JP3019985B2 - Graphite mold for plastic molding - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a mold used for molding a plastic molded article, and more particularly to a graphite mold for plastic molding whose base material is made of a graphite material.

(Prior art) So-called plastics are generally lightweight, economical, workable,
A material with various properties such as corrosion resistance, electrical, mechanical,
It is used very widely, from all industrial uses such as automobiles to daily necessities. In order to mold these various plastic products, a mold made of a metal material of iron and its alloy is generally used.

When a mold made of this kind of metal material (hereinafter referred to as a mold) has an extremely large number of moldings, it is a necessary condition that the mold material be metal from the viewpoint of the mold life.
However, with the recent trend of high-mix low-volume production, there is an increasing need for prototypes of molds.

The proportion of the mold cost in the molded product is increasing, and the product cost is high.

The production of the mold requires a great deal of time and money.

Such disadvantages have been found in molds generally used in the past.

Therefore, the present inventors have specially proposed a mold using a high-strength and high-density graphite material that can sufficiently withstand the pressure during plastic injection molding and has a good polished surface as a mold material instead of metal. Various proposals are made in, for example, JP-A-63-162205. In making the invention proposed in this publication, the inventors focused on the following points.

(1) Graphite can be processed at high speed because the cutting resistance in machining is 1/5 to 1/10 of that of metal.

(2) Since graphite is a material that can be easily finished with metal by manual work, the site or process that has relied on electric discharge machining can be easily finished by manual work.

(3) Since graphite is a material having a very small coefficient of thermal expansion, it is easy to obtain accuracy in molding plastic.

(4) The specific gravity of the graphite mold is relatively 1/4 or less of the specific gravity of the mold, making it easy to handle the mold for plastic molding even for complicated or high-speed operations. The operation becomes simple.

(5) Since graphite has good heat conduction, the time required for recycling of heating and cooling can be short, so that high-speed cycle plastic molding can be performed.

According to the above results, it is possible to cope with the molding of a plastic product of a very small lot and a prototype.

And, (6) graphite has a high thermal stability of 3000 ° C, whereas the general heat resistance temperature of metal is several hundred ° C, and has a very small coefficient of thermal expansion. Is what it is.

By the way, the subsequent studies by the present inventors have found that the following points must be further considered in this type of graphite mold for plastic molding.

That is, first of all, in the case of forming a plastic product, for example, when taking an example of injection molding using a thermoplastic plastic as a material, the molding pressure of vinyl chloride resin is about 141 kg / cm ^2. In the case of acrylic resin, a molding pressure of about 700 kg / cm ² must be applied,
As a matter of course, the mold must be able to withstand such a molding pressure. Moreover, not only the molding pressure is applied to the molding die, but also, for example, in a mold in which the movable die is moved relative to the fixed die to form a closed molding cavity, the closed cavity is formed. In order to construct, the movable mold must be pressed against the fixed mold with a pressure (pressing force) higher than the molding pressure. The mold must be able to withstand this pressing force. When the mold is formed of a graphite material, the above-mentioned (1)
Although the advantages of (6) above are provided for a so-called mold, the strength against applied pressure is not as high as the mold.

Second, when the mold is formed of graphite material, if there is a gap between the graphite material and a member supporting the same, the graphite material is broken by a pressure change during a molding cycle using the graphite mold. The mold itself will be damaged. In order to avoid this, it is necessary to support the mold made of the graphite material without any gap.

Therefore, the present inventors have conducted various studies on how to give sufficient strength to the graphite mold while making full use of the characteristics of the graphite material as a mold. It was completed.

(Problems to be Solved by the Invention) The present invention has been made based on the above background, and a problem to be solved is to guarantee the strength of a graphite mold while sufficiently utilizing the characteristics of graphite. .

An object of the present invention is to provide a graphite mold for plastic molding which has good workability, is easy to handle, and can sufficiently guarantee strength.

