Rotary Joint Sealing Surface Manufacturing Variability

Jonathan Scare, Western Michigan University

Co-authored with Amanda Vella and Julia Sicoli.


Kadant Johnson LLC manufactures the model 3300SXB rotary sealing joint that links rotating machinery to a fixed pipe. The current manufacturing process of the 3300SXB body may result in a sealing surface with too much spherical variation. This leads to leaks and wear in the joint. The goal of this project was to isolate variables in the manufacturing process that impact the sealing surface and develop a solution to reduce their impact on the variability of the sealing surface. The variables investigated included the two machines used for production, TC11 and TC13, the quench-polish-quench (QPQ) surface treatment process, gripping of the part, and seal rings in the joint. The sealing surface was measured using a coordinate measurement machine (CMM) that recorded the deviations of 46 points from the nominal dimensions. These points were then compared to the baseline values of the current process. The statistical significance of each variable was determined using normality tests, 2-sample T-tests, and 2-sample variance tests. After analyzing all the factors, the machine type was found to be the only factor that significantly decreased the surface variability. This conclusion led to the recommendation that the newer machine, TC13, should be the primary machine used for the 3300SXB body manufacturing.