RU2804514C1 - Method for manufacturing casting moulds and cores using the technology of moulding cold-hardening mixtures (chm) into model-core equipment, the forming material of which changes the geometry in a short time - Google Patents

Abstract

FIELD: foundry production.

SUBSTANCE: method for manufacturing casting moulds and cores from cold hardening mixtures (CHM) includes 3D modelling of the casting, forming the form-generating surface of the model-core equipment in the form of many segments (2) and moulding CHM into the resulting form-generating surface. Using the specified CHM moulding, components of casting moulds and cores are produced, from which moulds and cores are then assembled. 3D models of these components are formed in a CAD system based on a 3D model of the casting, while an algorithm is entered into the programmable device and control codes are created for the controller, which supplies control signals to the actuators (3) to move the segments (2). The control signal is supplied to the actuator corresponding to the “X” and “Y” coordinates, which moves the segment along the “Z” axis relative to the forming surface. The segment, the height of which is specified technologically, is made in the cross section in the form of a regular triangle, a regular quadrangle or a regular hexagon.

EFFECT: stages of development of design documentation and production of model-rod equipment are eliminated.

5 cl, 13 dwg, 1 ex

Description

The method of manufacturing casting molds and cores using the technology of molding cold-hardening mixtures (CHS) into model-core equipment, the forming material of which changes the geometry in a short time, belongs to the field of foundry production, in the manufacture of casting molds and cores by molding.

A method of manufacturing casting molds of complex geometry from sand-polymer systems is known from the prior art [RF patent No. 2707372 MPK V22S 9/02, Bull. No. 33, Publ. 11/26/2019], including layer-by-layer computer modeling of the product, sand preparation, mixing sand with the catalyst in the preparation bunker, layer-by-layer application of sand to the substrate and layer-by-layer selective processing of each layer, in accordance with computer sections of the model until the programmed shape of the product is formed. Layer-selective processing of the sand-polymer mixture is carried out to the depth of the layer in two stages, first, on each applied layer, the processing is carried out by program-regulated introduction of a binder by injection into the sand layer according to the section being manufactured; upon completion of treatment with the binder, each layer is subjected to program-regulated processing of the contours cross-section produced by a laser, to improve the accuracy of the resulting product and increase the strength of the outer layer. Molding quartz sand with a particle size ranging from 0.05 to 0.16 mm and binders based on furan resins are used as a sand-polymer system

The disadvantages of this technical solution are the complexity and high cost of the complex of equipment used, the long production time of casting molds and cores, the subsequent cleaning of manufactured casting molds and cores, high requirements for the quality of sand, and the use of only one binder option.

Also known from the prior art is a method for manufacturing casting molds by compacting the molding sand with a multi-plunger press head [RF patent No. 2038893 MPK V22S 15/02, Published 07/09/1995], during the pressing process the molding sand is additionally affected through each press shoe of the multi-plunger head by synchronous oscillatory or synchronous periodic shock pulses directed along the line of action of each of the shoes.

The disadvantage of this technical solution is the need to design and manufacture a separate set of model-core equipment for each type of casting - this is a labor-intensive, time-consuming and financially expensive process.

In addition, a method for manufacturing casting molds by pressing is known from the prior art [RF patent No. 2220811, IPC V22S 15/02, Bull. No. 1, Publ. 01/10/2004], which includes introducing the model into a technological container, filling the technological container with the mixture, after which the model is lowered to its original position, thereby profiling the mixture in the technological container, after which upper or lower pressing is performed with a flat or profile plate.

The disadvantage of the known technical solution is the need to design and manufacture a specialized separate set of model-core equipment for each type of casting, as well as a set of model and press plates.

Also from the prior art, the closest in technical essence to the claimed invention is a Method for making molds in a special device [patent JPS No. 60-82250 B22C 15/02, 1985], consisting of many heat-resistant ceramic elements, independently moving up and down in frame in accordance with the required geometry. Heat-resistant fabric placed in the mold forms a smooth, defined surface of the mold into which the melt is poured.

The disadvantages of this technical solution are the limited use of types of cast alloys (only low-melting alloys), the complexity of the design due to the negative effect of the melt temperature, and the limited dimensions of the cast product.

This technical solution was adopted as a prototype.

The problem to be solved by the claimed technical solution is the production of casting molds and cores using the technology of molding chemical mixtures into model-core equipment, which consists of molding molds and cores in a device in which a geometric shape is formed in a short time under the control of a computer with a special software in accordance with a 3D model simulated on a computer in any available computer-aided design (CAD) system.

