According to B. Mallick at el conducted an experimental investigation for machining by micro-ECDM, each variable was coded and the upper level was taken as +1 and the lower level as – 1 of every process parameter in order to design the experiments in an optimized way. Flat end cylindrical stainless tool of diameter 250µm were used for each experiment and the experiments were conducted in a NaOH solution. The process parameters i.e. voltage, electrolyte concentration, duty ratio and pulse frequency was varied. Through this experiment it was found that the MRR increases when the applied voltage, electrolyte concentration, duty ratio is increased and decreases. Overcut always increases with increase of applied voltage, electrolyte concentration, duty ratio but it decreases with increase of pulse frequency up to 600Hz after that it will increase.
According to Sanjay K. Chak among these methods such as, abrasive electric discharge grinding (AEDG), abrasive electro chemical grinding (AECG), abrasive electric discharge machining (AEDM) / powder mixed electric discharge machining (PMEDM),) Abrasive assisted electrical machining, ultrasonic assisted electrical discharge machining (USEDM). Abrasives assisted ECDM process is gaining more popularity especially in micro machining of electrically non-conductive materials, because it involves combined action of electrical discharge, chemical etching and abrasive cutting. In this method it is found that Smaller abrasive grit size improves the dimensional accuracy and surface finish of the product that diametric overcut and surface roughness increased with increase in grit size. Material removal rate also increased with increase in abrasive concentration.
According to A. Kulkarni at el the ECDM cell has been fabricated using a Boro- silicate glass flask of 10 cm diameter. The arrangement of cathode, anode, and workpiece. The separation between the cathode tip and the workpiece was of the order of 400–500 µm. The depth of cathode inside the electrolyte was also maintained at a fixed distance where one gets the spark. The distance between cathode and anode is kept fixed at 3 cm in all the experiments. This experiment shows that the electrons flows towards the workpiece kept near the cathode tip. This flow of electron is seen as a current spike of about 20 A or more for a short duration of a few milliseconds the bombardment of electrons it raises the temperature of the workpiece briefly and then the temperature decreases due to quenching.
According to Amitabha Ghosh Electro Chemical Discharge machining has eliminate the limitation possessed by the ECM or EDM. This paper also states that though it appears to have potential for machining electrically non-conductive materials, it also has very limited acceptance because of its limited acceptance. A number of experiments had been conducted on this paper where the ECDM using artificially introduced inductance in the circuit (Basak 1991; Basak Ghosh 1995b) and it has been seen that increasing the inductance in the circuit increases the material removal rate. Another manufacturing application of ECDM is micro welding and it also possess great potential in fused deposition modeling for rapid prototyping.
According to Anjali V. Kulkarni in t5thisn paper the author states that ECDM is the hybrid machining process which comprises of techniques of Electro Discharge Machining (EDM) and Electro Chemical Machining (ECM). It is also known as electro chemical spark machining (ECSM) process. In this experiment anode was made up of inert materials while cathode is normally made of copper, dilute hydrochloric acid (HCl) was used as the electrolyte, a pyrometer was used to sense the high transient temperature. The experiment was also performed on silicon, brass and tantalum as work piece material. Through this experiment it was found that for the first time the transient and co-exist measurements were found. It was also found that the rise in the temperature was because of the bombard of electrons during the discharge process and that it can also be used for micro fabrication.
According to Yong Liu at el, conducted and experiment of ECDM with a rotary helical electrode to fabricate ultra-clear glass. Using a rotary helical tool in electrochemical discharge drilling, electrochemical discharge milling, and wire ECDM, the effects of pulse voltage, frequency, duty factor, and feed rate on the used were pulse voltage—37 V, frequency—3000 Hz, duty factor—70%, feed rate—1 _m/s, spindle speed—3000 rpm, and electrolyte—3 mol/L KOH.
It was found that high quality array micro holes were successfully fabricated with a lower diameter, Thickness of the glass was300 _m. A minimum side gap of 27.2_m could be obtained with electrochemical discharge drilling. This paper also established a mathematical model for ECDM process to guide the machining of microstructures on ultra-clear glass, and with the increase in voltage the side gap also increases.
According to Indrajit Basak at el, in this paper the author compares the ECDM and Electro Chemical Arc Machining (ECAM) and the work piece due to the breakdown of the entrapped bubbles, which phenomenon has been confirmed through a number of experiments. On the other hand, in ECDM the discharge is between the tool and the surrounding electrolyte. the electrodes is in the range of 280-300 V, while in ECDM discharge occurs when the value of the applied voltage is in thes range of 20-40 V. The author set up an experiment for material removal rate through ECDM, and it was found that A variable full-wave rectified D.C. supply of frequency 100 Hz was provided by means of a variac and a rectifier.
