Abstract
Currently, micro gears are mostly fabricated by LIGA technology and micromachining. These processes have some limitations. Forming processes not only satisfy mass production and appropriate productivity rate but also present superior mechanical properties. A major problem preventing the bulk micro metal forming is the preparation of micro billets and their precise transfer between the forming stages. The purpose of this study is developing a method to form a micro gear without the need to a separate micro billet preparation. In this paper, pure copper sheets were compressed into the predetermined micro gear profiles though their thicknesses, so that there is no need for preparation of micro billets and also its troublesome transforming. The tests were performed at room temperature, in two cases of single extrusion process and extrusion-forging process. Micro gears with 6 teeth and 250μm in module were formed completely with good repeatability in both the cases. A major advantage of the proposed study compared with the blanking process is that, in blanking, the process is merely cutting the edges, while here the material fills the die by deformation. Thus, better mechanical properties will be achieved. Measuring the micro-hardness of the formed parts in comparison with raw material, verified this point. In general, the micro-hardnesses of combined extrusion-forging parts were higher than those of single extrusion ones in the same positions on the micro gears surface.
Highlights
Due to the wide applications of small gears, there are various methods for the production of micro gears in industries [1]
On the other hand, microforming techniques are able in mass production with high productivity rate, near net shape manufacturing and better mechanical properties [2, 3]
There would be some other questions that must be addressed, for example, in an extrusion of a micro gear shaft how an extruded part would be cut into small ones or how to prepare a micro billet without using separate process to circumvent the problem of positioning and handling
Summary
Due to the wide applications of small gears, there are various methods for the production of micro gears in industries [1]. Wang et al [7] formed a micro gear from bulk metallic glasses by a hot embossing process After the process, they used a chemical solution to solve the silicon die for ejecting the micro gear. Guo et al [12] forged micro gears from Zr-based metallic glass They measured the nano-hardness of the formed part and reported that the core of micro gear has the maximum of nano-hardness. There would be some other questions that must be addressed, for example, in an extrusion of a micro gear shaft how an extruded part would be cut into small ones or how to prepare a micro billet without using separate process to circumvent the problem of positioning and handling
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
