Modern Machinery (MM) Science Journal, March 2010

POSSIBILITIES OF FEM APPLIED IN THE VERIFICATION OF X-RAY MEASUREMENT

K. Frydrysek
Keywords: FEM | Stress redistribution | Layers´ removal | X-ray diffraction | residual stress

Residual stress diffraction measurements in a thin surface layer are completely nondestructive. For subsurface stress profiling, the destructive X-ray analysis can be performed by sequentially removing surface layers by using electrolytic or chemical polishing. When stressed layers are removed, the measured stress values in depths beneath the surface are in general affected by the relaxation create (…)

COMBINED LOADING OF THE SPECIMENS AND REALIZED EXPERIMENT

Fr. Fojtík, J. Fuxa
Keywords: Mean stress effect | Multi-axial fatigue | Experiment | High-cycle Fatigue | Combined loading

The article describes experimental results under combined loading of specimens manufactured from common construction steel 11523. Specimens were gradually loaded by amplitude of the torque and then by combination tension prestress. For evaluation of the results the Fuxa’s criterion was applied. The performed experiments and their results embody a good agreement with bellow mentioned conjugated stre (…)

PREDICTION OF MACHINE TOOL SPINDLE’S DYNAMICS BASED ON A THERMO-MECHANICAL MODEL

P. Kolar, T. Holkup
Keywords: Thermal expansion | Spindle dynamics | FEM modeling | Rolling bearing | Spindle

This paper presents a thermo-mechanical model of spindles with rolling bearings. The heat generated in the bearings and the motor is transferred to the ambient air, the motor coolant and the spindle head structure. It warms the spindle up and causes thermal deformations of spindle parts. Thermal deformation affects significantly properties (internal loads, stiffness) of rolling bearings and need to (…)

OPTIMIZATION OF ENERGY BY ROBOT MOVEMENT

Anna Smetanova
Keywords: Acceleration | Velocity | Measuring | Energy Consumption | Motion | Robot

This paper is describing the influences of movement parameters on energy consumption during robot operation. The experimental verification of mathematical models was performed in the laboratory of the Institute of Production Machines, Systems and Robotics at Brno University of Technology. The measure results are arranged in tables and diagrams from which final evaluation for praxis follow. One of t (…)

COMPENSATION OF MACHINE TOOL THERMAL ERRORS BASED ON TRANSFER FUNCTIONS

O. Horejs, M. Mares, P. Kohut, P. Barta, J. Hornych
Keywords: Transfer function | accuracy | Ultra precision | Compensation | Thermal errors

This paper reports on a new method for compensation of machine tool thermal errors that is based on system of thermal transfer functions. Due to their relative simplicity they enable real-time calculations which make them suitable for compensation algorithms of thermal displacements at tool centre point. The applicability and robustness of the thermal transfer function compensation model have been (…)