Products & Solutions

Semi-finished contact materials

Contact products for reliable switching operation

The main tasks of switching electrical contacts are to close and open electrical circuits, in the closed stage to transmit electrical signals without distortion, and to carry currents with the least amount of energy losses. In their wide range of applications silver based contact materials have to meet different requirements which cannot all be fulfilled by pure silver. The development of alloys made by melt-metallurgical processes and powder metallurgical composite materials broadened the range of properties of silver based materials significantly. This offers the user a wider spectrum of silver materials, optimized for a variety of application requirements.

Areas of application:

  • Telecommunication
  • and Data Technology
  • Automotive
  • Industrial Automation
  • Measurement and Control
  • Low Voltage Power Distribution
Silberdraht auf Rolle

Wires

Wires from silver and silver alloys (i.e. AgNi0.15, AgCu3, AgPd30, AgCdO int.ox), from powder metallurgical
silver-based materials (i.e. Ag/Ni, AgSnO , Ag/ZnO, Ag/CdO) and from high precious alloys (i.e. AuAg8, PdCu15) are manufactured by extrusion and subsequent drawing and annealing process steps. They are the starting material for the manufacture of a variety of contact parts and components.

All technologies shown are utilized at DODUCO and we offer any required depth of manufacturing integration.
Typical wire dimensions and tolerances:
0,5 ± 0,01 mm to 4,5 ± 0,04 mm

Contact Rivets

DODUCO ESPAÑA manufactures solid, composite bimetal and trimetal contact rivets for relays and all kinds of switching devices for the measurement and control of electricity.

On over 100 different rivet manufacturing machines, including internally developed cold and hot bonding machines, we produce about 1.5 billion rivets annually for customers around the world.  In addition we supply DODUCO’s internal stamped parts production with contact rivets.

As contact materials we use:

zwei Kontaktnieten silber- und kupferfarben stehend und liegend

Solid Rivets

Solid rivets are formed or headed from wire. Manufacturing is fully automated and scrap-free and therefore very economical.

Composite Rivets

Composite rivets are mostly produced directly from wires using different processes. This is achieved on specialty machines which to a large extend are developed by DODUCO. For manufacturing from wire DODUCO employs equipment for cold bonding as well as hot welding.

Trimetal Rivets

Tri-metal rivets are manufactured either by bonding of multiple wire segments or by cutting and forming from a suitable tri-metal strip. When using the latter method it is also possible to use different contact materials for the contact layers if different load conditions have to be controlled.

Miniprofiles

Miniature profiles, also called miniprofiles or weld tapes, are used in relays, switches, pushbuttons, miniature motors and positioning actuators as reliable contact components. They consist of a solid contact material or are composed of multiple precious metal and base metal layers.

The use of mini-profiles has the following advantages:

  • Precious metal savings: Optimum control of contact size and layer thickness of the contact material within small dimensional tolerances
  • Design options: Miniprofiles can closely match the application with shape and contact material combinations
  • Economics: Miniprofiles can be used for seam-welding in rolling direction of carrier strip material or for horizontal welding of profile/tape segments.

Forms of supply

The schematics show different design shapes for mini-profiles. Deciding on a specific mini-profile design, its dimensions and shape, is determined by requirements given from the electromechanical component.

Base materials

Selecting the base material of the profile serves the same purpose as the detailed design of the pattern on the very bottom surface. The welding heat should be concentrated in the transition of profile to carrier material. For this the base materials exhibit a comparably low electrical and thermal conductivity. During manufacturing of the miniprofile the different cold working properties of the base and contact materials have to be considered.
Miniprofiles can also be coated on the bottom side with a brazing alloy, preferably L-Ag15P (CP 102) with a > final thickness of 0.015 mm. With this coating added, a high percentage of bond area between carrier and
profile can be achieved.

Profile bottom surface

Miniature profiles are attached to the carrier materials by resistance welding or short-term brazing. The two most useful bottom profile designs are:
  • Weld rails: The number of rails as well as their height and width are determined by the total width of the profile.
  • Diamond pattern: They are mostly aligned in three rows along the length of the profile. Their defining parameters are their angle, width and height.

Welding of miniprofiles

The reliability of weld joints is dependent on the following paramters:
  • Material of the contact and profile bottom
  • Size of the profile to be welded
  • Shape and number of weld rails
  • Carrier or substrate material
  • Coating of the contact carrier strip
  • Dimensions and geometry of the stamped carrier strip
  • Surface cleanliness of the materials to be joined
  • Material and geometry of the welding electrodes
  • Mechanical and electrical parameters of the weld equipment

Dimensions and tolerances

The following are typical guidance values for the base width and thickness of DODUCO miniature profiles:

Profile width: > 0,50 +/- 0,020 mm,

Profile height:  >  0,25 +/- 0,005  mm.

The thickness of gold contact layers deposited by PVD is depending on requirements in the range of 0.2 to 5.0 μm with a thickness tolerance of approximately ± 10%

Contact tips

Flat or shaped contact tips, welded or brazed to contact carriers, are widely used in higher power electrical switching devices. Depending on the contact material and specific shapes these tips are produced by various manufacturing technologies.
The most frequently used ones are:
  • Stamping from strips and profiles
  • Cutting from extruded rods
  • Pressing, sintering and infiltration (PSI)
  • Pressing, sintering and re-pressing (PSR)
  • Pressing and sintering
zwei silbrige Kontaktplättchen, jeweils stehend und liegend
Bimetall-Band Überlappverbund (kupfer- und silberfarben) stehend

Strips and semi-finished contact materials

Strip materials are considerably larger in dimension than for example profiles, their manufacturing processes however are similar. Semi-finished materials and the contact components produced using them are mainly configured for the use in higher electrical loads. The contact materials employed are exclusively silver based and the properties of their underside are determined by the manufacturing technology and the carrier material.

Cold roll-cladding

Both components, the contact material as well as the carrier material are used in the form of endless strip. The bond between the materials is achieved by a high degree of deformation as well as special surface preparation right before the actual roll-bonding.

Do You Have Questions?

Drei-Personen-Symbol rot
Mr. Oliver Lutz

Sales Manager – Contact materials

Tel.: + 49 (0) 7231 602-566
Mail: kontaktwerkstoffe@doduco.net