A choice subject: systems that match the CNC machine tool can give a better ROI.

Author:Seeds, Dennis
Position:CNC controls

For those in the market for CNC controls, decisions can be a tall order.

But in the simplest terms, it comes down to matching the CNC controls to the machine, several control builders told Tooling & Production.

"If you are buying a custom machine, you're going to have a lot of choices because they haven't even started building it," said Paul Webster, CNC product manager for GE Fanuc. "If you are buying a commodity machine off the shelf, your choices are limited at that point."

Karl Rapp, Bosch Rexroth applications manager for machine tools, interjected the cost factor.


"Machine builders typically offer the lowest price for a machine if the customer does not want to change the CNC that is already engineered to run the machine," he explained. "In some cases however, a user may want more flexibility and/or different functionality or has specific process needs, and a different CNC platform may be required."

"Usually what your choices come down to is what the machining requires," Webster said. "The most important thing is getting the control system that matches the machine tool correctly," and gives the better ROI.

Another consideration is employee familiarity with the CNC platform.

"General wisdom is to choose the same CNC supplier again, that the staff may already know, to minimize training or use established connectivity," Rapp said. "But it never hurts to review the latest CNC controllers, as many of them use ISO-based G-code formats and offer PC-based human machine interfaces (HMI) that easily can be configured by the operator as needed."

Jon Cruthers, business development manager for the Motion Control Business Unit at Siemens, said the leading CNC suppliers have levels of controls to suit virtually all applications.

"This means they range from the simple prismatic parts to the most complex aerospace structures or medical implants, where axis interpolation and volumetric error compensation are critical to effective, repeatable machining," he noted.

"The most advanced CNCs now have full conversational programming, as well as cycle simulation software onboard," Cruthers said.

Operator interfaces should be considered, too. Conversational programming, which uses graphical input, is popular in small and medium operations, where machinists may design their own part programs. However, in...

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