A stepper-piezo-based co-actuation paradigm for tool positioning in parallel spark micro-electro-discharge machining

Abstract

We report a new method for tool positioning in micro-electro-discharge machining with multiple electrodes for generating parallel spark employing a combination of stepper motor and piezoactuator-based co-actuation method. The stepper motor was used for coarse positioning and the inequality arising due to difference in the tool size of multiple tools used in micro-electro-discharge machining was equated employing piezoactuation followed by electrical continuity test. Simultaneous sparks for two different electrodes could be observed employing this method. The voltage waveforms across the tool–workpiece interface also confirm the generation of simultaneous and parallel sparks across both the electrodes.

Micro-electrical discharge machining of difficult-to-machine materials: A review

“…To validate the applicability of the proposed framework, machining conditions were varied from fine-finishing to roughing, through eight different sets of process parameters. Kumar et al 86 reported a method for tool positioning in micro-EDM with multiple electrodes for generating parallel spark employing a combination of the stepper motor and piezo actuator–based co-actuation method. The stepper motor was used for coarse positioning, and the inequality arising due to the difference in the tool sizes among the multiple tools used in micro-EDM was equated through piezo actuation followed by an electrical continuity test.…”

Thermal and Mechanical Influence of Ultrasonically Aided Electrical Discharge Machining on Co-Cr Alloys

“…An example of the first direction is: the lack of machining rate due to low energy pulses and precision because of difficulties to position the tool-electrodes at array of microholes [6]. Other technical solutions are reported based on feed system using piezo elements [7], appropiate for narrow gap at microEDM [8], as well as strategies for tool wear compensation [9], specific to microEDM [10], real time monitoring of energy efficiency during 3D microEDM [11]. Some hybrid processes are tested using electrolyte as working liquid in EDM [12], ultrasonic assistance of microEDM, which has the capacity to increase the machining rate [13].…”

Fuzzy control of the dual-stage feeding system consisting of a piezoelectric actuator and a linear motor for electrical discharge machining

“…An EDG process should not only have high frequency response but also a long working range. A hybrid dual-stage feeding mechanism which consists of a servo motor to satisfy the long-range requirement and a PZT to realize high frequency response was recently developed by Hu et al, 10 and a PZT combined with a stepper motor was developed by Kumar et al 11 in a parallel spark micro-electrical discharge machining (micro-EDM). Using a PZT in dual-stage feeding system could theoretically increase the EDM machining speed, but the control of the two components which are moving at the same time is a challenging problem in optimizing its performance.…”