Published 1/25/2011

EDM Energy Conservation Without the Effort

Most machine tool energy conservation systems simply track power consumption, placing the burden of actually reducing energy use on manufacturers. GF AgieCharmilles aims to change that with the EconoWatt II, an automated system for wire EDM.

Machines
EDM

Edited by: Matt Danford

Former Senior Editor, Modern Machine Shop

Taking steps to reduce machine tool energy consumption offers more than just the warm, fuzzy feeling that often comes with doing one’s part for the planet. It can also impact the bottom line. However, this more tangible benefit goes only so far with most energy-saving systems, which are typically dashboard-type units that track machine power use and leave it to manufacturers to take appropriate steps for conservation.

One system recently developed for wire EDM machines promises to relieve users of that burden. Available from GF AgieCharmilles (Lincolnshire, Illinois), the EconoWatt II is an active conservation system that automatically initiates energy-saving routines at scheduled intervals.

EconoWatt II builds on developments pioneered in the manufacturer’s previous-generation system, the EconoWatt I. Both save energy by adjusting machine peripherals—for example, switching off pumps, generators, fans, chillers, lights and other such components when the machine is idle. The EconoWatt II features all the capability of the previous model along with additional functions, including wake-up cycles, humidity holding and temperature holding. Users can also access and program the unit remotely via GF AgieCharmilles’ E-Monitoring system.

However, the most significant differences between the two systems are ease of use and scheduling capability, the manufacturer says. Unlike the EconoWatt I, which operates via special M codes that must be input into the machine program, the EconoWatt II features an additional, dedicated control screen. This screen not only provides more intuitive operation, but also enables users to specify exactly when the system will activate and deactivate machine peripherals.

For example, a shop could instruct the system to switch peripherals off every day at 5 p.m. and back on again at 6 a.m., or to switch off during the weekend and power back up on Monday. Peripherals can also be programmed to switch off at the end of a part program, if the wire breaks and in the event of a machine error. To avoid losing time waiting for the machine to warm up, wake-up cycles can be programmed to restart the peripherals, circulate the dialectric and stabilize the machine’s temperature before production starts.

The system’s humidity holding function periodically activates dielectric pumps during idle periods to automatically maintain a stable, user-specified humidity level. According to the company, keeping parts wet in this way prevents pitting or rusting when exposed to shop air overnight. Likewise, keeping machine seals, power contacts and wire-threading jet nozzles wet and clean prevents contaminants from drying on their surfaces.

Similarly, the temperature holding function periodically activates circulation and chiller pumps while the generator, control screen and other components remain off. This maintains a constant, 68-degree temperature in the dielectric tank so the machine is ready for action once the peripherals are powered up again. A shop could, for example, run roughing passes unattended at night with assurance that the machine’s temperature will be sufficiently stabilized for precision finishing passes in the morning.

The unit also enables shops to track their energy savings via the Econometer, a speedometer-like display on the control screen. Users can view the machine’s current energy consumption level in kilowatts per hour as well as its consumption history, which dates back to the day the unit was installed.

Regardless of these automated functions, the primary purpose of the EconoWatt II is saving energy. According to GF AgieCharmilles, those savings can be significant—the manufacturer estimates that a wire EDM equipped with the system consumes only 1 kilowatt per hour while sitting idle.