This article describes the applications, process capabilities, and limitations and advantages of electrostream and capillary drilling. It describes equipment and. NPTEL provides E-learning through online Web and Video courses various streams. Book Source: Digital Library of India Item : Sridhar ioned.
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Process details of ESD and STEM are reported in [1, 5, 6, 7, 8] Kozak, Rajurkar and Balakrishna  have reported a mathematical model for determining relationship between the machining rate and working conditions electrolyte flow velocity, jet length and voltage.
So acidic electrolyte HCl is used for machining: The po- tential applications of ESD are in fuel injector nozzles of diesel engines, viscosity meters, watches, gas turbine vanes, eelctrostream. Problems such as tool wear and excessive heat generation at the tool and workpiece interface are encountered while employing conventional mechanical drilling techniques. In STEM, electrode is a carefully straightened acid-resistant metal tube coated with a film of enamel type insulation.
Thus, the hole width would increase much slower than its length. The work piece can be given horizontal feed manually, so that a hole can be drilled in a new position. The design of experiment is the procedure of selecting the number of trials and conditions for running them, essential and sufficient for solving a prob- lem that has been electrosfream with the required dlectrostream.
It is also considerably difficult to drill drillnig smaller than micrometer by conventional mechanical drilling. The tool feed rate is la. Basic components of an electrolyte supply system are as follows: The perspex bush firmly grips the nozzle, and the lock nuts are tightened over the bush on either side of the top cover plate of the chamber.
The ESD machine has been designed keeping in view of the fundamental mechanism of the process. As a result high voltages are essential to over- come the ohmic resistance due to this gap for machining to takes place.
Most of the industrial applications involve hole making in these mate- rials. This aspect led to the development of specialized EC drilling techniques, the prominent micro drilling techniques being shaped tube electrolytic machining STEMand electro stream drilling ESD. Values of taper electrostdeam are calculated from the profiles of holes in Fig 3.
Dr. V K Jain -Publications
This increase in current causes more luateritd removal. Chapman and Hail London, A Platinum wire inserted in nozzle acts as cathode while work piece is made anode. EDM and LBM are ther- mal drillinng and therefore cause the formation of heat alfected zones and micro cracks on the work surface, resulting in metallurgical damage of the workpiece surface material.
The pump selected for ESD has the following specifications, Head: Geometrical parameters such as taper angle of the holes ai’e presented.
Shaping of these materials by traditional methods is Figure 1. Taper crilling of ESD machined holes at different operating conditions Mxpcriincnis are planned according to central composite rotatable design for two input paranteters. With the above conversion the experiments are conducted in the random order according to the plan given in Table 2. Repro- ducibility of these experiments is shown in the Fig 3. An acidic electrolyte, however, dissolves the metal, and carries away as metal ions Fig 1.
The effect of applied voltage on spike volume was not significant.
electrostrwam This high voltage requirement in ESD is due to the large gap between erilling wire tip, and work piece material. The figure shows that the machined holes have conical profile i. They also reported the cost and drilling capability comparisons of various processes, Fig 1.
So instead of normal injection needles, using Titanium, Gold, or Platinum tubing may be effective. Insertion of a nozzle with a formed tip permits right angled drilling deep inside the prior hole Fig 1.
At the bottom of the hole due to large gap, the current density would decrease, with the result that comparatively lower overcut low mix takes place and hence the profile gets twisted towards the center. Sridhar Sastry, has been carried out under our supervision and that this work has not been submitted elsewhere for a degree.
Block diagram of the experimental system of study The arrows on the right show the numerical characteristic of the goals of inves- tigation and they are called responses yields. This feed is achieved with the help of T-slot and slide mechanism in the work vice. A thin, electrically charged electrolytic stream is obtained by pumping electrolyte through a specially drawn non-conducting nozzle glass nozzle of fine outlet diameter. The Basic components of a nozzle and its holding arrangement are as follows: At the two ends of the machined profile, readings of the micrometer were noted down.
One such problem is drilling small deep holes in the super al- loys. Basic ESD process details were reported by previous researchers.
Asymmetry is observed in opposite faces of hole profiles, this may be due location of hole center not exactly along the parting line; Platinum is used because of its good electrical conductivity, and its inertness to acidic action. Basic requirements taken into consideration while designing the machining chamber are as follows. Performed experiments demonstrated feasibility of the use of HCl as elec- trolyte in place of normally used NaCl.
I am very much grateful to my parents who always supported me despite many problems in all the circum- stances. Namdev for their consistent efforts in making the experimental set up.
Electrostream Drilling Of High Speed Steel
After 30 min, the pump is switched off. Initially the pump is switched on and electrolyte supply is ensured. Based on material to be machined elec- trolyte is to be selected, some of the materials, and electrolytes appropriate for their machining is as follows.
The chamber is provided with a detachable top cover plate for making ad- justments from the top drliling necessary. Work piece can be held in the work vice with the help of a tightening screw made of perspex. This aspect reduces the resistance to current flow and may help in improving process performance.