Evaluation of a Lathe with Ferrocement Bed

Abstract

In an earlier study, the feasibility of using ferrocement as a replacement to cast iron in the manufacture of machine tool structures was investigated by fabricating a prototype ferrocement bed for a centre lathe and testing the bed alone. Improved performance exhibited by the ferrocement bed in comparison with the parent cast iron bed under both static and dynamic loadings has inspired the authors to pursue the work and assess the bed in terms of the performance of the machine as a whole. A centre lathe was chosen for this purpose. The traditional cast iron bed in the machine was replaced by a ferrocement bed, designed and fabricated for accommodating all the necessary parts and attachments. The method of fabrication and installation of the bed are described in this paper. Identical vibration and cutting tests were performed in the original as well as the modified machines. Test results indicate that the machine with ferrocement bed provides significantly higher damping and natural frequencies, specially the torsional frequency, and results in an approximately 40% deeper cut than the original lathe before the onset of chatter. © 1993 CIRP.