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Manufacturing of Single Contact Parts

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→‎Weld Buttons

Solid contact rivets are the oldest utilized contact parts. Their manufacturing requires a ductile contact material and is done without scrap on fully automated special cold heading machines. A wire slug is cut off and the rivet head is formed by pressing and hammering. This way contact rivets with various head configurations such as flat, domed, spherical or pointed can be manufactured, depending on the final application and switch or relay design.

*Typical Contact Shapes of Solid Contact Rivets (<xr id="fig:Typical_Contact_Shapes_of_Solid_Contact_Rivets"/>)

*Contact Materials Au-, AgPd-, PdCu-Alloys, Ag, AgNi 0,15, AgCu, AgCuNi (ARGODUR 27), Ag/Ni, Ag/SnO2, Ag/ZnO,Ag/C 97/3*, Cu * dimensionally very limited

*Dimensional Ranges (<xr id="fig:Dimensional_Ranges"/>) 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.

*Quality criteria and tolerances (<xr id="fig:Qualitaetsmerkmale_und_Toleranzen"/>)

[[File:Ty_pical_Contact_Shapes_of_Solid_Contact_Rivets.jpg|right|thumb|Figure 1: Typical Contact Shapes of Solid Contact Rivets]]

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*Typical Contact Shapes of Solid Contact Rivets <xr id="fig:Typical_Contact_Shapes_of_Solid_Contact_Rivets"/>

*Contact Materials 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 * dimensionally very limited

*Dimensional Ranges <xr id="fig:Dimensional_Ranges"/> 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.

[[File:Dimensional Ranges.jpg|right|thumb|Figure 2: Dimensional Ranges]]

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*Qualitätsmerkmale und Toleranzen <xr id="fig:Qualitaetsmerkmale_und_Toleranzen"/>

[[File:Qualitaetsmerkmale und Toleranzen.jpg|left|~~Qualitaetsmerkmale und Toleranzen~~thumb|Figure 3: Quality criteria and tolerances]]

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<table class="twocolortable" border="1" cellspacing="0" style="border-collapse:collapse"><tr><th>Characteristics</th><th>Form A Form B Form CRounded headf Trapeziodal Trapeziodal head, radiused head,flat</th><th>Suggested test equipment</th></tr><tr><td>a) Head diameter d1 [mm]</td><td>d1< 4 + 0,06 During optical measurementd1> 4 - 0,06 disregard cornerradius R3</td><td>Comparator,Measuring microscope</td></tr><tr><td>b) Head thicknessk [mm]</td><td>d1< 4 + 0,03d1> 4 + 0,08</td><td>Micrometer, Dial indicator</td></tr><tr><td>c) Shank diameter d2 [mm]</td><td>d2< 2 - 0,06d2> 2 - 0,08</td><td>Micrometer</td></tr><tr><td>d) Shank length [mm]</td><td>+ 0,15</td><td>Micrometer, Dialindicator, Comparator</td></tr><tr><td>e) Radius at centerof contact surfaceR1 [mm]</td><td>Form A und B: Within the head thicknesstoleranceForm C: Allowable deviation from flatness: convex: within head thickness toleranceconcave: 0.005 d1</td><td>Comparator,Comparator template, Radius gage</td></tr><tr><td>f) Radius at edge of contact surface R2 [mm]</td><td>Form A: Smooth transition to R1Form B: 1.5 R2 allowedForm C: <0,1d1</td><td>Profile template,Comparator, Radius gage</td></tr><tr><td>g) RadiiR3 and R5 [mm]</td><td>Sligth rounding allowed</td><td>Comparator</td></tr><tr><td>h) Transition radius head underside to shank R4 [mm]</td><td>d2 < 2 R4 < 0,08 if covered by DIN 46240 pg.1 d2 > 2 R4 < 0,1d2 > 3 R4 < 0,2</td><td>Comparator if in doubt: microsection</td></tr><tr><td>i) Allowed deviationfrom cylindrical shape</td><td>max. 7° 30’: or d2 < l, l > 0,7 mm and k < 0,6 d1.max. 15°: for all other rivets</td><td>Comparator</td></tr><tr><td>k) Concentricity between head and shank center line [mm]</td><td>d1 < 4 0,15d1 > 4 0,2in general: approx. 70% of allowable deviationper DIN 46240</td><td>Comparator, Specialturn fixture</td></tr></table>

Clad rivets, for which only a part of the head (composite or bimetal rivets) or also the shank end (tri-metal rivets) are composed of contact material – with the balance of the body mostly being copper – have replaced the solid rivet for many applications because of economical considerations. The cost savings depend on the contact material and its required volume for a specific application. These composite rivets are also produced scrap-less from wire material on special machinery with two process variations utilized.

