Forming Microgears by Micro-FAST Technology

The use of microcomponents as well as intensive competition on manufacturing cost led to the requirement for cost-effective production of those components without much compromise on their final quality. To address this issue, a novel microforming technology, named as micro-field-activated sintering technology (Micro-FAST), was introduced for the fabrication of microcomponents, in which loose powders were pressed and sintered to form microgears via electroheating loop sintering and microforming. The whole process was realized in a Gleeble-1500D thermal simulation machine. A relative density of 98.7% was achieved after sintering microgears with eight teeth on it and 1.6 mm pitch diameter at 600°C, heating rate of 50°C/s, pressure of 100 MPa, and electroheating loop of five times. Being different from a conventional FAST process, the Micro-FAST process is of different characteristics largely due to the size effect. Effects of the external electric field, thermal field, and pressure field on the Micro-FAST densification process were analyzed. It was revealed that the deformation of the particles and fusion at the contact interfaces between particles are two important parameters to the densification of the green body and, hence, to the quality of the final component.