15 Months in the Real World
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Transcript of 15 Months in the Real World
15 Months in the Real World
Colin Sutherland
Overview
Background My Job A little project…
A little background…
Oakville is the only GE lamp plant in Canada
Had 60th birthday this August
•Makes 3 lamp types•Incandescent•PAR (Parabolic Aluminum Reflector)•Fluorescent Tubes
“Electrical Engineering Intern”
Ambiguous, like many things in the real world Jobs included:
Ordering parts, dealing with suppliers Updating/creating new electrical schematics Production/downtime reporting PLC Programming Organizing, working with electricians Etc
More like “Electrical Engineer”
And now for something thrilling…
Coating Problems on Light bulbs Coated to reduce glare
from the uncovered filament
Coating defects very visible when bulb lit up.
Not good for decorative lamps!
Defects = Shrinkage and recalls = waste = $ lost!
Coating Process
Dumper
AssemblyMachine
Coater OvenBulb
Spacer
Conveyor
Boxes In
Bulbs Out
What was wrong?
•Average DPM (Defects per million) of 2577
•Very High Variance and excursions
Weekly DPM for G25 Poor Coating 2007
0
2000
4000
6000
8000
10000
12000
12/24/2006 3/9/2007 5/23/2007 8/6/2007 10/20/2007 1/3/2008
Date
DP
M
DPM
3.0SL
Mean
Excursions
Why?
•Old system used a motor to detect powder height•Powder high -> motor has more resistance -> can be measured
•Problem?•Powder is messy! Can gum up mechanical systems•No visual feedback on height.•Hard to adjust
Why?
•Photoelectric sensor to check for powder density
•Sensitivity has to be manually adjusted
•Again, no feedback, no alarms when rejects occur!
Improving
•Other sensors tried in the past did not work•Needs to be accurate, and resistant to dust
Prototype set up
•Solution: Laser distance sensor•Visual feedback•Multiple Outputs
Improving
•Open at top for easy cleaning•Tube at bottom to limit powder flow up into bracket•Air piped into tube from back to keep powder out
•Used laser sensor to check for coating density
•More accurate•Easier to adjust•Multiple Outputs
ResultsWeekly DPM for G25 Poor Coating 2007-2008
0
2000
4000
6000
8000
10000
12000
12/24/2006 3/9/2007 5/23/2007 8/6/2007 10/20/2007 1/3/2008 3/18/2008
Date
DP
M
DPM
3.0SL
Mean
Excursions
•2008 Average of 668 DPM•Variance reduced
What did I learn?
You can never make something foolproof enough People will always find ways to mess things up
Need as much redundancy as you can fit in You can’t anticipate every possible scenario in time
But you need to Might have to add functionality afterwards
Important to have clear documentation