JP2006088177A - Method for manufacturing pattern for lost foam - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a pattern for lost foam with which a small number of patterns can be produced at a low cost and a date of delivery of the finish product can be shortened more than the conventional method. <P>SOLUTION: A block 18 of a lost foaming body is held with a holding device 20 and a working tool 10 is held with a working machine 16, so that the holding device 20 and the working machine 16 are made to change the positions and the angles in a relatively free directions. The block 18 is directly worked with the working tool 10 to manufacture a desired pattern 24 for lost foam. A wooden pattern or a metallic pattern is unnecessary to manufacture by directly manufacturing the pattern 24 for lost foam from the block 18, and in the case of needing a small number of the pattern 24 for lost foam, the manufacturing cost is reduced and also, a small number of patterns 24 for lost foam can be manufactured for short term and the date of delivery can drastically be shortened. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing a disappearing model that disappears due to molten metal during casting.

  Conventionally, when a product is produced by casting, the molten metal is poured into a space formed inside the mold, and after the molten metal is cooled, the mold is removed and the product is taken out. As a method for producing a mold, a method called a wood mold method has been conventionally known. In the wooden mold method, a wooden mold with the same shape as the product is made, and the mold (the upper mold and the lower mold) for finally casting the product is formed while repeatedly creating the inverted mold with sand or gypsum. Is.

  In this tree pattern method, a tree pattern must be made, but there is a drawback that the cost of manufacturing the tree pattern is high. Since the wooden mold requires storage and maintenance, it also has the disadvantage of high management costs. In addition, since the three-dimensional solid data and CAD / CAM cannot be used for the tree pattern, it cannot be applied to similar tree patterns. Furthermore, in the wooden mold method, when there is a space inside the product, the core has to be used, which is expensive to manufacture the core. In addition, advanced technology was required when making complex products, such as the need for drafts for extracting wooden molds. In addition, burrs appear in the finished product, and finishing was necessary.

  As a casting method for improving the drawbacks of the wooden mold method, a full mold casting method shown in Patent Document 1 has been proposed. Here, a product casting method by the full mold casting method will be described with reference to FIGS. In the full mold casting method, first, a disappearance model 30 (FIG. 3) made of a disappearable foam such as expanded polystyrene (a foam having a property of disappearing by a high-temperature molten metal) is manufactured by a mold. The disappearance model 30 is formed by integrally forming a product part 32 having the same shape as the final product and a hot water introduction part 34 communicating with the product part 32.

  Next, as shown in FIG. 4, the disappearing model 30 made of a disappearing foam such as expanded polystyrene is put in a frame 36, and the disappearing model 30 is filled with a sand mold 38. At that time, the free end of the hot water introducing portion 34 is exposed from the sand mold 38. Thereafter, the molten material of the material of the final product is poured from the opening of the hot water introduction section 34. The molten metal spreads throughout the vanishing model 30 while melting the vanishing model 30 that is a vanishing foam. As a result, the volume of the disappearing model 30 is replaced with the material of the final product. The material of the final product includes not only metals but also synthetic resins such as urethane.

  After the molten metal is cooled, the frame 36 is removed and the sand mold 38 is broken, so that the cast product 44 including the product part 40 and the hot water introducing part 42 shown in FIG. 5 can be taken out. The product part 40 can be made into a final product by cutting the part 42. Since the vanishing model 30 made of the vanishing foam is made of a mold, the surface accuracy of the vanishing model 30 can be a fine finished surface. Thus, since the surface of the product part 40 taken out from the sand mold 38 has a fine finished surface, it is not necessary to finish the surface of the product part 40 again.

Japanese Patent Laid-Open No. 5-237592

  In the full mold casting method, it has been necessary to make a mold (not shown) for making the disappearing model 30 made of a disappearing foam. Depending on the size and shape of the final product, the mold manufacturing costs are generally expensive, ranging from several hundred thousand to several million yen. Since the mold is expensive, the full mold casting method has been applied only when producing a large amount of the final product, that is, the disappearing model 30.

