The filling phase plays an important role in determining the quality of injection molded parts. Uniform melt-front velocity has been recommended for minimizing the part non-uniformity. On the basis of a capacitive transducer that has been developed for online measurement of melt front velocity, we propose an intelligent strategy for profiling injection velocity. The nonlinear response of melt development in a mold cavity is first acquired with a constant screw injection velocity. On the basis of this response, a stage division method is proposed to determine an appropriate stage number of a piecewise linear profile and the locations of the switch points. An optimization based on sequential simplex search is then conducted to search for the optimal profile of injection velocity. Online experimental tests on molds with different geometries show that the proposed method is effective in achieving a uniform mold filling. POLYM. ENG. SCI., 50:1358-1371, 2010. (C) 2010 Society of Plastics Engineers