‘It has always been normal to have machines run to warm up to avoid machining inaccuracies,’ said development manager for Mag Powertrain, Thomas Bayha.
The Mag Specht 500 platform for the powertrain sector is an agile manufacturing centre designed primarily for large batch production in the automotive industry.
During the warm-up programme, the machining method that represents six per-cent of the total energy consumption of the machine is the only capability not used.
The machine is only ready for use after operating temperature is reached and stabilised.
As temperature compensation is the key, the machine temperature is measured with several sensors on important components.
Mag Powertrain set itself the objective of drastically shortening this unproductive energy consumption phase.
Based on the data, the computer creates a 3D thermal machine model that is transmitted to the control to determine the position corrections.
The expansion coefficients for these parts are stored in an external computer.
This continues during the entire warm up and production phase, providing constant machining quality during what would otherwise be an unstable condition.
Initial results show that temperature compensation actually shortens the warm-up phase or makes it entirely unnecessary.
Exhaust air is also an energy waste phase the Mag engineers are aiming to tame.
Thousands of cubic meters of air flow through the machines daily to tidy the working area.
To minimise air requirements, the working volume of the machining centre was optimised to reduce the required volume of air.
By changing the air flow, the exhaust now sits in the middle above the machining table and this has reduced exhaust requirements to 540m3/h (19,000ft3/h) per hour.
Viewed in isolation, this has little meaning, but it’s important to understand that it takes a great deal of energy to move this air through duct systems and mist collectors.
If you compare it with the consumption of other machines, which use about 1,500m3/h (52,950ft3/h), there’s a significant energy saving.
Similar to the braking systems for cars or trains, the energy captured during braking is stored with a regenerative drive, and then released during the next demand cycle.
Mag engineers also focused on regenerative drive modules.
The magnetic valves on the machine have also been optimised so that they can now be operated with only 8W instead of 30W.
Another important contributor to higher energy efficiency is the cooling of the control cabinet, a factor often overlooked.
The cabinets are usually cooled regardless of their real temperature.
The system is designed to provide the required temperature even on the hottest summer days.
However, these extreme values are rarely reached.
In spite of this, the cooling systems always work under a full load.
Another energy saving reduction has been realised with the standby mode.
In contrast, the Mag Specht will amend the cooling demand based on the ambient temperature or the internal temperature, using temperature sensors, saving 1.2 per-cent of the energy needed in this area.
Using various standby strategies for coolants and exhaust systems, Mag has reduced this by 20 per-cent.
‘Current machines on standby consume about 50 per-cent less energy than under full load,’ said Bayha.
An automatic cycle modification was also integrated in to the Specht 500 concept that decreases or increases the positioning dynamics of the machine.
Using temperature compensation, it is now also possible to shut off the circulation of coolant during these idle phases.
This individual configuration for a particular production cycle brings additional savings.
The Specht 500 also uses Mag Powertrain’s dry machining technology, providing an economical use of lubricants and coolants.
This is a huge advantage in today’s automotive market with Ford, BMW and plenty of other major manufacturers investing heavily in dry machining techniques.
The mechanical assembly of the machine supports wet machining at low fluid levels as well as dry machining with maximum quantity lubrication.