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Properties of Plasma Welds. Rafael Jaramillo Greg Angelides Linda McLaren. Overview. Experimental Objectives and Motivation Previous Work Experimental Design Results Future Work. Objectives and Motivation. Create a complete database of plasma welds - PowerPoint PPT Presentation
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Properties of Plasma Welds
Rafael Jaramillo
Greg Angelides
Linda McLaren
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Overview• Experimental Objectives
and Motivation
• Previous Work
• Experimental Design
• Results
• Future Work
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Objectives and Motivation
• Create a complete database of plasma welds• Study how speed and amperage affect the weld attributes.
- width- depth- structure
• Determine whether temperatures read with a thermocouple correlate with Infrared Camera readings.
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Previous WorkTwo years ago an REU group created several plasma welds. Last year’s group organized them.
1.5 mm/s2.0 mm/s3.0 mm/s4.0 mm/s4.5 mm/s5.0 mm/s1.5 mm/s2.0 mm/s3.0 mm/s4.0 mm/s4.5 mm/s
60Amps 65 Amps 70 Amps 75 Amps
1.5mmps N/A
2.0mmps
2.5mmps
3.0mmps
3.5mmps N/A N/A N/A
4.0mmps N/A N/A N/A
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Experimental Setup
Fluke +Computer
Infrared Camera
Plasma Welding Robot
Sample Holder
Camera Control+ Television
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While Welding…
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Experimental Design Samples were cut and cleaned
Thermocouples were affixed
Sample was welded at specified
current and speed
Temperature Data was recorded using
a Fluke Hydra DAQ unit.
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Infrared Recordings were made during welding.
Cross sectional cut of samples
was made and put into molds
for microscope study.
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Polishing!
5 step polishing process
Fine polishing necessary for viewing microscopic structures
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Finding IR Camera Range Temp. range of IR camera had to
be set before welding process Tradeoff between visible
temperature range and temperature resolution
Range set at 200 – 700 oC Entire heating process could not
be captured
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Sample Weld Results
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Welding Temperature Plot
Sample 6
0
100
200
300
400
500
600
700
0 20 40 60 80
Time (s)
Tem
p
Upper Right
Lower Right
Lower Left
Upper Left
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IR vs. Thermocouple Temperature Readings
Sample 9, Upper Left
0
50
100
150
200
250
300
350
400
450
500
time
tem
p (
de
g. C
)
IR TemperatureData
ThermocoupleTemperature Data
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IR vs. Thermocouple Temperature Readings
Sample 9, Lower Left
0
100
200
300
400
500
600
700
800
900
time
tem
p (
de
g. C
)
IR Temp.
ThermocoupleTemp.
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IR vs. Thermocouple Temperature Readings
Sample 6, Lower Right
-100
0
100
200
300
400
500
600
700
800
0 10 20 30 40 50
time
tem
p (
de
g. C
)
IR Temperature
ThermocoupleTemperature
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Sources of Error
Unreliable thermocouples: ultrasonic welding process flattened the leads
IR data could not be taken at thermocouple’s exact location
IR camera pixel intensity found to be unreliable
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Thermocouple ProblemGood weld
Bad weld
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IR Pixel Intensity Problem
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Future Work
Examine samples under microscope for structural changes due to welding
Determine accurate method for measuring temperature
Compare to numerical model for welding process using MathCad
