JPH0422536A - Pattern for molding mold and method for molding mold - Google Patents

Abstract

PURPOSE:To recover shape with heating and to facilitate forming of a pattern by forming the pattern for molding mold with shape memory resin. CONSTITUTION:The shape memory resin-made pattern 5 is prepared and set to the prescribed position and sand 9 is packed along the shape of pattern 5. Successively, this is heated to the prescribed temp. and the pattern 5 is recovered into the shape being suitable to pull out to pull out the pattern 5. Therefore, even if the pattern 5 has complicated shape being difficult to pull out after molding the mold, as the pattern comes to the shape being suitable to pull out with recovery of the shape, this can be smoothly pulled out.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a molding model and a molding method, and particularly relates to a molding model using a shape memory resin.

(The section to be solved by the prior art and the invention) When manufacturing molds, for example, cores, the inside of the core is made to reduce the weight of the core and the amount of sand used. Pulling out is done. This product is conventionally manufactured as shown in FIG.

A core upper mold 103 is placed on the plate 101,
A hollow portion 105 of a predetermined shape is formed in this upper core mold 103 . In the middle of the hollow part 105 there is a protruding part 1 on the outside.
05a is formed.

On the other hand, on the plate 101 and within the hollow portion 105, a core lower mold 107 is arranged.

This core lower mold 107 includes a first lower mold 109 and a second lower mold 1.
10, and a nested third lower mold 111 divided into three equal parts. The reason why the lower core mold 107 is divided in this manner is to enable the drawing to be performed later when the protruding portion 105a is present.

In the above configuration, sand 115 is filled through the sand filling hole 113 formed in the upper core mold 103. The sand 115 is filled between the upper core mold 103 and the lower core mold 107, and is hardened at room temperature to form the core 117.

After the core 117 is formed, the plate 101 is lowered and the second lower mold 110 is pulled out, and then the third lower mold 111 is pulled out.
After pulling out inward one by one, the first lower mold 109 is pulled out.

This configuration has the following problems.

As already mentioned, the core lower mold 107 is divided into a large number of parts in consideration of withdrawal, which increases the number of steps required to manufacture the core 117, making the work complicated and increasing costs. There was a problem with this.

Such problems have been a problem not only in the production of the core, but also in the production of the main mold.

Similar problems also occur when manufacturing sprues used during casting. This will be explained with reference to FIG.

FIG. 9 is a diagram showing the configuration of the casting apparatus, in which a frame 201 is filled with sand 203, and a hollow part 205 (which will become a product part) of a predetermined shape and a sprue 207 are formed.

The sprue 207 is formed in a tapered shape so that its diameter decreases upward. The reason why the sprue 207 has such a shape is to take into account the fact that the weir rod that serves as a mold for forming the sprue 207 is pulled out from below.

However, if the sprue 207 has such a shape,
Due to the large volume of the lower part, there was a problem in that when pouring hot water, it was difficult for air to escape, causing air to be drawn in, resulting in product defects.

The present invention has been made based on the above points, and its purpose is to provide a molding model that facilitates molding, as well as a molding method using such a molding model. Our goal is to provide the following.

(Means for Solving the Problems) In order to achieve the above object, a molding model according to the present invention is characterized by being made of a shape memory resin.

Further, the molding model is characterized by comprising a split mold block and a holding member made of shape memory resin.

Furthermore, the mold forming method according to the present invention includes a step of arranging a model made of shape memory resin, a step of filling it with sand, and a step of restoring the model to a pre-given shape suitable for drawing by heating to a predetermined temperature. The present invention is characterized by comprising a step of pulling it out.

(effect) A molding model is formed from shape memory resin.

Therefore, during molding, the work becomes easier, the number of steps is reduced, and costs can be reduced.

In addition, when the model is formed using split mold blocks and a holding member made of shape memory resin, the work becomes easier, and
The number of steps is reduced, and costs can be reduced.

Next, in the case of the molding method, first, a model made of shape memory resin is prepared and placed at a predetermined location.

Next, fill it with sand. The sand is filled according to the shape of the model.