During ''cold bonding'' the process of heading the bond between the contact material and the copper is achieved without external heat energy by high plastic deformation at the face surfaces of the two wire segments (<xr id="fig:Cold_bonding_of_bimetall_rivets"/>). ~~<figure id="fig:Cold_bonding_of_bimetall_rivets">[[File:Cold_bonding_of_bimetall_rivets.jpg|right|thumb|Cold bonding of bimetall rivets (schematic)]]</figure>~~ The bonding pressure must be high enough to move the lattice components of the two metals within a few 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 a strong bond between the two metals.

During ''hot bonding'' the required heat energy is applied by a short term electrical current pulse (<xr id="fig:Hot_bonding_of_bimetal_rivets"/> ). ~~<figure id="fig:Hot_bonding_of_bimetal_rivets">[[File:Hot_bonding_of_bimetal_rivets.jpg|right|thumb|Hot bonding of bimetall rivets (schematic)]]</figure>~~ 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. 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 process which allows the head to shank diameter ratio to be reduced below 2:1.

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 is clad strip material, from which the contact rivets are formed in multiple steps of press-forming and stamping. Similar processes are used for larger contact rivets with head diameters > 8 mm and Ag-based contact materials.

*Typical contact shapes for composite rivets (<xr id="fig:Typical_contact_shapes_for_composite_rivets"/>)~~<figure id="fig:Typical_contact_shapes_for_composite_rivets">[[File:Typical_contact_shapes_for_composite_rivets.jpg|right|thumb|Typical contact shapes for composite rivets]]</figure>~~*Contact materials Ag, AgNi 0,15 ~~(ARGODUR)~~, AgCu, AgCuNi (ARGODUR 27), Ag/Ni ~~(SINIDUR), Ag/CdO (DODURIT CDO)~~, Ag/SnO2 ~~(SISTADOX)~~, Ag/ZnO ~~(DODURIT ZNO)~~

*Base materials Cu

*Dimensional ranges (<xr id="fig:Dimensional_ranges"/> ) 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. *Quality criteria and tolerances (<xr id="fig:Quality_criteria_and_tolerances"/>) <div class="multiple-images"><figure id="fig:Cold_bonding_of_bimetall_rivets">[[File:Cold_bonding_of_bimetall_rivets.jpg|left|thumb|Figure 4: Cold bonding of bimetall rivets (schematic)]]</figure> <figure id="fig:Hot_bonding_of_bimetal_rivets">[[File:Hot_bonding_of_bimetal_rivets.jpg|left|thumb|Figure 5: Hot bonding of bimetall rivets (schematic)]]</figure> <figure id="fig:Typical_contact_shapes_for_composite_rivets">[[File:Typical_contact_shapes_for_composite_rivets.jpg|left|thumb|Figure 6: Typical contact shapes for composite rivets]]</figure>

[[File:Dimensional_ranges.jpg|~~right~~left|thumb|Figure 7: Dimensional ranges]]

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*Quality criteria and tolerances <xr id="fig:Quality_criteria_and_tolerances"/>

[[File:Quality_criteria_and_tolerances.jpg|left|thumb|Figure 8: Quality criteria and tolerances]]