(Means and Actions for Solving the Problems) In order to solve the above problems, first, means taken by the invention according to the first claim will be described with reference numerals used in the embodiments. The base material (21) of the mold used for is formed of an isotropic graphite material, and part or all of the surface of the mold other than the molding cavity surface (22) of the isotropic graphite material is formed of a metal reinforcing member ( In a graphite mold (20) for plastic molding, which is supported by 23) to protect a substrate (21) made of an isotropic graphite material, the bottom surface (21a) of the substrate (21) is reinforced by a reinforcing member ( The support member (23) is brought into contact with the support member (23), and a support portion (24) integrally provided on both sides of the base material (21) is bolted to the reinforcement member (23) by a bolt (25). For plastic molding characterized by being pressed against the surface (20) "it is.

Here, the portion where the reinforcing member (23) is formed needs to be at least part or all of the mold surface other than the surface of the molding cavity (22). The reason is that the mold surface is formed by the reinforcing member (23) on the side of the molding cavity (22), and there is no point in meaninglessly forming the graphite mold (20) for plastic molding with a graphite material. As a matter of course, in the mold of the type in which the movable mold is pressed against the fixed mold, this is for reinforcing the outside of the molding cavity (22) in the direction in which the pressing force is applied.

To this end, the bottom surface (21a) of the base member (21) is brought into contact with the reinforcing member (23), and the support portions (24) provided integrally on both sides of the base member (21) are connected to the reinforcing member (23). It is necessary to support the reinforcing member (23) by pressing with a bolt (25) screwed on the side of the reinforcing member (23). That is, since the bottom surface (21a) of the base member (21) and the reinforcing member (23) are completely in close contact with each other, a problematic gap is always formed between the base member (21) and the reinforcing member (23). The support portion (24) formed integrally with the base material (21) is pressed and supported by a bolt (25) which is screwed and fixed to the reinforcing member (23). It is important.

In the graphite mold for plastic molding (20) according to the first aspect of the invention configured as described above, first, the base material is formed of a graphite material.
The cutting resistance is as low as 1/5 to 1/10, and the processing is very easy. Also, since the coefficient of thermal expansion is small, the molding accuracy is very high.

In the graphite mold for plastic molding (20), the bottom surface (21a) of the graphite base (21) located on the opposite side of the molding cavity (22) is reinforced by a reinforcing member (23). Although protected as shown in the figure, when a force is externally applied to the plastic molding graphite mold (20), the force is applied via the reinforcing member (23) to the plastic molding graphite mold (20). Distributed throughout. That is, the reinforcing member (23) ensures the strength of the graphite base material constituting the graphite mold (20) for plastic molding and also satisfactorily disperses the applied force.

Therefore, the entire surface of the bottom surface (21a) of the base material (21) is supported by the reinforcing member (23), and the base material (2
Since each support part (24) integral with 1) is pressed against the reinforcing member (23) by each bolt (25) screwed to the reinforcing member (23), the base member (21) and the reinforcing member (23) There is no gap between them, which allows the graphite substrate (21)
Is not damaged by externally applied forces.

Further, since a molding pressure of the injected ceramic material is applied to the molding cavity (22), the pressure is directly applied to the graphite base (21).
Is backed up by the reinforcing member (23), so that the molding pressure does not cause cracking or breakage.

Means adopted by the invention according to the second claim is, similarly, that “a base material (21) of a mold used for plastic molding is formed of a graphite material, and another part other than a molding cavity surface (22) of the graphite material is used. In a graphite mold for plastic molding (20) in which a part or all of the mold surface is supported by a metal reinforcing member (23) to protect a base material (21) made of a graphite material, A support member (24) is provided integrally on both sides of the support member, and the support member (24) is divided into two parts.
A graphite mold (20) for plastic molding, characterized in that these reinforcing members (23) are fixed to each other by bolts (25).

That is, what is important in the present invention is that the base material (2
The support portions (24) protruding on both sides of 1) are integrally formed on the base material (21) in the same manner as the graphite mold for plastic molding (20) according to the first claim. As shown in FIG. 4, the supporting portion (24) has a shape that can be sandwiched by the divided reinforcing members (23), and these supporting portions (24) are sandwiched by the reinforcing members (23). After the attachment, the reinforcing members (23) are fastened by bolts (25).

And in the graphite mold for plastic molding (20) thus constituted, the reinforcing member (23) in which the base material (21) is divided into two parts at each support part (24) formed integrally therewith.
The base material (21) is held without gaps by the divided reinforcing member (23). In particular, in the embodiment shown in FIG. 4, the lower surface of each support portion (24) is supported without any gap by the reinforcing member (23) located on the lower side in the figure.
The upper and lower surfaces of 4) and the end face of the step with the substrate (21) are held in a state of completely abutting on each reinforcing member (23).

