CQI case studies
CQI · Put your knowledge to work in context.
The ASQ Certified Quality Inspector (CQI) is a foundational credential for inspection professionals who work in support of - and under the direction of - quality engineers, supervisors, or technicians. Certified inspectors apply established body-of-knowledge techniques to evaluate hardware documentation, perform laboratory procedures, inspect products, measure process performance, record data, and prepare formal reports. The CQI case studies are 5 cases and about 4,205 words.
1Two Capability Indices, One Filling Line
A filling line targets 500.0 g with a label tolerance of 490–510 g. Over 30 days, 25 subgroups of n = 5 were plotted on an X̄–R chart and the chart shows no out-of-control points.
753 words, about 4 min2A Micrometer That Cannot Tell Good From Bad
A shaft diameter is specified 25.000 ± 0.020 mm and is checked on the shop floor with a digital micrometer. A gauge R&R study (10 parts, 3 operators, 3 trials) gives repeatability (EV) of 0.003 mm and reproducibility (AV) of 0.005 mm; the process sigma of the shaft is 0.012 mm.
859 words, about 4 min3Zero Acceptance Does Not Mean Zero Risk
A contact-retention feature on incoming connectors is inspected on receipt. Lots are 20,000 pieces and the current plan is a single sample of n = 50 with an acceptance number of zero.
736 words, about 4 min4Twelve Overdue Gauges Out of Eighty
During an internal audit of a machining cell, 12 of 80 gauges in use were found without a current calibration sticker; three of them had been used on a safety-critical bore dimension. The cell supervisor proposes to send the 12 gauges out, retrain the two operators, and rewrite the calibration procedure to require a monthly self-check.
914 words, about 5 min5Eight Above the Line and a Convenient Re-measurement
An X̄–R chart with subgroups of n = 5 monitors a bore diameter of 25.000 ± 0.100 mm. The chart was established three months ago and has been stable.
943 words, about 5 min