Coated Stamped Parts

Stamped parts can be selectively as well as completely electroplated with precious metals on the basis of gold, silver and palladium or un-precious metals like tin, nickel and copper. Galvanic methods allow the deposition of extremely thin metal coating within narrow manufacturing tolerances. The great intrinsic hardness and resistance to abrasion of galvanic coatings is a functional advantage for many applications. Since even very thin coatings show only very little porosity, they are appropriate for corrosion protection. The kind of coating as well as the sequence of coatings and their thickness will be selected according to the application and the electrical requirements.

Clad Stamped Parts

Many technical applications require thicker precious metal layers. The electroplating of such layers onto carrier materials is not economical. Expensive gold-, silver-, or palladium-based contact materials with very special physical and mechanical properties are often required. These materials are produced by melting and casting or by powder metallurgical processes, which are clad onto carrier strips. The carrier materials are copper and copper alloys.

Welded Stamped Parts

Resistance welded stamped parts can be produced economically according to different joining techniques for combination of contact and carrier materials. Descrete contact tips or contact tips cutted from wires or micro profiles can be welded directly to solid, pre- and post-stamped carrier strips or individual stamped pieces. Resistance welded stamped parts can be also produced from semi finished contact strips which are already seam welded with contact material. The contact material used is based on gold, silver and palladium. Depending on the properties of the contact materials and their design, contact pieces have an additional good weldable carrier material on their under side.

Brazed Stamped Parts

Brazed stamped parts can be produced according to two economical joining techniques of contact and carrier material. Contact material can be brazed on solid or pre- and post-stamped carrier strips as descrete contact tips or the brazed stamp parts are produced from semi finished contact strips which are already equipped with one or two contact profiles. In both joining procedures a short-time inductive heating process is applied. Characteristically for brazed stamped contact parts is that according to their electrical application, contact materials are mainly based on silver and that the high conductive carrier material has a larger cross-section.

Riveted Stamped Parts

Riveted stamped parts are equipped with already produced contact rivets - solid, bimetal and trimetal versions -, or contact material is used as wire; in this case wire sections are inserted into carrier perforations and shaped to rivets with appropriate tools - wire riveting process -. Each procedure has specific advantages. The application of bimetal and trimetal rivets enables the cost of precious metals to be minimized. In the wire riveting process, the quantity of precious metal is higher, but the processing procedure can be carried out at a considerably higher production rate.

Assembled Stamped Parts

Assembled stamped parts consist usually of two different strip carrier materials. Both single strips are connected to each other mechanically by a riveting process and additionally by resistance welding in order to improve the electrical connection. Different properties of individual components can be combined, depending on the demands placed upon the assembled part. The electrical conductivity and the mechanical stability of one material, for example, are combined with the elastic, magnetic and thermal properties of the other material.

Contact Rivets

Solid, bimetal or trimetal contact rivets made of silver-based materials are supplied in a variety of shapes and sizes. In case of very low electrical loads rivets can be additionally electroplated with pure and/or hard gold. Specific applications, i.e., in appliances under elevated temperature conditions, require a mechanical connection of the rivet to the carrier material and in addition a bonding via a brazing alloy. In this case, the shank and the underside of the rivet head is clad with a layer of a brazing alloy.

Contact Parts for Vacuum Switches

For vacuum switches mostly used in the medium voltage range AMI DODUCO provides powder metallurgical contact parts based on copper/chromium and copper/tungsten materials. These VAKURIT^® brand materials have low gas content, and excellent erosion resistance and welding properties, high breaking capacity, low contact resistance and a low chopping current that remains largely unchanged throughout the service life of a switching device. These contact parts are discs made of sintered blanks, machined on all sides, turned to the finished form according to customer drawings or brazed onto supports.

Contact Parts for High-Voltage Switches

For arcing contact parts in SF6 circuit-breakers, load interrupter switches and transformer tap changers AMI DODUCO offers materials based on copper/tungsten. These CUWODUR^® brand materials are combined with high conductive contact carriers mainly made of copper/chromium zirconium alloys. The main contact parts in SF6 circuit breakers for current transmission are based on copper/chromium/zirconium or silver bronze electroplated with silver. For disconnector switches, top-lay contact parts consist of silver metal oxide contact materials combined with highly conductive carriers. Contact parts for high-voltage switches are supplied as tulip shaped contacts and tubes, as tulip shaped spring contacts, contact pins and bars.