Evaluation of residual stress of metal micro structure electroformed with megasonic agitation. (November 2020)

• Record Type: Journal Article
• Authors: Du, Liqun; Zhai, Ke; Wang, Shuxuan; Zhang, Xi; Cao, Qiang; Wen, Yikui; Zhao, Wenjun; Liu, Junshan
• Is Part Of: Journal of manufacturing processes. Volume 59(2020)
• Page Start: 629
• Page End: 635
• Publication Date: 2020-11
• Subjects: Residual stress -- Nanoindentation -- Megasonic assisted electroforming -- Metal micro structure; Production management -- Data processing -- Periodicals; Manufacturing processes -- Periodicals; Procestechnologie; Productietechniek; Production -- Gestion -- Informatique -- Périodiques; Fabrication -- Périodiques; Manufacturing processes; Production management -- Data processing; Periodicals; 670.5
• DOI: 10.1016/j.jmapro.2020.10.010
• Languages: English
• ISSNs: 1526-6125

Abstract

Abstract: Micro electroforming has become one of the key technologies for metal micro devices fabrication. However, residual stress in electroformed layer of micro devices will reduce their dimensional accuracy and service life. Affected by residual stresse, there is serious bending deformation occurred in cantilevered micro structure during electroforming process. In this paper, megasonic agitation method was employed to obtain low stress in the cantilevered micro structure firstly. Then, the cantilevered micro structures electroformed with and without megasonic were tested by nanoindentation method. The difference of Suresh model and Lee model on the stress calculation results was discussed. By contrast with X-ray diffraction (XRD) method, the calculation results obtained by Lee model in nanoindentation testing are closer to the actual residual stress of the nickel electroformed layer. The nanoindentation testing results obtained by Lee model show that the mean compressive stress of micro structures electroformed with megasonic has a decrease of 57.84 % compared with that without megasonic. The research results indicated that megasonic agitation method is a low residual stress fabrication technique in micro electroforming process. Besides, nanoindentation is a feasible method to measure the residual stress of metal micro structure, due to its excellent properties of high spatial resolution and wide application range.