Spot weldability Lesson Objectives When you finish this lesson you will understand: Concept of Spot...
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Transcript of Spot weldability Lesson Objectives When you finish this lesson you will understand: Concept of Spot...
![Page 1: Spot weldability Lesson Objectives When you finish this lesson you will understand: Concept of Spot Weldability Electrode arrangements Learning Activities.](https://reader035.fdocuments.us/reader035/viewer/2022062222/5697bf7d1a28abf838c849a4/html5/thumbnails/1.jpg)
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Spot weldability
Lesson ObjectivesWhen you finish this lesson you will understand:• Concept of Spot Weldability• Electrode arrangements
Learning Activities1. View Slides; 2. Read Notes, 3. Listen to lecture4. Do on-line
workbook
Keywords: Current Level, Current Range, Lobe Curve, Electrode Life, Peel Test, Nugget Size, Button Size, Interfacial Failure, Shunting Effect, Multiple Direct Electrodes, Series Electrodes, Electrode Tooling
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Process Characteristics as a Measure of Weldability
• Current Level
• Current Range & Weldability Lobe
• Process Deterioration– Characterization of the loss in weld size at constant
welding conditions– Characterization of the variation in process
requirements for maintaining welds of an adequate quality
Peel Test Used As MeasurePeel Test Used As Measure
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Button Size as a Measure of Weld Quality
ButtonDiameter
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Modes of Failure in Spot Welds
Full Button Irregular Button
Interfacial Failure
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Process Characteristics as a Measure of Weldability
• Current Level
• Current Range & Weldability Lobe
• Process Deterioration– Characterization of the loss in weld size at constant
welding conditions– Characterization of the variation in process
requirements for maintaining welds of an adequate quality
Peel Test Used As MeasurePeel Test Used As Measure
![Page 12: Spot weldability Lesson Objectives When you finish this lesson you will understand: Concept of Spot Weldability Electrode arrangements Learning Activities.](https://reader035.fdocuments.us/reader035/viewer/2022062222/5697bf7d1a28abf838c849a4/html5/thumbnails/12.jpg)
Nugget Diameter vs. Weld Current
Expulsion
SmallNuggets
AcceptableNuggets
Minimum Nugget Diameter
Weld Current
Nug
get
Dia
met
er
Nominal Current
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Process Characteristics as a Measure of Weldability
• Current Level
• Current Range & Weldability Lobe
• Process Deterioration– Characterization of the loss in weld size at constant
welding conditions– Characterization of the variation in process
requirements for maintaining welds of an adequate quality
Peel Test Used As MeasurePeel Test Used As Measure
![Page 15: Spot weldability Lesson Objectives When you finish this lesson you will understand: Concept of Spot Weldability Electrode arrangements Learning Activities.](https://reader035.fdocuments.us/reader035/viewer/2022062222/5697bf7d1a28abf838c849a4/html5/thumbnails/15.jpg)
Current Range & Weldability Lobe
ExpulsionAcceptableNuggets
Small Nuggets
Minimum Nugget Diameter
Weld Current
Weld Current
ExpulsionLevel
TimeA Smaller
“Brittle” Nuggets
AcceptableNuggets
LobeCurve
Nu
gge
t Dia
met
er
We
ld T
ime
Time A
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Process Characteristics as a Measure of Weldability
• Current Level
• Current Range & Weldability Lobe
• Process Deterioration– Characterization of the loss in weld size at constant
welding conditions– Characterization of the variation in process
requirements for maintaining welds of an adequate quality
Peel Test Used As MeasurePeel Test Used As Measure
![Page 20: Spot weldability Lesson Objectives When you finish this lesson you will understand: Concept of Spot Weldability Electrode arrangements Learning Activities.](https://reader035.fdocuments.us/reader035/viewer/2022062222/5697bf7d1a28abf838c849a4/html5/thumbnails/20.jpg)
Process DeteriorationMinimumAcceptableDiameter
Number of Welds
Wel
d D
iam
eter
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Shunting Effect
AB
IB
IA
Itotal = IA + IB
IARA = IBRB
IB/Itotal = 1 - RB/(RA + RB)[Reference: Resistance Welding Manual, p.1-7, RWMA]
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Multiple Direct Electrodes
Series Electrode
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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]
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