Shine a light: Turning Performance

Machining hard materials is hard. There are numerous issues when turning, grinding and lapping hard, brittle materials, such as silicon, ceramics and glass, using conventional single-crystal diamond tools. Those issues include the formation of cracks and fractures in the workpiece, high tool wear, inaccuracy of the machined form and long cycle times, according to Dr. John Patten, director of the Western Michigan University Manufacturing Research Center.

To commercialize an alternative hard-material turning process developed at WMU, Patten and Dr. Deepak Ravindra, a senior research associate and postdoctoral fellow at the university, founded Micro-Laser Assisted Machining Technologies LLC. The company’s µ-LAM process reduces processing times by about 50 percent compared to conventional methods, Patten noted. In addition, the process causes recrystallization to occur in-situ during machining and heals, or anneals, a workpiece that might otherwise be damaged.

Courtesy of Micro-Laser Assisted Machining Technologies

Micro-Laser Assisted Machining Technologies recently set up its µ-LAM system on a Precitech 700 series diamond turning machine at a manufacturing facility for testing.

The µ-LAM process focuses an energy beam from a continuous-pulse fiber laser to generate a temperature higher than 1,000° C and a pressure in excess of 100 GPa from a single-crystal diamond tool to render a workpiece material more pliable and ductile and less brittle and less prone to fracture. Unlike other laser-assisted machining processes, which use other types of cutting tools and are less precise, Patten pointed out that the µ-LAM process passes the laser through the diamond tool without heating the diamond because heating it may cause the diamond to degrade or possibly decompose when exposed to air. “The diamond is transparent to the laser,” he said. “It’s really a hybrid, coupled configuration that’s pretty slick.”