Precise Control for Complex Fabrication

Jan. 25, 2012
Metal fabricator Waymatic achieves laser-level accuracy with a punch plasma machine using Sigma-5 servos and controllers and EtherCAT networking (CONTAINS VIDEO).

Waymatic Inc., a metal fabricator located in South Fulton, TN, recently upgraded its metal manufacturing operations to execute more precise, complex cutting operations, such a creating smooth, circular parts. To do this, the company now employs a Whitney 657 punch plasma machine, which achieves its highly precise motion abilities through the use of Yaskawa (Waukegan, IL) Sigma-5 servos and controls in conjunction with the EtherCAT industrial Ethernet protocol. (See a video of the Whitney 657 in action below.)

Jimmy Berry, engineering manager at Megafab/Whitney, the manufacturer of the model 657 punch plasma machine, said that EtherCAT was selected as the machine’s communication protocol for two principal reasons:
1.It was a not a proprietary protocol requiring the use of a specific brand of control hardware; and
2.It allowed for Internet access to the machine for remote tuning adjustments.
Before implementation of this machine, engineers at Waymatic had to “remove the servo drives and send them back to the manufacturer for re-programming” if tuning adjustments were needed, said Danny Frields, supervisor at Waymaytic. Remote access to the servos via the Internet enables them to be remotely tuned while still in the machine.
Creating circular metal parts is considered a complex process from a controls aspect because, as the cutting mechanism moves along the x and y axes, it operates at zero speed in certain points on each axis. At the zero speed moments, there is little feedback from the encoder, so the use of a high resolution encoder coupled with advanced amp and motor capabilities enables the cutting mechanism to transition through those zero speed points smoothly and ensure an accurate circular cut.
Whitney, the manufacturer of the punch plasma machines used by Waymatic, installed Yaskawa’s Sigma-5 servos and controls on this model 657 unit because the Sigma-5 series can match the performance of the servos and amplifiers for such high-speed, accuracy critical applications.
“We’re now able to achieve laser quality and accuracy using plasma,” said Frields. “The machine can operate at higher speeds on thinner gauge materials and get a more fluid flow through the material for good finished parts.”
Achieving laser-like quality on a punch plasma machine is a big benefit to Waymatic, because plasma machines are less costly to operate, have a higher level of uptime and lower maintenance requirements.