Besides the selection of the most suitable contact materials , the design and typeof attachment is critical for the reliability and electrical life of contactcomponents for electromechanical switching devices. The materials most important factors here are the material-saving useof high cost precious metals and the most economic economical manufacturing method forcontact parts are most important factors..

There are two basic manufacturing solutions available: One can start with singlecontact parts , such as contact rivets or tips , which then are attachedmechanically or by brazing or welding resp. to carrier parts. In the second case, a base material coated or clad with the precious contact metal - for specialapplications also clad with another non-precious material – in the form of stripsor profiles is manufactured as a semi-finished pre-material from which thecontact components are then stamped and formed. Besides mechanicalcladding other processes such as electroplating and deposition from the gasphase are utilized.Which of the following manufacturing processes is finally chosen , depends onthe final application of the contact components in their respective switchingdevices or electromechanical components. Other considerations , such as therequired number of electrical operations, the most economical use of preciousmetals and the anticipated volumes of parts are also important for the processselection.

===3.1 Manufacturing of Single Contact Parts===The group of single contacts includes contact rivets, contact tips, and formedparts such as weld buttons. Contact spheres (or balls) are today rarely usedbecause of economical considerations.<br>Main Articel: [[Manufacturing of Single Contact Parts| Manufacturing of Single Contact Parts]]

==Manufacturing of Semi-Finished Materials=3=Semi-finished contact pre-materials can be manufactured from solid precious metals, precious metal alloys or precious metal containing composite materials.1.1 Contact Rivets===<br>Main Articel: [[Manufacturing of Semi-Finished Materials | Manufacturing of Semi-Finished Materials]]

==Attachment of Single Contact Parts==3.1The following segments give an overview of the usually applied attachment technologies for contact parts to carrier components.1They include mechanical, as well as brazing and welding methods used for electrical contact assemblies.1 Solid Contact Rivets===

*Typical Contact Shapes == Evaluation of Solid Contact RivetsBild*Contact MaterialsBild*Dimensional RangesBildBraze or Weld Joints==The respective parameters cannot be chosen independently switching properties of each other.They mainly depend brazed and welded contact assemblies is strongly dependent on the ductility quality of the required joint between the contact materialand the carrier. Before afinal decision on the dimensions we recommend to consult with the contactmanufacturerThe required high quality is evaluated through optical methods, continuous control of relevant process parameters and by sampling of finished products.

===3.1.1.2 Composite Stamped Contact Rivets=Parts==Clad rivets for Stamped electrical contact parts typically consist of a base carrier material to which only a part of the head contact material is attached by various methods (<xr id="fig:Plated and contact containing pre-stamped strips and stamped parts"/><!--(composite or bimetal rivetsFig. 3.17) or also-->). They serve as the shank end (tri-metal rivets) are composed important functional components in many switching and electromechanical devices for a broad range of contact material – with electrical and electronicapplications. On thebalance of one hand, they perform the body mostly being copper – have replaced for many applicationssolid rivet versions because loss-free electrical current transfer and the closing and opening of economical considerations. The cost savingsdepend electrical circuits, while on the other hand, the contact material and its required volume for a specificapplication. These composite rivets carriers are also produced scrap-less from wirematerial important mechanical design components, selected to meet the requirements on special machinery with two process variations utilizedelectrical, thermal, mechanical and magnetic properties.

During ''cold bonding'' and heading the bond between the contact material andthe copper is achieved without external heat energy by high plastic deformationat the face surfaces The increasing miniaturization of the two wire segments ''(Fig. 3.1)''electromechanical components requires ever smaller stamped parts with low dimensional tolerances. The bonding pressureSuch precisionmust be high enough to move stamped parts are needed in the lattice components of automotive technology for highly reliable switching and connector performance. In the two metals within ainformation and data processingfew atom radii so that technology, they transfer signals and control impulses with high reliability and serve as the adhesion forces interface between atoms become effectiveelectronic and electrical components.Therefore the head to shank diameter ratio of 2<figure id="fig:Plated and contact containing pre-stamped strips and stamped parts">[[File:Plated and contact containing pre-stamped strips and stamped parts.jpg|left|thumb|Figure 1 must be closely met : Plated and contact containing pre-stamped strips and stamped parts for adifferent applications]]strong bond between the two metals.</figure><br style="clear:both;"/>Main Articel: [[Stamped Contact Parts| Stamped Contact Parts]]

