain a molded product. In this state, the vacuum state is immediately stopped, compressed air is put into the vacuum chamber 23, and the molded product is taken out.

If the depth of the molded product is shallow, it is possible to produce a large amount of molded products with good shape accuracy by the above molding, but the depth of the molded product is deep (for example, if the tray shape is deep drawing, In the case where there is no gradient and it is difficult to obtain sufficient strength and shape by vacuum alone, the pressing die 34 is used together as shown in FIG. Although this pressing die 34 differs depending on the thickness, material, and shape of the molded product, it becomes a convex shape that is smaller by about 2 to 10 mm than the inner dimension of the molded product, and presses the thermoplastic resin sheet 33 that has been softened by heating. The shape is close to the recessed recess 19. Thereby, the thickness of the molded product can be made more uniform.

A medium fiber board is also used as the material of the pressing die 34. Then, the thermosetting resin is infiltrated into the surface of the convex portion 35. In addition, the two-component mixed thermosetting resin applied to the surface of the concave portion 19 and the convex portion 35 not only makes the surface hard and smooth, but also improves the releasability of the molded product. That is, if the wood fiber is exposed as it is, the surface of the thermoplastic resin sheet 33 bites into the partial chipping or the material itself, and the release property or moldability deteriorates, but the surface is made smooth by the thermosetting resin. The surface biting of the thermoplastic resin sheet 33 is eliminated.

Furthermore, it is preferable to stick a cloth material (for example, “nel”) on the surface of the convex portion 35. As a result, the thermoplastic resin sheet 33 is more uniformly stretched, and the balance between strength and thickness is improved (the same applies to the following embodiments).

Then, the manufacturing method of the wooden type | mold used for the manufacturing method of the molded article which concerns on the 2nd Embodiment of this invention shown to FIG. 2, FIG. 3 (A), (B) is demonstrated.
In the wood mold 36 manufactured by the method according to the second embodiment, a plurality of recessed recesses 37 capable of simultaneously molding a plurality of molded products in one mold are formed. The mold body 38 uses a plurality of medium fiber boards (MDF) 39, 40 joined with a sealing adhesive, and the bottom board 41 also uses a medium fiber board. It is joined to the bottom of the portion 38 with a sealing adhesive.

A vacuum chamber 42 is formed below the bottom plate portion 41, and the vacuum chamber 42 is divided into a first chamber 43 and a second chamber 44 by a partition plate 45 in the vertical direction. 46 and 47 are peripheral portions forming the first chamber 43 and the second chamber 44, 48 is a plurality of communication holes formed in the partition plate 45, 49 is an auxiliary support member, 50 is a recess 37 and A 0.1 to 0.5 mm diameter vacuum hole communicating with one chamber 43 is shown. The manufacturing method of the wooden mold 36 is the same as that of the wooden mold 32 according to the first embodiment, and the rough engraving and finishing engraving of the plurality of recessed recesses 37 are sequentially formed by the NC machine tool. Finally, a two-component mixed thermosetting resin is applied to the inner surface of the recessed recess 37 to cure the surface. Thereafter, a release promoting resin (for example, silicon resin, Teflon (registered trademark) resin) is coated on the upper surface (the same applies to the first and third embodiments).

Next, the push die 52 used for this wood type | mold 36 is demonstrated. The pressing die 52 includes convex portions 53 corresponding to the plurality of recessed concave portions 37, and these are fixed to the common base plate 54. The convex portion 53 and the common base plate 54 are made of a single piece of wood fiber board material 55. The wood fiber board material 55 is constituted by joining a plurality of medium fiber boards with a thermosetting synthetic resin. Then, the main body 56 is formed by sequentially performing rough engraving, application of thermosetting resin, finishing engraving, and application of thermosetting resin by an NC processing machine.

The pressing mold 52 is composed of the pressing mold main body 56, a support member 57 provided on both sides of the pressing mold main body 56, and a ceiling plate 59 having an opening 58 formed in the center. Part 60. The pressing die 52 is attached to a predetermined position of the vacuum forming machine with a small vise by using the equipment attaching portion 60.
The usage method of the wood mold 36 and the push mold 52 is the same as that of the wood mold 32 according to the first embodiment. In FIG. 2, 71 is a communication hole.

