March 2009

Energy Consumption Forecasting and Optimisation for Tool Machines

MM (Modern Machinery) Science Journal, March 2009
A. Dietmair, A. Verl
Institute for Control Engineering of Machine Tools and Manufacturing Units (ISW), Universität Stuttgart, Germany
Abstract

Soaring energy prices, signs of a human-made climate change and legislative pressure have brought the energy consumption of machines to the attention of machine tool builders and their customers. To enable manufacturers and operators of machines to include energy consumption into their considerations in an objective way, we introduce an efficient method to model the energy consumption behaviour of machines. Based on that, we present methods to forecast the actual power drain profile and to optimise machines for minimal energy consumption under any given application scenario.

Keywords: Energy Efficiency, Virtual Prototyping, Machine Optimisation
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Machine tool with undisturbed frame

MM (Modern Machinery) Science Journal, March 2009
J. Sveda1, Z. Sika2, M. Valasek2
1Research Center of Manufacturing Technology, CTU in Prague, Czech Republic
2Department of Mechanics, Biomechanics and Mechatronics, CTU in Prague, Czech Republic
Abstract

One of the main disturbances of the machine tool frame is caused by operation of motion axis. Movement of high dynamic motion axis is connected with powerful force strokes that excite machine tool frame vibration and deteriorate machining surface quality and productivity. There are several possibilities how to suppress this vibration. One possibility is to use suspended motor, where the motor is connected with the machine body by spring and damper. This paper deals with new more advanced conception where the main motor is connected with the frame by an active element, that is controlled by intelligent control technique. The active element represents another linear motor, therefore the conception is shortly called “motor on motor”.

Keywords: Machine tool, linear motor, vibration suppression, control loop
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Automatic On-Machine Measurement of Complex Parts

MM (Modern Machinery) Science Journal, March 2009
J. Zeleny, M. Janda
Research Center of Manufacturing Technology, CTU in Prague, Czech Republic
Abstract

Milling spindles with inserted 3D tensometric touch probes were applied for on-machine measurement of highly precise parts produced on three - and five-axis milling machines equipped with linear motors and direct rotary drives. New methods of CNC control of angular NC axes during measurement were developed for parts containing hardly accessible surfaces. In-process calibration of multi-directional accuracy of probes has resulted in submicron sensitivity and highest absolute accuracy of on-machine measurements.

Keywords: Machining, accuracy, on-machine measurement
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Thermomechanical transfer functions and control of a machine tool cooling system

MM (Modern Machinery) Science Journal, March 2009
J. Hornych, P. Barta, M. Mares
Research Center for Manufacturing Technology, CTU in Prague, Czech Republic
Abstract

Nowadays the cooling systems are more than ever applied into the structure of a machine tool, but unfortunately there are no efforts being made in the control of the cooling systems, which doesn’t allow complete utilisation of their possibilities. This paper presents active cooling control (ACC) system, based on thermal transfer functions, which was experimentally tested on an inbuilt cooling jacket of a machine tool electrospindle.

Keywords: Thermomechanical transfer function, thermal error, machine tool
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