Cryogenic Machining Systems Can Extend Tool Life and Reduce Cycle Times

Efficient removal of heat from the tool/workpiece interface is the main route to high-productivity machining. Several conventional methods are available to accomplish that—dry machining, minimum-quantity lubrication, flood coolant and high-pressure coolant—but cryogenic machining can be added to the list.

However, not all systems using cryogens take the same path to longer tool life and higher speeds and feeds. Liquid nitrogen used in cryogenic machining can be delivered through a machine tool spindle and a cutting tool directly to the cutting edge. This is the method Cincinnati-based 5ME LLC employs with its Cryo technology. The cryogenic machining system uses tube-in-tube, vacuum-jacketed feed lines to deliver LN2 from an external bulk storage tank, or dewar (vacuum flask), to the cutting zone while protecting the integral machine components from being exposed to the low temperatures.

Installation of the Cryo kit doesn’t involve removing the spindle. Instead, a lance, which also has the tube-in-tube, vacuum-jacketed design to keep the OD at ambient temperature, runs through the drawbar ID.

A vacuum-jacketed line, however, doesn’t run through a cutter body, so 5ME designed a line of indexable and solid-carbide cutting tools insulated with PTFE (polytetrafluoroethylene) to use with its cryogenic machining technology. You cannot run the 5ME cryogenic machining technology system with non-5ME cryogenic tools so 5ME sells end users about 60 families of cutting tools, including endmills, facemills, high-feed mills, thread mills, drills and turning tools.

Although 5ME is machine tool agnostic and willing to work with any builder, targeted machines are medium-sized horizontal machining centers and large vertical machining centers. This means an HMC with at least a 630mm (24.8 ") pallet size and a VMC with a large spindle, such as CAT 50, CAT 60 or HSK 100A. Targeting these machines helps ensure a reasonable payback because the Cryo hardware kit is about 30 percent of the cost for a new machine tool that size and larger.

To read more, see the full article as it appeared in the February 2015 issue of Cutting Tool Engineering http://www.ctemag.com/aa_pages/2015/150209-Cryogenics.html