Our last article discussed a few different aspects of fusion splicer maintenance.  Today we want to continue that conversation and talk about maintaining the precision cleaver that accompanies your fusion splicer.  Remember that the performance of the precision cleaver is equally important to that of the fusion splicer.  Worn and contaminated cleaver blades are a major source of poor quality fusion splices.  Let’s look at a few factors which can affect performance.

If you take a close look at a precision cleavers blade you will never be able to see a worn blade.  With that said, cleaver blades should be rotated every 1,000 cleaves for single fibers and every 83 cleaves when working with 12 fiber ribbon cable. This practice will ensure that worn blades do not produce unacceptable cleave angles which are one cause of poor quality fusion splices. A worn cleaver blade will provide cleave angles greater than 1 degree.  Cleave angles over 1 degree will create gaps between the fiber endfaces which create bubbles and lines through splices.   Use the arc counter on the fusion splicer as a resource to indicate approximately how many cleaves a blade position has performed.  Another good indication of a worn cleaver blades is inconsistent cleave angles.  A worn blade can provide a good cleave angle on one fiber and a bad cleave angle on the next fiber.  Several consecutive poor quality cleave angles would suggest a potentially worn blade.


Cleaver blade in position 1 or 16

Cleaver blade in position 1 or 16


Rotating a cleaver blade can be performed in the field however care must be taken to ensure the process is performed properly. A good rule of thumb is not to attempt this process unless you have been trained to do so. Mistakes and accidents happen more frequently when people are not specifically trained for a task.  An example of this comes from a client who was trying to adjust their cleaver blade in the field. The technician did not pay close attention to the number of turns they  applied to the set screw which holds the wheel in place. At one point the set screw fell down inside the cleaver. The technician could not see the screw but could hear it moving around inside the cleaver. In an effort to recover the set screw, the technician removed 3 more screws at the bottom of the cleaver which appeared to hold a base plate in place. The end result of this action was the spring loaded tension system which automates the cleaver blade movement came apart rendering the cleaver useless.  This mistake required the cleaver to be reassembled by the manufacturer.


fractured cleave

Incomplete fiber cleave from extremely worn blade


Another aspect of a properly performing cleaver is to make sure the blade is not contaminated.  A contaminated blade can have skin oil, grease, icky pic, dirt or even dust on it which then gets transferred to the fiber during the cleave.  Once the fiber is contaminated it will cause poor quality splices which include bubbles, lines or other incomplete splices.  Combine a contaminated blade with a worn cleaver blade and a splicing project quickly slows down.  The images below are a result of contaminated cleaver blades.  None of these splices would be acceptable for traffic.


Bubble splice

Fusion splice with a bubble – again good cleave angles

Partial bubble splice

Fusion splice with partial bubble – notice the good cleave angles


Finally we just want to emphasize the importance of keeping your cleaver clean and in good condition; this includes storing the cleaver properly.  If a cleaver comes with a protective case be sure to use the case.  Typically hard plastic cases can really reduce the likelihood of damage and contamination during transport of the equipment.  The example below was taken a few years ago on a trip to an island nation where fiber optics was being installed frequently.  The technicians at this company did not take care of their equipment.  Units were not stored in the cases during transport and often were set on piles of dirt on the side of the ditch while  work was being performed.  Contamination and premature wear on equipment became major issues for this company as cleavers, splicers and OTDRs were being destroyed regularly.  Most units which required repair or maintenance were less than 2 years old.   Notice the paint is worn off this unit and NO is scratched in the paint to indicate this unit doesn’t work properly.  This cleaver was less than two years old and clearly not stored properly.


Bad Fitel Cleaver



If you spending a little bit of time and money to ensure your fusion splicer and cleaver receive the necessary maintenance, you can greatly improve the life expectancy of the machine. A prime example of prolonging a splicer’s life comes from a customer who regularly changes electrodes  and has the core alignment splicer calibrated annually. That splicer had over 37,000 arcs on the unit before they decided to buy a new splicer.   Customers who routinely service their splicers year after year  tend to have fewer problems than customers who only service the machine when issues occur. Being proactive instead of reactive can save downtime and money while maximizing splicer efficiency. This will ultimately help your bottom line.