Changes

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.

Solid contact rivets are the oldest utilized contact parts. Their manufacturingrequires a ductile contact material and is done without scrap on fully automatedspecial cold heading machines. A wire slug is cut off and the rivet head isformed by pressing and hammering. This way contact rivets with various headconfigurations such as flat, domed, spherical, or pointed can be manufactured, depending on the final application and switch or relay design.[[File:Ty_pical_Contact_Shapes_of_Solid_Contact_Rivets.jpg|right|thumb|Typical Contact Shapes of Solid Contact Rivets]]

*Typical Contact Shapes of Solid Contact Rivets (s. Picture <xr id="Typical Contact Shapes of Solid Contact Rivetsfig:Typical_Contact_Shapes_of_Solid_Contact_Rivets"/>)

*Contact Materials <br /> Au-, AgPd-, PdCu-Alloys, Ag, AgNi 0,15 (ARGODUR-Spezial), AgCu, AgCuNi (ARGODUR 27), Ag/Ni (SINIDUR), Ag/CdO (DODURIT CdO), Ag/SnO₂ SISTADOX), Ag/ZnO (DODURIT ZnO),Ag/C 97/3*, Cu<br /> <span class="small">^* dimensionally very limited</span>

*Dimensional Ranges (s. Picture <xr id="Dimensional Rangesfig:Dimensional_Ranges"/>) <br /> The respective parameters cannot be chosen independently of each other. They mainly depend on the ductility of the required contact material. Before a final decision on the dimensions we recommend to consult with the contact manufacturer. <br />*Quality criteria and tolerances (<xr id="fig:Qualitaetsmerkmale_und_Toleranzen"/>)<div class="multiple-images"><figure id="fig:Typical_Contact_Shapes_of_Solid_Contact_Rivets">[[File:Ty_pical_Contact_Shapes_of_Solid_Contact_Rivets.jpg|right|thumb|Figure 1: Typical Contact Shapes of Solid Contact Rivets]]</figure><figure id="fig:Dimensional_Ranges">[[File:Dimensional Ranges.jpg|right|thumb|Figure 2: Dimensional Ranges]] </figure><figure id="fig:Qualitaetsmerkmale_und_Toleranzen">[[File:Qualitaetsmerkmale und Toleranzen.jpg|left|thumb|Figure 3: Quality criteria and tolerances]]</figure></div><div class="clear"></div>

