Electrodes and Tooling

Lesson Objectives When you finish this lesson you will understand: The various electrode materials and design Electrode and part holders and fixtures Typical Applications Learning Activities 1.View Slides; 2.Read Notes, 3.Listen to lecture 4.Do on-line workbook 5.Do Homework Keywords Resistance 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 RWMA Class # Electrical Conductivity Composition (%) Ultimate Strength (ksi) Annealing Temperature (°C) Thermal Conductivity (Cal/cm-sec-°C) Cu 99-Cu, 1-Cd 99.2-Cu, 0.8-Cr 97-Cu, 2.5- Co, 0.5-Be Cu & Be Cu & Al (C) 82 (F) 48 (C) 52 (F) 20 (C) 23 (F) (F) 30 (C) 62 (F) 95 (C) 105 (F) 110 (C) 170 (F) (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 Welding Manual, p.18-2, RWMA]

Electrode Geometry “A” 6° 20° 45° ° Pointed Dome Truncated Cone Truncated Cone [Reference: Welding in the Automotive Industry, p.135, D. W. Dickinson]

Electrode Size Net Electrode Force (lb x 10 2 ) 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 Welding McGraw-Hill, 1950

W. Stanley, Resistance Welding McGraw-Hill, 1950

Interchangeable Die Set (a) (b) (c) [Reference: Resistance Welding Manual, p.17-6, RWMA] (b)

Tooling for Multiple Welding Stud and Jam Nuts Equalizing Bar Split and Clamped to Electrode Flexible Conductors Slip-Fit Lower Electrode Welding Pressure Adjustment Screw Compression Spring Flexible Conductors 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 Welding Manual, p.17-11, RWMA]

Workholding Devices: Dial Mechanisms [Reference: Resistance Welding Manual, 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 Welding Manual, p.17-13, RWMA]

Electrodes