Paper Title
Efficiency Improvement of Rice Polishing Cylinder used as Metakaolin Binder by Centrifugal Machine Casting Process

The objective of this research is to improve the effective of rice polishing cylinder which used metakaolin for binder replacement. In the present, the binder is calcined magnesite cement that imported from foreign. Therefore, this research used metakaolin to replace as 37% in order to reduce cost and used agricultural technology by centrifugal machine to improve the casting process instead original from hand which is based on the experience of the technician. The experimental design and evaluated by Minitab Release 14 from function factorial design. There have two factors which study were the velocity of centrifugal machine has separated three levels : 120, 130, 140 rpm and the saline degree has separated three levels: 28, 30, 32 degree. The response has two items which evaluated effective were average wear rate and average broken rice percent. From the evaluation, It found optimum condition as velocity: 130 rpm and saline degree as 30 degree. When used this optimum conditions to cast cylinder, It found the average wear rate was 3.86 g/hr and average broken rice percent was 24.31%. While compared with rice polishing cylinder from metakolin by hand casting, it found average wear rate was 7.27 g /hr and average broken rice percent was 32.53%. Therefore, it found the effective of rice polishing cylinder which casted by centrifugal machine had higher effectiveness than rice polishing cylinder which casted by hand. Index Terms - Centrifugal machine, metakaolin, agricultural technology, rice polishing cylinder.