Further, the means adopted by the invention according to the third claim is a method similar to that described above, wherein a base material (21) of a mold used for plastic molding is formed of a graphite material, and a part other than a molding cavity surface (22) of the graphite material is formed. In a graphite mold for plastic molding (20) in which a part or all of the mold surface is supported by a metal reinforcing member (23) to protect a substrate (21) made of a graphite material, A metal presser (26) is interposed between the reinforcing member (23) and the reinforcing member (23).
Reinforcing member (23) with bolt (25) screwed to 3)
A graphite mold for plastic molding (20), "

That is, what is important in the present invention is that the base material (21) made of a graphite material and the reinforcing member (23) made of a metal material are used.
For example, as shown in FIG. 7 or FIG. 8, a pusher (26) made of a metal material is interposed while being in contact with both, and the pusher (26) is provided with a reinforcing member ( Two
3) Reinforcing member (2
It is fixed to 3). In the embodiment described below, a pair of pushers (26) having a size to abut each of two adjacent sides of the substantially square base material (21) are employed. The other two sides of the substrate (21) are pressed against the reinforcing member (23) by the child (26).

In the graphite mold for plastic molding (20) according to the third aspect configured as described above, when fixing the base material (21) to the reinforcing member (23) via the presser (26),
The fastening of the pusher (26) with the bolt (25) can be performed while adjusting the contact state of the base material (21) with the reinforcing member (23). That is, in the graphite mold (20) for plastic molding shown in FIG.
By adjusting the amount of screwing of the bolt (25) to the reinforcing member (23), the presser (26) presses the substrate (21) to the left in the drawing, and the substrate (21) is fixed to the reinforcing member (23). (21) can be fixed. In addition, in the graphite mold (20) for plastic molding shown in FIG. 8, the presser (26) is configured to abut the inclined surface (23a) of the reinforcing member (23) by its inclined surface (26a). The pusher (26) can be moved to the left in the figure by adjusting the amount of fastening of the bolt (25) to the reinforcing member (23).

Therefore, in this graphite mold for plastic molding (20), by adjusting the amount of fastening of each pusher (26) to the reinforcing member (23) by the bolt (25), any one of the bases (21) can be formed. The surface supports the reinforcing member (23)
The contact is securely and without any gap, and the pressing force at the time of the contact can be adjusted by the tightening amount of each bolt (25).

In the invention according to the fourth aspect, the presser (26) in the graphite mold for plastic molding (20) according to the third aspect has an inclined surface (26a) and the inclined surface (26a). (26a) comes into contact with the inclined surface (24a) formed on the base material (21).

That is, in the graphite mold for plastic molding (20), a support portion (24) is integrally formed on a side portion of the base material (21), and the support portion (24) has an inclined surface (24a).
The inclined surface (24a) needs to have the following inclination. That is, the inclined surface (24a) is formed by the molding cavity (22) of the base material (21).
It is necessary to incline in such a state that it extends from the bottom surface (21a) to the bottom surface (21a), whereby the component force of the force received through the inclined surface (24a) is transmitted to the bottom surface (21a) of the base material (21) and the reinforcing member. (23) is made to work in the direction of supporting the pressure contact.

In the graphite mold (20) for plastic molding according to the fourth aspect configured as described above, when each pusher (26) is fixed to the reinforcing member (23) side by a bolt (25), this pusher ( The inclined surface (26a) of 26) presses the inclined surface (24a) on the base material (21) side, and a part of the pressing force reinforces the base material (21) through the inclined surface (24a). The base member (21) is pressed and supported against the reinforcing member (23) in a state of being in close contact with the reinforcing member (23). Thus, the base member (21) is held by the reinforcing member (23) without a gap, and the base member (21) having the molding cavity (22) is not easily broken. Further, even if the outer shape of the base material (21), particularly the size changes due to repair of the base material (21) or the like, the angle of the inclined surface (24a) formed on the support portion (24) of the base material (21) is changed. By constantly adjusting the pressing force of the pusher (26) with the bolt (25) without changing the shape of other members, the base material (21) is always reinforced in a stable state The member (23) can be pressed and supported.

