Single-cycle gas panel assembly

A single-cycle process has been developed in which the two halves of a gas panel are assembled, sealed, and filled in a continuous, automatically sequenced, controlled-ambient furnace. The entire fabrication operation, including seal, degas, backfill, and tip-off, may be accomplished in a single thermal cycle. During heat-up, the panel parts and furnace chamber are degassed in a programmed cyclic fill (to 20 mm of Hg) and pump-down (to 100 µm of Hg). The panels are sealed in a clean-air ambient at a temperature of 495 ± 5°C. Prior to backfilling with a purified Penning gas mixture and tip-off of the panel, the same gas is used in a cyclic fill and evacuate process to remove air and other contaminants. The entire panel fabrication program takes about 8 hours. Details of equipment construction and operation are presented, as well as advantages of the process compared to conventional gas panel fabrication processes.