In this research, a method employing micro-extrusion was designed to produce the micro-scaled barrel-shaped parts with complex geometrical features to study the feasibility of the proposed microforming method and its grain size effect on the formability of the complicated internal features in terms of deformation behavior, material evolution, accuracy of dimensions and final components quality. The results reveal that the deformation behavior is highly affected by grain size and becomes unpredictable with increased grain size. In addition, assembly parameters including feature dimension, tolerance and coaxiality also vary with grain size, and the variation of grain size needs to be accommodated by different assembly types, viz., clearance fit or transition fit. From the microstructural evolution aspect, it was identified there were two dead zones and four shear bands, and the formation of these deformation zones was barely affected by the variation in grain size. Though bulges, cracks, and fracture induced voids were observed on the surface of the final components, tailoring the microstructure of the working material with finer grains could significantly avoid these defects. This study advances the understanding of forming microparts by extrusion processes and provides guidance for microforming of similar microparts.
The full text can be downloaded at https://link.springer.com/article/10.1007/s40436-023-00456-y
Dien Hu
,
Jieyichen Fang
,
Feng Zeng
,
Ming-Wang Fu
. Grain size effect on the assembly quality of micro-scaled barrel formed by microforming[J]. Advances in Manufacturing, 2024
, 12(1)
: 19
-32
.
DOI: 10.1007/s40436-023-00456-y
1 Zheng JY, Shi S, Fu MW (2020) Progressive microforming of pin-shaped plunger parts and the grain size effect on its forming quality. Mater Des 187:108386. https://doi.org/10.1016/j.matdes.2019.108386
2 Raja CP, Ramesh T (2021) Influence of size effects and its key issues during microforming and its associated processes—a review. Eng Sci Technol 24:556–570
3 Barbier C, Thibaud S, Picart P (2008) Size effects on material behaviour in microforming. Int J Mater Form 1:439–442
4 Zhang B, Meng W (2021) Effects of punch geometry and grain size in micron scale compression molding of copper. Mater Des 206:109807. https://doi.org/10.1016/j.matdes.2021.109807
5 Xu Z, Peng L, Bao E (2018) Size effect affected springback in micro/meso scale bending process: experiments and numerical modeling. J Mater Process Tech 252:407–420
6 Chan WL, Fu MW (2012) Studies of the interactive effect of specimen and grain sizes on the plastic deformation behavior in microforming. Int J Adv Manuf Tech 62:989–1000
7 Özdemir İ (2014) Grain statistics induced size effect in the expansion of metallic micro rings. Int J Mech Sci 87:52–59
8 Amelirad O, Assempour A (2019) Experimental and crystal plasticity evaluation of grain size effect on formability of austenitic stainless steel sheets. J Manuf Process 47:310–323
9 Fang ZJ, Wang ZY, Zhou XG et al (2015) Grain size effect of thickness/average grain size on mechanical behaviour, fracture mechanism and constitutive model for phosphor bronze foil. Int J Adv Manuf Tech 79:1905–1914
10 Rajenthirakumar D, Sridhar R, Abenethiri R et al (2016) Experimental investigations of grain size effects in forward microextrusion. Int J Adv Manuf Tech 85:2257–2264
11 Zheng Q, Shimizu T, Yang M (2017) Grain size effect on mechanical behavior of thin pure titanium foils at elevated temperatures. Int J Mech Sci 133:416–425
12 Zheng JY, Wang J, Fu MW (2021) Experimental and numerical study of the size effect on compound meso/microforming behaviors and performances for making bulk parts by directly using sheet metals. J Manuf Process 66:506–520
13 Schubert A, Jahn SF, Müller B (2014) Modular tool concept and process design for micro impact extrusion. Precis Eng 38:57–63
14 Kada O, Wang Z, Miyanishi K et al (2020) Evaluation of anti-galling ability of zinc phosphate coating by backward extrusion of cylindrical cup. J Mater Process Tech 285:116765. https://doi.org/10.1016/j.jmatprotec.2020.116765
15 Zhang B, Meng WJ (2020) Scaling anomaly in the mechanical response in microscale reverse extrusion of copper. J Micro Nano-Manuf 8(1):010910. https://doi.org/10.1115/1.4046043
16 Ghassemali E, Tan MJ, Jarfors AE et al (2013) Optimization of axisymmetric open-die micro-forging/extrusion processes: an upper bound approach. Int J Mech Sci 71:58–67
17 Cao J, Krishnan N, Wang Z et al (2004) Microforming: experimental investigation of the extrusion process for micropins and its numerical simulation using RKEM. J Manuf Sci Eng 126:642–652
18 Jiang CP, Chen PS, Erisov Y et al (2022) Microforming a miniature cup-shaped internal gear using a cold lateral extrusion process. Metals 12(5):826. https://doi.org/10.3390/met12050826
19 Jäger A, Habr S, Tesař K (2016) Twinning-detwinning assisted reversible plasticity in thin magnesium wires prepared by one-step direct extrusion. Mater Des 110:895–902
20 Dong X, Chen F, Chen S et al (2015) Microstructure and microhardness of hot extruded 7075 aluminum alloy micro-gear. J Mater Process Tech 219:199–208
21 Fu MW, Chan WL (2013) Micro-scaled progressive forming of bulk micropart via directly using sheet metals. Mater Des 49:774–783
22 Chan WL, Fu MW, Yang B (2012) Experimental studies of the size effect affected microscale plastic deformation in micro upsetting process. Mater Sci Eng A 534:374–383
23 Chan WL, Fu MW (2013) Meso-scaled progressive forming of bulk cylindrical and flanged parts using sheet metal. Mater Des 43:249–257
24 Peng L, Lai X, Lee HJ et al (2009) Analysis of micro/mesoscale sheet forming process with uniform size dependent material constitutive model. Mater Sci Eng A 526:93–99
25 Meng B, Fu MW, Fu C et al (2015) Ductile fracture and deformation behavior in progressive microforming. Mater Des 83:14–25
26 Huang J, Xu Z, Peng L et al (2020) An experimental study on a rapid micro imprinting process. J Mater Process Tech 283:116716. https://doi.org/10.1016/j.jmatprotec.2020.116716
