I85PREP
⌘ K
CSQP study materials
CSQP study resources

CSQP: Supplier Quality Tools and Techniques

CSQP · Work through your exam, one topic at a time.

All guide sections

Supplier Quality Tools and Techniques

What this domain tests

Supplier Quality Tools and Techniques tests whether you can select and interpret the right tool for a supplier-quality problem. CSQP items cover APQP, PPAP, FMEA, control plans, MSA, SPC, capability, acceptance sampling, FAI, 8D, 5 Whys, fishbone, Pareto, and mistake-proofing. The exam emphasizes correct application and interpretation, not tool trivia.

Core rules and concepts

  • APQP structures product realization into phases with deliverables and gate reviews. PPAP provides evidence that the production process can reproduce the design record; submission levels range from warrant only to full evidence.
  • FMEA identifies failure modes, effects, causes, and controls. Use severity, occurrence, and detection to prioritize action; do not treat the RPN as the only decision rule.
  • A control plan links process characteristics to controls, sample size, frequency, and reaction plans.
  • MSA validates the measurement system. Gauge R&R below 10% is generally acceptable; 10-30% may be conditional; above 30% is usually unacceptable. Attribute studies use agreement and kappa.
  • SPC uses control charts to separate common and special cause. Apply Nelson rules or Western Electric rules. Capability indices are valid only after stability is established.
  • Cp compares specification width to process width; Cpk accounts for centering; Ppk uses overall variation. A Cpk of 1.33 is a common minimum for many customers.
  • Acceptance sampling uses AQL, LTPD, and OC curves. AQL is not a guarantee of defect-free lots.
  • 5 Whys and fishbone support root-cause analysis; Pareto prioritizes; mistake-proofing prevents recurrence.

Worked example

A process has USL 10.0, LSL 9.0, mean 9.6, and within-subgroup sigma 0.1. Cpk = min((10.0 - 9.6), (9.6 - 9.0)) / (3 x 0.1) = min(0.4, 0.6) / 0.3 = 1.33. For a gauge study, %GRR of 8% is acceptable, 22% is conditional, and 35% is unacceptable. Reasoning: check the control chart first; if the process is unstable, the Cpk is not meaningful. Also state which sigma was used and whether the study variation is compared to tolerance or process variation.

Traps that cost marks

  • Reporting Cpk from an unstable process.
  • Confusing Cp, Cpk, and Ppk or using the wrong sigma.
  • Accepting a gauge because calibration is current, without a GRR study.
  • Treating AQL as a lot defect-rate guarantee.
  • Choosing PPAP level without customer agreement.
  • Using 5 Whys superficially or confusing correlation with causation.