RU2359940C1 - Kit for moulding of large size figurine-shaped ceramic blanks with undercutting - Google Patents

Abstract

FIELD: production processes.

SUBSTANCE: invention refers to moulding technology of large size figurine-shaped ceramic products from aqueous slips. Moulding kit for large-size figurine-shaped ceramic blanks with undercutting includes water-absorbing matrix, iron core, units for their relative coaxial installation and in-feed. Iron core is additionally equipped with an insert made from easily deformable water repellent. Insert's inner profile repeats iron core profile in the place of supposed undercutting, and outer profile repeats blank inner profile.

EFFECT: decrease of technological allowance in moulded ceramic blanks.

2 ex, 1 dwg

Description

The invention relates to a technology for forming large-sized, complex-profile ceramic products from aqueous slips.

A device for casting hollow ceramic products is known, which according to the USSR author's certificate No. 1570900 of class B28B 1/26 contains a moisture-absorbing form (matrix), a core in the form of an elastic shell, a mechanism for deforming the elastic shell and providing recharge.

The disadvantages of the known device include the fact that the core, made in the form of an elastic shell, is not a structural element that forms the inner contour of the manufactured product. In this case, obtaining products with the same wall thickness in all sections is based on the assumption that the product wall thickness is set uniformly over the entire surface, which is not true, since a number of factors are involved in the formation of the product wall (gravitational deposition of particles contained in slip, profile of the molded product), which lead to the gradual filling of the mold cavity with solid sediment from its lower to upper part. In this case, the suction of moisture in the form from the collected shard continues further, as a result of which the collected workpiece is dried, accompanied by its shrinkage on the core, which often leads to its destruction.

The closest in technical essence to the claimed solution is a device for molding ceramic products from aqueous slips (patent for the invention of the Russian Federation No. 2191688, 1/28, B28B, 2000), including a moisture-absorbing matrix, core, nodes for their mutual coaxial installation and feeding. The outer surface of the core has a coating made of easily deformable hydrophobic material that compensates for the shrinkage stress of the product as it is dried in the mold during molding. The coating can be removable or stationary. The named set of features of the device allows to obtain high-quality products with a given inner contour from aqueous slips.

The disadvantage of this device is that it is intended for molding only such blanks, in the profile of which there is a widening angle of aperture, otherwise, after the molding process is completed, removing the core from the cavity of the molded blank will destroy the latter. At the same time, if the design provides for the so-called undercut (or inverse cone), then a substantial increase in the technological allowance in ceramic billets is necessary, from which the final product is subsequently machined. In this case, from 40 to 60% of the body of the workpiece is removed by machining, which, in turn, leads to a large consumption of feedstock, an increase in the duration of the molding of workpieces and to significant costs for machining.

The objective of the present invention is to provide a kit for forming complex profile ceramic blanks with undercut. The technical result is the reduction of technological allowance in molded ceramic billets.

The task is achieved in that in the kit for forming complex-profile ceramic billets with undercut containing a moisture-absorbing matrix, a core, units for their mutual coaxial installation and recharge, the core is additionally equipped with an insert made of easily deformable hydrophobic material, the internal profile of which repeats the core profile in place the proposed undercut, and the outer is the inner profile of the workpiece.

Additional installation on the core of the insert leads to the fact that during molding it displaces the slip and thereby prevents the collection of blanks at the insertion site, which allows molding blanks with any profile of the inner surface.

It was experimentally established that when forming workpieces with such a complex internal surface profile (with differences in thickness up to half the wall thickness), the workpiece at the place of undercutting is typed much faster than in other places. In this case, the accumulated layer of the workpiece begins to shrink on the insert and, only due to the fact that the insert is made of easily deformable material, the workpiece is not destroyed. The requirement for the hydrophobicity of the insert material is explained by the need to eliminate the undesirable effect of the selection of moisture from the slip in the molding process, which can lead to delamination of the workpiece.

It has been established that the implementation of the insert with an internal profile repeating the core profile at the place of the proposed undercut and an external profile repeating the internal profile of the workpiece provides free removal of the core from the cavity of the molded workpiece and eliminates the likelihood of the insert slipping from the core earlier than the set time, and ensures the preparation of workpieces with given a complex profile.

The drawing shows a General view of the claimed kit for forming complex profiles of ceramic blanks with undercut. The kit design includes a core 1, on which an insert 2 is mounted, a moisture-absorbing matrix 3, nodes 4 for their mutual coaxial installation and recharge nodes 5.

The device operates as follows. Before starting the assembly of the kit, an insert 2 made of easily deformable hydrophobic material is put on the core 1 opposite the place of the proposed undercut. After that, the thus assembled core with the insert is installed in the matrix 3 and fixed using the nodes 4 of the mutual coaxial installation of the matrix and the core. In the gap formed by the core 1 and the moisture-absorbing matrix 3, a slip is fed through the make-up nodes 5. During the collection of the product, the gap is filled with a solid precipitate, and due to the presence of an insert 2 on the core in the place of the proposed undercut, the slip is displaced and the workpiece is obtained with the desired internal profile. After molding, the core 1 is removed from the matrix 3, while the insert 2 is removed from the core due to the presence of the inverse cone on it and remains on the inner surface of the molded workpiece. Due to the design of the insert from easily deformable material, it is easily removed from the workpiece, which is also then removed from the matrix.

The implementation of the proposed technical solution is presented in the following examples.

Example 1

A complex profile billet (height 650 mm, base diameter 250 mm, thickness 16 mm) was formed on a kit known for the prototype, which included a moisture-absorbing matrix, a core, and units for their mutual coaxial installation and feeding from a slip of lithium aluminum silicate glass. The mass of the molded billet was 11.2 kg

Example 2

A similar set was molded on the proposed kit for forming complex-profile ceramic billets with undercut, with the difference that under its surface, at a height of 200 mm from the base, an undercut was made with a height of 100 mm and a depth of 4-5 mm. The specified undercutting is achieved by the fact that before assembling the kit, an insert made of easily deformable hydrophobic material is put on the core (the material ISOLON PPE 3000 produced by LLC Adgilayn, having a density of 33 kg / m ³ , compressive strength of 0.035 MPa, was used as the insert material water absorption <1% by volume). The insert has the shape of a ring 100 mm high, 5 mm thick, the inner diameter of the insert corresponds to the diameter of the core at the undercut.

In a set made according to the proposed technical solution, a preform was formed having a difference in wall thickness in the undercut zone of up to 4 mm. The mass of the workpiece was 10.45 kg (which is 6.7% of the saving of the feedstock).

The kit is easy to manufacture and operate, and is especially successfully used in the formation of complex ceramic blanks with reduced values of technological allowance.

Information sources

1. USSR copyright certificate No. 1570900, MKI V28V 1/26.

2. Patent for the invention of the Russian Federation No. 2191688, B28B 1 / 26,2000,

Claims (1)

A kit for forming complex-profile ceramic blanks with undercut, containing a moisture-absorbing matrix, a core, units for their mutual coaxial installation and feeding, characterized in that the core is additionally equipped with an insert made of easily deformable hydrophobic material, the inner profile of which repeats the profile of the core at the site of the proposed undercut, and external - the internal profile of the workpiece.