Epoxy-Glue-Patch-Cable-And-Pigtail-Manufacture-Line-Tools-And-Machine
Most factory-made terminations are the simple epoxy/polish type. These give the best connection, lowest losses and are relatively inexpensive.
Some manufacturers offer prepolished/splice connectors, but they are costly (about twice as much) and you have a connector loss plus two splice losses at every connection. They also take longer to make.
Gluing
Epoxy glues are used for bonding and terminating fiber optic connections. They are available in a wide range of thicknesses and colors, but it’s important to follow the manufacturer’s instructions to ensure proper curing. The adhesive should be applied in a thin layer and the fiber inserted quickly before the adhesive sets. It can take up to several days for epoxy-based adhesives to reach their maximum strength and durability.
To prepare the cable and fiber, strip the plastic jacket using a special tool. Afterward, clean the stripped fiber with isopropyl alcohol. Next, use a fiber holder block to attach the fiber to it. After that, place the connector on top and splice the ends of the cable to the holder block. Finally, put the spliced connector and fiber into an epoxy curing oven.
In addition to epoxy, many installers are using quick-setting anaerobic glues to replace epoxy in some applications. These glues are not as strong as epoxies, but they work epoxy-glue-patch-cord-and-pigtail-manufacture-line-tools-and-machine well in most circumstances. Another option is to use a heat-set adhesive or polish. These methods provide good performance and are relatively inexpensive, but they require an oven to cure the adhesive and are not as portable as a standard epoxy.
Cleaving
A good cleaver is needed for making clean stub fiber ends. The type used in fusion splicing works well, but there are other types of mechanical cleavers. The stub should be cleaned with a wipe dampened with isopropyl alcohol before cleaving. This will remove any dirt that might scratch the endface of the ferrule.
Most connectors, including virtually all factory-made terminations are the simple epoxy/polish type where the fibre is glued into the connector with epoxy and the end polished with special polishing film. This provides the best performance and lowest losses of any termination method and is also very inexpensive compared to other options. It can be cured overnight or in an inexpensive oven.
Some manufacturers offer a prepolished/spliced connector which already has the short stub fibre epoxied into the ferrule and the end polished perfectly. This saves a few steps, is fast, and requires less training than the epoxy polish type. The downside is that the loss of this type is a little higher, because you have a connector loss plus splice loss at every connection.
Some installers use anaerobic adhesives instead of epoxy. These work very well if your technique is good. The downside is that they do not cure as fast and may only be suitable for indoor use, since they do not have the wide temperature range of epoxies. They also do not leave a hard bead of epoxy on the end of the ferrule to support the fiber for cleaving and polishing.
Polishing
The most common connector type, and the one used in virtually all factory-made terminations, is the simple epoxy/polish type. These offer the best performance and lowest losses. They also require the least amount of skill to terminate – the small Plastic Multimode Fiber Optic Components bead of hardened epoxy that forms on the end of the connector ferrule makes the cleaving and polishing steps easy -practically foolproof.
A few newer connector types have eliminated the need for glue – they use a crimp to hold the fiber in place. These have a faster termination speed, but tend to offer higher loss characteristics and cost more than epoxy/polish types.
Some manufacturers make a special epoxy adhesive that cures in two minutes, without the need for an oven or any heat. This speeds up the termination time, but they can still be slow and require a significant level of training and skill to work with.
Straight solvents, like acetone and methyl ethyl ketone (MEK), can quickly dissolve uncured epoxy. These are often used in conjunction with a heated dip tank or ultrasonic bath to remove the epoxy. However, they are flammable and carcinogenic. A better option is to use a curing oven that provides stable and consistent heating across all of its heating blocks, which eliminates the need for these volatile chemicals. The AccuCure is just such an oven.
Terminating
For singlemode fiber, most terminations are done in the field by splicing a factory-made pigtail or splice-on connector onto tight buffered fiber. This is different from multimode terminations, which are typically made by gluing the connector directly on the installed cable. For field singlemode terminations, you can choose from a variety of different connector types and procedures to get good performance (low loss and low reflectance).
One component heat cure adhesive systems are simple to use because they do not require mixing. They usually have a paste-like consistency and work well for trowel application or bead extrusion. They can also be used as film adhesives or in high-temperature curing ovens.
Two-part epoxy glues are very popular for terminating connectors, and they offer a wide range of bonding properties. They are often formulated for specific applications, including temperature resistance, shearing and tensile strength. You can buy epoxy resin in kits with the polymer and hardener separate so that you must mix them, or you can buy them mixed together in a pre-measured syringe.
You can also buy dispensing systems for automated terminations. These can be pneumatic or displacement, and some have vision systems to ensure that the epoxy syringe is properly placed on the ferrule. These systems are more expensive than manual injection, but they can save a lot of labor and improve termination quality by eliminating human error.