What are the advantages of factory vs. field terminated assemblies?
When looking at terminating fiber optic connectors for a job there are several factors that are taken into account to help decide which way is best. There are field polish connectors in which some form of epoxy (glue) is used to hold the fiber in place. With this one, you have to polish it in the field as well which if you haven’t ever done it, can be very difficult. There are also factory polished style connectors that can be mechanical connectors, pigtails, splice on connectors or pre-terminated cable assemblies. The mechanical connectors have a piece of fiber already in them and you just have to align your field fiber up to the fiber inside the back of the connector. This can be difficult or take some time to master. A fiber pigtail consists of a piece of fiber optic cable that has a connector on one side and no connector on the other side. These can either be fusion spliced to another piece of fiber, or run through conduit and terminated at the other end. The alternate solution would be to have your cable assemblies built to the length that is needed with optical connectors already installed on them in a factory setting. Let’s look at some different qualities to see how this will be beneficial.
Polish Quality
All connectors whether installed in the field or in a factory have to be polished in order to work properly and get the end result of passing a signal over the fiber optic cable. So let’s look at the two different ways to polish. First, you can always hand polish a connector. In this process, you will use a polish puck, rubber durometer pad and a glass plate along with polish film to achieve a suitable connector endface. There are some technicians that have been doing this for a long time and could get close to a perfect polish on the ferrule endface. Not everyone can do a good hand polish. There are several factors that come into play and can cause various results on your finished optical connectors such as the amount of pressure applied while doing your figure 8 on the polish paper. When in a dusty area debris can get on the polish film, causing a connector to be ruined. See how little things in this process can affect the end of the connector and how long it takes to get a good connector? If a connector is bad due to being over polished, pitted or even shattered you will have to repeat the whole process.
On the other hand a factory polish is finished using a polish machine in a manufacturing facility. The amount of pressure is the same. Polish machines have holders that allow many connectors to be polished at once to save time. The procedures used have been honed over time to be the most efficient which helps to produce high quality polishes. In a factory all connectors are checked to a higher standard and are not allowed to be shipped until checked by quality control where they will be scoped and tested. This gives each and every factory connector a perfect outcome.
Plug & Play
When getting factory terminated fiber optic cable assemblies cut to length you are providing yourself with the simple concept of plug and play. This means all you have to do is run your link and then just plug the connectors into your rack, switch or connection point. This not only saves time on your cable installation but also will save you in labor and installation costs. Plug and play is not always a possibility due to restrictions in conduit size or the number of bends that are required to go through. We get that and that is why there are several ways that a connector can be put on a cable. All we are saying is, imagine if you get a house hold item such as a toaster; would you rather take the toaster out of the box, plug it into an outlet and have toast in a matter of minutes? On the opposite side; would you like to get a toaster that does not have a cord and you have to go find all the tools that are needed? Now you have to refresh yourself on how to strip a power cord so you can put a plug on one end. Then you have to open the toaster and get your other end prepped. Point being, we all like to just pull things out of the box, plug them in and away we go.
Pulling Eyes
What is easier than getting a cable that has all the connectors on it and a way to pull it in place? Essentially this is what you have with a pulling eye installed. All a pulling eye is, is a loop that is connected to the Kevlar of a cable assembly. Why the Kevlar? Kevlar, when you have multiple pieces stranded together is not only strong but almost impossible to break. It does not stretch when pulled on and it keeps the fiber cable from stretching. We have had instances when cable has not been pulled by the Kevlar, instead pulling on the jacket of the fiber. The jacket of the cable will stretch and eventually with too much pressure it will break. Also, when a jacket is pulled, when released you get what is called a growing effect of the fiber. Meaning it looks like kids through their growth spurts. The jacket after being released shrinks to try and get back to its original form. When this happens the fibers that are inside will come out the end making it look like your fiber is extending. Not only is this bad for the jacket that protects the fibers but it can also cause breaks in your cable that will not be realized until it is tested. So when pulling fiber cable, always make sure you are pulling correctly using the Kevlar. It’s better to just have a pulling eye installed and save yourself a huge headache.
Higher Overall Quality
When looking at fiber optic connectors there are several factors to consider. Looking above at all the advantages of a factory polish termination along with pulling eyes, you can see how it can save you money and time to go with the factory built cables. Now if you do have to install connectors in the field, the alternative would be to get connectors that are already factory polished such as the ones on a fiber pigtail used when fusion splicing. When doing a job, no one is purposely trying to have bad connectors. Factory polished connectors whether they are pigtails, mechanical connectors or pre-terminated fibers all have the high quality that you will need to show your customer that you take pride in the work you do and want to use the best possible connectors available. Nothing is better than a connector that is polished by a machine, and then put through a rigorous testing phase before they can be considered done and ready.
About the Author