Irregularities that occur in isolation or infrequently because of special causes such as scratch, cracks and blemishes are called _______.

Explanation:

Flaws:

These are the irregularities that occur in isolation or infrequently because of specific causes such as scratches, cracks, and blemishes.

Roughness:

It is defined as the finer irregularities in the surface texture, including those irregularities that result from an inherent activity of the production process.

Waviness:

It is the more widely spaced component of surface texture. Roughness may be superimposed on a wavy surface. Waviness is an error in form due to incorrect geometry of the tool producing the surface.

Lay:

It is the direction of the predominant surface pattern, ordinarily determined by the production process used for manufacturing the component.

Surface texture:

It is generally understood as the repetitive or random deviations from the nominal surface that form the pattern of the surface.