CRYOGENIC MACHINING SAFETY: The Facts to Know. The Steps to Take.October 25, 2019
Cryogenic machining is a transformative development in manufacturing. The ability to effectively cool tools at the precise point where needed not only substantively prolongs tool life and allows for increases in processing speeds, it expands the capability to work with harder, more advanced alloys and materials—and makes new classes of products possible.
Like almost any other new technology, the introduction of cryogenic machining also necessarily transforms the processes, practices, and thinking involved in the manufacturing process—and safety considerations are of particular importance.
Since 5ME® Cryogenic Machining Technology uses a nonpolluting, nontoxic inert gas—nitrogen—in place of toxic liquid coolants, there is an inherent improvement in overall safety simply by virtue of eliminating potential exposure to poisons or carcinogens. But, like virtually all other industrial activities, cryogenic machining does have its associated risks—and it’s important to fully understand them in order to avoid them.
What To Know
Awareness of a few fundamental best practices and safety principles goes a long way towards minimizing, if not eliminating, any risks associated with cryogenic machining. These flow from a basic understanding of how cryogenic machining works and what materials are used.
5ME Cryogenics involves the flow of liquid nitrogen (LN2) through a tool to provide optimal cooling at the cutting edge. Like all liquified gases, LN2 occupies only a small fraction of its ordinary volume in a gaseous state. In its liquid form, it is incredibly cold: at -321 degrees Fahrenheit. And in its liquid form, nitrogen must be stored and handled with due care.
Nitrogen is one of the world’s most abundant elements, making up the highest proportion of the air we breathe. But when it flows in liquid form through a tool or otherwise released from containment, it soon returns to a gaseous state, and its volume exponentially increases—potentially displacing air, reducing oxygen levels, and creating the potential for asphyxiation. It’s therefore critical that any activity involving cryogens, including machining, be conducted with suitable oxygen level monitors available and operational.
5ME Cryogenic Machining: Set Up for Safety
Naturally, LN2’s extremely cold temperature also requires users to take appropriate safeguards. Direct exposure to LN2, in the event of a leak or spill, can create a risk of freezing surrounding areas or causing tissue burns. Likewise, ‘boiled off’ nitrogen recently returned to gaseous form is also extremely cold and poses similar hazards. Such hazards can be easily mitigated through routine use of cryogen-proof gloves, aprons, and eye/face protection. A fortunate safety benefit is that cryogenically-cooled tools are typically managed by the machine’s automatic tool changer (ATC) and provide a convenient, visual ‘no touch’ warning to users: Visible white condensate indicates that a tool should be handled with caution, while conventional tooling often appears the same both at normal and dangerously hot temperatures.
Provided appropriate safety standards and practices are established and adhered to, cryogenic machining is a safe alternative to traditional practices. 5ME ensures that implementations of our technology do their part to safeguard workers, facilities, and the environment. Machines equipped with 5ME Cryogenics contain multiple pressure and temperature sensors throughout the cryogenic machining system to ensure that safe tolerances are maintained at all points and at all times. Any deviation from expected safe levels results in an immediate, automatic cryogenic system shutdown, which is fully integrated with the machine tool’s e-stop and feed hold functionality. 5ME® Cryogenic Machining Technology is also engineered and built to optimize safe handling of LN2 at all stages, and to mitigate any consequence from possible machine defects, malfunctions, human error, or other factors.
In any manufacturing environment, safety must always be the operators’ primary consideration. 5ME supports that commitment to safety by delivering cryogenic cooling systems that are engineered with safety foremost in mind, and by providing the information and support needed to implement this groundbreaking technology safely—and gain the optimal benefit from it.