The conventional processes for manufacturing the miniature gears include
hobbing, stamping, extrusion, die casting and powder metallurgy. But, these
processes suffer from some inherent limitations as mentioned in the Table 1.
Moreover, all these processes manufacture gears of low quality i.e. Deutsche normen
(DIN) quality number is in the range of 9-12 (Bralla, 1998; Davis, 2005; Townsend,
2011). DIN and American gear manufacturers association (AGMA) are the
international standards defining the quality of the gears in terms of micro-geometry
parameters. Lower DIN number or higher AGMA number indicates better quality of
the gear and vice-versa. Table 2 presents the quality requirements of the gears for
various applications in terms of DIN and AGMA numbers along with the
manufacturing processes used for the miniature gears.