*Qualitätsmerkmale und Toleranzen (s. Picture "Qualitaetsmerkmale und Toleranzen") [[File:Qualitaetsmerkmale und Toleranzen.jpg|right|thumb|Qualitaetsmerkmale und Toleranzen]] <table class="twocolortable" border="1" cellspacing="0" style="border-collapse:collapse"><tr><tdth><p class="s13">Characteristics</p></tdth><tdth><p class="s13">Form A Form B Form C</p><p class="s13">Rounded headf Trapeziodal Trapeziodal head, radiused head,flat</p></tdth><tdth><p class="s13">Suggested test equipment</p></tdth></tr><tr><td><p class="s13">a) Head diameter d₁ [mm]</p></td><td><p class="s13">d<span class="s14">₁</span><u>&lt;</u> 4 + 0,06 During optical measurement</p><p class="s13">d<span class="s14">₁</span>&gt; 4 - 0,06 disregard corner</p><p class="s13">radius R<span class="s14">₃</span></p></td><td><p class="s13">Comparator,</p><p class="s13">Measuring microscope</p></td></tr><tr><td><p class="s13">b) Head thickness</p><p class="s13">k [mm]</p></td><td><p class="s13">d<span class="s14">₁</span><u>&lt;</u> 4 + 0,03</p><p class="s13">d<span class="s14">₁</span>&gt; 4 + 0,08</p></td><td><p class="s13">Micrometer, Dial indicator</p></td></tr><tr><td><p class="s13">c) Shank diameter d<span class="s14">₂</span> [mm]</p></td><td><p class="s13">d<span class="s14">₂</span><u>&lt;</u> 2 - 0,06</p><p class="s13">d<span class="s14">₂</span>&gt; 2 - 0,08</p></td><td><p class="s13">Micrometer</p></td></tr><tr><td><p class="s13">d) Shank length [mm]</p></td><td><p class="s13">+ 0,15</p></td><td><p class="s13">Micrometer, Dial</p><p class="s13">indicator, Comparator</p></td></tr><tr><td><p class="s13">e) Radius at center</p><p class="s13">of contact surface</p><p class="s13">R<span class="s14">₁</span> [mm]</p></td><td><p class="s13">Form A und B: Within the head thickness</p><p class="s13">tolerance</p><p class="s13">Form C: Allowable deviation from flatness: convex: within head thickness tolerance</p><p class="s13">concave: 0.005 d<span class="s14">₁</span></p></td><td><p class="s13">Comparator,</p><p class="s13">Comparator template, Radius gage</p></td></tr><tr><td><p class="s13">f) Radius at edge of contact surface R<span class="s14">₂</span> [mm]</p></td><td><p class="s13">Form A: Smooth transition to R<span class="s14">₁</span></p><p class="s13">Form B: 1.5 R<span class="s14">₂</span> allowed</p><p class="s13">Form C: <u>&lt;</u>0,1d<span class="s14">₁</span></p></td><td><p class="s13">Profile template,</p><p class="s13">Comparator, Radius gage</p></td></tr><tr><td><p class="s13">g) Radii</p><p class="s13">R<span class="s14">₃</span>and R<span class="s14">₅</span> [mm]</p></td><td><p class="s13">Sligth rounding allowed</p></td><td><p class="s13">Comparator</p></td></tr><tr><td><p class="s13">h) Transition radius head underside to shank R<span class="s14">₄</span> [mm]</p></td><td><p class="s13">d<span class="s14">₂ </span><u>&lt;</u> 2 R<span class="s14">₄ </span><u>&lt;</u> 0,08 if covered by DIN 46240 pg.1 d<span class="s14">₂ </span>&gt; 2 R<span class="s14">₄ </span><u>&lt;</u> 0,1</p><p class="s13">d<span class="s14">₂ </span>&gt; 3 R<span class="s14">₄ </span><u>&lt;</u> 0,2</p></td><td><p class="s13">Comparator if in doubt: microsection</p></td></tr><tr><td><p class="s13">i) Allowed deviation</p><p class="s13">from cylindrical shape</p></td><td><p class="s13">max. 7° 30’: or d<span class="s14">₂ </span> <u>&lt;</u> l, l <u>&gt;</u> 0,7 mm and k <u>&lt;</u> 0,6 d<span class="s14">₁</span>.</p><p class="s13">max. 15°: for all other rivets</p></td><td><p class="s13">Comparator</p></td></tr><tr><td><p class="s13">k) Concentricity between head and shank center line [mm]</p></td><td><p class="s13">d<span class="s14">₁ </span><u>&lt;</u> 4 0,15</p><p class="s13">d<span class="s14">₁ </span>&gt; 4 0,2</p><p class="s13">in general: approx. 70% of allowable deviation</p><p class="s13">per DIN 46240</p></td><td><p class="s13">Comparator, Special</p><p class="s13">turn fixture</p></td></tr></table>

Clad rivets , for which only a part of the head (composite or bimetal rivets) or alsothe shank end (tri-metal rivets) are composed of contact material – with thebalance of the body mostly being copper – have replaced the solid rivet for many applicationssolid rivet versions because of economical considerations. The cost savingsdepend on the contact material and its required volume for a specificapplication. These composite rivets are also produced scrap-less from wirematerial on special machinery with two process variations utilized. 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 of the two wire segments ''(Picture Cold bonding of bimetall rivets)''. The bonding pressuremust be high enough to move the lattice components of the two metals within afew atom radii so that the adhesion forces between atoms become effective.Therefore the head to shank diameter ratio of 2:1 must be closely met for astrong bond between the two metals. (s. Picture "Cold bonding of bimetall rivets") [[File:Cold_bonding_of_bimetall_rivets.jpg|right|thumb|Cold bonding of bimetall rivets (schematic)]] During ''hot bonding'' the required heat energy is applied by a short term electricalcurrent pulse ''(Picture Hot bonding of bimetall rivets)''. 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.When using metal oxide containing contact materials the non-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.

