DE10311174A1 - Process for the production of a structured metal foil - Google Patents

Abstract

The die unit (1) with an upper part (6) and a lower part (7) produces structured metal foil (3) with at least two overlapping structures. It has at least three spatially separate working regions: a stamping region to remove foil material from certain positions of the foil (4), a primary shaping region (5) to apply the primary corrugated structure, and a secondary one to impose the secondary structure on the first structure.

Description

The present invention relates to a method for producing a structured metal foil, the serves in particular as a catalyst carrier body.

Such structured metal foils become long bands folded and into catalyst honeycomb bodies with a special geometry wound. The honeycomb body have a large number of honeycomb cells on the walls the catalytic process of a catalytically active coating. Built this way Catalysts are primarily used in motor vehicles, about the increasing mobility reduce air pollution caused.

Metal is there, in addition to ceramics, due to its advantageous physical-technical properties such as high mechanical and thermal stability, an ideal carrier material for the catalytically active coating.

This high stability allows extremely thin walls of the Honeycomb cells, so that a small amount of space of honeycomb cells can be realized, which also have a low overall mass exhibit. The large number of honeycomb cells enables a high conversion rate, which is reached after a short warm-up time due to the low mass of the honeycomb body becomes.

Since the conversion rate for a given Volume flow is proportional to the catalyst surface, leads to an increase in surface to a higher one Conversion rate. It has therefore long been a concern of catalyst developers the catalyst surface while reducing the construction volume and the mass enlarge.

In the past, metal bands with a wave structure were used for this. A method for producing a corrugated sheet is described in DE 199 57 585 A1 described. Here, a sheet is passed between two intermeshing corrugated rollers, so that a corrugated structure is formed on the sheet by bending and drawing operations between the interlocking shafts forming a profile segment.

A disadvantage of this prior art is that the combing Rolling with increasingly low material thicknesses of the metal sheet and increasingly smaller profile depths of the shaft structure the required manufacturing tolerances cannot comply. Burr formation occurs, which is very disruptive to the galvanic deposition of the catalytically active coating, so that the ability to convert of the catalyst is reduced instead of increased.

Object of the present invention is therefore to specify a process that makes manufacturing very thin, structured Metal foils with a large surface underneath Compliance with high quality standards allowed.

This task is solved in that a Metal foil in a progressive tool in one machining process provided with a first and at least a second structure where the second structure overlaps the first structure, and in the transition area between first and at least second structure metal foil material Will get removed.

This method according to the invention advantageously allows the production of extremely thin, structured metal strips in one machining step in a single tool with simultaneous Compliance with the smallest manufacturing tolerances. The method according to the invention is more economical than that described in the prior art, since it can be done on a machine with a tool can, since progressive dies can be punched with one machining step, Can introduce and / or bend. The inventive method reduces the formation of burrs on the workpieces, so that a complete catalytic effective surface on the metal support can be deposited. The work step provided according to the invention the material removal also ensures that an off the catalyst made of the material has a significantly longer service life has in everyday operation, the tensions due to the material removal degraded within the metal foil, and notch effect at the transition areas between the first and second structure can be avoided.

The process looks advantageous that work steps of the machining process are offset in time take place or individual work steps of the machining process offset in time and space respectively. The time offset of the work steps enables one continued flow of the material during of the successive molding processes, so that microcracks or structural breaks be avoided. Dependent on The material to be deformed can also be spatial Variation of the work steps within the progressive tool take place, so that even very sensitive metal foils with very good result can be processed.

The fact that the progressive die the first and second structure preferably as a wave structure in the Introduces metal foil, the surface without corners disadvantageous for the galvanization and edges significantly enlarged. corners and edges additionally to form dead volumes that the conversion rate of the catalyst belittle and have to therefore be avoided. The formation of the structure as a wave structure still has the particular advantage that the surface, not however, the flow resistance is increased beyond measure. An exhaust gas to be treated can therefore be cleaned without loss of performance become.

To increase the surface area, it is provided that the second structure is introduced into the wave crests and / or into the wave troughs of the first structure, and the waves of the second structure preferably have a higher frequency and a higher frequency have a smaller amplitude than the waves of the first structure. This processing step leads to an optimal enlargement of the surface.

