CQT flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Pareto Principle

Roughly 80 percent of problems stem from about 20 percent of causes, so improvement effort should target the vital few contributors displayed on a Pareto chart.

Cost of Poor Quality

Sum of internal and external failure costs such as scrap, rework, warranty, and returns; it excludes prevention and appraisal, which are conformance costs.

PDCA Cycle

Plan-Do-Check-Act: plan a change, run it, check results against the objective, then standardize the gain or act on what was learned.

Fishbone Diagram

Cause-and-effect diagram branching into categories such as man, machine, material, method, measurement, and environment to organize possible causes of one defined problem.

Five Whys

Root cause technique that repeatedly asks why a problem occurred, typically five times, until the underlying systemic cause rather than a symptom is identified.

Check Sheet

Structured form for tallying the frequency or location of events while data are collected, making patterns visible before charting or analysis begins.

Scatter Diagram

Plot of paired values for two variables; the pattern shows direction and strength of association but does not by itself prove causation.

Process Capability Index Cpk

Cpk equals the smaller of (USL minus mean) or (mean minus LSL), divided by three sigma; it measures capability while accounting for process centering.

Cp Ratio

Cp equals specification width (USL minus LSL) divided by six sigma; it expresses potential capability assuming the process is centered between the specification limits.

X-bar and R Chart

Paired control charts plotting subgroup averages and ranges; control limits are built with constants such as A2, D3, and D4 that depend on subgroup size.

p Chart

Control chart for the proportion of nonconforming units in a sample; used with attribute data when sample size may vary from subgroup to subgroup.

Central Limit Theorem

The distribution of sample means approaches normal as sample size grows, with standard deviation equal to the population sigma divided by the square root of n.

Producer's Risk

Alpha risk: the probability that a lot of acceptable quality is rejected by a sampling plan; it is commonly set at 0.05.

Standard Deviation

Square root of the average squared deviation from the mean; for a sample, the sum of squared deviations is divided by n minus one.

AQL

Acceptable quality level, the quality level a sampling plan is designed to accept most of the time; combined with lot size it selects the plan.

Tightened Inspection

Sampling switch triggered after two of five consecutive lots are rejected on original inspection; smaller acceptance numbers are used to protect the consumer.

Critical Defect

A defect judged likely to create a hazard or unsafe condition for the user; usually requires zero acceptance and full screening or testing.

First Article Inspection

Verification of the first production unit against all drawing and specification requirements before full production is authorized, documenting dimensions, materials, and processes.

100 Percent Inspection

Every unit is inspected or tested; suitable for critical characteristics or small lots but still subject to inspector error and fatigue.

Liquid Penetrant Testing

Nondestructive method that draws penetrant out of surface-breaking discontinuities in nonporous materials, revealing cracks and porosity as visible indications.

Measurement Traceability

Unbroken documented chain of calibrations linking an instrument's readings to national or international standards, with each comparison carrying a stated uncertainty.

Gage R&R

Study estimating measurement variation from equipment repeatability and appraiser reproducibility; percent GRR under 10 is acceptable and over 30 is unacceptable.

Accuracy versus Precision

Accuracy is closeness of a measurement to the true value; precision is closeness of repeated measurements to each other regardless of the true value.

Calibration

Comparison of an instrument's indication against a reference standard of known value with documented results; adjustment is a separate step performed only when needed.

Measurement Uncertainty

Non-negative parameter describing the dispersion of values attributed to a measurand; Type A comes from statistics, Type B from other information, combined by root-sum-squares.

Gauge Resolution

Smallest change in a quantity that an instrument can display or discriminate; it should be roughly one-tenth of the tolerance being measured.

Third-Party Audit

Independent external audit performed by a certification body to verify that an organization's quality management system conforms to a standard such as ISO 9001.

Corrective Action

Action taken to eliminate the cause of a detected nonconformity so it does not recur; distinguished from correction, which only fixes the existing problem.

ISO 9001:2015

International standard specifying requirements for a quality management system; it applies risk-based thinking and PDCA and requires no specific quality manual.

Quality Record

Document stating results achieved or providing evidence of activities performed; records are retained for defined periods and are not revised like controlled procedures.

Second-Party Audit

Audit performed by a customer or its representative on a supplier to verify that contractual and quality system requirements are being met.

Management Review

Top management's planned evaluation of the quality management system's suitability, adequacy, and effectiveness, using defined inputs and producing decisions on improvement and resources.