For composite rivets with AgPd alloys as well as alloys on During ''cold bonding'' the basis process of Au, Pd,heading the bond between the contact material and Pt the above methods cannot be used because copper is achieved without external heat energy by high plastic deformation at the face surfaces of the very different worktwo wire segments (<xr id="fig:Cold_bonding_of_bimetall_rivets"/><!--(Fig. 3.1)-->). hardening The bonding pressure must be high enough to move the lattice components of these materials compared to the base material coppertwo metals within a few atom radii, so that the adhesion forces between atoms become effective. Thestarting material for such composite rivets is clad strip material from which Therefore thecontact rivets are formed in multiple steps head to shank diameter ratio of press-forming and stamping.Similar processes are used 2:1 must be closely met for larger contact rivets with head diameters > 8 mmand Ag-based contact materials. (sa strong bond between the two metals. Picture "Hot bonding of bimetall rivets")

[[FileDuring ''hot bonding'' the required heat energy is applied by a short term electrical current pulse (<xr id="fig:Hot_bonding_of_bimetal_rivets"/><!--(Fig. 3.2)-->). In the case of Ag and Cu a molten eutectic alloy of silver and copper is formed in the constriction area between the two wire ends. When using metal oxide containing contact materials, the non-soluble oxide particles tend to coagulate and the bonding strength between the component materials is greatly reduced.jpg|right|thumb|Hot Therefore the cold bonding technology is preferred for these contact materials. During cold bonding, the required high surface deformation ratio can be reduced for the hot bonding of bimetall rivets (schematic)]]process which allows the head to shank diameter ratio to be reduced below 2:1.

*Typical contact shapes For composite rivets with AgPd alloys, as well as alloys on the basis of Au, Pd and Pt, the methods named above cannot be used because of the very different work hardening of these materials, compared to the base material copper. The starting material for such composite rivets (sis clad strip material, from which the contact rivets are formed in multiple steps of press-forming and stamping. Picture "Typical Similar processes are used for larger contact shapes for composite rivets")with head diameters > 8 mm and Ag-based contact materials.

[[File:Typical_contact_shapes_for_composite_rivets.jpg|right|thumb|*Typical contact shapes for composite rivets]](<xr id="fig:Typical_contact_shapes_for_composite_rivets"/>)

*Contact materials <br /> Ag, AgNi 0,15 (ARGODUR), AgCu, AgCuNi (ARGODUR 27), Ag/Ni (SINIDUR), Ag/CdO (DODURIT CDO), Ag/SnO₂ (SISTADOX), Ag/ZnO (DODURIT ZNO)<br />

*Dimensional ranges (s. Picture <xr id="Dimensional rangesfig:Dimensional_ranges"/>) <br />These parameters cannot be chosen independently of each other. They depend mainly on the mechanical properties of the contact material. Before specifying the final dimensions we recommend to consult with the contact manufacturer. <br /> [[File:Dimensional_ranges.jpg|right|thumb|Dimensional ranges]] *Quality criteria and tolerances (s. Picture "Quality criteria and tolerances")

[[File:Quality_criteria_and_tolerances.jpg|right|thumb|*Quality criteria and tolerances]](<xr id="fig:Quality_criteria_and_tolerances"/>)

