JPH10211622A - Production of mold - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a precise molded product by forming an injecting space of a certain thickness between a master molding surface and a molding layer opposite thereto and making a liquefied thermosetting synthetic resin set after it is injected into the injecting space. SOLUTION: A molding body 22 for a female mold A is first produced by mixing, e.g. aluminum powder into a two-pack resin, and kneading the mixture into a liquefied body. Then, a layer space 23a obtained between a master molding surface 21a of a master mold 21 and a molding layer 23 is vacuum drawn and thereafter the liquefied body so kneaded is injected via a gate in a manner as to break the vacuum so as to be loaded into the space 23a under atmospheric pressure. This liquefied body then penetrates into fine line-grooves formed in the master molding surface 21a of the master mold 21 from the periphery of the space 32a and a thermal conductor 26 and gets to fit well therein. Moreover, since bubbles are also evacuated, the molding surface of the molding body 22 gets to conform precisely to the surface of the master mold 21, whereby a highly precision molding surface is obtained that contains no bubbles.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a molding die used for molding such as injection molding, blow molding, meton molding, urethane rim molding or press molding.

[0002]

2. Description of the Related Art Conventionally, Japanese Unexamined Patent Publication No. Hei 8-47732 discloses a method using urethane, acrylic, epoxy or polyester.
A mixture of thermosetting synthetic resin mixed with an appropriate amount of an aggregate made of metal such as iron powder and a binder for preventing cracking is kneaded with a mixing machine, and the kneaded uncured material is used as a master mold. A molded product as a surface layer is obtained by applying the composition on a surface (master molding surface) and curing it while molding. FIG. 5 shows a molding die of the female die 1 including the molded bodies 3 and 13 and the male die 11, and in FIG.
On the rear surfaces of the molded bodies 3 and 13 of the male mold 11, holding members 2 and 12 made of concrete surrounded by molds 4 and 14 are cast. 16 are attached to the support plates 5 and 15.

[0003] The female mold 1 and the male mold 11 are set on a press machine, a work W is placed between them, and the male mold 11 is lowered to drop the male mold 11 into the female mold 1. W
Can be formed by retroactive deformation.

[0004] As described above, the moldings 3 and 13 are molded from a two-component mixed thermosetting synthetic resin as a main component to form a molding die. As a result, the manufacturing can be simplified and the manufacturing period can be shortened as compared with the case of manufacturing as a mold.

[0005]

However, conventionally, when molding the molded articles 3 and 13, the two-part mixed thermosetting synthetic resin in the form of a paste is formed into a layer and adhered to the surface of the master mold to be cured. If there are complicated fine lines and invoices on the surface of the master mold, the paste-like material will not fit into these fine lines and invoices, or air bubbles will be involved. Therefore, the precision of the molded bodies 3 and 13 is likely to be deteriorated, and therefore, a precise molded product cannot be obtained.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems. Even if complicated fine wires or the like exist on a master molding surface, a molded article can be molded so as to be sufficiently adapted to the master molding surface, and a precise molded product can be produced. To be able to get.

[0007]

[Means for Solving the Problems]

[0013] The invention according to claim 1 is a method for manufacturing a molding die comprising a molded article made of a two-component mixed thermosetting synthetic resin containing abrasion-resistant metal powder. An injection space having a constant thickness was formed between the molding layer and the molding layer facing the molding surface, and the liquefied thermosetting synthetic resin was injected into the space and then cured to produce a molding die.

According to a second aspect of the present invention, the molding layer is formed by impregnating a fiber sheet such as carbon with a thermosetting synthetic resin and thermosetting, and integrally molding with the injection-cured molded body. Make up the type.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. 1 and 2 are cross-sectional views showing one embodiment of a method for manufacturing a mold according to the present invention. In each figure, A is a female mold, B is a male mold, and these have the same configuration. And molded layers 22 and 42 as surface layers, molded layers 23 and 43 supporting the rear surfaces of the molded bodies 22 and 42,
Putty-like joining strength members 24 and 44 integrated on the back surfaces of the forming layers 23 and 43, strength members 25 and 45 integrated on the back surfaces of the joining strength members 24 and 44,
The heat conductors 26 and 46 buried in the rear portions of the heat conductive members 2 and 42 and covered with the molding layers 23 and 43 and formed of heat conduction pipes of cold or hot heat, and integrated with the rear surfaces of the strength members 25 and 45. High-hardness concrete 27, 47
Wood 28, 4 as rods buried in concrete 27, 47 so as to extend at right angles to
8. Wood 32, 52, iron plate forms 29, 49 located on the outer periphery of the concrete 27, 47, and flat mounting plates 30, 50 located on the rear surface of the concrete 27
And bolts 3 for attaching plates 30 and 50 to nuts 33 and 53 buried in the rear surfaces of concrete 27 and 47, respectively.
1, 51. The molded body 2 is composed of the above-mentioned joining strength members 24, 44, strength members 25, 45, and concrete 27, 47.
2, 42 holding members are configured.

