The Preform Soaking Oven System is designed and manufactured by ASI/Silica Machinery, LLC. This system is used to heat glass preforms after they have been sintered enabling excess gas still trapped in the preform after sintering to escape. Excess gas which is invisible to the naked eye, can cause bubble formation in the glass resulting in fiber breaks during the draw process, if not removed from the glass preform. If the Preform Soaking Oven is not used, it could take days or even weeks for the excess gas to escape at ambient temperature.

A further benefit of using the Preform Soaking Oven is a potential reduction in draw ramp up time since the glass preforms can be brought to the draw furnace already warm, reducing the time to bring the preform up to temperature at the draw tower.

Each Preform Soaking Oven is configured with 3 or 5 ovens which operate independently of each other.

The Preform Soaking Oven systems are comprised of four main parts, a main structure, ovens, a preform movement system, and a process control subsystem.

STRUCTURE

The structure is manufactured for strength and flexibility. The frame consists of two parts, a large base section which contains the ovens and load station, and a top section for loading.

The top section contains the vertical actuator and gripper. The small frame sits on a table on the Y-axis and Z-axis linear rails.

OVENS

The ovens consist of 3 cylindrical units for core soaking and 5 cylindrical units for clad soaking. The housing is a stainless steel cylinder. The outer surface of the preform is protected from contamination. In case of breakage, the system allows for the broken material to be removed.

PREFORM MOVEMENT SUBSYSTEM

Preforms are loaded and unloaded automatically. Each oven can be loaded and unloaded independent of the other ovens.

PROCESS CONTROL SUBSYSTEM

A PLC is used to control the actuators. It uses closed circuit control logic to enable the machine to perform safely.