The technical result consists in the possibility of obtaining a form-generating surface for the manufacture of casting molds and cores using CTS technology, excluding the stages of developing design documentation and manufacturing model-core equipment.

The main feature of the invention is the ability to obtain the required geometric shape without the use of consumables and additional material resources. This invention can be used in the manufacture of castings in molds, in casting using gasified models, in lost wax casting, in the manufacture of foundry equipment by pouring a plastic composition, in the casting of concrete products, in the manufacture of refractory, ceramic, glass products, in the manufacture of plastic parts by casting. in molds on thermoplastic machines and other industries where it is necessary to obtain geometric shapes in a short time (1-2 minutes).

In addition to the main objective of the invention for molding CTS mixtures into model-core equipment, the forming material of which changes the geometry in a short time, secondary possibilities arise, namely, copying the shape of physical objects without the use of a 3D scanner and other modern expensive technologies.

The problem is solved, and the specified technical result is achieved, due to the fact that the method of manufacturing casting molds and cores using the technology of forming chemical mixtures into model-core equipment, the forming material of which changes the geometry in a short time, includes modeling in 3D form, the formation of the geometric shape of the casting being manufactured in model-core tooling, subsequent production of casting mold components by molding in chemical melting, further assembly of the casting mold from the resulting molds and cores, pouring of the assembled mold, characterized in that each segment forming the geometry of the casting being manufactured in cross section is a regular or 3-gon , or a 4-gon, or a 6-gon, at a height specified technologically, the formation of the geometric shape of the future casting occurs on the basis of a 3D model of a casting mold component created in a CAD system by introducing changes in the model-core equipment of the algorithm into the programmable device, and namely, through a computer program, control codes are created for the controller, which supplies signals to the actuators to move multiple segments, while the control signal is supplied to a drive corresponding to a certain “X” and “Y” coordinate, which ensures the movement of the segment along the “Z” axis relative to zero plane of the model-rod equipment device.

The essence of the claimed invention is illustrated by graphic material:

Fig. 1 - Model-rod equipment

Fig. 2 - Outline of the resulting casting

Fig. 3 - Part to be manufactured

Fig. 4 - Casting manufacturing technology

Fig. 5 - 3D casting in CAD system

Fig. 6 - Mathematical shape of the casting core of the top

Fig. 7 - Molding of the rod using the CTS process

Fig. 8 - Top casting core

Fig. 9 - Mathematical shape of the bottom casting core

Fig. 10 - Molding of the rod using the CTS process

Fig. 11 - Bottom casting rod

Fig. 12 - Assembling a casting mold from the obtained cores

Fig. 13 - Pouring the assembled mold

Model-rod equipment (Fig. 1) consists of a frame 1 into which is built a group of movable segments 2, forming a matrix of segments that define the contour of the resulting casting 6 (Fig. 2). Segment 2 is made of a prismatic shape with base side a, height h, for example, it can be a regular 3x, 4x, 6-gon in cross-section. In the model-rod equipment, the dimensions (a, h) of segment 2 and the type of its geometry are determined, for example, a square section with a side of 10 mm, the transverse size of the square section of the segment is in the range from 2 mm to 100 mm.

The number of segments 2 along the “X” and “Y” axes is determined by the dimensions of the molding area of the casting. The height h of segment 2 is determined technologically by the magnitude of its maximum movement along the “Z” axis, depending on the specific design of the model-rod equipment. The molding area is a space in which movement of segments 2 is possible.

At the bottom of the frame 1, drives 3 are located, mechanically connected to segments 2.

The 3-stroke drive of 2 segments can be of different operating principles (servos, solenoids, flexible shafts, pneumatics, hydraulics).

According to the mathematical 3D model, with the help of a computer program, control codes are created for the controller (not indicated in the figures), which supplies control signals to the drives 3 to move the segments 2. Each segment 2 extends to a certain distance, in accordance with the signal that is addressed to it . Thus, the matrix of segments 2 is built in a short period of time in frame 1, repeating the mathematical 3D model built in a computer-aided design (CAD) system.

On top of the frame 1 model-rod equipment, with the segments 2 placed in it, a flask 4 is installed, which limits the spillage of the molding sand poured into the flask 4 during molding. After the molding sand has hardened, the flask 4, combined with the resulting casting core 5, is removed from the model-core equipment. The contour of the resulting casting 6 exactly repeats the constructed geometry of the matrix of segments 2 of the model-rod equipment.

