Design Project II - Fiber Optic Cable Manufacturing

	Design Project II - Fiber Optic Cable Manufacturing for Alcatel Telecommunications Cable
University Park, Spring Semester, 2000

Project Summary

Background

Fiber optic communications have been rapidly increasing over the last 30 years. Fiber optic cable has steadily replaced conventional co-axial (copper) lines as the standard transmission medium. This is mainly due to its low attenuation (signal loss) over long distances. Today, the use of fiber optics range from the telecommunications industry to cable TV and computer networks.

Theory

A strand of fiber is nothing more than a solid glass cylinder (core) surrounded by a different glass coating (cladding). Light is introduced into one end of the fiber. Due to the material differences in the core and cladding and the angle at which the light enters the fiber, light can travel along the length of the fiber with very little attenuation.

Problem Statement

Due to the fragility of the fiber, protection needs to be added before the fiber can actually be used in the commercial world. Alcatel’s cable plant takes up to 12 fibers and places them in a polypropylene tube. These tubes (buffered fibers at the left end of the cable in the Figure below) are bound together, surrounded by kevlar yarn and rip cords (yellow strands), and placed inside of a metal armor jacket (green tube), completing the core. To finish the process, a polyethylene jacket (black tube) is extruded over the entire core (shown below). Temperature of the extruded polyethylene jacket is around 460°F. The jacket must then be cooled before it can be wound on a spool. This is accomplished by guiding the cable through a trough filled with chilled water. The temperature of the water can be varied (thus varying the quenching rate) to alter the material properties of the jacket as specified by customers. After the cable exits the trough it passes through a laser gauge to monitor diameter. It then goes through a length counter and printer before being wound on a spool.

The problem Alcatel encounters is that after exiting the water trough, the cable must be totally free of any water before going through the remaining components. If the water is not totally removed, false diameter readings, improper length count and poor print quality occur. We currently use an “air wipe” (shown below) which blows the water off the cable as it comes out of the trough. The air wipe removes most of the water but is inefficient and noisy.

The schematic below illustrates the process described above.

Design Task

Design a system that will quench cool the cable jacket to 80 degrees F without leaving any residue prior to printing using the following criteria:

Quench/Cooling Rate:	Variable
Cable speed:	328 feet/min (maximum)
Cable diameter:	0.4” – 1.25”
Noise level:	< 85 dB (Avg. over 24 hrs.)
Space limitation:	No larger than current system (6' height, 3' width)
Bend radius:	15 times cable diameter (minimum) – prefer no bend
Safety:	Meet OSHA safety requirements
Electrical Power:	< 460, 230, or 110 VAC 3 phase or 1 phase
Cost:	< $5000

Deliverables

Design that meets the above criteria
Prototype of the design
an HTML report that documents the solution and includest

problem statement
description of design solution
drawings (fully dimensioned) that communicate the design
expected operational cost

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Project inquiries: Renata Engel, rse1@psu.edu
Last revised by: R. Engel, rse1@psu.edu, on March 7, 2000.
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