GB2142848A - Producing body with three- dimensional cavity system - Google Patents

Abstract

A plasma grid has all regions of its desired cavity system comprising cooling ducts 9 and feed ducts 4' first incorporated into individual parts of the body 2, 3, 3', 4, 5, and the individual parts are only then placed together and soldered to one another. This makes possible the provision even of cavity systems following very complex patterns, which were previously out of the question. <IMAGE>

Description

SPECIFICATION Method of producing metal bodies having three-dimensionally extending internal cavity systems The present invention relates to a method of producing metal bodies having a three-dimensionally branched cavity system arranged in the interior of the body, by which method the body is produced from a plurality of individual parts by soldering thereof.

The purpose of such a method is to provide metal bodies with a cavity system extending not only substantially in one plane, this cavity system itself being subject to specific high requirements in respect of gas-tightness and pressure resistance.

Such bodies having a complex cavity sys-- tem are used, inter alia, in plasma physics, for example as water-cooled grids for neutron sources.

Such grids can be produced by electroforming (electrodeposition), electron beam welding or diffusion welding. The corresponding production processes are as a rule very costly and are able to meet the demands made only partially, despite the high expenditure of the corresponding costs.

The object of the present invention is, then, to provide a novel method which permits the construction of bodies of the stated type in a simpler manner, substantially higher demands, in particular in respect of leak-tightness, on the bodies produced being met at the same time.

The method is distinguished, according to the invention, by the fact that all regions of the cavity system are first incorporated into the individual parts in accordance with the desired geometry, and the cavity system is only subsequently closed by the placing together and soldering to one another of all the individual parts.

Advantageously, reference surfaces corresponding to the envisaged region of the cavity system and remaining accessible after soldering are incorporated into the individual parts, the machining of the body to final size taking place according to these reference surfaces.

Preferably, the solder stock required for soldering is deposited in cavities provided for this purpose before soldering when the individual parts are placed together, the position and volume of the solder deposits being determined so that satisfactory filling of the soldered joints is ensured without cooling ducts being filled.

In a particularly advantageous embodiment of the method according to the invention, the procedure followed is that a crack-shaped solder deposit is arranged between the surfaces to be soldered of two individual parts to be placed together, and a force is applied during soldering, this being done to constrict the crack-shaped solder deposit to the width of the soldered crack. In this procedure, the solder can be applied directly to the parts to be soldered, or to one of them.

The soldering is preferably carried out in a vacuum oven and using a eutectic solder without flux.

The invention will be explained in somewhat more detail below with reference to the exemplary production of a plasma grid.

A plasma grid of this type has, for example, an annular edge zone and a central grid of disc-shaped design arranged therein, having a large number of passage holes for the plasma, cooling ducts being provided in the grid between the passage holes and being connected to feed lines and discharge lines for the cooling medium in the annular edge.

In the drawing: Figure 1 shows an extract from a lateral view, partly in section, of a plasma grid composed of a plurality of individual parts, having an incorporated cavity system, but before the final machining to finished size: Figure 2 shows an extract from the actual grid possessing the cooling ducts, and Figure 3 shows a view similar to Fig. 1, with the finally machined plasma grid.

The plasma grid shown in Fig. 1 of the drawing is composed of the actual grid 1, a feedring 2, the grid 1 being formed of two plates 3' and 3" joined together, and the cooling ducts 9 being formed on the underside of the grid plate 3' and the feedring 2, a cylindrical part 4 with connecting ducts 4' for cooling water and a flange 5.

According to the invention, the whole body is produced from the individual parts mentioned above. In the body, the cooling ducts 9 with the feed ducts 4' form a three-dimensional cavity system.

All regions of this cavity system are initially incorporated into the individual parts in accordance with the required or desired geometry, work of maximum precision being possible depending on the tools used.

The individual parts 2, 3', 3", 4 and 5 are then placed together and soldered to one another.

As the comparison between Figs. 1 and 3 shows, the individual parts are produced oversize at those surfaces which ultimately form the outer shape of the body, and the body is only machined to final size after the soldering of the individual parts.

