Binder removal studies in ceramic thick shapes made by laminated object manufacturing

Binder removal was studied in a body of alumina made by Laminated Object Manufacturing (LOM) with polymethyl methacrylate as binder, benzyl butyl pthalate and polyethelene glycol as plasticisers and glyceryl trioleate as dispersant with an optimized solids loading of 58% by volume. The burnout of the organics from laminated cuboids of different thickness was carried out in nitrogen atmosphere at different temperatures between 200 and 300 °C. The variation of the organic content from the core to the surface was also determined by thermogravimetric analysis (TGA) and FTIR studies. The organic content of the body at a particular temperature exposed for a particular time was modeled based on the parameter, S (∞ Deff/l2) where Deff is the effective diffusivity and l is the diffusion path length. The variation of S as a function of exposed surface area per unit volume of the cuboids is linear. Since the dependence of S on temperature follows an Arrhenius behaviour, the value of S can be predicted at any temperature and for any exposed surface area per volume of the cuboids. Thus the model can be used to estimate the organic content of the body exposed for a certain duration at a particular temperature.