A vacuum furnace is a furnace that operates with a vacuum inside, limiting contamination and controlling conditions more precisely than a traditional furnace would. Several manufacturers produce lines of vacuum furnaces for different applications, and it is often possible to lease units or buy used and refurbished ones, for people who cannot afford a brand new furnace. Leasing can also be a good option for determining which unit will meet the needs of a facility.

In a vacuum furnace, it is possible to create a vacuum in the staging area of the furnace. This allows for very precise temperature control, which can be critical for some processes. It also reduces the risk of contamination, as there is no convection in the vacuum to carry contaminants around, and heat transfer is also tightly controlled. Heating components to very high temperatures can expose them to the risk of oxidation in normal conditions, but with a vacuum furnace, there is no oxygen, and the surface of the object in the chamber will remain clean.

Very quick cooling is also available with this technology. The operator can flood the vacuum furnace with an inert gas to cool down the project inside. Quick quenching may be necessary for some kinds of projects, and in others it can be very useful. Vents attach to the furnace to safely dispose of any fumes and gases generated during the process.

For metallurgy, a vacuum furnace may be used to make a variety of metal alloys. This is a special concern with alloys for electronics, where any contamination can ruin the metal and cause serious problems. The controlled conditions are also critical for making special kinds of metal alloys that are very sensitive to temperature variations. If the temperature falls too low or high, it may change the characteristics of the metal and make it unsuitable for the task. When alloys involve expensive components, this can be a costly and time-consuming mistake.

Research scientists use vacuum furnaces for activities like fabricating components and conducting experiments. In addition, they can be useful for vacuum heat treatment of some product components. Some companies do their own heat treatment at their facilities while others may ship projects out to companies specializing in this industrial process. These firms often have very large vacuum furnaces to accommodate big projects and large batches, along with very skilled technicians to operate their furnaces for projects with low tolerances for error.