HOME  |  NEWS  |  BLOGS  |  MESSAGES  |  FEATURES  |  VIDEOS  |  WEBINARS  |  INDUSTRIES  |  FOCUS ON FUNDAMENTALS
  |  REGISTER  |  LOGIN  |  HELP
William K.
User Rank
Platinum
Low efficiency beacon symptom
William K.   9/23/2011 9:18:01 PM
NO RATINGS
The problem of moisture absorbtion is often nonlinear, which is why just baking the deteriorated units would not result in another five years of service. What probably happened is that after a bit of exposure the more moisture resistant portion deteriorated and the more porous material was exposed, at which point the process went much faster. So baking and re-coating could have been a solution, but the cost would probably be similar to installing a new antenna. Sometimes repairs are completely possible but not economical to do. Given what I know about high labor costs on railroads, I would presume that was the case here.

Yes, it was good detective work, although great detective work would have been to stop and think for a while and come with a suspect at the beginning.

dhall
User Rank
Iron
Re: Troubleshooting
dhall   9/1/2011 8:45:23 PM
NO RATINGS
If the parts absorbed moisture, why wouldn't baking them drive the moisture out and give you another 5 years of operation?  Obviously the design was faulty, but cycling the devices periodically through a drying operation could potentially save having to replace them unless they were very inexpensive and the cost of handling exceeded the replacement cost.

plasticmaster
User Rank
Silver
Re: Troubleshooting
plasticmaster   9/1/2011 9:30:42 AM
NO RATINGS
PTFE (DuPont "Teflon") is hydrophobic (water repelling). PET (material of the aforementioned housing) is hygroscopic (water absorbing). I know long term testing is sometimes sacrificed in order to get product to market. In this case the product worked for 5 years before failure. I would imagine, realistically, that when the problem was discovered, the solution would be to change the material to something better suited for long term outdoor use.

Sometimes the more expensive material is the cheaper (or should I say, more economical) and better choice in the long run.

tjgau
User Rank
Iron
Re: Troubleshooting
tjgau   8/31/2011 9:36:05 PM
NO RATINGS
I think it would have been a combination of incomplete specification & manufacturing (Moulding process & cleanness).
The materials used were those specified by the original European design. The manufacture of this product was taken over by another company shortly after so there was no further trend analysis data to see if the problem continued to other batch lots.

Toni

Jack Rupert, PE
User Rank
Platinum
Re: Troubleshooting
Jack Rupert, PE   8/31/2011 7:56:03 PM
NO RATINGS
So, was the root cause of the problem a specification problem, material choice, or manufacturing?

Tim
User Rank
Platinum
Troubleshooting
Tim   8/31/2011 5:32:02 PM
NO RATINGS
Good troubleshooting. It shows that even solid components can have a problem in them.



Partner Zone
Latest Analysis
A small team of engineers has created a tackling dummy robot that's comparable to training with human players on the football field.
Several plastics and elastomers have come out recently for different parts of cars, as well as for multi-material medical devices and for onboard base station antenna components.
Work in embedding conductive materials into commercially available yarn could lead to energy textiles that store power for use.
A ball bearing developed for turbofan engines by FAG Aerospace of Germany and MTU Aero Engines could have other uses such as turbines, pumps, and gearbox stages.
Fifty-six-year-old Pasquale Russo has been doing metalwork for more than 30 years in a tiny southern Italy village. Many craftsmen like him brought with them fabrication skills when they came from the Old World to America.
More:Blogs|News
Design News Webinar Series
8/13/2015 11:00 a.m. California / 2:00 p.m. New York
6/25/2015 11:00 a.m. California / 2:00 p.m. New York
6/24/2015 11:00 a.m. California / 2:00 p.m. New York
9/10/2015 11:00 a.m. California / 2:00 p.m. New York
Quick Poll
The Continuing Education Center offers engineers an entirely new way to get the education they need to formulate next-generation solutions.
Aug 31 - Sep4, Embedded System Design Techniques™ - Writing Portable and Robust Firmware in C
SEMESTERS: 1  |  2  |  3  |  4  |  5  |  6 |  7


Focus on Fundamentals consists of 45-minute on-line classes that cover a host of technologies. You learn without leaving the comfort of your desk. All classes are taught by subject-matter experts and all are archived. So if you can't attend live, attend at your convenience.
Next Course August 25-27:
Sponsored by MICROMO
Learn More   |   Login   |   Archived Classes
Twitter Feed
Design News Twitter Feed
Like Us on Facebook

Sponsored Content

Technology Marketplace

Copyright © 2015 UBM Canon, A UBM company, All rights reserved. Privacy Policy | Terms of Service