M.K. Rashid (Sultanate of Oman)
: Toolpost Modeling, Smart Material, Machining errors, Intelligent manufacturing.
: Healing tool vibration error in old turning machines can reduce industrial waste; save money and, improve design flexibility of new cutting tools. Smart material is used to counteract radial disturbing cutting force. Structural stiffness ratios and its impact on the use of smart material in intelligent toolpost for error elimination are investigated using the finite element method. The derived conclusions in the present work proved the limited use of lumped mass modeling in toolpost system dynamic response. Then time dependent dynamic response is obtained for toolpost using pulse width modulation (PWM) as voltage excitation for smart material. Results show that error elimination and transient response control requires minimum number of PWM cycles in each force period. Time delay between actuation force and voltage has an adverse effect on error elimination if exceed certain limit. Calculations showed that error elimination and transient response using dynamic vibration absorber does not ensure favorable results in solving tool vibration problem. However, increasing toolpost damping within a reasonable range can affect toolpost response but the major improvement in tool error reduction is noticed by modifying the PWM voltage and its time duration. Estimated static voltage in error elimination does not necessarily applied in dynamic switching. Tool bit to actuator stiffness and tool carrier (holder) to actuator stiffness both are preferred to be as high as possible.
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