(Example) Next, the graphite mold for plastic molding according to each invention (20)
Will be described in accordance with examples. In FIG. 1, a graphite mold (20) for plastic molding according to each invention is connected to an injection molding machine (1).
0), the injection molding machine (1
0) is the plastic material input from the hopper,
While being pressurized and kneaded by the screw (11) in the cylinder (12), it is sent to the molding cavity (22) on the side of the graphite mold for plastic molding (20), and at the same time, the plastic material is heated to its plasticizing temperature. It has become. Then, the plasticized plastic material is forcibly fed into the cavity of the graphite mold (20) for plastic molding according to the present invention.

Graphite mold for plastic molding (20) is the base material (21)
Is made of a graphite material. In the embodiment shown in FIGS. 1 and 5, it is of a two-part type.

Using an isotropic graphite material, a fixed mold and a movable mold for forming a mold as shown in FIG. 5 were formed, and a mold for injection molding was produced. The processing time required for this forming was reduced to about 1/8 compared to the metal forming.

In this graphite mold for plastic molding (20), as shown in FIG. 1 or FIG. 2, metal mold is applied to at least the mold surface other than the molding cavity (22) surface of the graphite base material (21). The member (23) is formed integrally. In particular, in the embodiment shown in FIG. 1, the graphite mold for plastic molding (20) is of a two-part type of a fixed mold and a movable mold, and the surface of the reinforcing member (23) fixed to each mold side. Are formed so as to coincide with the parting surfaces of the fixed mold and the movable mold. Thus, when the fixed mold and the movable mold are pressed against each other by a strong pressing force, the protection between the fixed mold and the movable mold made of these graphite materials is ensured.

In addition, although the example which employ | adopted what was comprised as what extended also to the side part of the molding cavity (22) as the reinforcement member (23) in a present Example is shown, this has very high molding pressure. This is to deal with the case where the side area of the product is very large. Therefore, when a flat or similar plastic product is molded, the reinforcing member (23) is used as the molding cavity (22).
Need not be configured to extend to the side portion of.

Although various materials can be considered as a material for forming the reinforcing member (23), a metal is most suitable, and in this embodiment, a metal used as a so-called mold material such as S50C steel or SCM steel is used. Material used.

The above is the embodiment common to the respective inventions. Next, embodiments showing the characteristic portions of each invention will be described separately.

-Regarding the graphite mold (20) for plastic molding according to the first claim FIGS. 2 and 3 show the graphite mold (20) for plastic molding according to the first claim. The base material (21) constituting (20) is stored in a storage portion formed in the central portion of the reinforcing member (23), and the bottom surface (21a) of the base member (21) stores the reinforcing member (23). It comes into contact with the inner surface of the part. And this base material (21)
On both sides (upper and lower sides in FIG. 2), support portions (24) as shown in FIG. 3 are integrally formed, and these support portions (24) are reinforced by bolts (25). 23) Pressed and fixed to the side. Thus, the base material (21) is pressed and supported on the reinforcing member (23) at the bottom surface (21a). Of course, each support part (24) is formed at a place that does not interfere with the molding cavity (22), and the bolt (25) inserted into this support part (24) is connected to another base material (21) or the like (not shown). It is fastened in a state where it is pushed into the support portion (24) so as not to come into contact with it.

-Regarding the graphite mold (20) for plastic molding according to the second claim FIG. 4 is a cross-sectional view of the graphite mold (20) for plastic molding according to the second claim. In the graphite mold for plastic molding (20), the base material (2
The support portions (24) protruding from both sides of 1) are integrally formed, but in this case, each support portion (24) becomes a plate-like shape from the center of the base material (21) to the side. It protrudes.
Each of these support portions (24) is sandwiched by each of the sandwiching surfaces (23b) of the reinforcing member (23) which is equally divided into two, and each of the sandwiching surfaces (23b) is a surface of each of the support portions (24). It completely abuts the step formed at the end of the base material (21). Then, the reinforcing member (23) divided into two is sandwiched by the support portions (24) of the base material (21) in the state shown in FIG. 4 and integrated by tightening the bolts (25). Because

Thereby, in the graphite mold for plastic molding (20), the holding of the base material (21) by the reinforcing member (23) is performed by the support portion (24) of the holding surface (23b) formed on the reinforcing member (23). And it is surely performed by the close contact of the step portion of the base material (21).

