Development of a polymer impregnated concrete damping carriage for linear guideways for machine tools: Fid-Bau Portal

Development of a polymer impregnated concrete damping carriage for linear guideways for machine tools

Rahman, M. / Mansur, M.A. / Lee, L.K. / Lum, J.K.

Linear guideway systems of CNC machine tools are replacing the conventional slideways to achieve higher machining speed which has resulted in lower damping capacity. Damping carriages made of steel have been introduced to improve damping, however, that did not render significant improvement. Consequently, an attempt has been made in this study to improve damping in a CNC machine table by replacing the current steel damping carriage with one made of concrete since it has much higher internal damping. To select a suitable material for the carriage, the damping characteristics and strength of normal concrete, cellular concrete and polymer impregnated normal and cellular concrete have been investigated. It has been found that methyl methacrylate (MMA) polymer impregnated low-density cellular concrete (PC) exhibited higher strength, elastic modulus and damping capacity as well as strength at demoulding thus being the most suitable material for the purpose. Consequently, a new damping carriage has been designed and fabricated using PC and has been incorporated into the linear guidance table system of a CNC machine. From the modal analysis data, this newly designed PC damper not only has an improved damping capacity over the steel damper linear guide system, it has also compensated the design imperfection in the linear guidance system providing high damping at a lower frequency range. In addition, this new PC damper has also improved the damping capacity of the linear guidance system to a comparative level to that of the slideway system for most modal frequencies. This improved damping capacity of the lightweight damper offers higher rigidity to the table system while maintaining the efficiency of the system.