Faculty Publications

Now showing 1 - 2 of 2

Criticality of appreciating non-newtonianivity in plastic injection mould conduit design
(Begell House Inc., 2015) Lakkanna, M.; Kadoli, R.; Kumar, G.C.M.
The prime intention of this research was to emphasise criticality of Non-Newtonian injectant behaviour to design ideal runner conduits for plastic injection moulds. Power-law constitutive relation was representatively adopted so shear thinning index could contrast, both Non-Newtonian and Newtonian behaviours together. An a priori analytical solution was developed from Power-law constitutive relation analogous to celebrated Hagen-Poiseuille solution for tubular runner conduits. This solution leveraged the computational intelligence advantage to enable a design criteria for perfect injection into impression gap synchronising injector capacity, injectant character as well as desired moulding features. The proposed design criteria readily adapts in practise including extremely complicated feed system configurations. Further to incorporate comprehensiveness, continuous sensitivity method was also adopted to discriminate cruciality over an infinite dimension scale, which lead insight into various important aspects that would certainly form a basis to diagnose filling issues reasoning several defects. For representation a sample set of runners from realistic, productive moulds that were initially designed with Newtonian hypothesis and later during trails heuristically optimised were compared, interestingly, they were statistically skewed towards runner sizes that were directly determined appreciating Non-Newtonian injection behaviour. Therefore, it was concluded that Non-Newtonian injection behaviour should have significant prominence in injection mould design criteria. © 2015 Begell House, Inc.
Computational design of mould sprue for injection moulding thermoplastics
(Society for Computational Design and Engineering info@idsociety.org, 2016) Lakkanna, M.; Mohan Kumar, G.C.; Kadoli, R.
To injection mould polymers, designing mould is a key task involving several critical decisions with direct implications to yield quality, productivity and frugality. One prominent decision among them is specifying sprue-bush conduit expansion as it significantly influences overall injection moulding; abstruseness anguish in its design criteria deceives direct determination. Intuitively designers decide it wisely and then exasperate by optimising or manipulating processing parameters. To overwhelm that anomaly this research aims at proposing an ideal design criteria holistically for all polymeric materials also tend as a functional assessment metric towards perfection i.e., criteria to specify sprue conduit size before mould development. Accordingly, a priori analytical criterion was deduced quantitatively as expansion ratio from ubiquitous empirical relationships specifically a.k.a an exclusive expansion angle imperatively configured for injectant properties. Its computational intelligence advantage was leveraged to augment functionality of perfectly injecting into an impression gap, while synchronising both injector capacity and desired moulding features. For comprehensiveness, it was continuously sensitised over infinite scale as an explicit factor dependent on in-situ spatio-temporal injectant state perplexity with discrete slope and altitude for each polymeric character. In which congregant ranges of apparent viscosity and shear thinning index were conceived to characteristically assort most thermoplastics. Thereon results accorded aggressive conduit expansion widening for viscous incrust, while a very aggressive narrowing for shear thinning encrust; among them apparent viscosity had relative dominance. This important rationale would certainly form a priori design basis as well diagnose filling issues causing several defects. Like this the proposed generic design criteria, being simple would immensely benefit mould designers besides serve as an inexpensive preventive cliché to moulders. Its adaption ease to practice manifests a hope of injection moulding extremely alluring polymers. Therefore, we concluded that appreciating injectant?s polymeric character to design exclusive sprue bush offers a definite a priori advantage. © 2015 Society of CAD/CAM Engineers

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