JPS59229259A - Master mold for casting and molding method thereof by using shell sand - Google Patents

Abstract

PURPOSE:To form a master mold for casting which permits easy change in product shape by packing shell sand into the cavity part formed of a mold body for the cavity, a stationary mold body and a movable mold body, curing the sheel sand by heating and transferring the shape of the mold surface. CONSTITUTION:A stationary mold body 1 and a movable mold body 2 are moved to bring the bodies into press contact with a mold body 3 for a cavity then a blow head 12 is moved to be pressed to a sand blow port 13. Shell sand is blown and packed through the head 12 into the cavity part formed of the three mold bodies 1, 2, 3 and electricity is conducted to a heater 11. The part of the shell sand in contact with cavity forming parts 9, 10 is heated to cure by said conduction of electricity. A cured layer 14 formed in the above-mentioned way is transferred with the cavity shape of the body 3 and is usable as a stationary mold 15 and a movable mold 16 as it is.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an outer mold for fC casting, in which a cavity portion is formed by using shell molding sand, and a method for manufacturing the same.

(Prior Art) In the conventional mold casting method, a part of the cavity is formed using a metal mold that is assembled with a plurality of mold surfaces, so defects such as galling and deformation are likely to occur. Furthermore, when changing the shape of a product, all parts of the mold had to be corrected, which required a large amount of man-hours.

Further, there is a shell molding method to obtain a part of the integrated cavity f', but this method requires a long process and requires complicated steps such as peeling off the shell and assembling a mold.

(Objective of the Invention) The object of the present invention is to provide an outer casting mold that can easily change the shape of a product in place of a conventional mold, and to provide a molding method thereof.

The present inventor has developed shell casting sand (hereinafter simply referred to as shell sand) by using only the part that forms the cavity of each part of the mold.
The present invention was completed by noting that forming the cavity by the above method does not cause defects during casting as in conventional methods, and that the shape of the cavity can be changed without modifying the entire mold.

(Structure of the Invention) That is, the present invention uses shell sand to form a part of the cavity with shell sand inside the mold body, and the mold is constituted by such a fixed mold and a movable mold. This is a characteristic feature.

Furthermore, the casting mold method of the present invention involves crimping the fixed mold body and the movable mold body from both sides of the cavity mold body, thereby forming a gap between the cavity mold body and the fixed mold body or the movable mold body. After filling the cavity with shell sand, heating is performed by a heating device previously installed in the cavity mold body to transfer the shape of the cavity mold body to the shell sand. It is something.

Embodiments of the present invention will be described below with reference to the drawings.

(Example) In Fig. 1, 1 is a fixed mold body, 2 is a movable mold body, and 3 is a mold body for a fixed cavity. It is manufactured into a predetermined shape by etc. The fixed body 1 and the movable body 2 are provided with a gas vent pipe 4 and a gas vent hole 5, respectively, and the movable body 2 is also provided with an extrusion bottle 6 and an extrusion plate 7.
This is provided. On the other hand, the mold body 3 for fixed cavity is
It consists of a mold body part 8 and cavity forming parts 9 and 10, and a heater 11 is built in the mold body part 8.

The fixed mold main body 1 and the movable mold main body 2 sandwich the fixed cavity mold main body 3 therein and can be opened and closed freely in the direction of the arrow (in the left and right directions in the figure), and further in the lateral direction (perpendicular to the figure). It is also possible to move

To mold the casting outer mold of the present invention, the fixed mold body 1 and the movable mold body 2 are moved in a direction approaching each other by the operation of the cylinder, and the mold body 3 for the cavity is moved as shown in FIG.
71' low head 12.12
Move it from the position shown in the figure and press it against the sand blowing ports 13, 13.

In this way, the preparation for filling the shell with sand is completed, and then the blow head 12.
Blow in shell sand from 2, and when it is filled, heater 1
1, the part of the filled shell sand in contact with the cavity forming part 9.10 reaches a temperature of, for example, 300 to 400°C.
It is heated to harden. In this way, 'n7' is formed.
(The shape of the cavity of the fixed cavity mold body 3 is transferred to the hardened layer 14, so the fixed mold 1
5. Can be used as a movable type 16.

The above operation is performed, for example, at the position A in FIG. After returning to the position shown in FIG.
The mold is closed and the metal is poured into the mold through the sprue. At this time, in order to prevent deformation of the cast product and occurrence of appearance sink marks due to gas generated from the shell sand, gas is sucked through the holes 18 of the gas vent 117 buried in the shell sand in advance. While the cast mold is further moved in the direction of the arrow in FIG. 3, the hot water solidifies, so the fixed mold 15 and the movable mold 16 are opened at the position C in FIG. 3, and the extrusion bottle 6 is operated. Then remove all the product and destroy the mold. Next, at position D, air is blown into the gas vent pipe 4 to clean the insides of the fixed mold 15 and movable mold 16, and the process returns to position A to repeat the above steps again.

(Effects of the Invention) As mentioned above, in the outer mold of the present invention, a part of the cavity is formed by shell sand integrated into the mold body, so even when changing the shape of the product, only a part of the cavity needs to be modified, unlike the conventional method. There is no need to modify the entire mold. Since a part of the cavity is made of shell sand, it has good ventilation, and there is no occurrence of galling or appearance defects. This eliminates the need for vents and gas needles that were conventionally attached to areas where appearance defects were likely to occur.

In addition, according to the method of the present invention, the fixed cavity can be used to continuously form the entire cast outer mold, and it can be directly connected to the casting process, so it is suitable for the aging of decayed products. This significantly reduces manufacturing costs.

[Brief explanation of the drawing]

FIG. 11 shows a side view of an embodiment of the present invention (molding method), FIG. 2 shows a partial sectional view of the embodiment of the invention (outer mold), and FIG. 3 shows an explanatory diagram of the process. In the figure,

Claims (1)

[Claims] (1) An outer mold for casting using 1+-Luciel sand, characterized in that it consists of a fixed mold and a movable mold, in which a part of the cavity is formed from shell casting sand. After filling the cavity formed between the fixed mold body and the movable mold body with shell sand, it is heated by a heating device installed in the cavity mold body to heat the cavity mold body. A method for forming an outer mold characterized by transferring the shape of the mold surface onto shell sand.