Surface condition factor

The surface condition factor Z_R considers the following influences:

• Surface finish as affected by, but not limited to, cutting, shaving, lapping, grinding, shot peening
• Residual stress
• Plasticity effects (work hardening)

Standard surface condition factors for gear teeth have not yet been established for cases where there is a detrimental surface finish effect. In such cases, some surface finish factor greater than unity should be used.

The surface condition factor can be taken as unity provided the appropriate surface condition is achieved.