Forming Microgears by Micro-FAST Technology

Abstract

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.[ 2012-0294]Index Terms-Copper, field-activated sintering technique (FAST), micro-field-activated sintering technology (Micro-FAST), microgears, powders.

Sintering Kinetics of the Powder during Fields-Activated Micro-Forming and Sintering (Micro-FAST) of Copper Micro-Gears

“…This period is defined as the main densification realized process where the axial reduction increases rapidly (from -2.9553 mm to -3.3455 mm) with the temperature rising, which is shown in Fig.3. It is worth mentioning that there was a very obvious axial shrinkage of sample that occurred, which is a result of deformation and interface melting of particles and has been noted by authors [5,6,11]. (iv).…”

“…A novel micro-forming technology, named Micro-FAST (combining micro-forming and FAST), was proposed recently by the present authors for the forming of micro-components. Gears made of 316L stainless and Cu powder at the micro-scale have been fabricated successfully [5,6]. As the process illustrated in Fig.1, Micro-FAST is a method which can be used for the forming of micro-components with a variety of material systems, for instance, metals, ceramics and composites.…”

Forming of micro-components by electrical-field activated sintering

“…This paper demonstrated that Micro-FAST is a promising process for the rapid forming of microcomponents with a wide range of materials, especially with difficult-to-cut and difficult-to-form 10001-p. 6 ICNFT 2015 materials. The sintering time can be shortened with the optimised sintering parameters.…”

“…The main differences between this process with SPS and others are: AC current applied for high heating efficiency; larger heating rate-, holding time-and pressure-dependent densification; and moreover, simplified process setup and control. Encouraging findings have been made using Micro-FAST with metallic materials [5,6]; however, the feasibility of forming ceramic materials still needs to be investigated further.…”

Simulation of heat distribution in particles during micro field-activated sintering by considering electrical concentration and contact resistance

“…2. A relative density of 98.7% was achieved [3]. Micro-parts can be prepared in a short time (about 10 min) with a high relative density (over 90%) through Micro-FAST, indicating that Micro-FAST is more effective way in comparison with the traditional sintering technology.…”