Control Planning

Example(Controlling the Welding of Thin Ship Structures)

If the data were real, what is the smallest number of applications of gauge R&R (crossed) and statistical process control charting (SPC) that must have been performed?

Answer:At least five applications of gauge R&R (crossed) and four applications of Xbar & R charting must have been done. Additionally, it is possible that a pchart was set up to evaluate and monitor the fraction of nonconforming units requiring rework, but the capability from that p-chart information is not included in the table.

Example:Assuming no safety issues were involved, might it be advisable to remove of the characteristics from the “critical” list and save inspection costs?

Answer 2: Gauge R&R results confirm that penetration was well measured by the associated X-ray inspection. However, considering Cpk > 2.0 and σL > 6.0, inspection of that characteristic might no longer be necessary. Yes, removing it from the critical list might be warranted.