CQT case studies

CQT · Put your knowledge to work in context.

The Certified Quality Technician (CQT) is a professional certification offered by ASQ for people who support quality assurance and control processes by performing inspections, collecting data, and analyzing results. ASQ describes the CQT as a critical role in ensuring compliance with quality standards and improving product reliability, which makes the credential a natural fit for inspectors, lab and test technicians, and others doing hands-on quality work who want a formal, recognized demonstration of their competence. The CQT case studies are 5 cases and about 5,182 words.

Solder Defect Reduction: Pareto by Count Versus Pareto by Cost

Over five weeks a contract electronics plant logged 600 solder-related defects on 42,000 boards. Counts and average rework cost per event: bridging 212 ( 6), insufficient solder 148 ( 6), tombstoning 96 ( 42), missing component 71 ( 18), wrong component 38 ( 55), damaged component 22 ( 30), other 13 ($20).

942 words, about 5 min 2

X-bar and R Chart, Capability, and a Supervisor Who Trusts the Specification

A bottling line fills 500 mL nominal to a specification of 500 ± 8 mL, at about 28,000 bottles per day. Fill volume is monitored with an X-bar and R chart, n = 5, k = 25 subgroups.

1,002 words, about 5 min 3

Acceptance Sampling: Two Rejections, a Certificate of Conformance, and a Misread AQL

Receiving inspection at a harness plant uses ANSI/ASQ Z1.4, general inspection level II, single sampling, normal inspection, AQL 1.0. Connector lots of 2,400 pieces map to code letter K, which gives n = 125, Ac = 3, Re = 4.

1,057 words, about 5 min 4

A Micrometer With a Known Error, a Marginal Reading, and a Failing Gage R&R

A machinist checks shafts of 25.000 ± 0.015 mm on the shop floor with a 0-25 mm micrometer with 0.001 mm resolution and manufacturer accuracy of ±0.004 mm. The annual calibration certificate has just returned showing an as-found error of +0.007 mm at the 25 mm point; the three previous cycles were +0.002, +0.003, and +0.004 mm.

1,060 words, about 5 min 5

Internal Audit Findings: A Safety-Critical Out-of-Calibration Tool and a CAPA That Closed Itself

A 180-person injection molder holds ISO 9001 certification. This year's internal audit raised three items.

1,121 words, about 6 min