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Electrodes and Tooling
Electrodes and Tooling
Lesson ObjectivesWhen you finish this lesson you will understand:• The various electrode materials and design• Electrode and part holders and fixtures• Typical Applications
Learning Activities1. View Slides; 2. Read Notes, 3. Listen to lecture4. Do on-line
workbook5. Do Homework
KeywordsResistance Welding Electrodes, RWMA Classification, Electrode Geometry, Multiple Welding Tools, Fixtures
Electrode Functions
• Conduct the welding current to the work
• Transmit the proper electrode pressure or force to the work in order to produce a satisfactory weld
• Help dissipate heat from the weld zone
RWMA Electrode Material Standards
• Group A - Copper Base Alloys– RWMA Class 1
• Zirconium Copper
• Cadmium Copper
• Chromium Copper
– RWMA Class 2• Chromium-Zirconium
Copper
• Chromium Copper
– RWMA Class 3• Cobalt-Beryllium
Copper
• Nickel-Beryllium Copper
• Beryllium-Free Copper
– RWMA Class 4• Beryllium Copper
– RWMA Class 5• Aluminum Copper
RWMA Electrode Material Standards (CONT.)
• Group B - Refractory Metals and Refractory Metal Composites– RWMA Class 10
• Copper Tungsten
– RWMA Class 11• Copper Tungsten
– RWMA Class 12• Copper Tungsten
– RWMA Class 13• Tungsten
– RWMA Class 14• Molybdenum
• Group C - Specialty Material– RWMA Class 20
• Dispersion-Strengthened Copper
Electrode Materials
RWMAClass #
ElectricalConductivity
Composition(%)
UltimateStrength
(ksi)
AnnealingTemperature
(°C)
ThermalConductivity
(Cal/cm-sec-°C)
-
1
2
3
4
5
Cu
99-Cu,1-Cd
99.2-Cu,0.8-Cr
97-Cu, 2.5-Co, 0.5-Be
Cu & Be
Cu & Al
90
92
80 (C)82 (F)48 (C)52 (F)20 (C)23 (F)
18 70 - 0.16
30 - -
60 (F)
30 (C)62 (F)95 (C)105 (F)110 (C)170 (F)
660 0.82
710
0.77 (C)0.75 (F)0.43 (C)0.45 (F)0.18 (C)0.19 (F)
930 (C)900 (F)1020 (C)900 (F)
* C = Cast, F = Forging
Typical Hardness-Temperature Curves
[Reference: Resistance WeldingManual, p.18-2, RWMA]
Electrode Geometry
“A” “A” “A” “A”6° 20°
45°
3
14
14
14
14
45°20°
Pointed
DomeTruncated
ConeTruncated
Cone
[Reference: Welding in the Automotive Industry, p.135, D. W. Dickinson]
Electrode SizeNet Electrode Force (lb x 102)
Electrode Face Diameters (inch)
Electrode Body Diameters (inch)
[Reference: Resistance Welding Manual, p.18-14, RWMA]
Spot Welding Electrode Nose Geometries
[Reference: Resistance Welding Manual, p.18-15, RWMA]
Type “A” Type “B” Type “C” Type “D” Type “E” Type “F”Pointed Dome Flat Offset Truncated Radius
W. Stanley, Resistance WeldingMcGraw-Hill, 1950
W. Stanley, Resistance WeldingMcGraw-Hill, 1950
Interchangeable Die Set
(a) (b) (c)
[Reference: Resistance Welding Manual, p.17-6, RWMA]
(b)
Tooling for Multiple Welding
Stud and Jam NutsEqualizing Bar
Split and Clampedto Electrode
Flexible Conductors
Slip-Fit
Lower Electrode
Welding PressureAdjustment Screw
Compression Spring
FlexibleConductors
Slip-Fit
Workpiece
(a) (b)
[Reference: Resistance Welding Manual, p.17-8, RWMA]
Tooling for Multiple Welding (CONT.)
[Reference: Resistance Welding Manual, p.17-8, RWMA]
(a) (b)
Tooling for Multiple Welding (CONT.)
(a) (b)
[Reference: Resistance Welding Manual, p.17-9, RWMA]
Press Welding Machine Fixtures
[Reference: Resistance WeldingManual, p.17-11, RWMA]
Workholding Devices: Dial Mechanisms
[Reference: Resistance WeldingManual, p.17-11, RWMA]
Workholding Devices: Shuttle Devices(a) (b)
[Reference: Resistance Welding Manual, p.17-12, RWMA]
Workholding Devices: Conveyor Type Fixtures
[Reference: Resistance WeldingManual, p.17-13, RWMA]
Electrodes
