scholarly journals Manufacturability and Surface Characterisation of Polymeric Microfluidic Devices for Bio-medical Applications

2021 ◽  
Author(s):  
Yugandhar Arcot ◽  
Samuel G.L ◽  
Lingxue Kong
Keyword(s):  
Research Work ◽  
Microfluidic Devices ◽  
Surface Characteristics ◽  
Micro Milling ◽  
Microfluidic Channels ◽  
Machining Processes ◽  
Surface Characterisation ◽  
Polymeric Microfluidic ◽  
Micro Features ◽  
Mechanical Micromachining

Abstract Microfluidic devices fabricated through mechanical micromachining techniques have already been reported to be highly economical when compared to other techniques. Direct mechanical machining processes are generally classified as a one-step manufacturing process, having the advantages of rapid prototyping and batch production. Though there are advancements in ultra-precision machining techniques, the real challenge of direct machining polymeric microfluidic channels is the occurrence of poor surface integrity owing to the change in mechanical as well as viscoelastic properties. This forms the key objective of the present research work, where the major emphasis has been given to understand the applicability of micro-milling techniques in fabricating microfluidic devices, especially for bio-applications. In this research, the mechanical micro-milling technique was used to create microscale channels on polymethylmethacrylate (PMMA) and polycarbonate (PC) materials; wherein the process capability was mainly assessed based on the surface characteristics of the micro features. Furthermore, for the quantitative analysis, a comparative study was also performed by measuring the surfaces roughness and surface energy of the microchannels made by various fabrication routes such as hot embossing and lithography. The experimental results indicate that the micro-milling of PMMA is the preferable choice for fabricating microfluidic devices when compared to PC. Also, for showing the manufacturability of the mechanical micromachining technique, microfluidic channels with serpentine channels were machined with a depth and width of 50µm and 200µm respectively. The applicability of the fabricated microfluidic devices was further validated by evaluating the functioning of these devices for blood cell separation at different dilution rates.

scholarly journals FEM and Analytical Modeling of the Incipient Chip Formation for the Generation of Micro-Features

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3789
Author(s):  
Michele Lanzetta ◽  
Marco Picchi Picchi Scardaoni ◽  
Armin Gharibi ◽  
Claudia Vivaldi
Keyword(s):  
Material Properties ◽  
Analytical Modeling ◽  
Cutting Tool ◽  
Sustainable Manufacturing ◽  
Cutting Parameters ◽  
Micro Machining ◽  
Machining Processes ◽  
Steel Alloys ◽  
Diamond Blade ◽  
Micro Features

This paper explores the modeling of incipient cutting by Abaqus, LS-Dyna, and Ansys Finite Element Methods (FEMs), by comparing also experimentally the results on different material classes, including common aluminum and steel alloys and an acetal polymer. The target application is the sustainable manufacturing of gecko adhesives by micromachining a durable mold for injection molding. The challenges posed by the mold shape include undercuts and sharp tips, which can be machined by a special diamond blade, which enters the material, forms a chip, and exits. An analytical model to predict the shape of the incipient chip and of the formed grove as a function of the material properties and of the cutting parameters is provided. The main scientific merit of the current work is to approach theoretically, numerically, and experimentally the very early phase of the cutting tool penetration for new sustainable machining and micro-machining processes.

A Comparative Study of Tribological Behavior of Steel Sliding Against WC Under Mineral and Biodegradable Oil Lubrication

2012 ◽  
Author(s):  
Anup Darshan ◽  
UmaMaheshwera Reddy Paturi ◽  
Narala Suresh Kumar Reddy ◽  
Srinivasa Prakash Regalla
Keyword(s):  
Tribological Properties ◽  
Positive Impact ◽  
Research Work ◽  
Mineral Oil ◽  
Optical Microscope ◽  
Machining Processes ◽  
Alternative Source ◽  
Pin On Disc ◽  
Steel Disc ◽  
Machining Operations

