The Detection (D) rating in a Failure Mode and Effects Analysis (FMEA) assesses the effectiveness of current controls in detecting a potential failure mode before the product reaches the customer. The rating scale is typically inverted, where a high number (e.g., 10) signifies a very low probability of detection, and a low number (e.g., 1) signifies a very high probability of detection.

In the provided FMEA table, the "No solder" failure mode has a Detection rating of 8. The other failure modes ("Too much solder," "Location of solder," and "Stringing solder") all have a Detection rating of 2. Since "No solder" has the highest D rating, it is the least likely to be caught by existing process controls, and therefore the most likely to be seen by a customer.

B. Too much solder: This option has a low Detection rating (D=2), indicating that current controls are highly effective at identifying this failure before shipment.

C. Location of solder: This option also has a low Detection rating (D=2), meaning it is very likely to be detected internally.

D. Stringing solder: With a low Detection rating (D=2), this failure mode has a high probability of being caught by the existing process controls.

1. Stamatis

D. H. (2003). Failure Mode and Effect Analysis: FMEA from Theory to Execution (2nd ed.). ASQ Quality Press. In Chapter 5

"The FMEA Form

" the Detection ranking is explained. A high ranking (e.g.

9 or 10) is defined as "Absolute uncertainty the control will detect the failure mode

" while a low ranking (e.g.

1 or 2) means "The control is certain or almost certain to detect the failure mode" (pp. 119-121). This supports that the highest number (8) represents the failure most likely to escape detection.

2. AIAG & VDA. (2019). FMEA Handbook (1st ed.). Automotive Industry Action Group & Verband der Automobilindustrie. In Step 5: Risk Analysis

the evaluation of Detection is detailed. The rating tables (e.g.

Table D3 for Process Controls) show that a high rating like 8 corresponds to a "Low" detection opportunity

whereas a rating of 2 corresponds to a "High" detection opportunity. This confirms that the failure with D=8 is most likely to reach the customer.

3. Montgomery

D. C. (2020). Introduction to Statistical Quality Control (9th ed.). Wiley. Chapter 1

"Quality Improvement in the Modern Business Era

" discusses FMEA as a key engineering tool for risk assessment. The text explains that the Risk Priority Number (RPN) is a product of Severity

Occurrence

and Detection

where the Detection rating reflects the probability that the failure will not be detected before it reaches the customer (Section 1-4.3).