JPS59185543A - Forming method of casting mold - Google Patents

Abstract

PURPOSE:To harden uniformly a casting mold formed of molding sand with a small amt. of binder by packing the molding sand contg. a specifically composed water-soluble binder into the space formed of a pattern plate and a molding flask to mold the casting mold, and rapping the mold then coating said water- soluble binder on the mold and curing the binder by hot wind. CONSTITUTION:A pattern plate 1 provided with a pattern is enclosed with a molding flask 2, and molding sand S kneaded with a water-soluble binder is packed under pressure into the space formed of said plate and flask. A binder of the compsn. consisting essentially of saccharides, a water-soluble crosslinking agent selected from the methylol- or alkylated methylol-urea or melamine, and a catalyst for reaction of said crosslinking agent selected from an org. acid, inorg. acid or the metallic salt, ammonium salt or alkanol amine salt thereof is used as said binder. Such casting mold is rapped from the pattern plate and the above-mentioned water-soluble binder or the water soluble binder contg. suitable heat-resistant aggregate is uniformly spray-coated on the surface thereof and thereafter hot wind or the like is passed through the mold to cure the mold.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for molding a mold using foundry sand mixed with a water-soluble binder, and more specifically, the present invention relates to a method for molding a mold using foundry sand mixed with a water-soluble binder. a water-soluble crosslinking agent selected from the group consisting of compounds;
Foundry sand kneaded with a water-soluble binder containing as an essential component a catalyst for the reaction of the crosslinking agent selected from organic acids, inorganic acids, or their metal salts, ammonium salts, or alkanolamine salts. This invention relates to a mold making method using a mold making method.

That is, the present invention uses a water-soluble binder whose main component is sugar, which has the property of becoming water-insoluble and self-hardening through a chemical reaction, and which makes it possible to obtain a mold with high hardness with a small amount of addition. The purpose is to provide a method.

The present invention will be explained below based on examples.

As shown in Fig. 1, a wooden model plate with a model (1) is placed on the soil surface, and a casting flask (2) is placed on it.
), a saccharide, a water-soluble crosslinking agent selected from the group consisting of a methylolated product or an alkylated methylolated product of urea or melamine, an organic acid,
A water-soluble binder (hereinafter referred to as water-soluble binder) containing as an essential component a catalyst for the reaction of the crosslinking agent selected from inorganic acids or their metal salts, ammonium salts, or alkanolamine salts. Added and kneaded foundry sand (S) (
The foundry sand (hereinafter referred to as foundry sand) is packed while being compacted to a predetermined density.
S) After smoothing the upper surface so that it is approximately flush with the upper surface of the casting flask (2), as shown in Fig. 2, attach the Geed Parakin (3) to the lower surface, and (3) A plate material (5) having a plurality of ventilation holes (4) penetrating through the lower surface and a vent plug (not shown) embedded in the ventilation holes (4) is attached to the casting flask (2). Place the molding sand ( Release the model plate (1) with model from S) (Fig. 3). At this time, since the foundry sand (S) is packed to a predetermined density and the viscosity of the water-soluble binder acts between the sand particles, the model plate with model (1) cannot be released from the mold. However, it never loses its shape. Next, as shown in FIG. 4, an aqueous solution of a water-soluble binder or an aqueous solution containing a water-soluble binder and heat-resistant aggregate in an appropriate ratio is sprayed onto the surface of the mold of the foundry sand (S). The molding sand (S) is applied in a mist form 1 using the device (6), and permeates evenly onto the surface of the mold. After coating, the cover member (8) equipped with the air supply hole (7) is placed in the casting flask (2).
), and then when room temperature or heated compressed air is supplied into the cover member (8) from the air supply hole (7), the compressed air oozes out the aqueous solution. The molding sand is evacuated from the mold surface through the molding sand to the outside through the ventilation hole (4). In this way, when compressed air is aerated into the molding sand from the mold surface for a predetermined period of time, the molding sand is hardened at a high speed sequentially from the mold surface, and eventually a mold (M) whose entire surface is uniformly hardened is formed. Molded. In particular, the mold surface of the molding sand impregnated with the aqueous solution has a much higher mold hardness than the inside of the mold. After that, board material (5)
and cover member (8) as shown in FIG.
A pair of completed molds is obtained by overlapping the other half of the mold, which has been hardened and molded in the same manner as described above.

In addition, in the above embodiment, the space defined by the model plate with model (1) and the casting flask (2) was filled with molding sand (S) to a predetermined density while being compacted. It may be filled to a predetermined density by blowing, squeezing, vibration, etc. Further, in the above embodiment, after reversing, the model plate with model (1) is released from the molding sand (S), an aqueous solution is applied to the mold surface of the molding sand (S), and then the molding sand is Although it was designed to harden at a high speed, molding sand (S) was placed in the space defined by the model plate with model (1) and the casting flask (2).
After filling to a predetermined density, immediately release the model plate (1) with model from the molding sand (S) without reversing the flask (2), and pour the casting from below the flask (2). Sand (S
), and then apply the aqueous solution to the mold surface of the foundry sand (
S) may be cured at high speed from the mold surface.

In addition, in the above embodiment, after applying the aqueous solution to the surface of the molding sand mold, compressed air was vented through the surface of the molding sand mold. It may be allowed to harden naturally.

As is clear from the above description, according to the present invention,
The space defined by the model plate with model and the casting flask is filled with molding sand containing a water-soluble binder, and the mold is cut out. An aqueous solution, or an aqueous solution containing a water-soluble binder and a heat-resistant aggregate in an appropriate ratio, was applied approximately evenly to harden the foundry sand. The mold surface of the foundry sand can be molded to a predetermined mold hardness with the binder, and since there is no need to use a large amount of water-soluble binder, the fluidity of the foundry sand is improved, and furthermore, It has the effect of eliminating casting defects due to gas defects and contributing to improved productivity, making it a significant contribution to this type of industry.

[Brief explanation of the drawing]

FIGS. 1 to 61 are process diagrams showing embodiments of the present invention. (1): Model board with model (2): Casting frame ＼1 Warm 1 figure ÷ 3 figure 5 figure ¥2 figure Homare 4 figure Rin 6 figure

Claims (1)

[Claims] Sugar and methylol of urea or melamine are placed in the space defined by the model plate with model and the flask. a water-soluble crosslinking agent selected from the group consisting of compounds or alkylated methylolates, and a catalyst for the reaction of the crosslinking agent selected from organic acids, inorganic acids, or metal salts, ammonium salts, or alkanolamine salts thereof. After filling the #molding sand to a predetermined density with the addition and kneading of a water-soluble binder containing as an ingredient, the model plate with the model is released from the molding sand, and on the mold surface of the molding sand, An aqueous solution of the above-mentioned water-soluble binder, or an aqueous solution containing the water-soluble binder and heat-resistant aggregate in an appropriate ratio, is applied approximately evenly, thereby hardening the foundry sand. How to make a mold.