Newest Issue

Research Papers

J. Micro Nano-Manuf. 2017;6(2):021001-021001-9. doi:10.1115/1.4038629.

The micro/nanotextured cemented carbide surface of different wettability was produced by laser scanning and fluorinated treatment. The tribological properties of the untextured, oleophobic and oleophilic micro/nanotextured surface were investigated experimentally including the effects of crank speed and contact pressure by a reciprocating friction and a wear tester. For all tested surfaces, the friction coefficient of the surface decreased as both the increasing crank speed and contact pressure increased. Compared to the untextured surface, the friction coefficient of the micro/nanotextured surface was significantly decreased, being sensitive to the wettability of the surface. Besides, the tribological properties of the oleophobic micro/nanotextured surface were superior to the oleophilic micro/nanotextured surface under the same experimental conditions. The improvement in tribological properties of the oleophobic micro/nanotextured surface could be attributed to the low wettability, which was beneficial to rapid accumulation of the lubricating oil on the surface.

Commentary by Dr. Valentin Fuster
J. Micro Nano-Manuf. 2017;6(2):021002-021002-7. doi:10.1115/1.4038675.

This paper develops a novel standing surface acoustic wave (SAW) device with three pairs of interdigital transducers (IDTs) to fabricate the patterned microstructure arrays with the assistance of ultraviolet (UV) polymerization. The working principle, structural design, and fabrication of the SAW device are presented. Then, experimental setup was conducted to investigate the fabrication process and method of the patterned microstructure arrays on a thin photosensitive polymer surface. By adjusting the working wavelength and input voltage and selecting the pairs of IDTs, several types of patterned microstructure arrays, such as linear and latticed undulate with different surface morphologies, could be fabricated. For the application of the microstructure arrays, L929 mouse fibroblasts are cultured on the surface with linear undulate microstructure arrays. Preliminary results showed that the cells aligned well with the direction of the patterned surface and the array can enhance the cell culturing. Therefore, using the developed SAW device with the assistance of UV polymerization is an effective method to fabricate the patterned microstructure arrays, which may have great potential in the applications of biomedical and/or microelectronic fields.

Commentary by Dr. Valentin Fuster
J. Micro Nano-Manuf. 2018;6(2):021003-021003-7. doi:10.1115/1.4038803.

Engineered microenvironments along with robust quantitative models of cell shape metrology that can decouple the effect of various well-defined cues on a stem cell's phenotypic response would serve as an illuminating tool for testing mechanistic hypotheses on how stem cell fate is fundamentally regulated. As an experimental testbed to probe the effect of geometrical confinement on cell morphology, three-dimensional (3D) poly(ε-caprolactone) (PCL) layered fibrous meshes are fabricated with an in-house melt electrospinning writing system (MEW). Gradual confinement states of fibroblasts are demonstrated by seeding primary fibroblasts on defined substrates, including a classical two-dimensional (2D) petri dish and porous 3D fibrous substrates with microarchitectures tunable within a tight cellular dimensional scale window (1–50 μm). To characterize fibroblast confinement, a quantitative 3D confocal fluorescence imaging workflow for 3D cell shape representation is presented. The methodology advanced allows the extraction of cellular and subcellular morphometric features including the number, location, and 3D distance distribution metrics of the shape-bearing focal adhesion (FA) proteins.

Commentary by Dr. Valentin Fuster
J. Micro Nano-Manuf. 2018;6(2):021004-021004-6. doi:10.1115/1.4039031.

In this work, investigations were made for enhancing wear properties of rapid tooling (RT) by reinforcement of fillers (nanoscaled) for grinding applications. The RT has been prepared by using biocompatible composite material (BCCM) feed stock filament (consisting of Nylon 6 as a binder, reinforced with biocompatible nanoscale Al2O3 particles) on fused deposition modeling (FDM) for the development of grinding wheel having customized wear-resistant properties. A comparative study has been conducted under dry sliding conditions in order to understand the tribological characteristics of FDM printed RT of BCCM and commercially used acrylonitrile butadiene styrene (ABS) material. This study also highlights the various wear mechanisms (such as adhesive, fatigue, and abrasive) encountered during experimentation. Finally, the FDM printed RT of proposed BCCM feedstock filament is more suitable for grinding applications especially in clinical dentistry.

