Electronics Assembly Knowledge, Vision & Wisdom
Mysterious Drop In Production Yield
Mysterious Drop In Production Yield
A factory manufactured membrane switches. After installing exhaust fans the yield dropped. What was causing this decrease in production?
Mysteries of Science
Dr. Gilleo
Mysteries of Science by Dr. Ken Gilleo
Dr. Gilleo is a chemist, inventor and general problem solver. Ken has been tracking industrial forensics and collecting case histories for decades. These cases are taken from the vast world of industry and commercial enterprise.

Check out Dr. Gilleo's eBook, 100 Mysteries Solved by Science. We hope you enjoy these case histories. You need not be an engineer or scientist to understand the problems and appreciate the solutions.
Submit A Comment
Comments are reviewed prior to posting. You must include your full name to have your comments posted. We will not post your email address.

Your Name


Your Company


Your E-mail


Your Country


Your Comment



Transcript
A factory manufactured membrane switches, flat control panels found on microwave ovens and other appliances. Business was booming, and more capacity was needed. Analysis showed a bottle neck was applying the clear over coat giving the desired level of gloss. All of these coatings required several minutes in the oven.

The factory decided to try Rad-Cure, a new process for radiation curing.  Using this method the coating could be applied and cured within seconds using a small UV processor unit.

Everything seemed to be running well during two months of testing and the decision was made to set up a full UV process line. The new process was set up and running well except for one minor problem. The UV coating had a very strong acrylic odor that bothered the workers. A bigger exhaust fan on the roof eliminated the odor.

Two months later during a quality audit the coating yield which should have been higher was now only 90%, although the scrape rate was only 1%. 

What was causing this decrease in production?

Here's the rest of the story.

One operator found some of the membrane switches in the parking lot. She mentioned that every so often she heard a fluttering in the exhaust pipe.

The strong exhaust fan was occasionally sucking a membrane switch up from the conveyor and blowing it through the roof. The fix was to extend the "draw" area to pull exhaust before and after the UV processor to reduce the air velocity. The lesson is to localize the problem zone and carefully observe.

Comments
No comments have been submitted to date.
Free Newsletter Subscription
Every issue of the Circuit Insight email newsletter will bring you the latest information on the issues affecting you and your company.

Insert Your Email Address

Directory Search


Program Search
Related Programs
bullet Pay Clerk Production Woes
bullet Danger on the Adhesive Coating Line
bullet Innovative Impromptu Air Conditioning
bullet Epoxy Resin and the Red Gas Cloud
bullet Recurring Transmitter Failure - Disconnected Transcript
bullet Brighter Chrome on the Third Shift
bullet Mysterious Drop In Production Yield
bullet The Puzzling Z-Axis Adhesive
bullet The Hot Chip Scale Package
bullet Resistor Values off the Mark
More Related Programs