EVALUATION OF FRICTION CHARACTERISTICS OF POWDER BED BY INTRUSION METHOD USING CONICAL ROTOR

A new technique of evaluating the friction characteristics of a powder bed is described. A rotary-type rheometer with conical rotor was empl oyed to measure the torque variation curves as the intruding distance of the rotor into the powder bed. The apparatus were evaluated using a standardized viscosity oil, and the shearing stress at an arbitrary i ntruding distance into the powder bed was converted into the apparent viscosity coefficient eta(8). The relation between eta(8) and the void fraction of the powder bed were discussed based on Andrade's equation . It has been demonstrated that the measuring system and evaluating me thod presented here are effective for sensing of slight changes in the surface conditions in mixing of powders.