JP4620765B2 - Manufacturing method of wood mold used for vacuum forming - Google Patents

Description

The present invention uses a wood fiber material having heat resistance, impact resistance and durability for an artificial tree, and is used for vacuum molding a molded product having irregularities from a heated planar thermoplastic resin sheet. In particular, the present invention relates to a method for manufacturing a wood mold used for vacuum forming that can be formed by performing 2-axis or 3-axis simultaneous machining by 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 an object of the present invention is to provide a method for manufacturing a wooden mold that can be used repeatedly, can be precision machined, and is used for vacuum forming at a low manufacturing cost.

Wood-type production method for use in vacuum forming according to the first aspect of the invention along the object, the manufacture of wood type used in vacuum forming a molded article having an uneven from planar thermoplastic resin sheet heated pressurized A method,
From the surface side to the said mold material main body part of the wood fiber material which has the mold material main body part which consists of a medium fiber board, and the bottom board part which the bottom of the mold material main body part was joined with the sealing adhesive, and the back surface became smooth A first step of performing rough machining of a hollow recess (cavity) with a finishing allowance of 0.2 to 0.6 mm from the finished dimension of the molded product in a state where NC processing is performed and the front side periphery is maintained flat; ,
A second step of applying a two-component mixed first thermosetting resin on the rough engraving and curing the resin;
A third step of further NC processing the surface of the resin-cured rough sculpture, and finishing and engraving the hollow recess in the mold body body;
A fourth step of applying a two-component mixed type second thermosetting resin to the surface of the finish engraving and curing at least the surface;
A peripheral portion having a flat bottom end surface is formed around the bottom portion of the bottom plate portion, and a vacuum chamber is formed inside thereof, and a diameter penetrating the recessed portion and the vacuum chamber is 0.1 to 1 mm (note that In the case of forming with a drill, 0.5 to 1 mm is preferable) a fifth step of forming a plurality of vacuum holes,
And a sixth step of coating at least the recessed portion with a mold release accelerating resin (for example, silicon resin, Teflon (registered trademark) resin).
In addition, an uneven | corrugated pattern may exist in a hollow recessed part inside.

Moreover, the manufacturing method of the wooden type | mold used for the vacuum forming which concerns on 2nd invention is a manufacturing method of the wooden type | mold which concerns on 1st invention. WHEREIN: The said vacuum chamber is vertically divided into the 1st chamber and the 2nd chamber by the partition member. The partition member is separated, and a communication hole having a diameter of 5 to 60 mm penetrating vertically is formed in the partition member.

According to a third aspect of the present invention, there is provided a wood mold manufacturing method used in vacuum forming according to the first and second inventions, wherein the first and second thermosetting resins are mixed in two liquids. Type urethane resin (including polyurethane resin). In addition, as the thermosetting resin, for example, urea resin, melamine / urea resin, phenol resin, unsaturated polyester, silicone resin, and the like may be used.

In addition, it is preferable to use a medium fiber board having a density of 0.4 to 0.8 and a bending strength of 150 kg / cm ² or more (more preferably 300 kg / cm ² or more).

Moreover, the manufacturing method of the wooden type | mold used for the vacuum forming which concerns on 4th invention is a manufacturing method of the wooden type | mold which concerns on the 1st- 3rd invention. WHEREIN: The said said hollow recessed part with respect to one said wooden fiber material Is formed.

Note that the sealing adhesive only needs to be liquid-impermeable after the wood fiber material is bonded and cured, so a thermoplastic adhesive (preferably resistant to high temperatures) or thermosetting adhesion An agent may be used.

Since the wood mold manufacturing method used for vacuum forming according to claims 1 to 6 uses a wood fiber material as a main material, it can withstand vibrations and impacts of a cutting machine. By processing, the mold required directly and inexpensively can be manufactured. 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 of manufacturing a wood mold used for vacuum forming according to claim 2, the vacuum chamber formed in the bottom plate portion is separated into a first chamber and a second chamber vertically by a partition member. Since the communicating hole penetrating vertically is formed, vacuum forming can be performed more uniformly, and the resin product can be stably molded.

In the manufacturing method of the wood type | mold used for the vacuum forming of Claim 3, since the 1st, 2nd thermosetting resin is a two-component mixed type urethane resin, it is thermosetting with respect to a wood fiber material. It is possible to provide a wood type having high resin permeability and higher strength.

