Extended Reach Cryogenic Machining

This new cryogenic system marries a precision milling head with a ram-type boring mill for extended-reach machining on large, high-accuracy composite and sandwich structures.

A new cryogenic FTR AutoDrill that marries a nimble, powerful precision milling head with a rigid ram-type boring mill for extended-reach machining on large, high-accuracy composite and sandwich structures is the first machine equipped with multi-patented cryogenic machining technology from MAG (Erlanger, KY) to be used at Boeing’s South Carolina facility beginning in Q2 2013. The FTR AutoDrill is equipped with multi-patented MQC (Minimum Quantity Cryogenic) tool cooling technology. The machine’s ultra-precise cutting head produces extreme accuracy on countersink depth.

The machine will be used to process high-value 787 fuselage barrels by drilling assembly holes and milling section edges, windows, and door cut outs. Unique in the industry, it will be equipped with MQC liquid-nitrogen tool cooling that yields smoother cuts, increased process speeds, longer tool life, and reduced frictional heat and material adhesion. MQC is also eco-friendly, producing dry chips without releasing airborne mists or greenhouse gases.

MQC delivers liquid nitrogen at -321 deg F (-196 deg C) through the spindle, directly to the tool tip and cutting zone. According to Michael Judge, the vice president of cryogenic business development at MAG, the key to MQC effectiveness is plumbing liquid nitrogen through the insert to allow a heat-sink effect rather than traditional chip zone cooling. “Cryogenic machining has never been done this efficiently before, with liquid nitrogen passed through the spindle and through the insert,” he explained. “Through-tool cooling provides the most efficient heat transfer model and consumes the least amount of liquid nitrogen, with flow rates of less than 0.1 liter per minute per cutting edge.”

The FTR AutoDrill is a hybrid floor-type horizontal boring mill equipped with a unique 2-axis spindle carrier. It incorporates an ultra-precise machining head capable of extreme countersink accuracy, utilizing a Fischer 15 kW (20 hp) 24,000 rpm spindle equipped with HSK-50A tool interface and power drawbar.