المجلة الدولية للعلوم والتقنية

The critical speeds are the key factor for dynamic stability in rotary machines, from the vibration point of view. The critical speeds of an existing centrifugal casting machine (CC machine) are found. The referred CC machine was previously designed, constructed and tested at the College of Engineering Technology (formerly known as the Higher Institute of Mechanical Professionals) in Tripoli, as mentioned in a previous publication. The dynamic stability is analyzed and the natural frequencies of the rotor system and their related critical speeds are identified using finite element analysis (FEA). The analysis is conducted for different thicknesses and different lengths of mold material. The main objective of this analysis is to seek improvement of the CC machine, in terms of produced cylinder sizes. The CC machine proved to be suitable for the production of the specified product cylinders, with limitations on its length and speed of the driving motor. Longer cylinders could still be produced by modifying the existing CC machine and employing longer molds, thus higher driving speeds are eventually needed.