-Regarding the graphite mold (20) for plastic molding according to the third claim FIGS. 5 to 7 show the graphite mold (20) for plastic molding according to the third claim. Reinforcing member (23) for substrate (21) in mold (20)
Is supported via a pusher (26) arranged between the base material (21) and the reinforcing member (23). In this case, basically, as in the case of the graphite mold for plastic molding (20) according to the first claim, the base material (21) is made of a reinforcing member (23).
It is stored in the storage part formed in the center part of
The support of the base member (21) against the reinforcing member (23) is not performed by pressing the bottom surface (21a) of the base member (21) against the reinforcing member (23), but by pressing the side surface of the base member (21). (twenty three)
This is performed on the side surface inside the storage portion formed in the above. In particular, in the present embodiment, the upper left corner portion of the substantially square base material (21) shown in FIG. 6 is supported by being pressed toward the reinforcing member (23) by two sides sandwiching the upper left corner portion. It is like that.

That is, as shown in FIG. 6, the graphite mold for plastic molding (20) has substantially the same length as each side between the lower side and the right side of the base material (21) and the reinforcing member (23). The pushers (26) are housed therein. As shown in FIG. 7, these pushers (26) are bolts (25) arranged in the same direction as the bottom surface (21a) of the base material (21). ) Is pressed and supported on the opposite side. Therefore, each bolt (25) is formed on the reinforcing member (23) and screwed into a screw hole parallel to the bottom surface (21a) of the base material (21). ) Is set in consideration of the pressing of the reinforcing member (23). In particular, the pressing surface of each pusher (26) in the graphite mold for plastic molding (20) is orthogonal to the bottom surface (21a) of the substrate (21). For complete contact, the contact surface on the side of the base material (21) is also formed so as to be orthogonal to the bottom surface (21a).

FIG. 8 shows another embodiment of the graphite mold (20) for plastic molding according to the third aspect. In the graphite mold for plastic molding (20), the pusher (26) constituting the plastic mold (20) is provided on the side opposite to the surface in contact with the substrate (21).
Inclined surface (26) which gradually reduces the thickness of this pusher (26)
a) is formed, and of course, the inclined surface (23a) corresponding to the inclined surface (26a) of the pusher (26) is also provided on the reinforcing member (23) side.
Is formed. In this embodiment, a bolt (25) for attaching the pusher (26) to the reinforcing member (23) is used.
The direction of the axis is perpendicular to the bottom surface (21a) of the base material (21), and the pusher (2
By tightening 6) to the reinforcing member (23) side, the guide of the inclined surface (26a) on the pusher (26) side and the inclined surface (23a) on the reinforcing member (23) side guides the drawing in FIG. The pressing force to the left acts on the pusher (26). In order to make such an operation sufficient, the insertion hole for the bolt (25) formed in the pusher (26) is formed to allow the bolt (25) to work in the lateral direction. ) Are formed sufficiently larger than the diameter.

-Regarding the graphite mold (20) for plastic molding according to the fourth claim In Figs. 9 and 10, the graphite mold (20) for plastic molding according to the fourth claim is shown. The graphite mold (20) also has a pusher (26) arranged between the base material (21) and the reinforcing member (23). The graphite mold for plastic molding (20) differs from that according to the third claim in that the base material (21) has an inclined surface (24a) on its side surface.
The pusher (26) abutting on 1) also has an inclined surface (26a) corresponding to the inclined surface (24a). That is, the base material (21) is, as shown in FIGS. 9 and 10,
It has a support part (24) projecting to the side, and the support part (24) is formed with an inclined surface (24a). What is important in this case is that each inclined surface (24a) is moved from the side of the molding cavity (22) of the base material (21) to the bottom surface (21a).
, So that the pressing force of each pusher (26) is reduced by a component force in a direction parallel to the bottom surface (21a) of the base material (21) and the bottom surface (21a). Is to be divided into a component force for pressing the reinforcing member (23) side.

