Resin Mould for Ceramic Slip Rotary Moulding (CSRM) System

A type of porous resin was proposed to replace the existing plaster mould for Ceramic Slip Rotary Moulding (CSRM) system. The proposed resin is often used in high pressure casting of ceramic sanitary ware and table ware. The effect of resin mould in terms of mechanical strength (flexural properties), porosity percentage and percentage of water absorption as well as moulding process were recorded and compared with previous studies of plaster mould. Five (5) samples of porous resin were prepared according to ASTM 790 for flexural test and ASTM D570 for water absorption test. To determine the porosity percentage, mercury porosimeter test was conducted. The result shows that higher the water plaster ratio resultant in higher porosity percentage and water absorption. The result showed that, the proposed porous resin has great potential in replacing plaster mould as mould material for CSRM system. The mould has a uniform open pore to enable the filtration process to take place within the mould and the slip and has a great mechanical strength. However, porous resin is still a semi-permanent mould with definite service life.

Effect of processing factors on the characteristics of centrifugal casting

Centrifugal castings are produced by pouring liquid metal into rotating moulds. It solidifies under the influence of centrifugal forces, directed from the center to the periphery of the mould on account of mould rotation, and exhibits directionality in solidification which helps to eliminate voids and discontinuities in the resultant casting, usually encountered in gravity castings. Also, a compositional gradient is sat up in the melt which can be monitored, to produce functionally graded materials (FGMs) of choice with multi-functionality. The pouring rate, pouring temperature, mould temperature, and mould material can be suitably selected and altered in isolation or in combination, to generate a desired thermal gradient in the melt which decides its cooling rate. The cooling rate of the melt has the greatest impact on the grain structure of the casting. On the other hand, the grain structure of the casting governs its mechanical performance and decides the suitability for any specific end-use. Thus, different processing factors influence the characteristics of centrifugal casting. In the present article, a sincere attempt is made to analyze the effect of these factors and to enumerate the role played by each one of these factors in deciding the centrifugal casting characteristics.

Investigation of the interactions between titanium and calcium zirconium oxide (CaZrO3) ceramics modified with alumina

Powdered mixtures of CaO, ZrO2 and Al2O3 in various ratios were hot pressed. The mixtures reacted with titanium at 1600?C for 30min in argon to evaluate the suitable ceramic crucibles for casting of titanium. The interfacial microstructures between titanium and ceramic composites were characterized using X-ray diffractometer, scanning and transmission electron microscope. The produced hot pressed mixtures that were chemically bonded together, contained calcium aluminate (CaAl2O4), calcium dialuminate (CaAl4O7), cubic zirconia (c-ZrO2), and calcium zirconium oxide (CaZrO3). The increase in Al2O3 amount led to the decrease in CaZrO3 amount and an increase in the amount of CaAl2O4, CaAl4O7 and c-ZrO2 due to the reaction of CaO and Al2O3. At the end of the reaction of the ceramic mixtures with Ti at 1600?C for 30min, the acicular ?-Ti and ??-Ti were formed at the interface of Ti and the composites containing up to 10 vol.% Al2O3. In composites containing more than 20 vol.% Al2O3, Ti3Al5 was found at the interface instead of ?-Ti and ??-Ti. Furthermore, CaZrO3, ZrO2 and Ca3Al2O6 existed on the sides of the ceramic far away from the interface. CaZrO3/Al2O3 composites with less than 20 vol.% Al2O3 could be a potential crucible or mould material for productive applications in titanium casting.

Multi-Objective Evolutionary Algorithms

The primary objective in designing appropriate particle reinforced polyurethane composite which will be used as a mould material in soft tooling process is to minimize the cycle time of soft tooling process by providing faster cooling rate during solidification of wax/plastic component. This chapter exemplifies an effective approach to design particle reinforced mould materials by solving the inherent multi-objective optimization problem associated with soft tooling process using evolutionary algorithms. In this chapter, first a brief introduction of multi-objective optimization problem with the key issues is presented. Then, after a short overview on the working procedure of genetic algorithm, a well- established multi-objective evolutionary algorithm, namely NSGA-II along with various performance metrics are described. The inherent multi-objective problem in soft tooling process is demonstrated and subsequently solved using an elitist non-dominated sorting genetic algorithm, NSGA-II. Multi-objective optimization results obtained using NSGA-II are analyzed statistically and validated with real industrial application. Finally the fundamental results of this approach are summarized and various perspectives to the industries along with scopes for future research work are pointed out.