<table border="1" cellspacing="0" stylediv class="bordermultiple-collapse:collapseimages"><tr><td><p classfigure id="s13fig:Cold_bonding_of_bimetall_rivets">Criteria</p></td><td><p class="s13">Form B Form C</p><p class="s13">Trapezoidal head, Trapezoidal head radiused flat</p></td><td><p class="s13">Suggested test</p><p class="s13">equipment</p></td></tr><tr><td><p class="s13">a) Head diameter</p><p class="s13">d<span class="s14">₁ </span>[[mm]</p></td><td><p class="s13">During optical measurement disregard corner radius R<span class="s14">₃ </span><u>+</u> 0File:Cold_bonding_of_bimetall_rivets.1</p></td><td><p class="s13">Comparator, measu-</p><p class="s13">ring microscpope</p></td></tr><tr><td><p class="s13">bjpg|left|thumb|Figure 4: Cold bonding of bimetall rivets (schematic) Head thickness</p><p class="s13">k [mm]</p></td><td><p class="s13">+ 0.1</p></td><td><p class="s13">Micrometer,</p><p class="s13">Dial indicator</p></td></tr><tr><td><p class="s13">c) Shank diameter</p><p class="s13">d<span class="s14">₂ </span>[mm]</p></td><td><p class="s13">Deviation from roundness and conical shape of</pfigure><p class="s13">shank only within allowed diameter tolerance d<span class="s14">₂ </span> <u>&lt;</u> 1.5 - 0.08</p><p classfigure id="s13fig:Hot_bonding_of_bimetal_rivets">d<span class="s14">₂ </span>&gt; 1[[File:Hot_bonding_of_bimetal_rivets.jpg|left|thumb|Figure 5 - 0.1</p></td><td><p class="s13">Micrometer</p></td></tr><tr><td><p class="s13">d: Hot bonding of bimetall rivets (schematic) Shank length l]]</pfigure><p classfigure id="s13fig:Typical_contact_shapes_for_composite_rivets">[mm]</p></td><td><p class="s13">+ 0.15</p></td><td><p class="s13">Micrometer, Dial indicator, Comparator</p></td></tr><tr><td><p class="s13">e) Radius at center</p><p class="s13">of contact surface</p><p class="s13">R<span class="s14">₁ </span>[mm]</p></td><td><p class="s13">Form BFile: <u>+</u> 10%, but not below</p><p class="s15">+<span class="s13"> 0Typical_contact_shapes_for_composite_rivets.5 mm</span></p><p class="s13">Form Cjpg|left|thumb|Figure 6: Allowable deviation from flatness: convex: within head thickness tolerance concave: 0.005 d<span class="s14">1</span></p></td><td><p class="s13">Comparator, Comparator template, Radius gage, Profile template</p></td></tr><tr><td><p class="s13">f) Radius at edge</p><p class="s13">of Typical contact surfaceshapes for composite rivets]]</pfigure><p classfigure id="s13fig:Dimensional_ranges">R<span class="s14">₂ </span>[[mm]</p></td><td><p class="s13">per DIN 46240File: Form B and C max. 0Dimensional_ranges.5 without DINjpg|left|thumb|Figure 7:max. 1Dimensional ranges]]</pfigure></td><td><p classfigure id="s13">Profile template,</p><p class="s13fig:Quality_criteria_and_tolerances">Comparator, Radius gage</p></td></tr><tr><td><p class="s13">g) Radii</p><p class="s13">R<span class="s14">₃ </span>and R<span class="s14">₅ </span>[mm]</p></td><td><p class="s13">Sligth rounding allowed</p></td><td><p class="s13">Comparator</p></td></tr><tr><td><p class="s13">h) Transition radius</p><p class="s13">head underside to shank R<span class="s14">₄ </span>[mm]</p></td><td><p class="s13">d<span class="s14">₂ </span><u>&lt;</u> 2 R<span class="s14">₄ </span><u>&lt;</u> 0File:Quality_criteria_and_tolerances.08 d<span class="s14">₂ </span>&gt; 2 R<span class="s14">₄ </span><u>&lt;</u> 0.1 d<span class="s14">₂ </span>&gt; 3 R<span class="s14">₄ </span><u>&lt;</u> 0.2</p></td><td><p class="s13">Comparator, if in doubt: micro-section</p></td></tr><tr><td><p class="s13">i) Allowed deviation from cylindrical shape</p></td><td><p class="s13">d<span class="s14">₁ </span> <u>&lt;</u> 4 up to 7°30’ + 2°30’</p><p class="s13">d<span class="s14">₁ </span>&gt; 4 up to 10° + 5°</p></td><td><p class="s13">Comparator, Measu- ring microscope, if in doubtjpg|left|thumb|Figure 8: microsection</p></td></tr><tr><td><p class="s13">k) Concentricity bet-</p><p class="s13">ween head Quality criteria and shank center line [mmtolerances]</p></td><td><p class="s13">5% of d<span class="s14">₁</span></p></td><td><p class="s13">Comparator,</p><p class="s13">Measuring microscope, Special turn fixture</p></td></tr><tr><td><p class="s13">l) Contact layer</p><p class="s13">thickness [mm]</pfigure></td><tddiv><p div class="s13clear">In center area of 0.5 d<span class="s14">₁ </span>s<u>&gt;</u> nominal thickness</p><p class="s13">Remaining head area must be covered</p></td><td><p class="s13">Measuring micros- cope, Microsection</p></td></tr></tablediv>

