Capability Spotlight: Plastic Extrusions for Telecommunications

Posted on: November 15, 2021

Low-loss optical fiber has been one of the most transformative innovations that our world has seen in the past half-century. Optical fiber enables many of the technologies that people rely on today, including voice and data communications. 

Prior to 2020, the ability to connect virtually was considered a convenience. Today, it’s essential—for business, for telemedicine, for education, and for human connection. 

How are fiber optic cables assembled?

Extruded plastic buffer jackets provide protection to the fibers inside, much like the exterior of the cord on any common household item—the difference is what’s inside. Further, manufacturers configure the fiber optic cables differently depending on the application. The types of configurations include: 

  • Cables with a centrally located single buffer tube containing one or more optical fibers 
  • Cables with several buffer tubes that are stranded in a helical or alternating helical arrangement
  • Cables with slotted cores containing optical fibers

Stranded buffer tubes typically contain 12 or more fibers or in some cases, ribbons. However, some applications call for lower fiber counts per buffer tube but require the cable to have the same dimensions as one with a standard count. That’s where filler rods come in.

Why do fiber optic cables need filler rods?

Imagine trying to lie on a pool raft filled only halfway with air. The raft would quickly fold and crumple underneath you! That’s what would happen to fiber-optic cables without the use of filler

rods. Filler rods provide stability to cables that have lower fiber counts but require the same dimensions as those with higher counts. 

Filler rods also help manufacturers of cables streamline their production since they can continuously produce buffer tubes in a single dimension that accommodates any fiber count. 

Materials used for fiber optic filler rods

There are two main polymers used for filler rods: solid or foamed high-density polyethylene (HDPE) or polypropylene (PP, either a polypropylene homopolymer or a polypropylene-polyethylene copolymer resin material). HDPE is a cost-effective material for these applications, while PP has a higher cost but better mechanical and physical properties which prevents it from sticking to the buffer jacket in the application.

Precision and quality matter in fiber-optics

Maintaining tolerance is critical when producing fiber-optic filler rods, so it’s important to select a contract manufacturing partner with a robust quality program and experience in the sector. Identifying a partner with ISO 9001:2015 certification is a great start, followed by a visit to the facility if possible to observe their quality processes in action. 

If you’re looking for a partner for extrusions in your telecommunications application, Custom Profiles can help. You deserve great results and a team that’s dedicated to helping you keep our world connected. For more information about working with us, connect with us online today.

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