In order to permit assembly and final machining, reference surfaces or markings are incorporated into the individual parts, which surfaces or markings must also still be accessible after the soldering, as for example at the points A, A' in Fig. 1, as the machining of the body to final size also takes place in accordance with these markings.

In order to ensure the relative positioning of individual parts during soldering, fixing ele ments (for example dowel 7, Fig. 1) can be provided, these being removed at the time of final machining of the body.

For soldering the individual parts of the body, the necessary supply of solder is introduced into cavities or solder deposits provided for the purpose during the placing together of the parts, the position and volume being determined in such a way that satisfactory filling of the soldered joints is ensured.

As shown in Fig. 1 (for example points L, L6), crack-shaped solder deposits are arranged between the surfaces to be soldered of the individual parts, it being possible to press the parts together during soldering in such a way that the crack-shaped solder deposit is constricted to the width of the soldered crack desired.

The groove-shaped solder deposits are intended to communicate with the soldered crack.

These grooves are also removed during machining to final size (cf. Figs. 1 and 3).

It is possible for the individual parts of the body to be formed to be soldered to one another at the same time, or individual parts are first soldered together by groups and then these groups are connected to one another in a second soldering operation.

The soldering can be carried out, for example, in a vacuum oven. Soldering is done using, for example, a eutectic solder without flux.

The procedure according to the invention which has been described permits the production of a wide range of metal bodies having a cavity system arranged therein. It has been found that exceptional tightness can be achieved, with maximum dimensional accuracy of the finally machined body. Cavity systems following extremely complex patterns can also be installed in a very simple manner.

It will of course be understood that the present invention has been described above purely by way of example, and modifications of detail can be made within the scope and spirit of the invention.

Claims (15)

1. Method of producing metal bodies having a three-dimensionally branched cavity system located in the interior of the body, by which method the body is produced from a plurality of individual parts by soldering thereof, characterised in that all regions of the cavity system are first incorporated into the individual parts in accordance with the desired geometry, and the cavity system is only subsequently closed by the placing together and soldering to one another of all the individual parts.

2. Method according to Claim 1, characterised in that the individual parts are produced oversize at those surfaces which form the outer shape of the body, and the body is machined to the final size only after soldering.

3. Method according to Claims 1 and 2, characterised in that reference surfaces, which correspond to the region of the cavity system located in the particular individual part and also remain accessible after soldering, are incorporated into the individual parts, and the machining of the body to final size is carried out according to these reference surfaces.

4. Method according to one of Claims 1 to 3, characterised in that elements for fixing the relative positions of the individual parts during soldering are disposed on the individual parts.

5. Method according to Claims 1 and 4, characterised in that the fixing elements are removed by the machining of the body to final size.

6. Method according to one of Claims 1 to 5, characterised in that the stock of solder required for the soldering is deposited in cavities provided for this purpose or on individual parts before soldering when the individual parts are placed together.

7. Method according to Claim 6, characterised in that the position and volume of the solder deposits are determined so that satisfactory filling of the solder joints is ensured.

8. Method according to Claim 6, characterised in that a crack-shaped solder deposit is arranged between the surfaces to be soldered of two individual parts which are to be placed together, and a force is applied during soldering to constrict the crack-shaped solder deposit to the width of the soldered crack.

9. Method according to Claim 6, characterised in that a groove-shaped solder deposit is arranged in the individual parts and communicates with the soldered gap.

10. Method according to Claim 9, characterised in that the solder grooves are removed during machining to finished size.

11. Method according to one of Claims 1 to 10, characterised in that all individual parts are soldered together at the same time.

12. Method according to one of Claims 1 to 10, characterised in that groups of individual parts are soldered at the same time, and these groups are connected to one another in a second soldering operation.

13. Method according to one of Claims 1 to 12, characterised in that the soldering is carried out in a vacuum oven.

14. Method according to Claim 13, characterised in that soldering is carried out using a eutectic solder without flux.

15. A method of producing metal bodies having three-dimensionally extending internal cavity systems substantially as hereinbefore described with reference to the accompanying drawings.