Modern Machinery (MM) Science Journal, October 2008

Machine Tool Lightweight Design and Advanced Control Techniques

M. Sulitka, L. Novotny, J. Sveda, P. Strakos, J. Hudec, J. Smolik, P. Vlach
Keywords: feed drive complex model | control of flexible structures | non-conventional materials in the machine tool design | machine tool energy consumption | machine tool lightweight design

Mass reduction of the machine tool movable parts is a tool for achieving lower energy demands of the machine tool operation. Lower weight can bring elevation of the machine tool dynamic properties with the application of new materials, which assure the equivalent static and dynamic compliancy compared to the usage of common materials. However, if the machine frame compliancy is increased, it is pos (…)

Variation of Eigenvalues of a HPC Motor Spindle due to Changing Axial Depth of Cut

B. Späh, S. Kern, R. Nordmann
Keywords: semi-discretization | active vibration control | chatter-suppression | milling

The influence of the milling-process on the system-dynamics of a hybrid bearing HPC (high performance cutting) motor spindle is investigated. An additional electromagnetic actuator allows for identification and active vibration control. Semi-discretization is used to calculate the eigenvalues of the motor spindle depending on increasing axial depth of cut. This result is used to design a controll (…)

Economy of Titanium Milling

G. J. Trmal, P. Bach
Keywords: tool wear | cost of machining | titanium

This paper describes benefits of close collaboration between technologists and analysts of machine tools. After all, any innovation in machine design can only be proven by producing components of required quality more economically. The combined expertise can be utilized especially in machining new materials, such as titanium, which are more difficult to machine. The decisive factor in optimization (…)

Mechatronic Approach in Modelling, Identification and Control of Thermal Deformation of Quill

Martin Mares, Pavel Barta
Keywords: Matlab | control | identification | thermal transfer function | thermal error | quill | Machine tool

The demands on machining accuracy have been increasing lately and therefore research of thermal behaviour of machine tool structures is crucial for successful manufacturing. Generated heat diffuses into the structure of the machine tool components. This process is affected by heat sinks such as heat transfer on the surfaces and cooling systems. Meanwhile the heat warms up the structure of the mach (…)

Operational behaviour of high speed spindle unit

J. Jedrzejewski, W. Kwasny, Z. Kowal, W. Modrzycki
Keywords: high speed | spindle unit | Machine tool

The paper presents the behaviour of a high speed spindle unit during operation, with changes of: speed, centrifugal forces, bearing working clearance/tension, thermal deformations and temperature distribution. Moreover, spindle and rolling elements of bearing material’s influence on heating up and spindle displacements will be shown for different spindle working conditions.

Modelling the orthogonal machining process using cutting tools with different geometry

J. Zouhar, M. Piska
Keywords: Johnson – Cook | LS-DYNA | orthogonal cutting | FEM

This paper deals with modelling of the orthogonal machining process using tools with different geometries. The finite element method (FEM) is used for a simulation based on the Lagrangian formulation including ANSYS/LS-DYNA software. The constitutive Johnson – Cook material model regarding strain, strain rate and temperature to predict material plasticity and chip separation is used. Chip morpholo (…)