It is also provided that film material by punching out, preferably in the form of an elongated hole, in the transition area between the first and second structure is removed. The punch in The shape of an elongated hole is particularly advantageous and easy to implement, however, the invention also encompasses other forms such as bone, circular or double hole shape.

An embodiment of the invention is provided that metal foil with a thickness of 0.02 to 0.12 mm, preferably with a thickness of 0.04 mm, and with a film width from 50 to 180 mm is processed.

Furthermore, it is advantageously provided that the metal foil through at least one feed device guided the progressive tool becomes. The use of at least one feed device, preferably two feeding devices at the beginning and at the end of the progressive tool allows an optimal processing sequence.

The following are based on the figures the drawing explains further details and advantages of the invention. in the Individuals provide the

1 : a flow chart of a machining process,

2 : a schematic diagram of a progressive tool

3 : a perspective view of a corrugated metal foil produced according to the invention and

4 : a cross section through the same.

As in 1 shown, a process cycle begins with the transport 1 the metal foil to be machined into the progressive die that comes from a press bed 2 and one through an eccentric disc 3 powered moving bear 4 consists of the bear 4 the tool 5 carries one or more stamps 6 . 6 ' for the actual material processing. This structure of the progressive tool is the 2 refer to. The time of material processing in a machining process is controlled by the length of the stamp: the longest stamp 6 hits the metal foil first and locks it in place 7 , The bear's further downward movement 4 brings the next longer stamp 6 ' in contact with the metal foil. These now bring the primary structure 8th into the material. The introduced zone of the primary structure is spatially offset by at least the surface of the locking stamp. In the next step, the next longest stamp brings the secondary structure 9 into the metal foil. From this point on, the bear is 4 reached the lowest point of its vertical movement. So that's the tool 5 moved together, further material is no longer deformed. The next step 10 then carries out the punching in the area between the primary and secondary structure. The wavy metal strip produced by this process is then fed through a further material feed 1 conveyed from the progressive die and fed to further processing. In the processing operation described, at least one complete, depending on the material properties, two or more complete structural units are introduced into the metal foil.

Instead of directly following the two embossing work steps 8th and 9 Depending on the properties of the workpiece, it is also provided according to the invention that the further material processing takes place only after the workpiece has been transported within the tool to the position of a second stamp, which then, as already described, is the second introduction 9 and subsequent punching 10 performs.

The primary structure created in this way is a wave 2.5 mm long and 1.6 mm high. The wavy secondary structure has a length of 1 mm and a height of ~ 0.5 mm. 4 shows a cross section through a corrugated metal foil produced by the method according to the invention, the cutting plane in the in 3 drawn level II.

1

transport

2

Press bed

3

eccentric

4

bear

5

Tool

6

stamp

7

lock

8th

Embossing primary structure

9

Embossed secondary structure

10

material cut

Claims (8)

Method for producing a structured metal foil, in particular as a catalyst carrier body, characterized in that a metal foil is provided with a first and at least a second structure in a progressive tool in one machining operation ( 8th . 9 ), the second structure superimposing the first structure and removing metal foil material in the transition region between the first and at least the second structure ( 10 ) becomes. A method according to claim 1, characterized in that work steps of the machining process are delayed take place or individual work steps of the machining process temporally and spatially staggered. A method according to claim 1 or 2, characterized characterized in that the progressive tool brings the first and second structure preferably as a wave structure in the metal foil. Method according to Claim 1, 2 or 3, characterized in that the second structure is introduced into the wave crests and / or into the wave troughs of the first structure ( 9 ) and the waves of the second structure preferably have a higher frequency and a lower amplitude than the waves of the first structure. Method according to one of the preceding claims, characterized characterized in that foil material by punching, preferably in the form of an elongated hole, in the transition area between the first and second structure is removed. Method according to one of the preceding claims, characterized characterized that metal foil with a thickness of 0.02 to 0.12 mm, preferably with a thickness of 0.04 mm, and with a film width of 50 to 180 mm is processed. Method according to one of the preceding claims, characterized characterized in that the metal foil by at least one feed device is guided through the progressive tool. Method according to one of the preceding claims, characterized characterized in that in one machining operation, preferably two wave structures are introduced into the metal foil.