*Typical contact shapes <table class="twocolortable"><tr><th><p class="s13">Criteria</p></th><th><p class="s13">Form B Form C</p><p class="s13">Trapezoidal head, Trapezoidal head radiused flat</p></th><th><p class="s13">Suggested test</p><p class="s13">equipment</p></th></tr><tr><td><p class="s13">a) Head diameter</p><p class="s13">d<span class="s14">₁ </span>[mm]</p></td><td><p class="s13">During optical measurement disregard corner radius R<span class="s14">₃ </span><u>+</u> 0.1</p></td><td><p class="s13">Comparator, measu-</p><p class="s13">ring microscpope</p></td></tr><tr><td><p class="s13">b) Head thickness</p><p class="s13">k [mm]</p></td><td><p class="s13">+ 0.1</p></td><td><p class="s13">Micrometer,</p><p class="s13">Dial indicator</p></td></tr><tr><td><p class="s13">c) Shank diameter</p><p class="s13">d<span class="s14">₂ </span>[mm]</p></td><td><p class="s13">Deviation from roundness and conical shape of tri</p><p class="s13">shank only within allowed diameter tolerance d<span class="s14">₂ </span> <u>&lt;</u> 1.5 -metal rivets (s0.08</p><p class="s13">d<span class="s14">₂ </span>&gt; 1.5 - 0.1</p></td><td><p class="s13">Micrometer</p></td></tr><tr><td><p class="s13">d) Shank length l</p><p class="s13">[mm]</p></td><td><p class="s13">+ 0. Picture 15</p></td><td><p class="s13">Micrometer, Dial indicator, Comparator</p></td></tr><tr><td><p class="s13">e) Radius at center</p><p class="Typical s13">of contact shapes surface</p><p class="s13">R<span class="s14">₁ </span>[mm]</p></td><td><p class="s13">Form B: <u>+</u> 10%, but not below</p><p class="s15">+<span class="s13"> 0.5 mm</span></p><p class="s13">Form C: Allowable deviation from flatness: convex: within head thickness tolerance concave: 0.005 d<span class="s14">1</span></p></td><td><p class="s13">Comparator, Comparator template, Radius gage, Profile template</p></td></tr><tr><td><p class="s13">f) Radius at edge</p><p class="s13">of tricontact surface</p><p class="s13">R<span class="s14">₂ </span>[mm]</p></td><td><p class="s13">per DIN 46240: Form B and C max. 0.5 without DIN:max. 1</p></td><td><p class="s13">Profile template,</p><p class="s13">Comparator, Radius gage</p></td></tr><tr><td><p class="s13">g) Radii</p><p class="s13">R<span class="s14">₃ </span>and R<span class="s14">₅ </span>[mm]</p></td><td><p class="s13">Sligth rounding allowed</p></td><td><p class="s13">Comparator</p></td></tr><tr><td><p class="s13">h) Transition radius</p><p class="s13">head underside to shank R<span class="s14">₄ </span>[mm]</p></td><td><p class="s13">d<span class="s14">₂ </span><u>&lt;</u> 2 R<span class="s14">₄ </span><u>&lt;</u> 0.08 d<span class="s14">₂ </span>&gt; 2 R<span class="s14">₄ </span><u>&lt;</u> 0.1 d<span class="s14">₂ </span>&gt; 3 R<span class="s14">₄ </span><u>&lt;</u> 0.2</p></td><td><p class="s13">Comparator, if in doubt: micro-metal rivetssection</p></td></tr><tr><td><p class="s13">i) Allowed deviation from cylindrical shape</p></td><td><p class="s13">d<span class="s14">₁ </span> <u>&lt;</u> 4 up to 7°30’ + 2°30’</p><p class="s13">d<span class="s14">₁ </span>&gt; 4 up to 10° + 5°</p></td><td><p class="s13">Comparator, Measu- ring microscope, if in doubt: microsection</p></td></tr><tr><td><p class="s13">k) Concentricity bet-</p><p class="s13">ween head and shank center line [mm]</p></td><td><p class="s13">5% of d<span class="s14">₁</span></p></td><td><p class="s13">Comparator,</p><p class="s13">Measuring microscope, Special turn fixture</p></td></tr><tr><td><p class="s13">l) Contact layer</p><p class="s13">thickness [mm]</p></td><td><p class="s13">In center area of 0.5 d<span class="s14">₁ </span>s<u>&gt;</u> nominal thickness</p><p class="s13">Remaining head area must be covered</p></td><td><p class="s13">Measuring micros- cope, Microsection</p></td></tr></table>

