Study On Thermal Debinding Behavior Of Thick Body Made By Ceramic Injection Molding

Ceramic injection molding (CIM) is a sort of precise molding technology for ceramicproducts with complex shape. It is usually considered to fabricate small or thincomponents due to the difficulty of debinding process. To make ceramic products withcomplex shape, large thickness and big scale by CIM technology, it is imperative toovercome the difficulty of debinding thick green body.The thermal debinding for common used CIM wax-based binder was studied with themethods of TG/DTA,3D optical microscope and dye stain to investigate the subjectsincluding thermal characteristics of binder, the macro phenomenon during thermaldebinding and the micro structure of debinded body on cylinder green samples. the restsubstance in the debinded body was analysed by FTIR as well.The study found wax-based binder would expend due to wax melting, therefore thedrive force of wick debinding was concluded from co-operation of capillary pressurebetween body and wick powders and expansion pressure by the binder.Meanwhile, thermal debinder was divided to two stages by the pyrolysis point: liquiddebinding at low temperature and gas debinding at high temperature. In gas debindingstage defects as bubble was common, which could be restrain by sufficient liquiddebinding and reducing heating rate.The expending behavior was revealed by dye stain method, which could be explain byshrinking undegraded core model and uniform distributed model.the analysis to the surface of debinded body showed the composition of rest binder inthe body changed with the temperature rising, finding and explain the reason for thesurface densification.At last a thick ceramic ring used in engine cylinder was made by CIM method makinguse of knowledge of the study above, which proved one successful practice.