Finite element analysis and experimental study of the performance of insulin pen needles

Objective To compare and analyze the relationship between geometric parameters of the needle of different insulin pens and their puncture force, flow rate, and pressing force. Methods The human skin tissue model and needle model were established, and the finite element simulation analysis of needle puncture was performed. Using a test platform, 25 kinds of needles with different geometric parameters were tested for the puncture force, pushing pressure, flow rate and other parameters. The influence of geometric parameters on the performance of the needles were analyzed. Results The puncture force of the needle was closely related to its section design. Compared with the three-section needle, the five-section needle increases the secondary inclination angle and the condyle angle, increases the contact area between the needle and the tissue, and make the change of the contact angle more smoothly, which reduce the needle penetration force. The smaller the outer diameter of the needle, the smaller the penetrating power. The larger the inner diameter of the needle, the greater the fluid flow rate, the smaller the pushing pressure, and the higher the injection accuracy. Conclusions Five-section, ultra-thin-walled or ultra-thin-walled needles have more excellent performance. On the basis of ensuring the strength of the needle, the needle's geometry can be optimized to reduce the puncture force. The results of this study can provide theoretical basis and experimental basis for the design of needles for insulin pens. Key words: Insulin pen needle; Puncture force; Flow rate; Finite element analysis