During ''hot bonding'' the required heat energy is applied by a short term electricalcurrent pulse ''Vinaricky, E. (Fig. 3Hrsg.2)''. In the case of Ag and Cu a molten eutectic alloy ofsilver and copper is formed in the constriction area between the two wire ends: Elektrische Kontakte, Werkstoffe und Anwendungen.When using metal oxide containing contact materials the nonSpringer-soluble oxideparticles tend to coagulate and the bonding strength between the componentmaterials is greatly reduced. Therefore the cold bonding technology is preferredfor these contact materials. The during cold bonding required high surfacedeformation ratio can be reduced for the hot bonding process which allows thehead to shank diameter ratio to be reduced below 2:1.Verlag, Heidelberg, Berlin 2002

For composite rivets with AgPd alloys as well as alloys on the basis of AuWitter, PdG., J.; Horn,G.: Contact Design and Pt the above methods cannot be used because of the very different workAttachment in: Electrical Contacts.hardening of these materials compared to the base material copperHrg. Thestarting material for such composite rivets is clad strip material from which thecontact rivets are formed in multiple steps of press-forming and stamping: Slade, P., G.Similar processes are used for larger contact rivets with head diameters > 8 mmand Ag-based contact materials, Marcel Dekker, Inc.,New York, Basel, 1999

Fig 3Mürrle, U: Löten und Schweißen elektrischer Kontakte.2In: Werkstoffe fürelektrische Kontakte und ihre Anwendungen: Hrg. Hot bonding of bimetal rivets : Schröder K.-H. u. a.;Expert-Verlag, Band 366, (schematic1997), 146 - 175

*Dimensional rangesDorn, L.: Grundlagen der Löttechnik. in: Hartlöten Grundlagen undbildThese parameters cannot be chosen independently of each otherAnwendungen. Hrsg.: Dorn, L. They dependmainly on the mechanical properties of the contact materialu. Before specifyingthe final dimensions we recommend to consult with the contact manufacturera., Expert-Verlag, Band 146 (1985) 15-40

*Typical contact shapes of triDVS-metal rivetsMerkblatt 2813: Widerstandsschweißen von elektrischen Kontakten,bildDüsseldorf: DVS-Verlag 2009

===3.1.1.3 Braze Alloy Clad Contact Rivets===For special cases, especially high surrounding temperatures with high thermaland mechanical stresses during switching operations, a full metallurgical bondbetween the contact rivet and the contact carrier may be required to prevent aloosening of the connection and early failures of the device. To accomplish thissuperior bond a thin layer of brazing alloy is added to the underside of the headand the rivet shank. During assembly a thermal treatment is added after themechanical staking. ===3.1.1.4 Contact Rivets with Brazed Contact Material Layers===For certain applications contact rivets with non-ductile or brittle materials suchas tungsten, silver–tungsten, or silver–graphite are required. Rivets with thesecontact materials can only be fabricated by brazing. Small round tips are brazedto pre-fabricated copper or steel bases using special brazing alloys in areducing atmosphere. ===3.1.2 Contact Tips===Flat or formed contact tips, welded or brazed to contact carriers, are frequentlyused in switching devices for higher power technology. Depending on thecontact material and specified shapes these tips are produced by variousmanufacturing processes. The most frequently used ones are[[de: *Stamping from strips and profiles*Cutting from extruded rods*Pressing, Sintering, and Infiltrating*Pressing, Sintering, and Re-Pressing*Pressing and Sintering For stamping sufficiently ductile semi-finished materials are needed. These aremainly silver, silver–alloys, silver–nickel, silver–metal oxide, and silver–graphite(with graphite particle orientation parallel to the switching surface). silver–metaloxides and silver–graphite need an additional well brazable or weldable silverlayer on the underside which can be bonded to the bulk of the contact materialby various processes. To further facilitate the final attachment process strips andprofiles are often coated on the brazing underside with an additional thin layer ofbrazing alloy such as L-Ag 15P (CP 102 or BCuP-5).For Ag/C with the graphite orientation perpendicular to the switching surface thebrazable underside is produced by cutting tips from extruded rods and burningout graphite in a defined thickness. The press-sinter-infiltrate process (PSI) is used mainly for Ag/W and Cu/Wmaterial tips with tungsten contents of > 50 wt%. A silver or copper surplus onthe underside of the tip later facilitates the brazing or welding during finalassembly. The press–sinter–re-press method (PSR) allows the economic manufacturing ofshaped contact parts with silver or copper contents > 70 wt%. This process alsoalloys parts pressed in two layers, with the upper being the contact material andthe bottom side consisting of pure Ag or Cu to support easy attachment. Press–sinter processes are limited to smaller Ag/W contact tips with a Agcontent of approximately 65 wt%. *Contact materialsbild *Typical contact shapes of tips and formed contact partsbild *Dimensional rangesbildBecause of the wide variety of shapes of contact tips and formed contact partsthe user and manufacturer usually develop special parts specific agreementson quality and tolerances. ===3.1.3 Weld Buttons===Technologien_für_die_Herstellung_von_Kontaktteilen]]