DE202010003542U1 - Novel production of contacts - Google Patents

Abstract

Electrical contacts produced by metal spraying, characterized in that the electrical contact (1) is sprayed onto the prepunched contact carrier (2) and / or a carrier tape (9).

Description

1. Description of current manufacturing processes.

• – Schmelzmetallurgische Herstellung
• – Pulvermetallurgische Herstellung
• – Galvanische Herstellung
• – Gesinterte Einzelkontakte (pulvermetallurgisch)

The production of electrical contacts including the most silver-containing contact materials is described in textbooks and many publications. There are essentially the following production methods:

• - Melt metallurgical production
• - Powder metallurgical production
• - Galvanic production
• - Sintered single contacts (powder metallurgical)

• – Schmelzen
• – Stranggießen
• – Sintern
• – Strangpressen
• – Plattieren
• – Band- und Drahtwalzen
• – Längsteilen von Bändern
• – Drahtziehen
• – Profilwalzen und Profilziehen
• – Weichglühen
• – Stanzen, Prägen und spanend bearbeiten
• – Löten und Schweißen

The main production technologies are:

• - Melting
• - continuous casting
• - sintering
• - Extruding
• - plating
• - Band and wire rollers
• - slitting bands
• - wire drawing
• - Profile rolling and profile pulling
• - soft annealing
• - Stamping, embossing and machining
• - soldering and welding

It can be seen from this that the current production from the raw material via the semi-finished material to the finished contact is very cumbersome, time-consuming and expensive.

Another disadvantage is that the composition of the materials can be varied only within a narrow range. In the manufacturing technologies described, the silver-containing materials must always be so ductile that they remain deformable. Thus, the content of material additives (eg, metal oxides, graphite, and the like) is limited, although higher additions would be desirable from the switching characteristics of the switching device.

2. Neuartge production of electrical contacts.

Because of the complex and costly production of the contacts, solutions were sought to produce these contacts differently and, above all, much cheaper. A promising possibility is the application of the contacts directly on the contact carrier by metal spraying.

Metal spraying is mainly known for the production of wear and corrosion protection layers. However, it is increasingly becoming a shaping manufacturing process, as in the present case for the first time for the production of electrical contacts.

Metal spraying can be divided into thermal and kinetic processes.

Both methods are suitable for the production of contacts, depending on the composition of the contact material, its size and its later application.

For the metal spraying a powder mixture of the components of the contact material is needed. This powder mixture is sprayed directly onto the carrier material as a contact by means of a spraying device. Due to the high impact energy creates a firmly adhering connection (partially with melting) between contact and carrier material. The so sprayed contacts are free of pores.

In some spraying processes, it is also possible to use wires of the desired composition instead of the powder mixture.

There are two options for spraying the contact:

Execution example: 1

Spraying the contacts on the prefabricated contact carrier. (see picture)

The contact carriers are mounted on a guide rail and covered with a mask. In the mask openings (cavities) are punched, which correspond to the shape of the contact and the thickness of the mask corresponds to the thickness of the contact.

Exemplary embodiment: 2

Spraying the contacts on a carrier tape. (see picture)

It is also possible to inject the contacts on the non-stamped carrier tape. For this, the carrier tape is covered with a mask. Both can be fixed in the correct position via pre-punched holes. The mask has the thickness of the contact and cavities are punched whose contour corresponds to the molded contact. The spacing of the cavities is equal to the width of the contact carrier. Both, mutually fixed bands pass in front of the spray head, wherein the cavities are filled with the contact material. In the next step, the mask is removed from the carrier tape. Subsequently, from the carrier tape (with the sprayed contacts) in a tool, the contact carrier produced by stamping and stamping.

3. Description of the metal spray equipment.

Commercially available systems can be used both for the thermal (flame spraying) and the kinetic (cold gas spraying) process.

The metal spray systems are housed in a noise protection chamber with air extraction and exhaust air purification by means of filters (recovery of silver or precious metals) and ventilation. The material transport in front of the spray head is done by special devices.

From this it can be seen that for the novel contact production, the cost of machines is significantly lower than in previous methods. Based on the experience and knowledge so far, the cost savings over the current procedures will be over 50%.

4. Advantages.

• - Significant reduction in the cost of manufacturing contacts compared to current procedures
• - Instead of the complex semi-finished product only a powder mixture or a wire is needed
• - No additional fine silver and solder layers are required on the contact base
• - The welding or soldering of the contacts on the contact carrier is eliminated
• - The composition of the material components is arbitrarily changeable, since the contact materials must not be deformed during manufacture
• Gradient materials can be made, with different concentrations of one or more components, depending on the thickness of the contact
• - Low investment costs (compared to semi-finished products)
• - saving on energy costs
• - Reduction of material waste
• - Prevention of hydrogen-containing protective gases

Claims (7)

Electrical contacts made by metal spraying, characterized in that the electrical contact ( 1 ) on the pre-punched contact carrier ( 2 ) and or a carrier tape ( 9 ) is sprayed on. The on a guide rail ( 3 ) lined up contact carrier ( 2 ) and or a carrier tape ( 9 ) are characterized in that they are provided with a mask ( 4 ) whose cavities ( 5 ) and the size of the contact ( 1 ) correspond. Electrical contacts according to the preceding claims, characterized in that the guide rail ( 3 ) and or the carrier tape ( 9 ) with the mask ( 4 ) by means of catch pin ( 6 ) and catch hole ( 7 ) connected is. Electrical contacts according to the preceding claims, characterized in that the guide rail ( 3 ) and or the carrier tape ( 9 ) with the mask ( 4 ) in front of the spray device ( 8th ) is transported. Electrical contacts according to the preceding claims, characterized in that after the metal spraying the mask ( 4 ) from the guide rail ( 3 ) and or the carrier tape ( 9 ) is deducted. Electrical contacts according to the preceding claims, characterized in that after the metal spraying of the contacts ( 1 ) on a contact carrier ( 2 ) and or a carrier tape ( 9 ) in a tool contact carrier ( 2 ) or punched. Electrical contacts according to the preceding claims, characterized in that the mixture of the metallic components of the sprayed-on contacts ( 1 ) are freely selectable and thus can be optimally adapted to the special requirements of the switching device.

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