Advancements in vacuum furnace controls are aimed at reducing the need for operator intervention.
Before the early 1980s, most vacuum furnaces relied on relays, timers, manually operated push buttons and dedicated process-control instruments to control the furnace sequencing and operation. To execute a specific cycle, a furnace operator usually had to manually initiate a series of predetermined functions, such as starting the vacuum pumps, starting furnace heating, backfilling the furnace, ending the cycle and other operations. These vacuum furnaces could produce consistent batches of product with a high degree of reliability, but the level of operator skill and attention required often affected the final results. In addition, the reliability of mechanical relays, timers and push buttons exposed to dust, humidity and other factors dependent on a variety of environments was somewhat unpredictable. Thorough operator training and a well-planned preventative maintenance program were required to keep malfunctions and furnace downtime to a minimum.