In FIG. 1, a molded body 22 of a female mold A is formed by mixing 75% of aluminum powder into a two-liquid resin, kneading and liquefying the liquid, and forming the master mold 21 into a master mold. After vacuuming the layered space 23a obtained between the surface 21a and the molding layer 23, the space 23a is filled with the force of the atmospheric pressure so as to break the vacuum while injecting through a gate (not shown). . Such a molded body 22 has a linear expansion coefficient of approximately 60 ×
It is reduced from 10 ⁻⁶ to approximately 30 × 10 ⁻⁶ .

In this case, the molding layer 23 is formed by impregnating a fiber sheet such as FRP or carbon fiber with a thermosetting synthetic resin such as phenol resin in a molding die (not shown).
6 is set so as to cover it, and is put into a heating furnace and cured to form a hat shape. By arranging this on the master mold 21, the master molding surface of the master mold 21 is removed. A molding space 23a is obtained between the two.

In this case, the outer peripheral edge 23b of the molding layer 23
Is in contact with the outer peripheral surface of the master mold 21 and is pressed by the tip of the cylindrical iron plate formwork 29, so that the space 23a can be kept airtight. After evacuating the molding space 23a,
The space 23a is filled with a liquid material containing a thermosetting synthetic resin as a main component through a gate (not shown) while breaking the vacuum, whereby the liquid material is filled with the space 23a and the heat conductor 26. From around, it penetrates into a fine line groove or the like formed on the master molding surface 21a of the master mold 21 and gets accustomed to it. Further, the air bubbles are evacuated. Molding surface is master mold 21
It is a high-precision molding surface that does not contain air bubbles that exactly fits the surface.

The bonding strength material 24 is fixed to the rear surface of the molding layer 23 and functions as a bonding material for the strength material 25. The bonding strength material 24 is, for example, a thermosetting mixture of two powders of iron powder. A paste-like material mixed with a water-soluble synthetic resin is adhered to the surface of the molding layer 23, and the strength material 25 is a thermosetting synthetic resin of a two-liquid mixture of a material such as stone, sand, etc., which is familiar with concrete 27. Is adhered to the surface of the bonding strength material 25. The bonding strength material 24 and the strength material 25 are provided in a heating furnace and are cured by heating.
As the concrete 27, a cement material is used in which a fine powder ferrer such as water, an admixture, sand, iron powder or aluminum powder is kneaded with high-speed rotation of a mixer.

In the hard concrete 27, a cylindrical iron plate formwork 29 is erected on the outer periphery of the master mold. Cement is put into the internal space in the iron plate formwork 29. The cement material is solidified with the wood 28 and the wood 32 buried vertically, covered with a plate 30 and a nut 33 buried.

The wood 28 and the wood 32 are buried at their ends in the strength material 25, and the strength material 25 is thermoset in a vertically standing state to maintain a state perpendicular to the molding layer 23. The cement material is put into the iron plate formwork 29 including the wood 32. The wood 32 is provided at a predetermined number of woods 28, and the rear end of the wood 32 is a flat mounting plate 3.
Although it is grounded to zero, the rear ends of the many pieces of wood 28 are floating above the flat mounting plate 30.

The timbers 28 and 32 have knots extending in the longitudinal direction (vertical direction). Here, regarding the coefficient of linear expansion, since the molded body 22, the molded layer 23, the bonding strength member 24, and the strength member 25 are each mainly composed of a thermosetting synthetic resin, the coefficient of linear expansion is approximately 30%. × 10 ^−6, so that even if the molded body 22 contracts or expands,
3. Since the joint strength material 24 and the strength material 25 contract and expand in synchronization with the molded body 22, the stress does not act much on the molded body 22, and the molded body 22 is not cracked.

On the other hand, the concrete 27 having a high hardness has a small coefficient of linear expansion of about 6.8 × 10 ^{−6 to} 12.7 × 10 ⁻⁶ .
As a result of inhibiting the expansion, stress is applied to the molded body 22, which may cause cracks in the molded body 22.

Therefore, in the present embodiment, the concrete 2
In 7, wood 28 was buried. This wood 28 has a small linear expansion coefficient in the vertical direction (vertical direction) of about 3 × 10 ^{−6 to} 5 × 10 ⁻⁶ , but has a horizontal linear expansion coefficient of 36 × 10 ^{−6 to} 6 × 6.
Since it is as large as about 0 × 10 ⁻⁶ , the wood 28 largely shrinks and expands in the lateral direction, so that the shrinkage and expansion of the concrete 27 as a whole can be increased. 22 can be matched (aligned) to contraction and expansion. For this reason, even if the molded body 22 is subjected to a thermal cycle, there is no possibility that the molded body 22 receives stress from the concrete 27 and cracks. Also, the wood 32 located at a predetermined interval
With regard to (5), since the concrete 27 itself runs longitudinally, cracks in the concrete 27 itself, which occur due to the provision of the wood 28, can be reliably prevented.

