Warwickshire-based Walter Ewag UK
, a member of the United Grinding Group
, reports that energy savings of up to 40% can be achieved through optimised operation of its Walter Helitronic tool grinding and erosion machines by, for instance, sensible warm-up and shutdown programs, the recovery of thermal energy and optimised machining via machine control software routines.
This figure also includes an 11% reduction in the machines’ energy consumption as Walter now uses more environmentally-friendly components in machine-build compared to those widely available 15 years ago. All measures (and claims) are independently assessed by experts from the German Steinbeis Sustainable Energy Competence Center.
Walter’s awareness of climate protection begins with the design and construction of its machines – for example, by utilising modern drives and improved part loading, compressed air and extraction, as well as by the use of energy-saving LED lights and frequency-controlled coolant pumps and continues through production by optimised machine operation. Some of the technology improvements made include:
• Feed and spindle drives – use of highly efficient synchronous motors and regenerative braking energy feedback into the power grid, including linear motors in the vertical axis on certain models and passive weight compensation.
• Coolant supply via frequency-controlled pump. High efficiency motors (efficiency class IE4) and up to six individually switchable coolant valves optimise coolant supply.
• LED lights are used in all machines, including the status light.
• Central lubrication – ‘impulse’ lubrication means, for example, that the lubricating oil pump runs only for a few seconds until lubricating pressure is built up. The pump is then switched off until the next lubrication cycle.
• Each machine’s vapour separator is equipped with potentiometer control and a free-running fan wheel, which allows optimal adjustment of the extraction volume. The EC motors are IE4 rated.
In addition, Walter Ewag UK says machine users can adopt various routines to gain further improvements in energy efficiency, including:
• Off-work switching – each Walter machine has an ‘off-hours’ switch so if the machine remains switched on beyond the end of the shift, a standby mode if effected after the last tool has been processed. In such mode the coolant pumps, extraction system, hydraulics and grinding spindles are set to ‘off’ and the axes drives are set to pulse lock.
• The machine warm-up program can be automatically started at a selected date and time. The machine remains in stand-by mode and, one hour before the start of work, it starts to warm up so it is at operating temperature and can go into production immediately when the operator arrives.
• During work breaks or in the case of any ’inactivity’, a number of units are switched off - ie vapour extraction, coolant pumps and sealing air.
• Machines with linear and torque motors have a central supply and return of the motor cooling medium, and customers have the option of using the waste heat generated for heating buildings.
• Machining process simulation – with the Helitronic Tool Studio software or Cybergrinding, tools can be simulated in advance on an external PC workstation to save valuable working time while also reducing the test operation and test parts.