Now a days for machining operations apart from good tribological properties, the lubricant is also expected to be non-hazardous and non-polluting. When considering the ecological and environmental aspects in machining processes, the use of biodegradable oil can be an alternative source of lubricant due to its positive impact to employee health and environmental pollution. In this regard, our research work uses vegetable based cutting fluids developed from canola and sunflower oil, in an attempt to provide an eco-friendly environment. Experiments are carried out on a pin-on-disc tribometer with tungsten carbide (WC) pin against AISI 4340 steel disc for different sliding times under different environments, thus simulating the machining environment. The tribological properties, wear and friction of vegetable based oils were comparatively investigated with a commercially available mineral oil. Wear tracks and roughness profiles of test specimens were compared by using optical microscope and profilometer respectively. Results indicated that vegetable based canola oil demonstrated excellent tribological properties compared to that of commercial mineral oil.

Experimental Analysis of Process Parameters to Manufacture Micro-Cavities by Micro-Milling

2012 ◽  
Vol 498 ◽  
pp. 91-96 ◽  
Author(s):  
J. Gomar ◽  
A. Amaro ◽  
E. Vázquez ◽  
J. Ciurana ◽  
C. Rodríguez
Keyword(s):  
Automotive Industry ◽  
Micro Milling ◽  
Geometric Features ◽  
Milling Machine ◽  
Machining Processes ◽  
New Approach ◽  
Biomedical Field ◽  
Dimensional Errors ◽  
Conventional Machining ◽  
Potential Opportunity

The use of conventional machining processes has been subject to important decline probably due to the increment in the use of emerging technologies. Therefore, the main applications of these traditional processes, such as automotive industry, are in crisis. In order to have a chance to compete successfully in the new trends, the machining industry must meet the needs of alternative sectors such as biomedical field. The aim of this study is to prove the capacity of micro-milling, by machining complex micro-cavities on aluminum workpiece using a conventional milling machine. Results are obtained by evaluating accuracy and geometric features. This study finds that the feed per tooth is a significant factor in order to obtain better results. The use of coolant increases the tool wear and therefore dimensional errors. This scope is a potential opportunity to reutilize the conventional machines from a new approach.

Solution to Inverse Problem of Manufacturing by Surface Modification With Controllable Surface Integrity Correlated to Performance: A Case Study of Thermally Sprayed Coatings for Wear Performance

2017 ◽  
Vol 139 (6) ◽  
Author(s):  
X. P. Zhu ◽  
P. C. Du ◽  
Y. Meng ◽  
M. K. Lei ◽  
D. M. Guo
Keyword(s):  
Inverse Problem ◽  
Surface Modification ◽  
Surface Integrity ◽  
High Performance ◽  
Surface Characteristics ◽  
Spray Angle ◽  
Functional Surface ◽  
Machining Processes ◽  
Wear Performance ◽  
Surface Features

Inverse problem of manufacturing is studied under a framework of high performance manufacturing of components with functional surface layer, where controllable generation of surface integrity is emphasized due to its pivotal role determining final performance. Surface modification techniques capable of controlling surface integrity are utilized to verify such a framework of manufacturing, by which the surface integrity desired for a high performance can be more effectively achieved as reducing the material and geometry constraints of manufacturing otherwise unobtainable during conventional machining processes. Here, thermal spraying of WC–Ni coatings is employed to coat stainless steel components for water-lubricated wear applications, on which a strategy for direct problem from process to performance is implemented with surface integrity adjustable through spray angle and inert N2 shielding. Subsequently, multiple surface integrity parameters can be evaluated to identify the major ones responsible for wear performance by elucidating the wear mechanism, involving surface features (coating porosity and WC phase retention) and surface characteristics (microhardness, elastic modulus, and toughness). The surface features predominantly determine tribological behaviors of coatings in combination with the surface characteristics that are intrinsically associated with the surface features. Consequently, the spray process with improved N2 shielding is designed according to the desired surface integrity parameters for higher wear resistance. It is demonstrated that the correlations from processes to performance could be fully understood and established via controllable surface integrity, facilitating solution to inverse problem of manufacturing, i.e., realization of a material and geometry integrated manufacturing.