[[File:Typical_contact_shapes_of_tri-metal_rivets.jpg|right|thumb|*Typical contact shapes of tri-metal rivets]](<xr id="fig:Typical_contact_shapes_of_tri-metal_rivets"/>)

*Contact materials <br /> Ag, AgNi 0,15 (ARGODUR), AgCu, AgCuNi (ARGODUR 27), Ag/Ni (SINIDUR), Ag/CdO (DODURIT CDO), Ag/SnO (SISTADOX)₂ , Ag/ZnO (DODURIT ZNO)<br />

*Dimensional ranges (s. Picture <xr id="Dimensional rangesfig:Dimensional_ranges2"/>)

<div class="multiple-images"><figure id="fig:Typical_contact_shapes_of_tri-metal_rivets">[[File:Typical_contact_shapes_of_tri-metal_rivets.jpg|left|thumb|Figure 9: Typical contact shapes of tri-metal rivets]]</figure><figure id="fig:Dimensional_ranges2">[[File:Dimensional_ranges2.jpg|right|thumb|Figure 10: Dimensional ranges]]</figure></div><div class="clear"></div>

*===Standard values for rivet dimension=== <table border="1" cellspacingclass="0twocolortable" style="border-collapsewidth:collapse75%"><tr><tdth>d₁</tdth><tdth><p class="s13">k</p></tdth><tdth><p class="s13">1</p></tdth><tdth><p class="s13">d₂</p></tdth><tdth><p class="s13">&alpha;</p></tdth><tdth><p class="s13">r₁</p></tdth><tdth><p class="s13">s₁</p></tdth><tdth><p class="s13">s₂</p></tdth></tr><tr><td><p class="s13">3.0</p></td><td><p class="s13">0.8</p></td><td><p class="s13">2.0</p></td><td><p class="s13">1.5</p></td><td><p class="s13">7.5°</p></td><td><p class="s13">4.0</p></td><td><p class="s13">0.4</p></td><td><p class="s13">1.0</p></td></tr><tr><td><p class="s13">4.0</p></td><td><p class="s13">1.0</p></td><td><p class="s13">2.5</p></td><td><p class="s13">2.0</p></td><td><p class="s13">7.5°</p></td><td><p class="s13">8.0</p></td><td><p class="s13">0.5</p></td><td><p class="s13">1.2</p></td></tr><tr><td><p class="s13">5.0</p></td><td><p class="s13">1.2</p></td><td><p class="s13">3.0</p></td><td><p class="s13">2.5</p></td><td><p class="s13">10°</p></td><td><p class="s13">12.0</p></td><td><p class="s13">0.6</p></td><td><p class="s13">1.4</p></td></tr></table>

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.

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.

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:

*Pressing, Sintering, and Infiltrating*Pressing, Sintering, and Re-Pressing

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–metalSilver–metal oxides and silver–graphite need needs 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 involves alloying the parts pressed in two layers, with the upper top being the contact material andthe bottom side consisting of being pure Ag or Cu to support for easy attachmentadhesion.

Press–sinter processes are limited to smaller Ag/W contact tips , with a Agcontent of approximately 65 wt%.

*Contact materials <br /> Ag, AgNi 0,15 (ARGODUR Spezial), AgCu, AgCuNi (ARGODUR 27), Ag/Ni (SINIDUR), Ag/CdO (DODURIT CdO), Ag/SnO₂ (SISTADOX), Ag/ZnO (DODURIT ZnO), Ag/C (GRAPHOR), Ag/W (SIWODUR), Ag/WC (SIWODUR C), Ag/WC/C (SIWODUR C/C), Ag/Mo (SILMODUR), Cu/W (CUWODUR)<br />