Then, the manufacturing method of the wooden type | mold used for the manufacturing method of the molded article which concerns on the 3rd Embodiment of this invention shown in FIG. 4 is demonstrated. In this embodiment, the manufacturing method of the wood mold 63 is the same as that of the wood mold 32 according to the first embodiment, but that the four protrusions 65 are formed around each recess 64, and The difference is that a concave-convex pattern 67 is formed on the bottom surface of each concave recess 64 to reinforce the molded product.

For the manufacture of the wood mold 63 with the protrusions 65 formed, a mold body main body having a thickness including the height of the protrusions 65 may be prepared, and NC processing (rough engraving and finishing engraving) may be performed. NC processing may be performed by firmly sticking a wood fiber material corresponding to 65 to a predetermined position of the mold body main body with a thermosetting resin. Reference numeral 68 denotes a mold material main body, 69 denotes a bottom plate, and the vacuum chamber is omitted.

In the above-described embodiment, the medium fiber board (MDF) is used as the wood fiber material, but a hard fiber board (hard board) having a higher packing density for wood may be used.
In the above embodiment, the dimensions are specified to some extent and the shape of the molded product is also specified. However, as long as the gist of the present invention is not changed, the dimensions and shapes can be changed freely. The present invention applies.
In the above embodiment, the wood mold is disposed under the thermoplastic resin sheet and vacuum forming is performed. However, the wood mold may be disposed on the thermoplastic resin sheet and vacuum forming may be performed. it can. In this case, the position of the pressing die is arranged under the thermoplastic resin sheet.

10: Wood fiber board, 11: Mold body, 12: Bottom plate, 13: Front surface, 14: Back surface, 15: Front surface, 16: Back surface, 18: Roughened surface, 19: Recessed recess, 20: Vacuum hole, 21 22: peripheral portion, 23: vacuum chamber, 25: partition plate, 26: first chamber, 27: second chamber, 28: communication hole, 30: vacuum hole, 32: wood type, 33: thermoplastic resin sheet, 34: Push mold, 35: Convex part, 36: Wood type, 37: Concave concave part, 38: Mold material main body part, 39, 40: Medium fiber board, 41: Bottom plate part, 42: Vacuum chamber, 43: First chamber 44: second chamber, 45: partition plate, 46, 47: peripheral portion, 48: communication hole, 49: auxiliary support member, 50: vacuum hole, 52: push die, 53: convex portion, 54: common base plate , 55: wood fiber board material, 56: press die main body, 57: support material, 58: opening, 59: ceiling board, 0: equipment mounting portion, 63: wood-type, 64: recess recess, 65: protrusion, 67: uneven pattern, 68: mold member body portion, 69: bottom plate

Claims (5)

The mold material main body of the wood fiber material having the mold material main body and the bottom plate portion joined to the bottom with a sealing adhesive and having a smooth back surface is subjected to NC processing from the front side, and a plane is formed on the front side periphery. In a maintained state, a first step of rough engraving of a recessed portion leaving a finishing allowance of 0.2 to 0.6 mm from the finished dimension of the molded product, and a first thermosetting resin on the rough engraving The second step of applying and curing the resin, the third step of further machining the surface of the resin-cured rough engraving and finishing the recesses in the mold body, and the finishing engraving A fourth step in which a second thermosetting resin is applied to the surface of the substrate and at least the surface thereof is cured; and a peripheral portion having a flat bottom end surface is formed around the bottom of the bottom plate portion, and a vacuum is formed on the inside. Forming a chamber and directly passing through the recess and the vacuum chamber. There a fifth step of forming a plurality of vacuum holes of 0.1 to 1 mm, to produce a woody-type have a sixth step of coating a release promoting resin at least in the recess concave portion, on the wood type A heated flat thermoplastic resin sheet is disposed, and the vacuum chamber is depressurized and adsorbed in the recessed recess, and then the thermoplastic resin sheet is cooled by the wood mold and manufactured. Manufacturing method of molded products. 2. The method of manufacturing a molded product according to claim 1, wherein the vacuum chamber is separated into a first chamber and a second chamber by a partition member vertically, and a communication hole penetrating vertically is formed in the partition member. A method for producing a featured molded article . The manufacturing method according to claim 1 or 2, wherein the molded article, the first, second thermosetting resin, the production method of a molded article, which is a two-liquid mixing type urethane resins. The method of manufacturing a molded article according to any one of claims 1 to 3, the manufacturing method of a molded article, wherein the wood fiber material is medium density fiberboard or hardboard. The method of manufacturing a molded article according to any one of claims 1 to 4, a manufacturing method of a molded article, wherein a plurality of said recesses recess is formed on one of the wood fiber material.

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