Paul M. Khoury

Capstone Design Project: VHC Assembly

For millions of people with asthma, a valved holding chamber, or VHC, allows them to maximize their intake of a dose of aerosol asthma medicine from a puffer, rescue inhaler or similar device [1]. Monaghan Medical is a producer of such devices, and maintains an in-house assembly process that conjoins a mask to the holding chamber. Due to supplier issues, excess molding flash occasionally appears on the edges of the silicone masks; when the mask is press fit to the chamber, the flash is at risk of shearing and this flash becomes foreign object debris, or FOD, that contaminates the device. FOD is considered a safety hazard for users of the Flow-Vu AVHC.

The team, tasked with eliminating this FOD, tackled this problem with a multi-pronged approach. Four members of the team focused on preventing the creation of FOD – aiming for a prophylactic solution. The other three members worked on developing a second line of defense by developing systems that remove FOD if it was still created. The former suite of solutions consists of a expander that widens the hole of the mask and the closes it around the chamber so that a forceful and shear-producing press-fit is no longer required and poka-yoke fixtures so that ensure the mask and chamber remain in place and in their correct orientations throughout the assembly process, reducing the chance of misalignment-based damage. The latter category of solutions include various ways of removing FOD: an automated brush and a air-based suction device. This report details the design process, prototype features, evaluation results, and final recommendations for the Monaghan team to tackle the FOD issue from multiple angles and deliver a comprehensive and practical process improvement solution.