  If the final product is manufactured in large quantities, it is reasonable to make a mold for making the disappearance model 30. However, if only a small number of final products are manufactured, make an expensive mold. Was not cost effective, so a small number of final products could not be made by the full mold casting method. For this reason, in the case where only a small number of final products are manufactured, the wooden method has been conventionally employed. However, because it takes time to manufacture the wooden mold, it takes at least about two weeks from the time the product is ordered until the delivery date of the product, and it cannot meet the demand for shortening the delivery date of the final product from the supplier. There was a drawback. Even if the full mold casting method is adopted without considering the cost, it takes time to manufacture the mold for making the disappearance model 30. As with the law, it took at least about two weeks, and it was impossible to meet the demand for shortening the delivery time of the final product from the supplier.

  The present invention has been made in view of the above points, and an object thereof is to provide a method for producing a disappearing model that can produce a small number at a low cost and can significantly reduce the delivery time of the final product compared to the conventional method. It is what.

  In order to achieve the above object, the present invention holds a block of an extinguished foam by a holding device, holds a processing tool by a processing machine, and allows the holding device and the processing machine to be free from relative positions and angles. The vanishing model is directly created from the block with the processing tool. The present invention stores a relative position and angle between the holding device and the processing machine when manufacturing the first first disappearance model in a computer so that the second and subsequent disappearance models are manufactured. The computer is configured to trace the relative position and angle of the first first holding device and the processing machine. In the present invention, the processing tool is composed of a hemispherical portion at the tip and a cylindrical portion following the semispherical portion.

  The present invention is applied when a small number of vanishing models are manufactured, and a vanishing model is directly produced and manufactured with a processing tool in a block made of a vanishing foam. In the present invention, since it is not necessary to make a wooden mold or a metal mold, the manufacturing cost is low, and the manufacturing time of a small number of disappearing models can be greatly shortened. As a result, it is suitable for manufacturing a small variety of products and can meet the demand for short delivery times.

  Next, the present invention will be described with reference to the drawings. FIG. 1 is a view showing the front and side of an example of a processing tool used in the method for manufacturing a disappearance model according to the present invention. The processing tool 10 used in the present invention is obtained by integrally connecting a hemispherical portion 12 on the front end side and a cylindrical portion 14 subsequent thereto. In the hemispherical portion 12, the height H may be larger or smaller than the radius (1 / 2D). That is, the “hemisphere” in the present invention is not limited to a shape in which the center of the tip protrudes and is not necessarily cut into halves. The hemispherical portion 12 preferably has a plurality of blades extending from the zenith portion to the connecting portion with the cylindrical portion 14 in a spiral shape. Further, it is preferable that the blade formed in the cylindrical portion 14 extends from the hemispherical portion 12 in a spiral shape to the end of the cylindrical portion 14 in the axial direction. As the blade of the processing tool 10, one that finely finishes the surface of the disappearing foam to be processed is used.

  Next, a method for manufacturing the disappearance model using the processing tool 10 will be described with reference to FIG. As shown in FIG. 2, the processing tool 10 is attached to a processing machine 16 such as a ball mill. The processing machine 16 is installed on the ground. A block 18 made of a disappearing foam such as expanded polystyrene is prepared, and the block 18 is held by a chuck 22 of a holding device 20. It is assumed that the holding device 20 can change its position and angle in a free direction such as up, down, left, and right with respect to the ground (processing machine 16). That is, the block 18 made of the disappearing foam is set so that the position and the angle can be freely changed with respect to the processing tool 10. The position of the block 18 (holding device 20) can be moved with respect to the ground without moving the position of the processing tool 10 (processing machine 16) with respect to the ground. The position of the machine 16) may be movable with respect to the ground, and the position of the block 18 (holding device 20) may not be moved with respect to the ground. That is, it is sufficient that one of the processing tool 10 and the block 18 can be freely moved by changing the position and angle relative to the other, and the operation is performed by the computer 23.

