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