Vol. 3 No. 2
Year: 2013
Issue: Feb-Apr
Title : Optimization
of Coating Materials Used on Expandable Polystyrene Pattern in Investment
Casting Process
Author Name :
Girendra Bhati, sudhir
kumar, Ajay Kumar , Daizy Rajput
Synopsis :
In the present
scenario, the dimensional accuracy and surface roughness of casted complex
shape products have become a critical issue to reduce machining cost in terms
of time, price and scrap materials. So, different types of casting processes
have been introduced. One of the important casting process is Investment
Casting Process with Expandable Polystyrene Pattern, instead of wax pattern. In
this casting process, the shell is made by decomposition of Expandable Polystyrene
pattern with the application of heat. During the foam removal process, several
problems have been created such as bending, expansion, distending and crack of
the shell. In this paper, Zirconium Flour and Mullite sand (Aluminium-Silicate)
have been introduced as coating materials with different ratio, with binder as
Sodium Silicate and Potassium Silicate. Twelve samples have been prepared and
the densities and viscosities of each sample are calculated. Twelve shells are
also generated. For selection of best shell material composition, Analytical
Hierarchy Process (AHP) is used. Sample 7 has the best result. Also, Potassium
Silicate is found better than Sodium Silicate as binder, to reduce distending
of shell, cracks, etc. and to increase surface finish and strength to weight
ratio of shell.
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