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</div>

<tr><th>Criteria</th><th>Form B Form CTrapezoidal head, Trapezoidal head radiused flat</th><th>Suggested testequipment</th></tr><tr><td>a) Head diameterd1 [mm]</td><td>During optical measurement disregard corner radius R3 + 0.1</td><td>Comparator, measu-ring microscpope</td></tr><tr><td>b) Head thicknessk [mm]</td><td>+ 0.1</td><td>Micrometer,Dial indicator</td></tr><tr><td>c) Shank diameterd2 [mm]</td><td>Deviation from roundness and conical shape ofshank only within allowed diameter tolerance d2 < 1.5 - 0.08d2 > 1.5 - 0.1</td><td>Micrometer</td></tr><tr><td>d) Shank length l[mm]</td><td>+ 0.15</td><td>Micrometer, Dial indicator, Comparator</td></tr><tr><td>e) Radius at centerof contact surfaceR1 [mm]</td><td>Form B: + 10%, but not below+ 0.5 mmForm C: Allowable deviation from flatness: convex: within head thickness tolerance concave: 0.005 d1</td><td>Comparator, Comparator template, Radius gage, Profile template</td></tr><tr><td>f) Radius at edgeof contact surfaceR2 [mm]</td><td>per DIN 46240: Form B and C max. 0.5 without DIN:max. 1</td><td>Profile template,Comparator, Radius gage</td></tr><tr><td>g) RadiiR3 and R5 [mm]</td><td>Sligth rounding allowed</td><td>Comparator</td></tr><tr><td>h) Transition radiushead underside to shank R4 [mm]</td><td>d2 < 2 R4 < 0.08 d2 > 2 R4 < 0.1 d2 > 3 R4 < 0.2</td><td>Comparator, if in doubt: micro-section</td></tr><tr><td>i) Allowed deviation from cylindrical shape</td><td>d1 < 4 up to 7°30’ + 2°30’d1 > 4 up to 10° + 5°</td><td>Comparator, Measu- ring microscope, if in doubt: microsection</td></tr><tr><td>k) Concentricity bet-ween head and shank center line [mm]</td><td>5% of d1</td><td>Comparator,Measuring microscope, Special turn fixture</td></tr><tr><td>l) Contact layerthickness [mm]</td><td>In center area of 0.5 d1 s> nominal thicknessRemaining head area must be covered</td><td>Measuring micros- cope, Microsection</td></tr></table>

*Typical contact shapes of tri-metal rivets (<xr id="fig:Typical_contact_shapes_of_tri-metal_rivets"/>)~~<figure id="fig:Typical_contact_shapes_of_tri-metal_rivets">[[File:Typical_contact_shapes_of_tri-metal_rivets.jpg|right|thumb|Typical contact shapes of tri-metal rivets]]</figure>~~*Contact materials Ag, AgNi 0,15 ~~(ARGODUR)~~, AgCu, AgCuNi (ARGODUR 27), Ag/Ni ~~(SINIDUR)~~, Ag/CdO ~~(DODURIT CDO)~~, Ag/SnO ~~(SISTADOX)~~2 , Ag/ZnO ~~(DODURIT ZNO)~~

*Base materials Cu

*Dimensional ranges (<xr id="fig: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>

[[File:Dimensional_ranges2.jpg|right|thumb|Figure 10: Dimensional ranges]]

</figure>

*Standard values for rivet dimension</div><div class="clear"></div>

===Standard values for rivet dimension===

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

*Contact materials 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)~~

*Typical contact shapes of tips and formed contact parts (<xr id="fig:Typical_contact_shapes_of_tips_and_formed_contact_parts"/>)

[[File:Typical_contact_shapes_of_tips_and_formed_contact_parts.jpg|~~right~~left|thumb|Figure 11: Typical contact shapes of tips and formed contact parts]]

</figure>

*Dimensional ranges Attachment Method: Welding Bonding Area: approx. 5 – 25 mm2 Attachment Method: Brazing Bonding Area: > 25 mm2

The manufacturing of weld buttons from bi– or tri–metal strip requires a ductile contact material. Weld buttons with tungsten contact layers are therefore produced by brazing of tungsten discs to a weldable pre-formed base.

*Typical contact forms of weld buttons (<xr id="fig:Typical_contact_forms_of_weld_buttons"/>)~~<figure id="fig:Typical_contact_forms_of_weld_buttons">[[File:Typical_contact_forms_of_weld_buttons.jpg|right|thumb|Typical contact forms of weld buttons]]</figure>~~*Contact materials Ag, AgNi 0,15 ~~(ARGODUR-Spezial)~~, AgCu, AgCuNi (ARGODUR 27), Ag/Ni ~~(SINIDUR), Ag/CdO (DODURIT CdO)~~, Ag/SnO2 ~~(SISTADOX)~~, Ag/ZnO ~~(DODURIT ZnO)~~

*Carrier materials Ni, Fe, CuNi, CuNiZn et.al.

*Dimensional Ranges (<xr id="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>

[[File:13neuDimensional -Ranges.jpg|~~right~~left|thumb|Figure 13: Dimensional Ranges]]

</figure>

*Quality criteria of standard weld buttons <xr id="fig:16Quality_criteria_-of_standard_weld_-buttonsneu"/>

[[File:16Quality_criteria_-of_standard_weld_-buttonsneu.jpg|~~right~~left|thumb|Figure 14: Quality criteria of standard weld buttons]]

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==References==

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