SU1764771A1 - Method for removing fusible patterns from shell molds - Google Patents

Description

one

(21) 4847377/02 (22) 26.04.90 (46) 30.09.92, Byul. №36

(71) Scientific and Production Association for Mechanical Engineering for Livestock and Fodder Production

(72) C. F. Zharkov and Yu. L. Perevozkin

(56) Engineering monograph Casting on melted models. / Under the editorship of Ya. I. Shklennnik and V. A. Ozerov, M ,: Mashinostroenie, 1971, p. 242.

For the application of the Federal Republic of Germany No. 497195, cl. B 22 d (31s 8/07), 1965.

(54) METHOD FOR REMOVING SLIMMING MODELS FROM SHELL FORMS

(57) Use: The invention relates to foundry, in particular, to

the process of making molds using one-off models, and can be used to remove models from the mold cavity in the process of casting on melted models. SUMMARY OF THE INVENTION: Shell molds are positioned above the surface of the smelting bath by a stack down, tilted at an angle of up to 20 ° C to the horizontal, the superheated model melt is fed continuously into the drain cavity, rotating the mold around the drain axis at a speed of 0.1-2. 5 rps At the same time, the degree of impregnation of the shell of the mold with the model composition is drastically reduced, which allows for a more complete burning out of the remnants of the composition in a shorter time, improving the quality of the castings and improving the environmental situation in the workshop.

with

The invention relates to a foundry, in particular, to a process for the manufacture of casting molds based on one-off models, and can be used to remove models from a mold cavity in a casting process on melted models.

The purpose of the invention is to reduce the consumption of the model composition, improve the quality of castings and improve the environmental situation in the workshop.

This goal is achieved by the fact that the overheated melt of the model composition is continuously fed into the cavity of the shell shell, its tilt with the casting bowl downwards at an angle of 0 ° -20 ° to the horizontal and rotating the shell shape around the sink axis at a speed of 0.1-2.5 turnover per second.

An example of the method.

The proposed method is implemented using a device schematically represented in FIG. 1, 2, 3.

The device (FIG. 1) includes a closed container 1 with an electric heater 2 for overheating the model composition used as a heat carrier, a pump 3, a coupling 4, a tubular shaft 5, a drive shaft 6 of the tubular shaft, a pallet 13 and a sump tank 14.

Before mounting the mold to smelting, one to three holes are made along the large circumference of the sprue bowl model. For example, a through-slotted hole (seen in Fig. 2) is melted with a steam iron, which allows the molten composition to flow freely from the mold without creating a voltage on the shell.

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Removing fusible models from the shell forms as follows:

the shell mold 8 together with the metal frame-skeleton 7 is fixed on the tubular shaft 5 and turn on the actuator 6 of the tubular shaft (the slope of the stand on the tubular shaft to the horizontal is 0 ° -20 °), then turn on the pump 3, through which the superheated melt the composition through the coupling 4, the shaft 5 and the one-to-frame 7 enters the cavity of the shell shape through the holes 9 in the stand of the ke-frame (Fig. 2). The one-to-frame 7 cross-section has a tubular-ribbed shape (FIG. 3). The ribs allow for a sufficient gap between the inner surface of the sleeves and the outer surfaces of the one-frame carcass. This gap allows free flow to the gating pan of the superheated coolant flowing through the holes 9 (Fig. 2), which melts the models from the inside,

Uniform washing of the internal surfaces of the models is achieved due to the fact that the coolant is supplied with continuous rotation of the mold 8 around the axis of the stand. In this way, the heating and melting front of the models moves in radial directions from the axis of rotation to the peripheral parts of the mold, which makes it possible to minimize the force effect of the heated model material on the shell.

During the period of melting, the rotating shell of the mold 8 is securely held on the stand-skeleton due to the presence of the support sleeve 11 and the pressure cap 12 (Fig. 2), made of a material that does not soften during the melting of the models. For example, at temperatures of the heat carrier up to 110 ° C, polystyrene foam can be used, at temperatures up to 135 ° C - polyurethane foam. Due to this, cases of destruction of forms during rotation are eliminated. Note. The rate of penetration of the shell around the stockpile axis is about 1.2 revolutions per second.

nii. After the removal of the models is completed, the one-to-frame framework is unscrewed, and the pressure cap and support sleeve fade during subsequent calcination of the shell molds. The melted composition together with the coolant flow flows through the sprue 10 (Fig. 2) onto the pan 13, and from there flows into the settling tank 14 (Fig. 1). After the models are completely melted, the flow of coolant stops, and after draining the remnants of the model composition from the cavities of the shell mold, the tubular shaft turns off,

the shell form is screwed from the frame of the frame, which is then removed from the tubular shaft. Model removal time is 20 min. The results of model removal, depending on the angle of inclination of the stand of the form to the horizontal and the speed of rotation of the shell form around the stand, are given in Table. 1 and 2 respectively.

The use of the proposed method allows to reduce the consumption of the model composition due to the less impregnation of the shell by it, to improve the sanitary conditions of work on the calcination operation of the mold due to the smaller amount of the composition left in the shell and to reduce the waste of castings.

Claims (1)

Claims of Invention A method for removing low-melting models from shell molds by exposing them to an overheated molten composition, the composition of which corresponds to that of models, characterized in that, in order to reduce the consumption of a model composition, improve sanitary working conditions and improve the quality of castings, shell forms are located above the gating tray. bowl down at an angle of up to 20 ° to the horizontal, and the superheated melt of the composition is continuously fed into them through the cavity of the stand, rotating them around the axis stand at a speed of 0.1-2.5 rev / s. Table 1 Note. The angle of inclination of the axis of the axis to the horizontal - 10th  T OUT 2 3 model Department FIG. J / 2 FIG. 2 eight Fig.Z A - A