An adaptor and its method of use for cleaning the work piece chuck clamping surfaces of a turning center. The stent is rotated to spin off the excess of the coating. The object is attained by a process for producing a microsphere including: separating a disperse phase from a continuous phase by a substrate 1 having a through-hole 7; and extruding the disperse phase into the continuous phase through the through-hole 7, in which the substrate having the through-hole 7 with a width of 0.