In order to achieve the above, in the embodiment shown in FIG. 9, each bolt (25) is connected to the reinforcing member (23) of the base material (21).
And the bolt (25) is screwed to the reinforcing member (23).
In the embodiment shown in FIG. 10, each of the bolts (25) is arranged in parallel with the reinforcing member (23) of the base material (21). The pusher (26) is pressed in the horizontal direction in the figure by adjusting the screwing amount with respect to (23). In any of the examples, the pressing force of the pusher (26) is increased by the interaction between the inclined surface (24a) on the base (21) side and the inclined surface (26a) on the pusher (26) side. The force can be divided into a direction parallel to the bottom surface (21a) of the base 21) and a force toward the bottom surface (21a) of the base member (21).

-Other graphite molds (20) for plastic molding The inventions described above can be implemented by appropriately combining them. For example, FIG. 11 shows an example in which the inventions according to the first and third claims are combined. In this graphite mold for plastic molding (20), the base (21) is formed by each presser (26). ) Is pressed in a predetermined direction, and the support portion (24) formed on the base material (21) in this state is attached to the reinforcing member (23) by the bottom surface (21a) of the base material (21).
It is fixed so as to be pressed against. Accordingly, in the graphite mold for plastic molding (20), the bottom surface (21a) of the base material (21) is pressed and supported by the reinforcing member (23) side, and the two sides of the base material (21). Are pressed against the corresponding two surfaces on the reinforcing member (23) side, and the support of the substrate (21) to the reinforcing member (23) is further strengthened.

In addition, by applying the invention according to the third or fourth claim to the graphite mold for plastic molding (20) according to the second claim, each support portion (2) of the base material (21) can be obtained.
4) The pressing force is generated not only between the reinforcing member (23) and the base material (21) by interposing each presser (26), but also by simply sandwiching the reinforcing member (23) into two parts. It is also possible to carry out.

(Effects of the Invention) With the above-described configuration, according to each invention, it is possible to provide a graphite mold for plastic molding which has good workability, is easy to handle, and can sufficiently guarantee strength. is there. In addition to this effect,
Each invention also has the following effects.

In the invention according to the first claim, the support portion (24) is integrally formed on the side of the base material (21), and the support portion (24)
Is fixed to the reinforcing member (23) side by the bolts (25), so that it is not necessary to apply such a complicated processing to the reinforcing member (23) side, and the base material (21) itself is This is because each supporting portion (24) can be formed by utilizing the easiness of processing the constituting graphite material, so that it is possible to easily form the graphite mold (20) for plastic molding as a whole. You can do it. In addition, the base material (21) is connected to the reinforcing member (2
3) Since the support can be made without any gap on the side, the press-contact support of the base member (21) to the reinforcing member (23) can be surely performed.

In the graphite mold for plastic molding (20) according to the second aspect, the support of the base material (21) with respect to the reinforcing member (23) is achieved by sandwiching each support portion (24) with the divided reinforcing member (23). Because it is made to do, reinforcement member (23)
The support force of the base material (21) by the support member (24) can be dispersed over the entire support portion (24), whereby the reinforcing member (2
The supporting of the substrate (21) by the method (3) can be performed without generating a local force. This allows
In the case where the entire substrate (21) is supported without gaps, the support can be performed safely and reliably.

In the graphite mold for plastic molding (20) according to the third aspect, the base member (21) is pressed and supported by the reinforcing member (23) via the presser (26). The base member (21) can be pressed in a predetermined direction of the reinforcing member (23) by the entire contact surface of the base member (21) with the base member (21). In other words, the support of the base member (21) against the reinforcing member (23) is not performed by the local force on the base member (21), but by using the maximum area that the base member (21) can press. Can be made, the presser (26)
The damage of the base material (21) due to the pressing force can be prevented as much as possible. In the graphite mold for plastic molding (20), the contact surface of the pusher (26) may be configured to contact the entire side surface of the base material (21). The entire contact surface is directly base material (21)
In addition to the fact that the contact can be made easier, the contact surface of the pusher (26) can be easily adjusted later.

