JPS58215241A - Molding method of casting mold - Google Patents

Abstract

PURPOSE:To obtain a casting mold having high dimensional accuracy without using any org. binder by coating a mold coating material on the surface of a pattern, packing molding sand contg. a self-curing inorg. binder as a binder in the pattern, allowing the sand to cure and transferring the mold coating with induction heating. CONSTITUTION:A mold coating material is coated on the surface of a pattern 1, whereafter molding sand added with a self-curing inorg. binder such as Portland cement as a binder is packed in the pattern and is allowed to cure. The pattern is then heated by high frequency induction heating to move the mold coating film from the pattern 1 to the sand mold 3 side, thereby transferring the mold coating 2. The casting mold having high dimensional accuracy and a smooth surface is molded stably by using the above-mentioned method without using any thermosetting org. binder.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a mold making method. A mold making method is known in which foundry sand using a thermosetting organic binder as a binding agent is poured into a model coated with a liquid mold coating agent, and heated using a dielectric heating method to harden the foundry sand and transfer the coating mold. ing. However, the mold making method using heat (, +, ox organic binder) requires a lot of thermal energy to harden the mold, and a large amount of gas when pouring.
In addition, there was a problem in that dust was generated and the work environment deteriorated. In addition, when dielectric heating is used as a heating method, the frequency of the current used is confusing, and there are concerns that it may affect the human body.
Various considerations were necessary in relation to the radio wave frequency law.

In view of the circumstances described in Section 2, this invention does not use a thermosetting binder, and produces UJ with a smooth surface that is characterized by the precision of the method.
Its purpose is to provide a mold making method that allows molds to be made (74), and its characteristics are as follows:
After applying the molding agent to the model surface, it becomes self-hardening! 1 (1) Molding sand containing machine binder as a binder is filled in the mold, hardened, and the coating mold is transferred by induction heating.

FIGS. 1 and 2 are explanatory diagrams illustrating the molding method according to the present invention, and a detailed explanation will be given below based on these diagrams.

As the model (2), commonly used molds such as wooden molds and metal molds can be used. After applying a liquid mold coating agent to the surface of this model 10 by brushing or the like, it is filled with foundry sand to which self-hardening inorganic binder is added as a binder. As the self-hardening inorganic binder, an inorganic binder that hardens through a chemical reaction, such as a hydraulic inorganic binder such as Portland cement or alumina cement, can be used.

This foundry sand hardens over time, or may be subjected to a suitable heat treatment to accelerate hardening. After filling the molding sand into the model coated with the φ molding agent, heating is performed by image frequency induction heating, and the coating mold 2 is transferred. If the model is a wooden mold or other non-conductive mold, it may be necessary to add a conductive substance (for example, an electrolyte solution) to the mold coating agent.This heating will cause the coating film to move from model 1 to sand mold 3. In order to ensure efficient transfer in this case, there are substances in the coating agent that promote induction heating, such as iron oxide,
It is desirable to add an appropriate amount of special additives such as silicon carbide. If the model 1 is a mold, the model itself generates heat, so such special additives are not necessary. The mold thus obtained has two coated mold layers on its surface, so its precision is poor and its surface is extremely smooth. First, embodiments of the present invention will be described.

〔Example〕

Directly apply the coating agent described in 1. to the surface of the model with the uneven shape shown in Figure 1 by brushing.
wet sand).

(φ type agent) (Note) * A normal solution of Na0+1 or K01-1 was used.

(Kneaded sand for SJ mold) Next, a coil was placed around the outer periphery of the model 1, and heating was performed using high frequency induction heating (5 kW, 1QN river 1 grade) to transfer the coating mold 2. During this heating, 6
■There was no generation of flammable gas and no large amount of heat radiation. As a result, as shown in FIG. 2, a desired mold was obtained in which a coating layer (about 1 layer thick) was formed on the surface of the sand mold 3. This mold had no defects such as cracks on its surface and had extremely high precision.

As explained above, the mold making method according to the present invention involves self-hardening the foundry sand to which a self-hardening inorganic binder has been added, and transferring the coating layer to the surface of the molding sand, which improves stability. It is possible to easily create molds with excellent precision. Since the heating necessary for transferring the coating mold is performed using an induction heating method, the coating mold can be heated uniformly over the entire surface, and various considerations related to the frequency quotient can be avoided when using the dielectric heating method. is not necessary, and the heating device is easy to handle. In addition, there is no need to heat the sand mold to harden it, and the heat energy input is mainly used to transfer the coating mold, so the amount of heat energy required is small, and from an energy saving perspective. It is extremely excellent. Furthermore, since inorganic bi/tar is used as a binder, less scum is generated during pouring, and the working environment can be maintained in a good condition.

[Brief explanation of the drawing]

FIGS. 1 and 2 are explanatory views of the molding method according to the present invention. ■ ・Model, 2...painting mold, 3...sand mold. Patent applicant Yamakawa Sangyo Co., Ltd. Agent Patent attorney Hiroshi Sugawara

Claims (1)

[Claims] (1) After applying a mold coating to the model surface, molding sand containing self-hardening inorganic binder as a binder is filled with it, hardened, and the coating is transferred using an induction heating method. A mold making method.