Automatic feed back circuit to keep constant revolutions of handpiece under variety of working condition.自動回溯回路設(shè)計(jì),可確保手機(jī)在各種加工條件下可常速運(yùn)轉(zhuǎn).The drum is rotated at 20 revolutions per minute for 10 minutes.圓筒以每分鐘20轉(zhuǎn)的速度轉(zhuǎn)10分鐘.The s...