Rotational Molding worked example

Wall Thickness Estimate with defect severity rating of 3 score: a worked example

This worked example runs the wall thickness estimate numbers for a tougher week than the baseline: defect severity rating of 3 score instead of the typical 6 score. This wall thickness risk estimate is a weighted FMEA-style score that ranks how much a wall-thickness defect on a rotomolded part threatens quality.

The inputs for this scenario

Defect severity rating: 3 score (the input this scenario stresses; the baseline uses 6)
Defect occurrence likelihood rating: 4 score (held at the documented default)
Detection difficulty rating: 3 score (held at the documented default)

Working through the calculation

The calculation starts from the formula this tool documents: Wall Thickness Estimate risk score = severity × 0.40 + occurrence × 0.35 + detection × 0.25.
Risk score works out to 3.35 score at these inputs, and this is the headline figure for the scenario.
Severity works out to 3 score at these inputs.
Occurrence works out to 4 score at these inputs.
Detection works out to 3 score at these inputs.

How this compares with the baseline

Against the tool's baseline example, where defect severity rating sits at 6 score and the headline result is 4.55 score, this scenario comes in 26.37% below the baseline at 3.35 score.
Use it during PFMEA reviews or process troubleshooting to rank rotomolded wall-thickness failure modes for corrective action. A result at this level usually justifies acting on the stressed input before touching anything else, because every other figure in the table is downstream of it.

Results at a glance

Risk score: 3.35 score (headline result)
Severity: 3 score
Occurrence: 4 score
Detection: 3 score

Run it with your numbers

To rerun this with your own numbers, open the live Wall Thickness Estimate calculator, set defect severity rating to your actual value, and adjust the remaining inputs to match your operation.

Last reviewed 2026-05-12.