RU2382696C1 - Method for manufacturing of core with easily deformable coating - Google Patents

Abstract

FIELD: technological processes.

SUBSTANCE: method for manufacturing of core with easily deformable coating, where a gypsum layer is applied onto metal frame of core, gypsum layer is finished down to specified profile and size. Gypsum mould, which completely follows profile and dimensions of core, is taken off produced core, core is bored along its whole surface. After boring, gypsum surface of core is coated with varnish, internal surface of gypsum mould is lubricated with solid oil, gypsum mould is installed on core with provision of gap between gypsum mould and core. Rubber-like polymer is poured into produced gap, maintained until final polymerisation of polymer, and gypsum mould is withdrawn.

EFFECT: simplified technology of manufacturing.

4 dwg

Description

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

One of the main elements of molded kits for producing large-sized complex-shaped ceramic products by casting from aqueous slips into porous molds is the core, which provides the necessary profile of the inner surface of the molded product.

A known method of manufacturing a core described in RF patent No. 2234482 dated 09/20/2004 and comprising applying a layer of gypsum (or other plastic material) on a metal frame, treating gypsum to the desired profile, applying a layer of epoxy resin to the gypsum, which is finally processed after drying and hardening to the required size and profile. The manufacture of the core by this method is extremely simple and cheap, which in the conditions of small-scale production with frequent changes in the range of products is a big advantage [1].

The disadvantages of this method include the fact that the result is a core with a fairly rigid outer surface. In the operation of mold kits with the core thus obtained, it is not uncommon for a fully assembled blank to shrink on a rigid core, which often leads to destruction of the blank.

The closest is the technical solution described in the patent of the Russian Federation No. 2191688, 10.27.2002, the device claimed in this patent contains a core on the outer surface of which there is a coating made of easily deformable hydrophobic material. Moreover, the coating can be removable or stationary. The use of this coating avoids the destruction of the workpieces due to their shrinkage on the hard core [2].

A method of manufacturing such a core is similar to that described above and involves applying a layer of gypsum (or another plastic material) on a metal frame, processing the gypsum layer to a given profile and size, grooving it on the thickness of the coating (or cover), applying an easily deformable coating, or putting on a microporous rubber cover .

The disadvantages of this method include the fact that the application of an elastic coating on a curved surface is usually carried out as follows: first, the elastic plates are cut, then glue is applied to the surface, the cut plates are laid and pressed until the glue hardens, and then the joints are closed. As practice has shown, this technology is quite time-consuming and does not provide a high-quality (smooth, even) core surface, which in turn negatively affects the resulting workpieces.

The manufacture of a removable cover made of microporous rubber is an expensive operation since It requires the manufacture of special technological equipment for each specific type of product, which in the conditions of small-scale production with frequent changes in the range of products is unprofitable.

The present invention is a significant simplification of the manufacturing technology of large-sized complex-profile cores with easily deformable coating.

This object is achieved by the fact that the proposed method of manufacturing a core with an easily deformable coating, including applying a layer of gypsum (or other plastic material) on a metal frame, processing the gypsum layer to a predetermined profile and size, its groove on the coating thickness, applying an easily deformable coating, characterized in that after processing, the plaster cast is removed, and after the groove, the gypsum surface of the core is varnished, the inner surface of the gypsum cast is lubricated a, installing a plaster cast on the core, pouring a rubber-like polymer into the resulting gap, holding until it is fully polymerized, removing the plaster cast.

Silicone rubber SKTN with catalyst KT-68 was used as a rubber-like polymer.

The authors experimentally established that the given set of features allows one to obtain a large-sized complex profile core with a surface uniformly coated with easily deformable hydrophobic material, while ensuring high accuracy of the obtained product profile.

It has been established that the use of rubber-like polymers or materials based on them makes it possible to obtain coatings with highly elastic properties over the entire range of operating temperatures.

In addition, it was found that to ensure good adhesion of the coating material with the gypsum part of the core, its surface should be varnished. To ensure unimpeded extraction of the gypsum cast after polymerisation of the rubbery polymer, the inner surface of the cast should be lubricated.

The proposed technical solution is implemented in the manufacture of a large complex core with an easily deformable coating having a base diameter of 200 mm and a height of 650 mm.

A method of manufacturing a core with an easily deformable coating is illustrated in the following drawings.

Figure 1 presents a General view of the core, consisting of a metal frame 1 and gypsum 2; figure 2 is the same core with gypsum cast 3; figure 3 presents the filling of rubber-like polymer 4; figure 4 is a General view of the core with an easily deformable coating.

The core with an easily deformable coating was made as follows.

A layer of gypsum 2 was applied to the metal frame 1 of the core, which was processed to the desired profile and size (Fig. 1). A gypsum cast 3 was taken from the core thus obtained, completely repeating the profile and dimensions of the core (Fig. 2). After that, the gypsum part of the core was machined to a depth of 5 mm over the entire surface and varnished over the resulting surface. The inner side of the gypsum cast 3, the inverse of the core surface, was greased with a solidol, after which the gypsum cast 3 was installed on the core. Due to the fact that only the gypsum part of the core was machined, the plaster cast 3 was planted in the same place as the metal frame 1 of the core, which ensured that the gap between the plaster cast 3 and the core was uniformly set. A mixture of silicone rubber (grade SKTNg) with a catalyst (grade CT-68, introduced in an amount of 1.5-2 wt.%) Was poured into the gap thus formed (Fig. 3). After the final polymerization of rubber, the gypsum cast 3 was removed and as a result a large-sized complex core was obtained, the outer surface of which has an ideally even, smooth easily deformable coating (Fig. 4). Moreover, the control of the geometric dimensions of this core showed that this core fully complies with the requirements of the drawing.

Using the core thus obtained, a series of blanks for the head antenna fairings was molded. Moreover, despite a large overexposure (more than 5 hours) of blanks in the form, not a single blank was defective, and the coating remained in a working position.

Thus, the proposed technical solution allows to obtain large-sized complex-profile cores with an easily deformable coating of any size and profile with minimal labor and a minimum amount of technological equipment (production in laboratory conditions is possible).

Information sources

1. RF patent No. 2234482 from 09.20.2004, bull. Number 23.

2. RF patent No. 2191688, 10.27.2002, bull. No. 30.

Claims (1)

A method of manufacturing a core with an easily deformable coating, characterized in that the gypsum layer is applied to the metal frame of the core, the gypsum layer is processed to a predetermined profile and size, a gypsum cast is taken from the obtained core that completely repeats the core profile and dimensions, the core is grooved over the entire surface, and after grooving, they cover the gypsum surface of the core with varnish, lubricate the inner surface of the gypsum cast with solid oil, and set the gypsum cast on the heart With a gap between the plaster cast and the core, a rubber-like polymer is poured into the formed gap, maintained until polymer is fully polymerized, and the plaster cast is removed.

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