Smart actuator stiffness and switching frequency in suppression of vibration of a cutting tool

Abstract

Techniques for suppression of vibration in cutting tools can save old machines and enhance design flexibility in new manufacturing systems. Structural stiffness interaction, with the use of smart materials, in an intelligent toolpost is investigated using the finite element method. The results proved the limited use of lumped modeling in driving conclusions and developing a toolpost system for dynamic response control. A transient solution is obtained for the toolpost response in which a smart material actuator is excited using pulse width modulation (PWM) for voltage generation to counteract the radial disturbing cutting force. Calculations showed that error elimination and transient response control require a minimum number of PWM cycles in each force period. Time delay between the actuation force and voltage has an adverse effect on error elimination, if it exceeds a certain limit. Increasing damping within a reasonable range might not eliminate the transient response originated by the voltage switching of the smart material actuator. The estimated static voltage in error elimination cannot necessarily be used in dynamic switching. The tool bit to actuator stiffness and tool carrier (holder) to actuator stiffness ratios are both preferred to be above ten when space and weight limitations do not exist.

Improving Machining Accuracy Using Smart Materials

“…For present results, toolpost dimension and, material are given in Table 1. Previous work (Rashid, M. K. 2004) indicated the use of few PWM, cycles per force period produced unfavorable switching dynamic excitation. Twenty PWM cycles for each force period produce good results more than forty has a little effect.…”

“…Nature and type of signals that control smart material actuator and how can affect toolpost dynamic response suffer from scarcity of information. Recently a systematic engineering approach is used to investigate an optimum fixture-workpiece contacts property (Satyanarayana & Melkote, 2004), machining fixtures dimension (Hurtado & Melkote, 2001) and structural stiffness in toolpost dynamic (Rashid, 2004) by using the finite element approach.…”

The use of active materials for machining processes: A review

“…The improvement in surface quality was confirmed in these studies. Several simulation studies or experiments on machine-representative structures also demonstrated the feasibility of piezoelectric materials in vibration or chatter suppression in various turning or milling operations [62][63][64][65][66][67].…”

Simulation study on the improvements of machining accuracy by using smart materials

“…There is scarcity of information about the nature and type of signals that control the smart material actuator and how they can affect toolpost dynamic response. Recently, a systematic engineering approach was used to investigate an optimum fixture-workpiece contact property [8], machining fixture dimension [9] and structural stiffness in toolpost dynamics [10] by using the finite element approach.…”