摘要：Lancet needle, having three planes at the tip to generate a sharp lancet point, is the most common needle tip geometry and used for medical procedures. This research presents two five-plane lancet needle designs, the five-plane lancet needle with two back bevels （FLN-B） and five-plane lancet needle with two front bevels （FLN-F）, to study the effects of two additional bevel planes on the reduction of soft tissue cutting force. Mathematical models to calculate the inclination angle and rake angle along the cutting edges of FLN-B and FLN-F are developed. By using the grinding process, the prototype FLN-B and FLN-F needles are fabricated. And their inclination and rake angles along the cutting edges are investigated and compared to that of regular lancet needle. Needles insertion tests were conducted on soft PVC phantom which mimics the soft tissue. The initial peak insertion force and steady-state cutting force during needle insertion were identified, and the effect of cutting edge on needle soft tissue cutting force was studied. Compared to lancet needle, FLN-B and FLN-F both have higher inclination and rake angles at the tip cutting edge, could reduce the initial peak needle insertion force and tissue cutting forces, and thus can efficiently cut the soft tissue for medical applications.