  The hemispherical portion 12 of the processing tool 10 is used when a groove, a dent, or a curved surface is formed on the block 18. On the other hand, the cylindrical portion 14 of the processing tool 10 is used when forming and processing a plane. Since one of the processing tool 10 and the block 18 is set so as to be movable at any angle with respect to the other, it can be formed and processed in any shape. As a result, for example, the disappearance model 24 shown in FIG. 3 can be directly processed from the block 18 made of the disappearing foam using the processing tool 10. The vanishing model 24 has the same shape as the vanishing model (vanishing model 30 shown in FIG. 3) made of a conventional mold for convenience of explanation. This vanishing model 24 connects a product part 26 (the same shape as the product part 40 made of a conventional mold) and a hot water introduction part 28 (the same shape as the hot water introduction part 42 made of a conventional mold). It is of shape.

  In the present invention, the machining tool 10 including the hemispherical portion 12 and the cylindrical portion 14 forms and processes grooves, dents, curved surfaces, and planes, so that it is not necessary to replace the machining tool 10. For this reason, compared with what uses a some processing tool, if the processing tool 10 which consists of the hemispherical part 12 and the cylindrical part 14 is used, processing time can be shortened.

  As described above, according to the present invention, the disappearance model 24 having a desired shape is directly created from the block 18 of the disappearing foam such as foamed polystyrene using the processing tool 10. Evanescent foams such as expanded polystyrene have good workability and have the advantage that 3D solid data and CAD / CAM can be used easily. Further, when the first first disappearance model 24 is made from the block 18, the computer 23 stores the relative position and angle between the holding device 20 and the processing machine 16, and the second and subsequent disappearance models. At the time of manufacturing 24, the computer 23 causes the relative position and angle between the first holding device 20 and the processing machine 16 to be traced. As a result, the manufacturing time of the second and subsequent disappearance models 24 can be greatly shortened.

  As described above, in the present invention, when a small number of products are requested to be manufactured, a small number of disappearance models 24 can be made in a short period of time. A small number of requested products can be manufactured in a short time. In the present invention, it is not necessary to create a tree pattern as compared with the conventional tree pattern method, and therefore a small number of disappearance models 24 can be created in a short time. By using the small number of disappearance models 24, a small number of final products can be manufactured in a short time, and the delivery time of a small number of final products can be greatly shortened. Further, the present invention does not require an expensive mold for making the disappearance model 30 as compared with the conventional full mold casting method. Since the disappearance model 24 can be manufactured in a short time, the final product can be delivered in a short time. Furthermore, by using a finishing blade for the processing tool 10, the surface of the vanishing model 24 can be made fine, and the product can be made as cast (no surface processing after casting is required). it can.

It is a figure which shows the front and side of an example of the processing tool used for the manufacturing method of the model for disappearance concerning the present invention. It is the schematic which shows the method of manufacturing the model for disappearance using a processing tool. It is a front view of the model for disappearance. It is sectional drawing which shows the state which put the model for disappearance in the sand mold. It is a disassembled sectional view which shows the state which isolate | separates a product part and a hot water introducing | transducing part from the casting manufactured with the sand mold.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Processing tool 12 Hemispherical part 14 Cylindrical part 16 Processing machine 18 Block 20 Holding device 23 Computer 24 Disappearance model 26 Product part

Claims (3)

Holding the block of the vanishing foam with a holding device, holding the processing tool with a processing machine, setting the holding device and the processing machine so that the relative position and angle can be freely changed, and the processing tool A method for producing a disappearance model, wherein the disappearance model is created directly from the block. The relative position and angle between the holding device and the processing machine when the first first disappearance model is manufactured are stored in a computer, and the first time when the second and later disappearance models are manufactured, 2. The method for manufacturing an erasure model according to claim 1, wherein the first holding device and the processing machine are traced in relative positions and angles. 2. The method for manufacturing a vanishing model according to claim 1, wherein the processing tool is composed of a hemispherical portion at the tip and a cylindrical portion following the hemispherical portion.

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