The implementation of a method for manufacturing casting molds and cores using the technology of molding chemical mixtures in a model-core tooling, the forming material of which changes the geometry in a short time, is explained below.

Based on the 3D model of the mold component created in the CAD system, control codes are created for the controller using a computer program, which sends signals to the actuators to move segments 2. Segments 2, in a particular case, are moved by an electromechanical drive 3. Control the signal is supplied to the individual drive 3 of segment 2 corresponding to a certain coordinate “X” and “Y”, which in turn ensures the movement of segment 2 along the “Z” axis relative to the zero plane of the model-rod equipment (only up or down). Thus, the entire system of segments 2 is simultaneously, within a short period of time, lined up and fixed in accordance with the contour of the resulting casting 6.

Next comes the molding stage, in which the molding or core mixture is poured into the model-core tooling, with the formed geometric shape, with the flask 4 installed, to produce a casting mold using the molding mixture according to the CTS process. In a private version, a flask 4 or a filling frame is used.

The molded component of the casting mold - the casting core 5 is removed from the model-core equipment together with the flask 4. The casting mold is assembled from all its components and is filled with melt.

An example of the method.

There is a requirement to produce a cast blank for a specific part (Fig. 3). A 3D model of the part is built, a technology for manufacturing the casting is developed (allowances for machining are applied, the mold connector is determined, the gating system is calculated and added) taking into account the capabilities of the technology with 3D modeling in the CAD system. The developed casting manufacturing technology (Fig. 4) is added to the 3D model of the part and a 3D model of the casting (Fig. 5) with elements of the gating system is created.

Based on the 3D model of the casting (Fig. 5), with the help of specially developed software, a control information system is transmitted to the model-core equipment for the production of casting molds and cores, according to which a geometric shape (Fig. 6) for molding the casting core is built in a short time for the casting you are interested in.

Using the molding method according to the CTS process (Fig. 7), the molding mixture is poured into the model-rod equipment device (Fig. 1) with a pre-installed flask, and a certain time is maintained for hardening. Then the resulting rod with the flask is removed from the device, the flask is separated from the rod (Fig. 8), which is sent to the assembly and mold filling area.

The casting core of the bottom shape is manufactured in the same way (Fig. 9, 10, 11).

The assembly of the casting mold from the obtained cores (Fig. 12) occurs in the assembly and pouring area after cleaning and painting its components.

The pouring of the assembled casting mold (Fig. 13) occurs with a melt specific for the casting being manufactured.

Next, the final operations are carried out - knocking out, cutting and cleaning the elements of the supply system, cleaning the casting, heat treatment. After this, the manufactured casting is transferred for machining.

Claims (5)

1. A method for manufacturing casting molds and cores from CTS, including modeling the casting being manufactured in 3D form, in accordance with the geometric shape of which the geometric shape of the forming surface of the model-core equipment is formed, made in the form of a plurality of segments, equipped with actuators for moving the segments, by means of introducing a certain algorithm into the programmable device, while control codes are created through a computer program for the controller, through which signals are supplied to the actuators to move the segments, and the molding of the chemical composition into the resulting forming surface of the model-rod equipment, characterized in that by molding the chemical composition into the resulting forming surface Model-core equipment produces components of casting molds and cores, from which casting molds and cores are subsequently assembled, and the formation of 3D models of components of casting molds and cores is carried out in a CAD system based on the 3D model of the casting being manufactured when a certain amount is entered into the programmable device algorithm, whereby through a computer program control codes are created for the controller, through which control signals are supplied to the actuators for moving the segments, and the control signal is supplied to the actuator corresponding to a certain coordinate “X” and “Y” for moving the segment, ensuring the movement of the said segment along the “Z” axis relative to the zero plane of the forming surface of the model-rod equipment, while each segment of the form-building surface of the model-rod equipment in cross section is made in the form of a regular triangle, or a regular quadrangle, or a regular hexagon, and its height is specified technologically. 2. The method according to claim 1, characterized in that for the production of castings of different geometric shapes, a one-time change in the geometric shape of the forming surface of the model-rod equipment is carried out. 3. The method according to claim 1, characterized in that the size of the segment and its geometric shape are determined by a programmable device. 4. The method according to claim 1, characterized in that a square section segment with a side of 10 mm is used. 5. The method according to claim 1, characterized in that a square section segment with a transverse dimension ranging from 2 to 100 mm is used.