Next, the model is heated to a predetermined temperature to restore the shape to a predetermined shape suitable for drawing, and is then pulled out. Even if the model has a complicated shape that is difficult to pull out after molding, it can be pulled out smoothly because the shape recovery makes the model suitable for pulling out.

(Example) A first embodiment of the present invention will be described below with reference to FIG.

FIG. 1 shows the application of the present invention to the production of cores.

First, a core upper mold 1 is arranged, and this core upper mold 1 is split in half and can be divided into pieces 1a1 lb. Further, a hollow part 3 of a predetermined shape is formed in the upper core mold 1, and the hollow part 3 has an outwardly protruding part 3a in the middle thereof.

On the other hand, a model 5 as a core lower mold made of shape memory resin is provided on a plate 6 and inserted into the hollow part 3 of the core upper mold 1. this is,
This is provided to hollow out the inside of the core, thereby reducing the amount of core sand used and making the core lighter.

Further, a heating/cooling medium introduction hole 13 is formed in the plate 6, and a heating/cooling medium pipe 15 is connected to this heating/cooling medium introduction hole 13.

When making the model 5, shape memory resin is, for example, 15
Heat to 0°C to create and memorize the original shape. This shape is such that the model 5 as the lower core mold can be easily pulled downward after core molding (for example, the shape shown by the dotted chain line in FIG. 1).

Note that examples of such shape memory resins include Nosolenx (trade name, manufactured by Nippon Zeon Co., Ltd.).

In the case of this embodiment, the model 5 is first inserted into the core upper mold 1.

After inserting the model 5, hot water or hot air is supplied through the heating/cooling medium pipe 15 and the heating/cooling medium introduction hole 13 to heat it to about 40 to 50°C,
Pressure is applied to expand it, and the surface thereof and the surface of the hollow portion 5 are placed in a state where they are appropriately separated from each other.

Then, instead of hot water or hot air, cold water or cold air is supplied through the heating/cooling medium piping 15 and the heating/cooling medium introduction hole 13 to cool the model 5 to about 10° C. and solidify it. At this time, the shape of the model 5 remains unchanged.

Next, the sand filling hole 7 formed in the upper core mold 1 is filled with sand 9. This sand 9 has gas hardening properties, and by supplying gas, it hardens in a shape that follows the shape of the space between the upper core mold 1 and the model 5.

Next, model 5 is taken out. In this case, via the heating/cooling medium pipe 15 and the heating/cooling medium introduction hole 13,
Supply hot water or warm air again to heat model 5 to 40°C to 50°C.
It is heated to about °C and then this hot water or hot air is discharged. By this heating, the model 5 is restored to the pre-memorized shape as shown by the two-dot chain line in the figure. In this state,
Pull out the model 5, then remove the upper core mold 1.
A core 11 having a predetermined shape can be obtained.

According to this embodiment, the following effects can be achieved.

First, manufacturing of the core 11 becomes easier. This is because the model 5 is made of shape memory resin and can be easily pulled out by heating and restoring the shape.

Therefore, even if the model has a shape that is difficult to pull out after molding, there is no need to construct the model by dividing it into a plurality of pieces as in the past, and it is easy to handle.

Moreover, since the number of work steps is also reduced, it is possible to reduce the labor and time required for work, and it is possible to reduce costs.

Furthermore, since it is made of shape memory resin, it can be processed at low temperatures and is easy to work with.

Next, a second embodiment will be described with reference to FIG.

This embodiment is also an example of manufacturing a core, and a split mold block 23 is held by a holding member 21 made of shape memory resin.
It is designed to support.

First, the core upper mold 25 is arranged, and this core upper mold 2
A hollow portion 27 of a predetermined shape is formed within the hollow portion 5 . The upper part of the hollow part 27 protrudes outward, so that the lower mold of the core must be a split mold. A split mold block 23 serving as a core lower mold is inserted into the hollow portion 27 . The split mold block 23 is divided into a plurality of pieces (four pieces in this example) 29 so that they can be pulled out later.

A pressing member 21 is arranged inside the split block 23. This pressing member 21 has a substantially hollow shape, and is made of shape-memory resin, as described above, and has the shape shown by the dotted chain line in FIG. 2 memorized in advance.