And in the graphite mold (20) for plastic molding according to the fourth claim, in addition to the above-mentioned effects according to the third claim,
The pressing force of the pusher (26) can be finely adjusted later. That is, each pusher (26) has an inclined surface (26a) that comes into contact with the inclined surface (24a) on the base (21) side, and the inclined surface (26a) connects the base (21) to the reinforcing member ( 23) The force can be dispersed in the holding direction with respect to the base material (2
The pressing support of the reinforcing member (23) of 1) can be performed while finely adjusting the state without adversely affecting the base material (21). Also, while the base material (21) is used for a long period of time, by repairing the base material (21), the outer shape of the base material (21) itself may be different from the initial shape, Since the pressing support of the base member (21) against the reinforcing member (23) can be performed by fine adjustment of each pusher (26), it can sufficiently cope with this.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of a graphite mold for plastic molding according to the present invention and an injection molding machine employing the same, and FIG. 2 is a movable mold constituting the graphite mold for plastic molding according to the first claim. FIG. 3 is an enlarged sectional view of a main part taken along line III-III of FIG. 2, and FIG. 4 is a sectional view of a graphite mold for plastic molding according to the second claim. 5 to 8 show a graphite mold for plastic molding according to the third claim, and FIG. 5 is a cross-sectional view of a molding machine employing the graphite mold for plastic molding.
FIG. 6 is an enlarged plan view of the graphite mold for plastic molding,
FIG. 7 is an enlarged sectional view of a main part taken along the line VII-VII of FIG. 6, and FIG. 8 is an enlarged sectional view of a main part corresponding to FIG. 7 showing another embodiment. Further, FIG. 9 is an enlarged sectional view of the graphite mold for plastic molding according to the fourth claim, FIG. 10 is an enlarged sectional view of a main part showing another embodiment, and FIG. 11 is an invention according to the first claim. It is a top view which shows the graphite mold for plastic molding comprised combining the invention which concerns on 3rd claim. EXPLANATION OF SYMBOLS 10: Injection molding machine, 20: Graphite mold for plastic molding,
21: Base material, 21a: Bottom surface, 22: Mold cavity, 23
…… Reinforcing member, 23a …… Slope surface, 23b …… Clamping surface, 24 ……
Supporting portion, 24a: inclined surface, 25: bolt, 26: presser, 26a: inclined surface.

Continued on the front page (72) Inventor Shun Takagi 300 Aoyagi-cho, Ogaki-shi, Gifu IBIDEN Inside Aoyagi Plant (72) Inventor Jun-ichi Sato 654 Kawawa-cho, Midori-ku, Yokohama-shi, Kanagawa Prefecture Fujitsu Chemical Co., Ltd. (72) Inventor Saburo Shida 401, 2-7-14 Osaki, Shinagawa-ku, Tokyo (56) References JP-A-62-225312 (JP, A) JP-A-2-172708 (JP, A) JP-A Heisei JP-A-2-172706 (JP, A) JP-A-63-162205 (JP, A) JP-A-2-270509 (JP, A) JP-A-3-253313 (JP, A) U) (58) Field surveyed (Int. Cl. ⁷ , DB name) B29C 33/38

Claims (4)

(57) [Claims] A base material of a mold used for plastic molding is formed of an isotropic graphite material, and a part or all of a mold surface other than a molding cavity surface of the isotropic graphite material is formed of a metal reinforcing member. In the graphite mold for plastic molding, which is supported by and protects the base material made of the isotropic graphite material, while the bottom surface of the base material is brought into contact with the reinforcing member,
A graphite mold for plastic molding, wherein support portions integrally provided on both sides of the base member are pressed against the reinforcing member by bolts screwed to the reinforcing member side. 2. A base material of a mold used for plastic molding is formed of a graphite material, and a part or all of a surface of the graphite material other than a molding cavity surface is supported by a metal reinforcing member. In a graphite mold for plastic molding adapted to protect a base material made of a graphite material, a support part is integrally provided on both sides of the base material, and the support part is sandwiched by the reinforcing member divided into two parts. A graphite mold for plastic molding, wherein both reinforcing members are fixed to each other by bolts. 3. A base material of a mold used for plastic molding is formed of a graphite material, and a part or all of the surface of the graphite material other than a molding cavity surface is supported by a metal reinforcing member. In a graphite mold for plastic molding adapted to protect a base material made of a graphite material, a metal-type presser is interposed between the base material and the reinforcing member, and the presser is screwed to the reinforcing member. A graphite mold for plastic molding, which is fixed to the reinforcing member by bolts. 4. The graphite mold for plastic molding according to claim 3, wherein said presser has an inclined surface which comes into contact with an inclined surface formed on said base material.