A Functional Approach to Fixing Flow Oscillation

An automated instrument for veterinary diagnostics utilizes a positive displacement syringe pump to move fluid within the system. Large fluctuations in flow rate have been identified in some instruments, resulting in system error flags. A problem-solving approach is described to show the methodology used to understand and mitigate the failure. Multiple problem-solving tools were incorporated where appropriate to solve this problem. Measurement systems analysis and assembly/disassembly were used to focus the investigation to the point where it was clearly determined that the assembly process impacted the failure mode across the full range of measured results. Structural and functional decomposition techniques were used to identify the causal mechanism for the failure, leading to several possible resolutions.