In the method for manufacturing a wood mold used for vacuum forming according to claim 4 , a plurality of recessed portions are formed for one wood fiber material, so that a plurality of molded products can be molded simultaneously.

Next, embodiments of the present invention will be described with reference to the accompanying drawings for understanding of the present invention.
Here, FIGS. 1A to 1C are explanatory views of a manufacturing method of a wood mold used for vacuum forming according to the first embodiment of the present invention, and FIG. 2 is a second embodiment of the present invention. FIG. 3A is a plan view of the wood mold produced by the wood mold production method used for vacuum forming according to FIG. 3, FIG. 3A is a plan view of the wood mold, FIG. (C) is a side sectional view, a plan view, and a front sectional view of a wooden mold manufactured by a manufacturing method of a wooden mold used for vacuum forming according to a third embodiment of the present invention.

With reference to FIGS. 1 (A) to (C), a method for manufacturing a wood mold used for vacuum forming 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 have heat resistance and stop the penetration of the liquid thermosetting resin before curing penetrating 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 the front side peripheral edge is maintained in a flat surface, leaving a finishing allowance of 0.2 to 0.6 mm from the finished dimensions. 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 12 to the recess 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 vacuum forming 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 vacuum forming 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.

Manufacture of wood-type 63 the protrusion 65 has been formed, to prepare a mold material body portion of the thickness including the height of the protrusion 65 may be performed NC machining (coarse engraving and finishing carved), projecting The NC processing may be performed by firmly sticking the wood fiber material corresponding to the portion 65 to a predetermined position of the mold main body portion 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.

(A)-(C) are explanatory drawings of the manufacturing method of the wooden type | mold used for the vacuum forming which concerns on the 1st Embodiment of this invention. It is a sectional side view of the wood type | mold manufactured with the manufacturing method of the wood type | mold used for the vacuum forming 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 manufactured with the manufacturing method of the wooden type | mold used for the vacuum forming which concerns on the 3rd Embodiment of this invention, a top view, and a front end view.

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 (6)

Molded article having an uneven from planar thermoplastic resin sheet heated pressurized to a wood-type production method used to vacuum forming,
From the surface side to the said mold material main body part of the wood fiber material which has the mold material main body part which consists of a medium fiber board, and the bottom board part which the bottom of the mold material main body part was joined with the sealing adhesive, and the back surface became smooth Performing NC processing, with the front side peripheral edge maintained in a plane, a first step of rough engraving of a recessed recess leaving a finishing allowance of 0.2 to 0.6 mm from the finished dimension of the molded product;
A second step of applying a two-component mixed first thermosetting resin on the rough engraving and curing the resin;
A third step of further NC processing the surface of the resin-cured rough sculpture, and finishing and engraving the hollow recess in the mold body body;
A fourth step of applying a two-component mixed type second thermosetting resin to the surface of the finish engraving and curing at least the surface;
A peripheral portion having a flat bottom end surface is formed around the bottom portion of the bottom plate portion to form a vacuum chamber inside thereof, and a plurality of diameters of 0.1 to 1 mm penetrating through the recessed portion and the vacuum chamber A fifth step of forming a vacuum hole of
A method for producing a wood mold used for vacuum forming, comprising: a sixth step of coating at least the depression recess with a release promoting resin. 2. The wood mold manufacturing method according to claim 1, wherein the vacuum chamber is vertically divided into a first chamber and a second chamber by a partition member, and the partition member has a communication hole having a diameter of 5 to 60 mm penetrating vertically. A method for producing a wood mold used for vacuum forming, characterized in that it is formed. 3. The method for manufacturing a woody mold according to claim 1, wherein the first and second thermosetting resins are two-component mixed urethane resins. Wood mold manufacturing method. The manufacturing method of claim 1 wood type as claimed in any one of 3, wood-type production method, wherein a plurality of said recesses recess is formed on one of the wood fiber material. 2. The method for manufacturing a wood mold according to claim 1 , wherein the material of the peripheral portion formed in the fifth step is made of a medium fiber board or hard wood . 3. The wood mold according to claim 2 , wherein a second vacuum hole having a diameter of 0.1 to 1 mm is formed from the first chamber to the peripheral edge on the front side of the mold body. Manufacturing method.

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