Page 21 - MetalForming August 2013

“This feature greatly increases draw process capability and consistency,” says Meggitt manufacturing engineer- ing manager John Krochmal, “which facilitates the production of our deep- drawn fire-safety components, includ- ing fire-suppression bottles designed for aircraft-engine extinguishing.”
Advanced Technologies for Pre-Preventive Maintenance
Meggitt’s new made-to-order hydraulic press plays a critical role in the company’s manufacturing process, so reliability is paramount. Therefore, Beckwood included several reliability- focused features well-accepted by Krochmal and the rest of the Meggitt manufacturing team.
For example, Meggitt’s press includes an onboard press-health monitoring system (Beckwood dubs it Heartbeat). The setup actively monitors the hydraulic fluid in the press to help ensure optimum operating efficiency. The ability to continuously monitor fluid health against acceptable fluid standards limits or eliminates a major cause of unplanned hydraulic-press downtime: contaminated oil.
Using the Heartbeat system, the press HMI displays actual measured ISO codes, the channel size (μ) and the system’s moisture-sensor reading (per- cent relative humidity) related to the hydraulic fluid inside the system. Also displayed are limits to these variables, as defined by Meggitt engineers. When these limits are surpassed, the Heart- beat sensors trigger warning indica- tors, also displayed on the press HMI. This notice, in advance of any compo- nent failure or decreased press per- formance due to contaminated oil, allows Meggitt’s maintenance team to schedule necessary maintenance, such as replacing standard filter elements, in a timely manner. This avoids any unex- pected component failure and down- time due to unchecked contamination.
Remote Troubleshooting and Diagnostics
Meggitt’s press also is equipped with a WebPort Communication Module,
This screenshot of the press’s fluid- health system helps operators under- stand how fluid contamination can impact press performance. The system provides warnings if fluid health declines past a defined point.
allowing Beckwood engineers and serv- ice technicians to remotely log in to perform factory diagnostic support and troubleshooting. Through the WebPort, program updates also can be remotely uploaded, notes Beckwood engineering manager Darrell Harrelson.
“WebPort connectivity creates game-changing capabilities with regard to troubleshooting and on-the-fly enhancements,” says Harrelson. “For example, a manufacturer operating a WebPort-enabled press can conceive of an HMI or program change in the morning and be operating with the desired change before lunch—all via the remote connection.”
For additional reliability, the hydraulic circuit of the press was sim- plified by offering separate individ- ual circuits for the main ram, bed cushion and knockout cylinder. Each has its own dedicated pump and motor combination, easing trou- bleshooting and allowing Meggitt’s maintenance personnel to more quickly zero-in on any potential issues which might arise.
Variable-Frequency Drive a Money Saver
Another item on Meggitt’s wish list, increased energy efficiency, came to fruition thanks to the inclusion of a unique variable-frequency drive ( VFD) system, supplied by Parker Hannifin. In a traditional hydraulic press, the ram is powered by a hydraulic cylinder pres-
surized by a pump or hydraulic power unit, and the hydraulic pump runs at full speed throughout the entire process—approach, pressing and retract. Output is regulated by valves. Meggitt’s 500-ton draw press employs a VFD-controlled pump.
“Traditional constant-speed pumps tend to waste energy and fail to provide the required flexibility,” says Harrel- son. “Servo-driven systems can work well, but too often are associated with prohibitive cost and complexity, espe- cially at the power rating required for larger presses. Finally, a typical off-the- shelf VFD often lacks the ‘smarts’ need- ed to control and regulate a hydraulic system to the degree that press appli- cations demand. Parker, however, rec- ommended a drive that included the functionality needed to power our hydraulic system with the efficiency and capability required.”
The drive (Parker Hannifin’s AC890 drive) installed on the hydraulic pump of Meggitt’s new press allows the pump to operate at its optimum speed for each portion of the press cycle. The drive controls the pump’s electric motor, adjusting and regulating speed and torque to provide the necessary flow rate and pressure for the machine’s operation—and no more. The drive includes function-block programming and state machine logic, so with min- imal development the press can be programmed for actual press sequences such as “return on pressure” or “return on position.”
Energy savings are verified by examining the press’s power usage over several operating cycles. By low- ering the speed of the pump, less power is consumed versus traditional methods of hydraulic speed control. “And, by lowering energy cost, the effective cost of each drawn part drops proportionally,” confirms Krochmal. Finally, when only the power needed to perform the work is expended, the pressure drop throughout the entire hydraulic system is minimized, in turn reducing the cooling requirements needed to keep the press at optimal operating temperature.
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