*Typical contact shapes of tips and formed contact parts (s<xr id="fig:Typical_contact_shapes_of_tips_and_formed_contact_parts"/>)<figure id="fig:Typical_contact_shapes_of_tips_and_formed_contact_parts">[[File:Typical_contact_shapes_of_tips_and_formed_contact_parts. Picture "jpg|left|thumb|Figure 11: Typical contact shapes of tips and formed contact parts]]</figure><br style="clear:both;")/>*Dimensional ranges<br />Attachment Method: Welding <br />Bonding Area: approx. 5 – 25 mm²<br />Attachment Method: Brazing <br />Bonding Area: > 25 mm² <br />

[[File:Typical_contact_shapes_of_tips_and_formed_contact_parts.jpg|right|thumb|Typical contact shapes of tips and formed contact parts]] *Dimensional ranges Attachment Method: <br /> Welding Bonding Area: approx. 5 – 25 mm² Attachment Method: Brazing Bonding Area: > 25 mm² <br /> Because of the wide variety of shapes of contact tips and formed contact parts, the user and manufacturer usually develop develops special parts , part specific agreementson quality and tolerances.

For contacts used at higher temperatures, such as for example in controls forstove tops, the use of contact rivets or the direct welding of silver based contactmaterials on steel or thermo-bimetal carriers is usually not feasible. For suchapplications , weld buttons are suitable contact components. Weld buttons are round or rectangular tips manufactured from clad contact bimetalor in some cases tri-metal semi-finished materials. The surface layer isproduced from the specified contact material, the bottom weldable layer from amaterial with higher electrical resistivity such as steel, nickel, or for example acopper-nickel alloy. For precious metal savings a third high conductive layer ofcopper may be inserted between the contact material and weld backing. Toimprove the welding process the underside often has an embossed pattern withone or more weld projections.

The manufacturing of weld Weld buttons are round or rectangular tips, manufactured from bi– clad contact bimetal or tri–metal strip requires in some cases tri-metal semi-finished materials. The surface layer is produced from the specified contact material, the bottom weldable layer from a ductilematerial with higher electrical resistivity such as steel, nickel or for example a copper-nickel alloy. For precious metal savings, a third high conductive layer of copper may be inserted between the contact materialand weld backing. Weld buttons To improve the welding process, the underside often has an embossed pattern with tungsten contact layers are thereforeproduced by brazing of tungsten discs to a weldable pre-formed baseone or more weld projections.

*Typical contact forms The manufacturing of weld buttons (sfrom bi– or tri–metal strip requires a ductile contact material. Picture "Typical Weld buttons with tungsten contact forms layers are therefore produced by brazing of weld buttons")tungsten discs to a weldable pre-formed base.

[[File:Typical_contact_forms_of_weld_buttons.jpg|right|thumb|*Typical contact forms of weld buttons]](<xr id="fig:Typical_contact_forms_of_weld_buttons"/>)

*Contact materials <br /> Ag, AgNi 0,15 (ARGODUR-Spezial), AgCu, AgCuNi (ARGODUR 27), Ag/Ni (SINIDUR), Ag/CdO (DODURIT CdO), Ag/SnO₂ (SISTADOX), Ag/ZnO (DODURIT ZnO) <br />

*Dimensional Ranges (s. Picture <xr id="Dimensional fig:13neuDimensional -Ranges"/>)

*Quality criteria of standard weld buttons (<xr id="fig:16Quality_criteria_-of_standard_weld_-buttonsneu"/>)<div class="multiple-images"><figure id="fig:Typical_contact_forms_of_weld_buttons">[[File:Typical_contact_forms_of_weld_buttons.jpg|left|thumb|Figure 12: Typical contact forms of weld buttons]]</figure><figure id="fig:13neuDimensional -Ranges">[[File:13neuDimensional -Ranges.jpg|rightleft|thumb|Figure 13: Dimensional Ranges]]</figure>*Quality criteria of standard weld buttons (s. Picture <figure id="Quality criteria of standard weld buttonsfig:16Quality_criteria_-of_standard_weld_-buttonsneu")>[[File:16Quality_criteria_-of_standard_weld_-buttonsneu.jpg|rightleft|thumb|Figure 14: Quality criteria of standard weld buttons]]</figure>[[Category:Manufacturing Technologies for Contact Parts|Category]]</div><div class="clear"></div>