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
When you think of the DARPA Robotics Challenge, you may imagine complex humanoid contraptions made of metal and wires that move like a Terminator Series T-90. But what actually happened at the much-vaunted event was something just a bit different.
The machine is claimed to be the largest and most powerful electric pipe-bender on the market, exerting nearly 500,000 lb-ft of torque.
Traditional dev kits are based on a manufacturer’s microcontroller, radio module, or sensor device. The idea is to aid the design engineer in developing his or her own IoT prototype as quickly as possible. A not-so-traditional IoT development kit released by Bosch aims to simplify IoT prototyping even further.
This consulting firm has put together a report detailing the growing biomimicry design field in the US and around the world, from naturally bacteria-repelling surfaces to keratin-inspired polymers.
Here's a list of engineering and tech jobs ranked by outlook, work environment, stress, and income.
More:Blogs|News
Design News Webinar Series
1/28/2016 11:00 a.m. California / 2:00 p.m. New York
12/8/2015 11:00 a.m. California / 2:00 p.m. New York
2/18/2016 11:00 AM PT | 2:00 PM ET
2/24/2016 11:00 AM PT | 2:00 PM ET
Quick Poll
The Continuing Education Center offers engineers an entirely new way to get the education they need to formulate next-generation solutions.
Jan 11 - 15, Designing ARM Devices Using Segger Tools
SEMESTERS: 1  |  2  |  3  |  4  |  5  |  6 |  7 | 8 | 9


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.
Learn More   |   Login   |   Archived Classes
Twitter Feed
Design News Twitter Feed
Like Us on Facebook

Sponsored Content

Technology Marketplace

Copyright © 2016 UBM Canon, A UBM company, All rights reserved. Privacy Policy | Terms of Service