SU778902A1 - Method of producing casting moulds by vacuum moulding method - Google Patents

Description

(54) METHOD OF MANUFACTURING HOUSING (Yuga: VACUUM FORMING PROCESSES)

The invention relates to foundry and can be exploited in the manufacture of molds from squeaky sands strengthened under the action of a sandstone (by vacuum molding) .- h ;: --C:. ::; There is a known method of making foundry forms, which includes applying to the model equipment of a sealing refractory coating, installation, flask casting, heating the model to 105-108 C filling sand in a flask, connecting the strips to the vacuum crust: & and removing the LIJ model tooling. Heating the model increases the strength and density of the coating by accelerating the process of its formation. When the model equipment is disconnected from the vacuum system and the cavity of the mold is connected to the vacuum, the hermetic refractory coating ot is drawn from the surface of the model plate and the model and the form is attracted to the working surface by the action of vacuum. Drying and coating formation occurs very quickly under the influence of heated model tooling. The sand that fills the cavity is in contact with the dried coating and cannot be embedded in it, which causes insufficient contact and weak: adhesion of the grains of sand to the coating. ---:,. ;:. ; ; „.., - .. h In this leads to the fact that when you remove the model equipment, the transfer of coatings to ionta: the full surface of the half-form is difficult and if there are developed horizontal and vertical surfaces, the coating is destroyed, therefore the area of application of this method is limited by iFele half-molds for fine molds; . - -. -, -i:: /;,; There is also a known method of making forms of a mold: including applying a synthetic film to the model equipment, setting the flask, filling the flask with a dry refractory filler preheated to 60-90 ° C, connecting the jolos to the flask to the vacuum system and removing the tooling | 2. This method is characterized by increased gas formation in the J form. Due to the combustion of a synthetic film when pouring a liquid metal.

The closest to the inventions) by technical essence and excellent result is a method of making casting molds by the process of vacuum forming, which includes the setting of the flask, applying the Pyi-oaiero coating to the model equipment of the refractory-hermetic, sanding the sandstone in the mold, the mold, Snap. Before filling, sand is brought to a temperature of 20-60 0, the coating is dried: produced by warm air.

This method is characterized by a weaker adhesion of the fireproofing sealing coating to the surface of the mold half ..-.

The purpose of the invention is to prevent the partial destruction of the coating during the removal of model equipment and increase its strength of adhesion to the form. -. .

The goal is achieved in that the method includes the installation of flask on a model Plate with equipment, application of a refractory and sealing coating to the model equipment, heating of the dry refractory filler to a predetermined temperature and filling it in the flask, adding the half-finished O1 to the vacuum system and removing the model equipment the dry refractory filler is heated to 100–160 s before filling it in a flask.

Sand; The mold box filling cavity is in contact with the non-hardened coating and is easily inserted into it. In the case of Lontakte coating with a hot nei5, fast binding films of the binder on the filler grains and the formation of a solid frame structure occur. When removing the model equipment, the coating easily separates from the surface of the heated model equipment and forms the working surface of the Apparatus under the action of cohesive forces with grains, sand and vacuum connected to the half-mold.

Due to the fact that the heat flow to the fireproof Seal; 1 coating on the sand side increases the strength of adhesion of the coating to the yoloform and facilitates the separation of the coating from the surface of the unheated model tooling. The proposed method is suitable for the manufacture of small, medium-sized and large-sized configurations. -; -v,. Lowering the temperature of the sand less results in an increase in the depth of the binding of the binder into the surface of the lorma, which causes the fallout of the roof.

An increase in the teksheratura of sand is 160 sprivo; it is to the rapid evaporation of the binder and the formation of gas defects.

In the proposed method, the sand is heated in a kiln only for the first molding. At the same time, it is advisable to heat the amount of sand from which the semi-form face layer is formed, directly in contact with the refractory-hermetieira (with a soft coating. Heating the rest of the filling mass of sand that does not perform thermal work, not.

Q is required

. V. further, the pesokh does not require heating, TaiK as the temp- is necessary. The culture is maintained under the heat of the metal being poured, and when it is heated up excessively, the sand is cooled.

 PRI (“After the installation of the flask, the surface of the model is covered with a synthetic film on which a refractory gas-impermeable coating is applied with a THICKNESS of 0.7–1.0 mm, containing an effective weight.%: And; Hyrg6 powder 60,

hydrolyzed ethyl sulfate 40. The flask is filled with organic sand with a temperature of 100-1 ° C. For the first molding, sand finishing to the required temperature is carried out by. heating in the oven. Subsequently, after the sand is heated, metal is filled with sand and the sand is cooled down to 6 of a given temperature (100-1bO ° C) in a cooling

0 device. After sealing the control unit, a vacuum of 350-500 mm Hg is connected to the mold. Open the model from the vacuum cticTeMu h KDkoT from the half-form, then remove the synthetic film. The coating under the action of rarefaction and physicochemical interaction with the sand is transferred from the film to the contact surface of the semi-Forsch.

The adhesion strength of the coating, achieved in the proposed method, is 1.5–2 times higher than in the known method. This eliminates the partial destruction of the coating during the removal of the model and equipment and, on this basis, 5 reduces the scrap of iron castings by 1.0-1.5% and reduces the amount of cleaning and chopping works by 10-15%.

Claims (3)

Invention Formula . Method of making casting molds by the process of vacuum forming, including the installation of the flask on a model plate with the equipment, applying to the model equipment refractory-sealing coating /, heating dry 5 refractory filler to a predetermined temperature and filling it in a flask, connecting the half-form to a vacuum system and removing the model snap-in, characterized in that, in order to prevent partial destruction of the coating when removing the model snap-on and increasing its adhesion to the mold, dry refractory nap The filler before filling it in the flask on; warm to 100-160 ° C. Sources of information accepted in attention during examination 1. USSR author's certificate No. 556883, cl. B 22 C 9/00, 1975., 2. USSR author's certificate I 579084, class, B 22 C 9/00, 1975. 3. USSR author's certificate 532455, cl. B 22 C 9/00 1976.