Schneidkantenpräparation von VHM-Mikrofräsern*/Cutting edge preparation of cemented carbide micro milling tools – A comparison of different fine machining processes

2015 ◽  
Vol 105 (11-12) ◽  
pp. 805-811
Author(s):  
E. Uhlmann ◽  
D. Oberschmidt ◽  
A. Löwenstein ◽  
M. Polte ◽  
I. Winker
Keyword(s):  
Tool Wear ◽  
Milling Process ◽  
Cutting Edge ◽  
Micro Milling ◽  
Machining Processes ◽  
Process Reliability ◽  
Cutting Edge Preparation ◽  
Milling Tools ◽  
Edge Preparation

Die Prozesssicherheit beim Mikrofräsen lässt sich mit einer gezielten Schneidkantenverrundung erheblich steigern. Dabei werden durch verschiedene Präparationstechnologien unterschiedliche Geometrien und Einflüsse auf den Fräsprozess erzeugt. Der Fachbeitrag behandelt den Einsatz präparierter Mikrowerkzeuge in Zerspanversuchen, in denen auf die Zerspankräfte, den Verschleiß sowie die Oberflächengüten eingegangen wird.   Process reliability in micro milling can be increased by a defined cutting edge preparation. Different cutting edge preparations cause different effects on tool behavior in the downstream micro milling process. In this paper, the process forces, the tool wear and the surface quality of prepared micro milling tools are characterized in cutting tests.

scholarly journals Self-Aligned Interdigitated Transducers for Acoustofluidics

2016 ◽  
Author(s):  
Zhichao Ma ◽  
Adrian J. T. Teo ◽  
Say Hwa Tan ◽  
Ye Ai ◽  
Nam-Trung Nguyen
Keyword(s):  
Acoustic Wave ◽  
Surface Acoustic Wave ◽  
Particle Separation ◽  
Microfluidic Devices ◽  
Current Approach ◽  
Droplet Generation ◽  
Microfluidic Channels ◽  
Clean Room ◽  
Precise Location ◽  
Innovative Method

Surface acoustic wave (SAW) is effective for the manipulation of fluids and particles in microscale. The current approach of integrating interdigitated transducers (IDTs) for SAW generation into microfluidic channels involves complex and laborious microfabrication steps. These steps often require the full access to clean room facilities and hours to align the transducers to the precise location. This work presents an affordable and innovative method for fabricating SAW-based microfluidic devices without the need of clean room facilities and alignment. The IDTs and microfluidic channels are fabricated in the same process and thus precisely self-aligned in accordance with the device design. With the use of the developed fabrication approach, a few types of different SAW-based microfluidic devices have been fabricated and demonstrated for particle separation and active droplet generation.

MCDM-Based Optimization of Performance Characteristics During µEDMing of SS 304

2021 ◽  
pp. 18-32
Author(s):  
Premangshu Mukhopadhyay ◽  
Goutam Kumar Bose ◽  
Pritam Pain
Keyword(s):  
Stainless Steel ◽  
Work Performance ◽  
Research Work ◽  
Performance Characteristics ◽  
Micro Edm ◽  
Grey Relational Grade ◽  
Research Findings ◽  
Micro Features ◽  
Grey Relational ◽  
Edm Process

Micro-EDM is most widely used for developing perfect drilled micro features/parts. Research was carried out to improve the material removal and tool wear of any conductive machined product by EDM and micro-EDM process. In this chapter, RSM was used for designing the experiments with 20 set of experiments. In this present research work, performance characteristics like MRR and Overcut have got a different level of importance. Here the stress was given on MRR rather than on OC. In this MCDM analysis, the weight of MRR is considered to be maximum (i.e., larger is better), and other weights of other responses are considered to be the minimum (i.e., smaller is better). Finally, in the midst of all the combinations of process parameters considered one that acquires the highest grey relational grade is the best parametric combination. The research findings in the area of machining of stainless steel 304 will be helpful to manufacturing engineers for selecting the optimized parametric combinations of micro-EDM process with stainless steel.

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