Taking cutters into their own hands

It doesn’t do a parts manufacturer any good to apply cutting tools that vary in tolerances when machining parts that require some of the tightest tolerances.

Miltera Machining Research Corp. is one such manufacturer that struggled with tolerances on the endmills it was using to produce components with tolerances as tight as 2 to 4 µm (0.00008″ to 0.00016″), said Michael Blackburn, president of the Cambridge, Ontario, company.

“Then we even go beyond that to the submicron level when talking about surface finishes,” he said.

Formed in 2007, the corporation employs 15 and specializes in prototyping and short-run production of complex components made of difficult-to-machine materials that typically need five-axis milling, multiaxis turning, grinding or electrical discharge machining.

Frustrated by the varying accuracy of its endmills, Blackburn said the company sought a solution.

“If you are fighting with finishes and dealing with issues on a part where you are chasing 2, 3, 4 microns, and then you are using cutting tools that have a 10-micron (0.00039″) tolerance, you are chasing your tail,” he said.

The business determined that it needed to produce endmills in-house to have the required extreme-tolerance tools, often with unique geometries, and searched for a suitable five-axis CNC tool grinding machine.

“Most companies said, ‘What you are doing is crazy and weird, and we’re not interested in helping you with that,'” Blackburn said.

The tool grinding area at Miltera Machining Research includes Anca MX7 Linear grinders. Image courtesy of Miltera Machining Research

One machine tool builder that was interested was Anca Inc. in Wixom, Michigan. He said the manufacturer was willing to help produce unconventional cutters, and the open architecture of Anca’s control enabled Miltera Machining Research to integrate with the control and have direct access to the core functionality of a grinder.

“That really made the difference for us,” Blackburn said, adding that his company has written software to control its grinders.

In addition, he said Anca offers grinding machines with linear motors, which enable a high level of accuracy. He noted that Miltera Machining Research has linear motors on its five-axis machines.

“A big attraction was just the ability of the machine to be stable and react in the way we would expect,” Blackburn said. “In comparing some of the other machines, we weren’t necessarily seeing that we get that same response.”

He said the design of Anca’s grinders allows Miltera Machining Research to modify machines, such as inspection systems, to suit its requirements.