Environmental impact of cryogenic machining

Sometimes the question arises to what extent cryogenic cooling is environmentally-friendly, as the gases used are a consumable, unlike other refrigerants that can be reused. Cryogenic processing does have interesting environmental advantages. The environmental impact of the entire cryogenic cooling process is many times lower than that of conventional cooling.

Compressed gas is used for cryogenic cooling during machining. This pressure (drop) causes a strong cooling of the gas. The temperature of CO2 drops to -78°C during expansion, while the temperature will be another 100 °C lower for liquid nitrogen. So, the cooling capacity is huge. During the machining, chips will be formed by bringing the material to flow. To reach this point - the forming of a chip- the temperatures will be high.

In addition to the cooling properties, the gases used are also completely neutral. This means that they have no chemical impact on the product or on humans. Both CO2 and nitrogen are gases that occur in the air. The CO2 used is captured from other industrial processes as by-products and therefore does not need to be specially produced. In contrast to conventional oil-based coolants, a metal product does not need to be cleaned afterwards. Only a drying process may be necessary to treat corrosion-sensitive materials. After all, some water can always be left behind due to possible ice formation.

However, the question sometimes arises as to whether cryogenic cooling is so environmentally friendly when compared with an emulsion cooling that can be reused many times. Cryogenic gases can only be used once.