A heating/cooling medium pipe 31 is connected to the holding member 21, and a heating/cooling medium is supplied into and discharged from the holding member 21 through the heating/cooling medium pipe 31.

In the above configuration, first, the split block 23 is assembled. Next, the holding member 21 is inserted inside the split mold block 23. Next, hot water or hot air is supplied to the holding member 21 through the heating/cooling medium piping 31, and
It is heated to about 0° C., expanded by applying pressure, and brought into contact with the split mold block 23. Then, instead of hot water or hot air, cold water or cold air is supplied via the heating/cooling medium pipe 31 to cool the pressing member 21 to about 10°C. By this cooling, the holding member 21 is solidified,
The split mold block 23 is supported from the inside.

A core upper mold 25 is placed there.

Next, the space between the upper core mold 25 and the split mold block 23 is filled with sand to form the core 33. Next, hot water or hot air is supplied into the holding member 21 through the heating/cooling medium piping 31 to heat the holding member 21 to about 40°C to 50°C, and then this hot water or hot air is heated to about 40°C to 50°C. Discharge. By this heating, the holding member 21 is restored to its original memorized shape, so that it can be easily pulled out from inside the split mold block 23. After that, by dividing the split mold block 23 and pulling it out, a core 33 of a predetermined shape can be obtained.

In the case of this embodiment, the following effects can be achieved.

First, manufacturing of the core 33 becomes easier. This is because the holding member 21 of the split mold block 23 is made of shape memory resin, and by heating and restoring its shape, it can be easily pulled out from the narrow entrance.

Further, since the number of work steps is reduced, it is possible to reduce the labor and time required for the work, and it is also possible to waste materials.

Furthermore, since it is made of shape memory resin, it can be processed at low temperatures and is easy to work with.

Next, a third embodiment will be described with reference to FIG.

In this embodiment, the present invention is applied to the manufacture of a main mold.

First, there is a frame 41, and within this frame 41, a model 43 of a predetermined shape is placed. This model 43 has a shape that is difficult to pull out and has an outwardly protruding portion, and is placed on a plate 45 .

This model 43 is made of shape memory resin, and first,
After forming the mold, a shape that can be easily pulled out from the mold (for example, the shape indicated by the dotted chain line in Fig. 3) is memorized in advance, and then this is heated to soften it and deformed into the shape of the product by applying an external force (for example, , the model 43 is made hollow, hot water is supplied inside, internal pressure is applied, and the model 43 is pressed against a mold, etc.), and the model 43 is cooled and solidified in that state.

Then, with this model 43 placed inside the frame 41, sand 47 is filled. The sand 47 is room temperature hardening,
Just by filling it, it hardens into a predetermined shape along the shape of the model 43.

Next, the model 43 is heated to about 40"C to 50"C to recover its original shape.The model 43 is then pulled out from the mold by lowering the plate 45.

In this way, the main mold 49 having a predetermined shape can be obtained.

In the case of the second embodiment, the following effects can be achieved.

First, even if the model has a complicated shape and is difficult to pull out from the mold, the mold can be easily manufactured without using a nest or core. This is because the model is made of shape memory resin and can be easily pulled out by heating and restoring its shape.

Furthermore, since the number of work steps is reduced, it is possible to reduce the amount of labor and time required for the work. As a result, costs can be reduced.

Furthermore, since it is made of shape memory resin, it can be processed at low temperatures and is easy to work with.

In addition, the surface of the model is clean, demolding is easy, and the product is finished neatly.

Next, a fourth embodiment will be described with reference to FIG.

This uses a model made of shape memory resin to manufacture the sprue.

There is a frame 51, and within this frame 51, models 53 (products) and 55 are placed.
(riseer) and a model 57 for forming a sprue.
(hereinafter referred to as a weir).

The models 53 to 57 are made of shape memory resin and placed on a plate 59.

After forming the mold, the weir rod 57 has a shape that allows the model to be punched out downward in the figure (the shape indicated by the dotted chain line in Figure 4), and is further heated while applying an external force. In addition, it is deformed into a tapered shape so that its diameter increases upward, and is then cooled and solidified.