When the female die A is completed, the female die A is turned upward as shown in FIG. 2 and used as a master die.
That is, a sheet wax 34 for thickening the molding is laid on the molding surface side of the female mold A, and the back surface of the sheet wax 34 is used as a master molding surface 34a. As in the case of the molding of A, the molded body 42, the molded layer 43, the joining strength material 44, the strength material 45,
Laminate concrete 47. Also in this case, wood 4
Since the concrete 8 is buried in the concrete 47, the contraction and expansion of the molded body 42 can be absorbed, and cracks generated in the molded body 42 can be prevented.

Moreover, since the wood 48 runs vertically on the concrete 47, cracks generated in the concrete 47 itself can be prevented. Also, wood 28, 48, wood 32,
52 hardly shrinks or expands in the vertical direction, so that the original function of the concretes 27 and 47 is not affected.

After the female mold A and the male mold B have been formed as described above, the female mold A and the male mold B are removed in actual use with the product thickened sheet wax 34 corresponding to the product to be molded removed. B is set on the illustrated ram of the injection molding machine, and the two are fitted as shown in FIG. 2, and a thermosetting or cooling is performed in a molding space obtained between the two (where the product thickened sheet wax 34 exists). The cured liquefied resin is injected through a gate (not shown). In this case, when the liquefied resin is a thermosetting resin, the molded bodies 22, 42 are heated by heating the heat conductors 26, 46. Can be. When the liquefied resin is a thermosetting resin, the molded bodies 22, 42 are cooled by cooling the heat conductors 26, 46 with a refrigerant, so that they can be taken out as a product after being cooled and hardened.

In the present embodiment, since the aluminum powder is mixed in the molded bodies 22 and 42, the molded bodies 22 and 42 are mixed.
2 itself has good thermal conductivity, the heat of the heat conductors 26 and 46,
Warm heat can be transmitted well to the molded bodies 22 and 42.

Further, since the light wood 28, 48 and the wood 32, 52 are buried in the concrete 27, 47, the weight of the mold itself can be reduced.

In this embodiment, when the molded article is a small product such as an electronic component and the molding die itself is small,
Concrete 27, 47 and wood 28, 5 as holding materials
It may be constituted by a simple one in which 2 is omitted.

In this manner, the joining members 24, 44 and the reinforcing members 25, 45 are also reduced in the coefficient of linear expansion of the molded bodies 22, 42.
Since the linear expansion coefficients are set to be substantially equal (aligned), cracks of the molded bodies 22 and 42 can be prevented.

[0032]

As described above, according to the present invention,
In a method of manufacturing a molding die comprising a molded article made of a two-component mixed thermosetting synthetic resin containing abrasion-resistant metal powder, a method comprising the steps of: Since a casting space having a constant thickness is formed, and the liquefied thermosetting synthetic resin is poured into the casting space and then cured to produce a molding die, a molding die having a highly accurate molded body can be obtained.

In the second invention, the molding layer is formed by impregnating a fibrous sheet such as carbon with a thermosetting synthetic resin and thermosetting, and forms a molding die integrally with the injection-cured molded body. With this configuration, a molding space for a molded body can be obtained by a simple method, and a molding die can be manufactured in a short time.

[Brief description of the drawings]

FIG. 1 is a sectional view showing one embodiment of the present invention.

FIG. 2 is a sectional view showing an embodiment of the present invention.

FIG. 3 is a cross-sectional view showing another embodiment of the present invention.

FIG. 4 is a cross-sectional view showing another embodiment of the present invention.

FIG. 5 is a sectional view showing an example of a conventional example.

[Explanation of symbols]

 22, 42 molded body 23, 43 molded layer 23a molding space 24, 44 joining strength material 26, 46 heat conductor 27, 47 hard concrete 28, 32 wood

Claims (2)

[Claims] 1. A method of manufacturing a mold comprising a molded article made of a two-component mixed thermosetting synthetic resin containing abrasion-resistant metal powder, comprising a master molding surface and a molding facing the master molding surface. Forming a molding space having a constant thickness between the layers and injecting and injecting the liquefied thermosetting synthetic resin into the molding space, and then curing the resin to produce a molding die; Method. 2. The molding layer is formed by impregnating a thermosetting synthetic resin into a fiber sheet made of carbon or the like and thermosetting, and forms a molding die integrally with the injection-cured molded body. The method for manufacturing a mold according to claim 1, wherein: