Simulation software dedicated for design of casting processes is usually tested and calibrated by comparisons of shrinkage defects

distribution predicted by the modelling with that observed in real castings produced in a given foundry. However, a large amount of

expertise obtained from different foundries, including especially made experiments, is available from literature, in the form of

recommendations for design of the rigging systems. This kind of information can be also used for assessment of the simulation predictions.

In the present work two parameters used in the design of feeding systems are considered: feeding ranges in horizontal and vertical plates as

well as efficiency (yield) of feeders of various shapes. The simulation tests were conducted using especially designed steel and aluminium

castings with risers and a commercial FDM based software. It was found that the simulations cannot predict appearance of shrinkage

porosity in horizontal and vertical plates of even cross-sections which would mean, that the feeding ranges are practically unlimited. The

yield of all types of feeders obtained from the simulations appeared to be much higher than that reported in the literature. It can be

concluded that the feeding flow modelling included in the tested software does not reflect phenomena responsible for the feeding processes

in real castings properly. Further tests, with different types of software and more fundamental studies on the feeding process modelling

would be desirable.

Electro-dynamic passive magnetic bearings are now viewed as a feasible option when looking for support for high-speed rotors. Nevertheless, because of the skew-symmetrical visco-elastic properties of such bearings, they are prone to operational instability. In order to avoid this, the paper proposes the addition of external damping into the newly designed vibrating laboratory rotor-shaft system. This may be achieved by means of using simple passive dampers that would be found among the components of the electro-dynamic bearing housings along with magnetic dampers, which satisfy the operational principles of active magnetic bearings. Theoretical investigations are going to be conducted by means of a structural computer model of the rotor-shaft under construction, which will take into consideration its actual dimensions and material properties. The additional damping magnitudes required to stabilize the most sensitive lateral eigenmodes of the object under consideration have been determined by means of the Routh-Hurwitz stability criterion.