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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The difference in the elecrrostream gives the depth of the machined hole. For conducting experiments at different electrolyte concentrations, the same proce- dure is repeated with a freshly prepared electrolyte. Electro stream drilling ESD was found to be a potential process for drilling micro holes in these materials.
With ESD holes as small as 0. In the present system a plastic tank of 25 liters capac- ity was made as a reservoir Pump A pump is required to force the drillling from the reservoir into the machin- ing zone.
The situations that make ECM a prime candidate for machining are as given below.
Full text of “Electrostream Drilling Of High Speed Steel”
H 2 S 04can be used to machine carbon steel, stainless steel, udimet, rene. The reason for an increase in diameter of the hole at the top surface is partly attributed to the stray current effect and partly due to the drillinb that this portion of drilling workpiece is subjected to electro-chemical dissolution throughout the period of drilling.
Reason for using split type work pieces is to visualize the depth profile after machining. Pipes are clamped at the junctions by wire clamping to avoid the release of pipes eoectrostream to electrolyte pressure.
The basic requirements which are kept in mind while designing the setup are as follows: The present chapter deals with the design, related instmmentation and experimentation. A platinum wire inserted in the nozzle acts as cathode.
Shaped tube electrolytic machining is a specialized ECM technique for drilling small, deep holes utilizing acid electrolytes. New York American Elsavier publishing company, 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. The magnitude of stray current will be more at higher voltage which leads to more widening of the lop surface diameter of the hole.
Platinum is used because of its good electrical conductivity, and its inertness to acidic action. Rigidity requirements for the tool is another major problem in conventional eleftrostream of small and deep holes. Out of which 5 experiments are conducted under the same operating conditions. Passivating electrolytes like NaCloz can be helpful in achieving good dimensional ac- curacy of the machined hole.
Basic requirements taken into consideration while designing the machining chamber are as follows. Additional head due to gravity is obtained by plac- ing the reservoir at an elevation. 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. The least count of the instrument is 0. It is also considerably difficult to drill holes smaller than micrometer by conventional mechanical drilling.
This high voltage requirement in ESD is due to the large gap between platinum wire tip, and work piece material. Reproducibility plot 36 ESD drilled holes have taper. The electro chemical reactions which might occur when machining iron with approximately zero pH hydro chlo- ric acid solution are given below. So the machined hole profile is captured using the shadow graph at 20X magnification. The 3-phase V A. To explain the concept drillimg rotatability, let the point 0, 0, Burgess in a paper for the electro chemical society in Dril,ing this peri- od the fresh incoming electrolyte scavenges the reaction products and build up of concentration of ions in the machining zone.
Electrostream Drilling Of High Speed Steel
Because of passivating electrolyte, good surface quality of the hole is expected. To meet the demands of technologically advanced industries like aeronautic, nuclear, gas-turbineautomobile, rapid developments have taken place in the field of material science to develope the materials having better properties in terms of strength, hardness, and toughness at elevated temperatures.
They conducted the experi- ments using NaCl electrolyte on Inconel alloy material. The reading were taken at 20X magnification. Work piece can be held in the work vice with the help of a tightening screw made of perspex.
As a result high voltages are essential to over- come the ohmic resistance due to this gap for machining electrostreak takes place. The difference in the two readings gives the amount elecrrostream material removed.
Basic ESD process details were reported by previous researchers. The starting distance between the wire end and work is always eelectrostream constant by adjusting the nozzle prior to every experiment.
They suggested guidelines for selecting a particular process. But drilling of small holes with large aspect ratios is beyond the scope of ECM because of over cutting on account of sideway current flow. Geometrical parameters such as electroatream angle of the holes ai’e presented. Electrolyte HCl Experiments were conducted using hydro chloric acid [HCl at different con- centrations. So far, electroxtream study reported involved the usage of salt electrolytes only.
But drilling deep, small holes with salt electrolytes produces a large volume of sludge, which tends to clog the flow of electrolyte. In the absence of knowledge of mathematical form of it can be approximated satisfactorily, within the experi- mental region, by a polynomial in the variables x. The complex designs associated with the jet engine hardware have posed 1 machining problems which are beyond the capabilities of conventional machin- ing processes.
Such quadratic type of designs are used when responses are not expected to be linear and the de- sign is needed to yield estimates of the curvature aspects of each response. Additionally, there electostream some obstruction to the coolant flow since the chip direction is opposite to the direction of drill penetration. Recent advances in science and technology, especially in areas such as nu- clear and aerospace engineering have imposed a severe demand on the materials requirements.
Gussef, a Russian scientist, in and much latter by C. Test conditions Figure 2. Using finite element technique FETanodic profiles for different cases have been obtained and a comparison has been made between experimental and analytical anodic profiles.