VT 2-4 Vertical Turning Machine: A step-change in the production of electric motors
02/27/2013 - Oliver Hagenlocher
According to market experts the demand for electric motors is going to grow dramatically – and this at a time when the new transmission systems are becoming highly efficient. It is the express desire of the EU commission that the inefficient motors presently used in the automotive industry and other sectors should be replaced by the new electric motors by 2020. What does this development mean for motor manufacturers who are trying to use innovation and outstanding quality as a means to reach the top spot in the market? The example of shaft machining provides the answer: to ensure that the manufacture of complex components becomes even more efficient, the focus must be on the systems used to make them. The EMAG Group has developed a tailor-made solution for the manufacture of shafts for electric motors: their fully automated VT 2-4 Vertical Turning Machine. It makes the called for step-change in shaft machining a reality.
According to latest EU guidelines on the manufacture of electric motors, the energy-efficiency of many electric transmission systems is to be increased by 30 percent in the next few years. This provides the first opening for the exploration of an enormous market opportunity for the manufacturers of electric motors. The development does, however, bring with it some challenges, as the manufacture of these components does not only call for manufacturing solutions of greater effectiveness. The design of these modern motors also increases the demands made on its constituent components. “We know about these challenges in the manufacture of the central components for electric motors”, explains Dr Guido Hegener, Managing Director of EMAG Salach Maschinenfabrik GmbH. “A particular focal point is the demanding shaft manufacture, where a lot depends on the machine tool used. In a batch production environment idle times must be kept short and component costs low. But this must be achieved without loss of flexibility in the production process.”
Automation ensures short idle times
The specialists at EMAG have developed such a solution for the machining of shafts of up to 400 mm length and 63 mm diameter in their VT 2-4 4-axis Vertical Pick-Up Turning Machine. When it comes to larger batch sizes, the real strength of this machine becomes very obvious: its automation provides for very fast chip-to-chip times and ensures component costs are kept low. Workpiece grabs are used to transport the raw-parts into the machine and retrieve them again on completion of the machining process. Depending on the component, the changeover time can be as short as six to eight seconds. “In a mass production environment such short idle times soon add up to provide enormous time savings”, adds Guido Hegener. “They also guarantee an energy-efficient production process, as a large part of a machine tool’s energy is consumed during downtimes.”
The actual turning process – with spindle speeds of up to 6,000 rpm – also helps to achieve extremely short cycle times. The shaft is clamped vertically between workspindle and tailstock and machined from two sides. This work is done by two turrets with twelve tool stations each. The stations can be equipped with turning tools and driven tools (with one station being occupied by the grab). For milling work – such as required for keyways – the machine can be optionally equipped with a Y-axis. The vertical alignment of the workpiece ensures permanent process integrity, as the unhindered chip flow prevents the build-up of chip nests in the machining area.
A true space-saver with many options
A decisive factor for economic production is the external dimension of the machine tool. In the case of the VT 2-4 the machine base is already small, as the vertical design does not take up much space. Production planners also don’t have to provide for additional raw-part and finished component storage, as this forms an integral part of the VT 2-4. These machines can also be linked-up in close formation, to form a neat manufacturing line. “We have developed an altogether very compact manufacturing system that is highly flexible and future-proof”, explains Guido Hegener.
Fast chip-to-chip times and the advantages of vertical machining – what are the chances of this concept in the market? “There are a lot of possible applications out there for this system, especially in the manufacture of shafts for electric motors”, says Guido Hegener. “We are offering a machine tool that allows the user to implement demanding machining processes and to save massively on costs. This kind of quality will no doubt assert itself.”
|Travel in X||mm||340|
|Travel in Z||mm||525|
|Main spindle power rating|
40% / 100% duty cycle
|kW||34 / 26.5|
40% / 100% duty cycle
|Nm||144 / 112|