Commentary by Dr. Valentin Fuster
J. Micro Nano-Manuf. 2018;6(2):021005-021005-12. doi:10.1115/1.4039295.

Miniaturization of components is one of the major demands of the today's technological advancement. Microslots are one of the widely used microfeature found in various industries such as automobile, aerospace, fuel cells and medical. Surface roughness of the microslots plays critical role in high precision applications such as medical field (e.g., drug eluting stent and microfilters). In this paper, abrasive flow finishing (AFF) process is used for finishing of the microslots (width 450 μm) on surgical stainless steel workpiece that are fabricated by electrical discharge micromachining (EDμM). AFF medium is developed in-house and used for performing microslots finishing experiments. Developed medium not only helps in the removal of hard recast layer from the workpiece surfaces but also provides nano surface roughness. Parametric study of microslots finishing by AFF process is carried out with the help of central composite rotatable design (CCRD) method. The initial surface roughness on the microslots wall is in the range of 3.50 ± 0.10 μm. After AFF, the surface roughness is reduced to 192 nm with a 94.56% improvement in the surface roughness. To understand physics of the AFF process, three-dimensional (3D) finite element (FE) viscoelastic model of the AFF process is developed. Later, a surface roughness simulation model is also proposed to predict the final surface roughness after the AFF process. Simulated results are in good agreement with the experimental results.

Commentary by Dr. Valentin Fuster
J. Micro Nano-Manuf. 2018;6(2):021006-021006-13. doi:10.1115/1.4039507.

The manipulation of the trajectory of high-pressure micro water jets has the potential to greatly improve the accuracy of water jet related manufacturing processes. An experimental study was conducted to understand the basic static and dynamic responses of high-pressure micro water jet systems in the presence of nonuniform electric fields. A single electrode was employed to create a nonuniform electric field to deflect a high-pressure micro water jet toward the electrode by the dielectrophoretic force generated. The water jet's motions were precisely recorded by a high-speed camera with a 20× magnification and the videos postprocessed by a LabVIEW image processing program to acquire the deflections. The experiments revealed the fundamental relationships between three experimental parameters, i.e., voltage, pressure, and the distance between the water jet and the electrode and the deflection of the water jet in both nonuniform static and dynamic electric fields. In the latter case, electric signals at different frequencies were employed to experimentally investigate the jet's dynamic response, such as response time, frequency, and the stability of the water jet's motion. A first-order system model was proposed to approximate the jet's response to dynamic input signals. The work can serve as the basis for the development of closed-loop control systems for manipulating the trajectory of high-pressure micro water jets.

Commentary by Dr. Valentin Fuster

Technical Brief

J. Micro Nano-Manuf. 2017;6(2):024501-024501-5. doi:10.1115/1.4038676.

This paper presents graphene growth on Pt thin films deposited with four different adhesion layers: Ti, Cr, Ta, and Ni. During the graphene growth at 1000 °C using conventional chemical vapor deposition (CVD) method, these adhesion layers diffuse into and alloy with Pt layer resulting in graphene to grown on different alloys. This means that each different adhesion layers induce a different quality and number of layer(s) of graphene grown on the Pt thin film. This paper presents the feasibility of graphene growth on Pt thin films with various adhesion layers and the obstacles needed to overcome in order to enhance graphene transfer from Pt thin films. Therefore, this paper addresses one of the major difficulties of graphene growth and transfer to the implementation of graphene in nano/micro-electromechanical systems (NEMS/MEMS) devices.

Commentary by Dr. Valentin Fuster

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In