Fiber Drawing Tower Ups Quality, Enables Diversity

Ruth A. Mendonsa

Fiberoptic Systems Inc. (FSI) of Simi Valley, Calif., a manufacturer of optical fiber and assemblies for the OEM market, experienced a significant increase in demand for its diverse products and services. The company needed to produce raw optical fibers with glass combinations, fiber diameters and bundle sizes that varied significantly from day to day, so it began a search for a method of automatically drawing glass optical fiber that would be easily adaptable to the complexity of the company's manufacturing schedules and that could be modified or upgraded with minimal cost, effort and downtime.

FSI's new optical fiber drawing tower provides many benefits.

The fruit of their labors

FSI chose Automation Engineering Inc. (AEI) of Woburn, Mass., a designer and builder of specialized automation machinery and advanced control systems for photonics manufacturing, to design and implement a drawing tower. AEI coordinated all aspects of tower design, fabrication and implementation, and customized the drawing tower design within a time frame more typical of a noncustom machine. The company worked closely with FSI during system development.

The resulting tower design provides greater rigidity, a more effective structure-and-ways design, extended preform length and feed-speed range, and scalable mechanical component design for ease of future expansion.

The controls employ a Pentium industrial PC running AEI's open-architecture FlexAuto software for all motion and process control, graphical operator interface and production-tracking functions. The tower has modem dial-in support for remote diagnostics and software upgrades. A color graphic touch-panel display unit provides intuitive feedback to operators and maintenance personnel.

Fiber optic sensors automatically detect and signal a break in the fibers during the drawing process. A microprocessor-driven fiber guide shuttle subsystem supports the drawing of "figure-8" bundles with coordinated electronic drive of the shuttle mechanism, allowing automatic adjustment of the shuttle for different bundle sizes.

Flexible, easy to use

The FlexAuto control software allowed AEI to configure the control logic for the new tower so that multiple series of production sets could be easily defined.

The staff can quickly enter different fiber diameters and bundle sizes for each set. For example, the production sets for the current shift could be set as six 1/4-in. bundles of 0.002-in. fiber, 10 1/8-in. bundles of 0.001-in. fiber, and four 3/8-in. bundles of 0.0015-in. fiber. The control system will automatically determine required motion control speeds and profiles and execute changes during the production shift without operator intervention.

This new drawing tower allows FSI to furnish products made under optimum conditions, pass along cost savings based on less waste and higher fiber yield, use enhanced production control to achieve shorter lead times, and provide an expanded product line using a greater diversity of glass optical fibers.