Before I learned something about cryogenic treatment, if someone had told me that freezing a tool to -300 to -321°F would increase tool life and decrease tool wear two- to five-fold, I would have thought that person was trying to pull the wool over my eyes. But it’s true, and I’m not alone in thinking it’s hard to believe. According to “Cryogenic Treatment and Cutting Tool Life,” widespread acceptance of this process has been relatively slow, not only because deep freezing tools for longer life seems unbelievable, but there is a perceived lack of scientific data to document what’s actually happening. Treated tools also show no cosmetic change after cryogenic treatment, which puts the process in question until customers see the increase in tool life for themselves.
Although it’s not scientifically proven, the process is effective and relatively simple. The parts being treated are placed in a unit that looks much like a chest freezer and any oxygen in the chamber is purged by liquid nitrogen, so no rust can form. The treatment begins with the cool-down stage, which usually takes 4 to 6 hours, depending on the weight of the parts.
The flow rate for the nitrogen and the various timed steps are controlled by a computer and use data collected from the experience. After the temperature fully drops, a “soak” lasts around 24 hours. Then a warm up to room temperature takes another 4 to 6 hours.