JPH04251632A - Method for molding mold - Google Patents

Abstract

PURPOSE:To remove troubles turning-over a mold and faults flowing-out a molten metal from a jointing face part at the time of a casting, etc., in the case of dividing the mold into a cope and a drag as the conventional method and to accurately obtain the reproductibity of mold having the shape of propeller, etc., in the mold used to casting of industrial product having complicate shape of propeller for a marine vessel and the others. CONSTITUTION:The organic series resin-made fine grains 2 are sealed in a flexible bag 1 for obtaining the above-mentioned target and after storing an inner mold shape by using a numerical controlled roller, etc., to this bag 1, air in the bag 1 is gradually removed and the shape of propeller, etc., is held and this is perfectly embedded into a sand mold 6, and after hardening the sand mold, by inserting a suction pipe 5 into the bag 1, the fine grains 2 in the bag 1 are sucked to the outer part. There after, by taking out the flexible bag 1 together with a hose 3 and the suction pipe 5 from the sand mold 6, the mold is completed.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for making molds used for casting marine propellers and other various industrial castings.

0002

[Prior Art] Conventionally, for example, a method for making molds for propellers of ships, etc., uses a plurality of templates that match the cross-sectional shape of the propeller blades, and after producing the upper and lower molds separately, they are combined. The so-called block molding method or frame molding method is commonly known.

0003

[Problems to be Solved by the Invention] However, such conventional casting manufacturing methods have the following problems. (1) Since the shape of the wing is molded using a plurality of templates that reproduce the partial cross-sectional shape of the wing, it is difficult to precisely reproduce the shape of the wing. (2) The mold must be finished manually, which takes a lot of man-hours. (3) The upper and lower molds must be manufactured separately, which increases the number of man-hours such as reversing the molds and aligning the molds, and there is a risk that molten metal may flow out from the alignment area during casting, leading to a serious accident.

[0004] The present invention aims to solve the above-mentioned problems and provide a new molding method that makes it possible to accurately reproduce molds with complex shapes such as wing surfaces without dividing the mold into an upper mold and a lower mold. It is something.

[0005]

[Means for Solving the Problems] Therefore, the mold making method of the present invention uses a machine such as a numerically controlled roller to mold a flexible bag containing fine particles made of an organic resin or other various materials. The shape of the inner mold is copied and memorized, and then the air inside the bag is gradually removed and vacuum is made to maintain the shape of the wing, etc., and the flexible bag retains the shape of the inner mold such as the wing shape. The mold is completed by completely embedding the mold in the foundry sand mold, inserting a suction tube into the bag to suck out the fine particles inside the bag, and then pulling out the bag from the sand mold. There is.

[0006]

[Operation] The mold making method of the present invention has the above-mentioned structure, and includes free deformation of fine particles sealed in a flexible bag due to external pressure, and memorization by creating a vacuum inside the bag. This makes it possible to reliably maintain the shape of the inner mold, and furthermore, by burying a flexible bag that maintains the shape of the inner mold in molding sand and sucking out the fine particles inside the bag with a suction pipe in the hardening mold, the mold is removed. The mold can be completed by sucking out the fine particles to the outside without dispersing the particles, and then pulling out the bag from the foundry sand mold, making it possible to obtain molds with complex shapes, such as the shape of propeller blades, with sufficient precision.

[0007]

[Example] An embodiment of the present invention will be explained below with reference to the drawings. Figs. 1 to 3 are schematic illustrations showing the manufacturing process of an airfoil as an embodiment of the invention, and Fig. 4 is a diagram showing the manufacturing process of an airfoil as an embodiment of the invention. It is an explanatory view showing a manufacturing method of a sand mold.

In FIGS. 1 to 3, polyethylene resin particles 2 with a diameter of about 2 mm, for example, are sealed inside a flexible bag 1 made of a material such as polyethylene or urethane rubber with a thickness of about 1 mm, and then an NC roller 4 is used to shape the wing surface. After transferring the image onto the flexible bag 1, the air inside the bag is gradually evacuated to about 10-1 torr using the hose 3 to maintain the shape.

Next, as shown in FIG. 4, the flexible bag 1 in which the shape of the wing surface was copied was embedded in a sand mold 6 made of silica sand mixed with 10% cement by weight, and the mold was hardened at room temperature. After that, the hose 3 attached to one end of the flexible bag 1 (
Another somewhat thin suction hose 5 is inserted into the bag (with an outer diameter of 20 mm and an inner diameter of 16 mm), and the fine particles 2 in the bag 1 are sucked out to the outside. At this time, the hose 3 is made of a material that is hard enough not to collapse even when suctioned by the suction hose 5, so the hose 3
Air flows in between the hose 5 and the hose 5. Thereafter, the flexible bag 1 is also pulled out from the sand mold 6 along with the hoses 3 and 5 to complete the mold.

0010

Effects of the Invention As described above, according to the mold making method of the present invention, it is possible to accurately reproduce molds with the shape of blades such as propellers having complex shapes, and the mold can be used as an upper mold as in the conventional method. By not manufacturing the lower mold separately, man-hours such as reversing the mold and alignment can be omitted, and accidents caused by molten metal flowing out from the alignment part can be prevented.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing a first step in an airfoil manufacturing process as an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a second step of manufacturing an airfoil in the same embodiment.

FIG. 3 is an explanatory diagram showing the third step of manufacturing an airfoil in the same example.

FIG. 4 is a cross-sectional explanatory diagram showing the sand mold forming method in the same example.

[Explanation of symbols] 1 Flexible bag 2. Fine particles 3 Hose 4 Roller 6 Sand mold

Claims (1)

[Claims] 1. A flexible bag filled with fine particles made of organic resin and other various materials is memorized using a machine such as a numerically controlled roller, and then the air inside the bag is gradually removed. The shape is maintained by applying a vacuum, and then the flexible bag, which maintains the inner shape, is embedded in a foundry sand mold, and the mold is hardened. Thereafter, a suction tube is inserted into the bag to remove the fine particles inside the bag. A method for making a mold, characterized in that after the bag is suctioned and discharged, the bag is further extracted from the foundry sand mold to complete the mold.