Time frequency analysis of dynamic syringe friction - the benefits of an O-ring plunger seal design

Syringe friction is of interest to control and system engineers designing automated pharmaceutical injection systems. The dynamic friction properties of a 4 lobe, O-ring plunger seal syringe design are examined with the Short Time Fourier Transform (STFT). The results are contrasted to the friction properties of a syringe design with a rubber cover plunger seal. Analysis indicates the magnitude of O-ring seal plunger friction is less than the rubber cover design's. Furthermore, the stick-slip effect of the O-ring design is much less than the rubber cover design. It is shown that the STFT is a useful analysis technique for studying tribological properties of a medical device.