JPS589742A - Molding method for mold - Google Patents

Abstract

PURPOSE:To obtain molds of extremely high dimensional accuracy by electrically heating the sand mold consisting of the molding sand obtd. by adding binders and a good electrical conductor material to wet sand treated with an electrolyte soln. and a mold coat consisting of a refractory mold coating material. CONSTITUTION:A refractory mold coating material is coated on the surface of a pattern 1 to form a mold coat 2, and the molding sand obtd. by adding and mixing inorg. and org. binders and a good electrical conductor material to and with the wet sand treated in an electrolyte soln. is cast thereon, whereby a sand mold 3 is formed. The mold coat 2 and the sand mold 3 are heated electrically over the entire part via electrodes 4, whereby the transfer of the moled coat to the sand mold and the dehydration and consolidation of the sand mold are effected simultaneously. The mold coating material of graphite type, zircon type or the like is used, and this is used after it is mixed with an aq. soln. of NaOH, etc. The wet sand treated with an aq. soln. of NaOH, etc. is used for the molding material after it is mixed with an inorg. binder such as bentonite and an org. binder such as starch and a good electrical conductor material.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a mold 114 method including the transfer of a coated mold onto a mold.

Conventionally, the binder used in the mold making method is
Regardless of whether organic or inorganic materials were used, after kneading and molding, the model was removed and the mold was painted. Therefore, a large number of man-hours are required, and the dimensional accuracy of the product is greatly affected by the skill or inadequacy of the coating mold. and〈K
In recent years, mold making methods using organic binders have been adopted in the foundry industry, and many advantages have been confirmed.
On the other hand, it cannot be said to be a perfect method as it has many drawbacks.

Therefore, the present invention has advantages that are completely comparable to molds using organic binders, and also has disadvantages that make it difficult to use.
-1. The purpose is to provide a rapid and high-quality mold manufacturing method that does not generate CO gas or dust during frame disassembly.

In other words, Jin's invention involves molding sand obtained by adding and mixing inorganic and organic binders and electrically conductive substances to wet sand treated in an electrolyte solution, and applying a resistive, natural molding agent to the surface in advance. The casting mold is characterized by pouring it around the model and heating the entire coating mold and sand mold with electricity, thereby simultaneously performing the transfer of the coating mold to the sand mold and the dehydration and consolidation of the sand mold.

Method K is below.

Another important feature of the present invention is that it is clean, resource-saving, and energy-saving, and meets the needs of the current era. A method has already been developed in which cement is mixed with silica sand and then energized.1 However, cement itself has the property of self-hardening, and it is natural that energizing such materials will cause hardening. The curing principle is completely different from the use of a binder as in the present invention.

The present invention will be explained in detail below.

The materials used in the present invention may be non-polluting, easily available and inexpensive materials.

First, as a fire-resistant coating agent, a general fire-resistant coating agent such as a commercially available graphite-based zircon type coating agent is used, and this is mixed with an electrolyte solution such as sodium chloride, potassium chloride, or calcium hydroxide. Consists of those obtained by mixing with an aqueous solution.

On the other hand, as a molding material, for example, an inorganic binder such as bentonite, kibushi clay, C, M-C, hexametaphosphoric acid, etc. or a number of compounds may be added to the wet state treated in an electrolyte solution as described above. Use the added mixture. Starch is also effective as an organic binder.

Apply the above mold coating agent to the surface of the wooden mold or metal mold. In the case of a wooden model, the coating aK on the wooden mold surface creates a non-conductive film.

The above-mentioned molding agent, kneaded sand, is poured and filled onto the model coated with the coating agent, and in this state, the entire coating mold and sand mold are heated with electricity.

Next, examples will be described. FIG. 1 is an explanatory diagram of the present invention.

In the figure, (1) shows a model, (3) shows a sand mold, (4) shows a current-carrying electrode, and (5) shows wiring to a power source.

Examples of the formulation of the coating mold and the mixing sand are as follows.

0) Coating type Graphite-based coating agent 100 parts Bentonite 3 parts Electrolyte solution 7 parts Hexametaphosphoric acid 4 parts (1)
Kneaded sand Treated sand in electrolyte solution 100 parts Bentonite 6 parts Good conducting material 6 parts were applied and filled sequentially as shown in Figure 1, then the electrode (4) was set □, and as a result of energizing, the result was about 20~ 4
The coating was completely transferred to the mold in 0 minutes, and the mold was completely dehydrated and solidified, and a mold with extremely high dimensional accuracy was obtained. The relationship between the lotus and mold anti-pressure force at this time is shown in Figure 2. First, in Figure 2, the energization time (minutes) on one axis,
The vertical axis shows the counter pressure (9.8 curves A and B).
, C are 100V and t5A, respectively. □ Judging from the results obtained above, the mold produced according to the present invention fully satisfies the requirements for a mold, the manufacturing time is quick, and the mold is easy to coat. The transfer into the mold was quick and the dimensional accuracy was also high.

Furthermore, since conventional molds are decomposed in the atmosphere, the emission of dust is a serious problem, whereas the method of this invention has the special feature of easily disintegrating just by immersing them in water. Because of this, there is no environmental pollution and it is extremely advantageous.

In addition, once used, 100 yen of Kusa sand can be collected in a wet state and recycled, making it a valuable resource with great benefits.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the present invention, and FIG. 2 is a curve diagram showing the relationship between current application time □ and mold resistance pressure in the previous invention. -Pa (1)...Model Q)...Painting mold (3)
...Casting sand mold (4)...Electrode,
” □ ・ ”Kidney

Claims (1)

[Claims] Foundry sand obtained by adding and mixing inorganic and organic binders and electrically conductive substances to wet sand treated in an electrolyte solution is placed around a model whose caulked surface has been coated with a fire-resistant coating agent. A mold making method characterized by pouring and heating the entire coated mold and sand mold with electricity, thereby simultaneously performing transfer of the coated mold onto the sand mold and dehydration and consolidation of the sand mold.