JPS59153565A - Casting mold for vacuum casting and mounting method thereof - Google Patents

Abstract

PURPOSE:To mount easily a casting mold which can produce a thin-walled casting having good dimensional accuracy without generating gas holes by providing plural recesses on the side faces of a sand mold opened with a runner from the cavity formed of the top and bottom dies toward the lower side. CONSTITUTION:A top mold 1 having a cavity and a bottom mold 3 penetrated with a runner from the cavity to the lower part are combined and stuck to form a casting mold 5 which is a sand mold. A flask 6 for mounting the casting mold is cylindrical and supports pawl parts 7 having plural projections in the lower part on the inside of the lower opening of said flask are supported by means of pins 7a, so that the upper parts of said pawls are made movable. A suspended pipe 8 is attached in the upper part of the flask 6 and has an evacuating port 9 for venting air. Recesses 1a conforming to the pawls 7 are provided on the mold 5 side. The flask 6 is lowered onto the mold 5 and the pawls 7 are entered in the recesses 1a, then the upper parts of the pawls 7 move to the recess side in the recesses 1a and stop in the bottom of the recess. The mold 5 is then held by the flask 6 and at the same time the side faces of the mold are held by means of a sealant 11.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a casting mold used for pressure reduction and a method for installing the same.

It was held down by formwork from the side and poured from the sprue at the top.

In the Suda shell stack mold, there was a presser from the top even though there was no side presser, and the metal was poured from the sprue in the same way. Moreover, since it is a cast product, a riser is also required to remove the gas generated from the sand mold and shell, and the ratio of these parts is high compared to the runner and riser and the cast product, and the yield is low. It is.

An alternative method is low-pressure casting, but since the mold is made of metal, it is cold and cannot be used for casting unless it is preheated. It does not fill even the thinner parts of the tank. In addition, since the mold is a metal mold, it has good airtightness, but since the gas in the gears and tee parts of the mold is not removed, there are many problems such as gas defects easily occurring in the product due to the gas getting caught up in the mold.

The present invention solves these drawbacks and provides a simple method for installing a mold using the vacuum casting method, which does not cause gas defects and can produce thin-walled castings with good dimensional accuracy. The purpose is to

The present invention is a vacuum casting mold that is made of a sand mold in which a cavity is formed by an upper mold and a lower mold, and a runner is opened below the cavity. The mold and the dividing surface of the mold are fixed to form an integral mold, and the mold can be inserted into a recess provided on the side surface of the integral mold by using the concave and convex portions on the inside of the mold frame for simple and convenient installation. It is something that exists.

Embodiments of the present invention will be explained with reference to the drawings. Fig. 1 is a sectional view of the upper mold and the lower mold, Fig. 2 is a sectional view of the combination of the upper mold and the lower mold and the mold mounting frame, and Fig. 3 is a sectional view of the mold mounting frame. The inside state diagram, FIG. 4, is a partially enlarged view of the mold mounting frame shown in FIG. 2.

In the figure, 1 is an upper mold, 2 is a cavity, 3 is a lower mold, and a runner 4 penetrates from the cavity 2 to the lower part, and these are combined to form a mold 5.

Reference numeral 6 denotes a mold mounting frame, which has a cylindrical shape and is open at the bottom, and has a claw portion 7 having a plurality of convex portions at the inner bottom thereof. The claw part 7 is supported by a bottle 7a, and the upper part is supported by an elastic material 7b.
It can be moved at. A suspended pipe 8 is attached to the upper part of the mold mounting frame 6, has a decompression port 9 for releasing air, and is connected to a vacuum pump (not shown).

In such a configuration, first the upper mold and the lower mold are formed with the necessary cavities 2 and sprues 4, respectively, and then the upper mold and the lower mold are glued together with an adhesive, or unevenness, fitting holes, or protrusions are formed. The mold 5 is fixed by positioning and seams etc., and a predetermined mold 5 is obtained. At the same time, mold groove (=J) is placed on the side of the mold.
A recess 1a corresponding to the claw portion 7 of the frame 6 is installed. The mold shall be a sand mold with air passage. The mold mounting frame 6 is lowered onto the formed mold 5, and the claw portion 7 of the mold mounting frame 6 is brought into contact with the side surface of the mold until it reaches the recess 1a. In the recess 1a,
The upper part of the claw part 7 moves toward the fourth part by the elastic member 7b and stops at the bottom of the recess. As a result, the -C1 mold 5 is held by the mold mounting frame 6 due to the insertion and removal of the claws 7 at a plurality of locations, and at the same time, the sides of the mold are held by the sealing material 11 located above the claws 7. Next, the vacuum pump is rotated to vacuum the gap 12 between the mold mounting frame 6 and the mold 5, and gradually
When the runner 4 becomes vacuum, the mold 5 is attached and the mold mounting frame 6 is moved onto a crucible or melting furnace (not shown) filled with the molten metal 13, and the runner 4 is immersed in the molten metal. 13 is not filled in the cavity.

The side surface of the mold 5 is used to attach the mold to the mold mounting frame 6, and although only the upper mold has a recessed part in Fig. 3, the lower mold is attached because the upper mold and the lower mold are fixed to form an integral mold. A furnace may also be used by providing a recess on the side of the mold.

Additionally, by making the outer shape of the upper mold 1 smaller than that of the lower mold 3 and holding it in the same manner as above with the lower mold 3, it is possible to narrow the cavity 10 in the frame of several molds and speed up the cycle time. It is what it is.

The inside of the mold mounting frame 6 is desirably tapered inward toward the top.

As explained above, the claws of the present invention can be inserted into the recesses on the side surface of the mold to facilitate attachment to the mold flask, and at the same time have the effect of improving immediate vacuum performance.

[Brief explanation of drawings]

Figure 1 is a sectional view of the upper and lower molds, Figure 2 is a sectional view of the combination of molds and the mold mounting frame, Figure 3 is a diagram of the state during casting after the mold is installed, and Figure 4 is the mold of Figure 2. FIG. 3 is a partially enlarged sectional view of the mounting frame.

Claims (1)

[Scope of Claims] 1. A sand mold having a cavity formed by an upper mold and a lower mold and a runner opened below the cavity is characterized in that a plurality of recesses are provided on the sides of the mold. Tozuru vacuum casting mold. 2. The divided surfaces of the upper and lower molds are fixed together to form an integral mold, and a convex part on the inside of the mold mounting frame is inserted into the concave part of the mold to make it easy to install. A method for preparing a mold for vacuum casting, characterized in that: 3. A convex portion on the inside of the mold receptacle (-1) moves in and out according to the unevenness of the mold.
How to install the vacuum casting mold described in Section 1.