Conference Papers

Permanent URI for this collectionhttps://idr.nitk.ac.in/handle/123456789/28506

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Author: search.filters.author.Ashrith, H.S.

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    Evaluation of circularity error in drilling of syntactic foam composites
    (American Institute of Physics Inc. subs@aip.org, 2018) Ashrith, H.S.; Doddamani, M.; Gaitonde, V.
    Syntactic foams are widely used in structural applications of automobiles, aircrafts and underwater vehicles due to their lightweight properties combined with high compression strength and low moisture absorption. Structural application requires drilling of holes for assembly purpose. In this investigation response surface methodology based mathematical models are used to analyze the effects of cutting speed, feed, drill diameter and filler content on circularity error both at entry and exit level in drilling of glass microballoon reinforced epoxy syntactic foam. Experiments are conducted based on full factorial design using solid coated tungsten carbide twist drills. The parametric analysis reveals that circularity error is highly influenced by drill diameter followed by spindle speed at the entry and exit level. Parametric analysis also reveals that increasing filler content decreases circularity error by 13.65 and 11.96% respectively at entry and exit levels. Average circularity error at the entry level is found to be 23.73% higher than at the exit level. © 2018 Author(s).
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    Experimental investigations on hole quality in drilling of cenosphere reinforced epoxy composite
    (Institute of Physics Publishing helen.craven@iop.org, 2019) Angadi, S.B.; Ashrith, H.S.; Gaitonde, V.N.; Karnik, S.R.; Doddamani, M.
    Cenosphere reinforced epoxy composites are steadily replacing the conventional materials in marine, aerospace and automobile structuresowing to their lightweight properties.Drilling is an important conventional machining process essential for assemblyof polymer composites using rivets and bolts. Drilling induces damage around the hole which significantly deteriorates composite performance. In the present study, hole quality characteristicssuch as cylindricity and delamination in drilling of fly ash cenosphere filled epoxy composites are investigated using coated tungsten carbide drill bits.Feed, cutting speed, filler content and drill diameter are considered as the drilling process variables.Samples are fabricated by varying cenosphere content from 10to 60by volume %inepoxy resin.Full factorial design (FFD) based experiments are conducted on CNC vertical machining center. Response surface methodology (RSM) based mathematical models are proposed to estimate the characteristics of the hole quality in developed composites. Analysis of variance is used to validate the developed mathematical models.Present study reveals that the cylindricity and delamination decreases with increasing feed. Increasing cutting speed decreases the cylindricity, however delamination is found to be increasing.Results also shows the importance of using high cenosphere content for producing sound quality holes, which is also beneficial from weight savingperspective. © 2019 IOP Publishing Ltd. All rights reserved.