Investigation and improvement of a process for vacuum-formed ceramic fibre composites, using a fractional 2n experimental design

Abstract

Refractory ceramic fibre products are used extensively as high temperature furnace linings, because of their properties of a lower thermal conductivity, improved resistance to thermal shock, cheaper installation and maintenance costs, and reduced wall thickness when compared with traditional firebrick linings. Vacuum forming of the ceramic fibre enables modular linings for small laboratory furnaces to be produced efficiently and cost effectively. This process involves drawing a slurry of ceramic fibre, binder and water through a porous mould, and subsequently oven drying the finished product. The product mass, which is strongly related to its relevant thermal and structural properties, was identified as a suitable response variable. A resolution IV fractional 2n factorial design was employed to investigate the effects of 15 key process factors on the product mass in just 32 experimental runs. Analysis of the results revealed that only two of the 15 process factors investigated in the experiment significantly affected the mean product mass, while none of these factors significantly affected the variability of the product mass. The experimental design is described, and its results and their implications are presented and discussed.