•The AIAG
defines a Special Product Characteristic as a product characteristic for which reasonably anticipated variation
could significantly affect a product’s safety or compliance with governmental standards or regulations,
or is likely to significantly
affect customer satisfaction with a product. Ford Motor Company divides Special Characteristics into two
categories: Critical Characteristics and Significant Characteristics
•
•Critical
Characteristics are defined by Ford as product or process requirements that affect compliance with government
regulation or safe product function, andwhich require special actions or controls. In
a design FMEA, they are considered PotentialCritical Characteristics. A Potential Critical Characteristic
exists for any Severity
rating greater than or equal to 9. In the process FMEA, they are referred to as Actual
Critical Characteristics. Any characteristic with a Severity of 9 or 10 which requires a special control to
ensure detection is a Critical Characteristic.
Examples of product or process requirements that could be Critical Characteristics include dimensions,
specifications, tests, assembly sequences,
tooling, joints, torques, welds, attachments, and component usages. Special actions or controls necessary to meet
these requirements may involve
manufacturing, assembly, a supplier,
shipping, monitoring, or inspection.
Significant Characteristics
require special controls because they are important to customer satisfaction.
Severity ratings between 5 and 8 coupled with an Occurrence rating greater
than 3 indicate Significant Characteristics. In a design FMEA, they are Potential
Significant Characteristics. In the process FMEA, if a special control is
required to ensure detection then an Actual Significant Characteristic
exists.
Companies have not
standardized a method for grouping and denoting Special Product
Characteristics. Nomenclature and notation will vary.