Abstract: A new online method was proposed in order to solve the problem of pipette online fixed-length cutting.The cutting motion was decomposed into three directions of movement^[1] (the axial,radial and cutter rotating).The speed of cutting the pipette,fixed-length cutting length,and the diameter of pipette were selected as the initial conditions,which contributed to establish the relation of variables including initial,radial,and axial velocity.Meanwhile,the movement relation could be derived by mathematical analysis to get the promising solution of the control movement and achieve the online fixed-length cutting^[2-3].This theoretical method has been proved by trial production prototype test,which could reduce the waste of raw materials,improve the production efficiency,and gain more economic benefits.

Key words: pipette, online fixed-length cutting, automation