What Are the Probable Causes of Light Leakage From Ferrule Barrel? Is It While Insertion of Fiber Into Ferrule or While Stripping Fiber With Fujikura Stripper?

QUESTION: What are the probable causes of light leakage from ferrule barrel?  Is it while insertion of fiber into ferrule or while stripping fiber with Fujikura stripper?

ANSWER:

We will contact you to discuss further but here are a few different possible issues:

• Insufficient epoxy at rear of ferrule, leading to fiber break.  This can be determined fairly easily by cross-section of failed parts.

• Fiber damage (nicking) during stripping, leading to fiber break.    Stripper causing fiber damage can often be identified by performing a fiber “bend test” immediately after stripping—–bend fiber 45-degrees in 4 directions (north, south, east, and west).   Nicked fiber should break if scored during stripping.    He should do this for 100% of production for a period of time, as it may not be evident all the time.  If he sees fiber breakage in more than, say, 1-2% of bend-tests, then likely he’s in need of replacing blades / further investigation of the strippers.

• Fiber damage during termination—rotating ferrule around to “spread the epoxy”, when fiber is fully inserted. Depends on ferrule manufacturer, but this can be an excellent way to score the fiber and severely weaken it.   He should check lines, see if operators are rotating ferrules—-sometimes it’s necessary if tight fit, but shouldn’t need to be done as a matter of course.   To see if his ferrules have such sharp edges inside, he can strip a 900um fiber, do a bend test to make sure fiber integrity is ok, then insert it into a ferrule (no epoxy) all the way, gently rotate the ferrule 360-degrees (no need to apply downward pressure, just rotate the ferrule), then remove and re-do the bend test.  If fiber breaks, this is an area of significant concern, especially if operators are rotating connectors during term.

ADDITIONAL CONTENT & RESOURCES:

• Category Resource:
  • FOC Cable Prep Page  
  • FOC Epoxy Page 
• Find More Information in this Blog:
  • Helpful Epoxy Tips (and a Few Tricks)
  • The processes involved in Termination play a CRITICAL role in determining the long-term reliability of the product

 Answered by AskFOC Technical Team May 4, 2017

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