Then, with the models 53 to 57 placed inside the frame 51, sand 61 is filled. The sand 61 hardens at room temperature, and hardens along the shapes of the models 53 to 57 just by being filled.

Next, the models 53 to 57 are heated to about 40°C to 50'C. This heating restores the models 53 to 57 to their memorized shapes. By lowering the plate 59 in this state, the models 53 to 57 are pulled out.

As mentioned above, after forming the mold, the weir rod can be punched out downward, so when forming the mold, a tapered rod whose diameter decreases downward is used to form the rod. The sprue also took on a similar shape.

In this way, in the case of this embodiment, the weir rod 57 is made of shape memory resin, and the problem of pulling it out is solved, so it is possible to form a tapered sprue whose diameter decreases downward. . Therefore, the problem of air entrainment can be solved.

Next, a fifth embodiment will be described with reference to FIGS. 5 to 7. This example also applies the present invention to the molding of the main mold.

First, as shown in Fig. 5.6, a lattice-shaped holding frame 65 is arranged above the lower mold model 63, and this holding frame 65 prevents the mold from cracking or being lifted by the hot water pressure during pouring. It is to be kept so that it does not occur.

Further, an upper mold 67 is arranged in a hollow part within the lower mold 63, and the intermediate part thereof becomes a part filled with sand of the upper mold.

This upper model 67 has a hollow body shape and is made of a shape memory resin, and has been given a memory in advance to an elongated shape (the shape indicated by the dotted chain line in FIG. 5) that can pass through the lattice of the holding frame 65.
In this state, the lower model 63 is passed through the lattice of the holding frame 65.
Insert inside.

Then, hot water or hot air is supplied into the upper model 67 to heat it to about 40° C. to 50° C. and pressurize it to expand it. At this time, an appropriate distance from the lower model 63 is provided. Next, the upper model 67 is cooled to about 1°C and solidified.

Next, sand is filled between the lower model 63 and the upper model 67 to manufacture a sand mold 69. Sand hardens at room temperature, so it hardens naturally just by filling it. Also, at this time,
A hot water lower 1 is also formed.

Then, the upper model 63 is heated again to about 40° C. to 50° C. to recover its original elongated shape, and then pulled out from the lattice of the holding frame 65.

Next, as shown in FIG.
3 and combined with a separately formed lower mold 73, the product is manufactured by pouring molten metal into the intermediate portion 75 between the two.

In the case of this embodiment as well, the main mold is easy to manufacture, and by forming a cavity in the upper mold during molding of the main mold, it is possible to reduce wasteful use of sand.

Note that the present invention is not limited to the above embodiments.

For example, not all of the model but a part of it may be made of shape memory resin.

Further, as shown in the second embodiment, shape memory resin can also be used as the holding member for the split mold block.

Further, the heating/cooling medium supply means may have separate systems for supply and discharge.

(Effects of the Invention) According to the mold-forming model and mold-forming method according to the present invention, the mold can be easily molded and costs can be reduced.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a core forming apparatus according to a first embodiment of the present invention, FIG. 2 is a sectional view of a core forming apparatus according to a second embodiment,
Figure 3 is a sectional view of the main mold forming device according to the third embodiment;
The figure is a sectional view of the casting device according to the fourth embodiment, FIGS. 5 and 6 are views showing the fifth embodiment, FIG. 5 is a sectional view of the main mold forming device, and FIG. ■-■ arrow view, FIG. 7 is a sectional view showing a state in which molded molds are combined, FIGS. 8 and 9 are views showing a conventional example, and FIG. 8 is a sectional view of a core molding device. FIG. 9 is a sectional view of the casting apparatus. 1... Core upper mold, 3... Hollow part, 5... Model, 7
... Sand filling hole, 9... Sand, 11... Core, 13.
... Heating/cooling medium introduction hole, 15... Piping for heating/cooling medium.

Claims (3)

[Claims] (1) A molding model characterized by being made of shape memory resin. (2) The molding model according to claim 1, wherein the model comprises a split mold block and a holding member made of shape memory resin. (3) a step of arranging a model made of shape memory resin; a step of filling with sand; and a step of heating the model to a predetermined temperature to recover the shape suitable for pulling out and pulling it out. A mold forming method characterized by the following.