How do you calculate an inspection bottleneck risk score?

Multiply the severity, occurrence, and detection scores together. In this example 6 x 4 x 3 yields a risk score of about 4.55 on the tool's normalized scale, ranking this station against others scored the same way.

What is a good inspection bottleneck risk score?

Lower is better — it means missed defects are minor, backlog is rare, and detection is strong. There is no universal threshold; rank stations relative to each other and attack the highest scores first.

What do severity, occurrence, and detection mean here?

Severity is how damaging a missed magnet defect is downstream, occurrence is how often the inspection station backs up or the defect arises, and detection is how reliably the station catches it. Higher detection difficulty means a higher, worse score.

Why multiply the scores instead of adding them?

Multiplication makes a station dangerous only when multiple factors are bad together — a severe defect that is also frequent and hard to detect. It amplifies compound risk, which is the point of an FMEA RPN.

Should I use the same scale for every station?

Yes. The formula note stresses using one scoring scale across comparable risks, because RPNs are only rankable when severity, occurrence, and detection are rated consistently. Mixing scales makes the comparison meaningless.

What if one factor is a 10 but the score is still moderate?

That is the known weakness of multiplicative RPN — a critical high-severity defect can be diluted by low occurrence or good detection. Always review the individual scores, not just the product; a lone high-severity 10 may warrant action regardless of the total.

Rare Earth Magnet & Motor Materials calculator

Inspection Bottleneck Calculator

The inspection bottleneck risk score is an FMEA-style risk priority number applied to the quality-control choke points in rare earth magnet and motor production — magnetization checks, flux verification, dimensional gauging, and coating inspection. Quality engineers use it to rank which inspection stations are most likely to stall the line or let a defect through, so limited engineering effort goes where it matters. In magnet manufacturing, inspection is frequently the constraint: flux and coercivity testing is slow and destructive sampling is limited, making backlog risk real. The score combines how bad a missed defect is, how often the station backs up, and how reliably it catches problems.

What this calculator does

Estimate inspection bottleneck for rare earth magnet and motor materials using production-ready inputs so teams can rank risks and decide which issue needs containment, controls, or escalation first.
Use it when inspection bottleneck in rare earth magnet and motor materials needs a defensible ranking against other rare earth magnet and motor materials risks for the next review.
It multiplies severity, occurrence, and detection scores into a single risk priority number for a given inspection bottleneck.

Formula used

Inspection bottleneck risk score = inspection bottleneck severity score × inspection bottleneck occurrence score × inspection bottleneck detection score
Use the same scoring scale across comparable inspection bottleneck risks.

Inputs explained

Defect Severity if Missed:
Likelihood of Inspection Backlog:
Detectability at Inspection:

How to use the result

Use it to prioritize which magnet QC stations to improve, staff, or automate first when inspection is constraining throughput.
The number is only meaningful within a consistent scoring scale; a 10x rating scale and a 5x scale are not comparable, and the multiplicative RPN can mask a single critical dimension like a high-severity defect.

Current U.S. benchmarks

The producer price index for copper and brass mill shapes stands at 559.593 (BLS, May 2026), up 76.8% from a year earlier. Quotes priced off last quarter's material cost miss this move. Global copper trades at $13,484 per tonne (IMF via FRED, May 2026).
The U.S. has 5,397 electrical equipment and appliances establishments employing about 369,437 workers (Census County Business Patterns, 2023).

Common questions

How do you calculate an inspection bottleneck risk score? Multiply the severity, occurrence, and detection scores together. In this example 6 x 4 x 3 yields a risk score of about 4.55 on the tool's normalized scale, ranking this station against others scored the same way.
What is a good inspection bottleneck risk score? Lower is better — it means missed defects are minor, backlog is rare, and detection is strong. There is no universal threshold; rank stations relative to each other and attack the highest scores first.
What do severity, occurrence, and detection mean here? Severity is how damaging a missed magnet defect is downstream, occurrence is how often the inspection station backs up or the defect arises, and detection is how reliably the station catches it. Higher detection difficulty means a higher, worse score.
Why multiply the scores instead of adding them? Multiplication makes a station dangerous only when multiple factors are bad together — a severe defect that is also frequent and hard to detect. It amplifies compound risk, which is the point of an FMEA RPN.
Should I use the same scale for every station? Yes. The formula note stresses using one scoring scale across comparable risks, because RPNs are only rankable when severity, occurrence, and detection are rated consistently. Mixing scales makes the comparison meaningless.

Last reviewed 2026-05-12.