On the Modeling of Friction in Micromachining Processes

2007 ◽  
Author(s):  
M. R. Lovell ◽  
P. H. Cohen ◽  
R. Shankar
Keyword(s):  
Friction Mechanisms ◽  
Machining Process ◽  
Micro Machining ◽  
Machining Processes ◽  
Macroscopic Theory ◽  
Contact Conditions ◽  
Macro Scale ◽  
Scale Models ◽  
Basic Understanding ◽  
Physical Phenomena

When machining miniaturized components, the contact conditions between the tool and workpiece exhibit very small contact areas that are on the order of 10−5 mm2. Under these conditions, extremely high contact stresses are generated and it is not clear whether macroscopic theories for the chip formation, cutting forces, and the friction mechanisms are applicable. For this reason, the present investigation has focused on creating a basic understanding of the frictional behavior in micro machining processes so that evaluations of standard macro-scale models could be performed. Specialized machining experiments were conducted on 70/30 brass materials using steel tools over a range of speeds, feeds, depths of cut and tool rake angles. At each operating condition studied, the friction coefficient and the shear factor, τk, were obtained. Based on the experimental results, it was determined that standard macroscopic theory for analyzing detailed friction mechanisms was insufficient in micro machining processes. An approach that utilized the shear factor, in contrast, was found to be better for decoupling the physical phenomena involved. Utilizing the shear factor as an analysis parameter, the parameters that significantly influence the friction in microscale machining process were ascertained and discussed.

Tribological Characterization of Machining at Very Small Contact Areas

2009 ◽  
Vol 131 (4) ◽  
Author(s):  
Michael R. Lovell ◽  
P. Cohen ◽  
Pradeep L. Menezes ◽  
R. Shankar
Keyword(s):  
High Speed ◽  
Friction Mechanisms ◽  
High Speed Steel ◽  
Small Scale ◽  
Machining Processes ◽  
Macroscopic Theory ◽  
Contact Areas ◽  
Tribological Characterization ◽  
Physical Phenomena

When machining miniaturized components, the contact conditions between the tool and the workpiece exhibit very small contact areas that are on the order of 10−5 mm2. Under these conditions, extremely high contact stresses are generated, and it is not clear whether macroscopic theories for the chip formation, cutting forces, and friction mechanisms are applicable. For this reason, the present investigation has focused on creating a basic understanding of the frictional behavior in very small scale machining processes so that evaluations of standard macroscale models could be performed. Specialized machining experiments were conducted on 70/30 brass materials using high-speed steel tools over a range of speeds, feeds, depths of cut, and tool rake angles. At each operating condition studied, the friction coefficient and the shear factor τk were obtained. Based on the experimental results, it was determined that the standard macroscopic theory for analyzing detailed friction mechanisms was insufficient in very small scale machining processes. An approach that utilized the shear factor, in contrast, was found to be better for decoupling the physical phenomena involved. Utilizing the shear factor as an analysis parameter, the parameters that significantly influence the friction in microscale machining processes were ascertained and discussed.

scholarly journals Effects of Lubrication on the Friction in Nanometric Machining Processes: A Molecular Dynamics Approach

2017 ◽  
Vol 869 ◽  
pp. 85-93 ◽  
Author(s):  
Martin P. Lautenschlaeger ◽  
Simon Stephan ◽  
Herbert M. Urbassek ◽  
Benjamin Kirsch ◽  
Jan Christian Aurich ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Machining Process ◽  
Substantial Part ◽  
Machining Processes ◽  
Lennard Jones ◽  
Nanometric Machining ◽  
Dry Contact ◽  
The Coefficient Of Friction ◽  
Dynamics Simulations ◽  
Physical Phenomena

Physical phenomena in a nanometric machining process were studied by molecular dynamics simulations. A cylindrical tool was indented and then moved laterally on an initially flat workpiece. The focus of the study is on the effect of lubrication on the nanoscale. Therefore, the indentation and the scratching were studied both in vacuum and submersed in a lubricant. All materials were modeled by Lennard-Jones truncated and shifted potential sites. It is observed, that in the lubricated case, a substantial part of the cutting edge of the tool is in dry contact with the workpiece. Nevertheless, compared to the dry scenario, the lubrication lowers the coefficient of friction. However, the work which is needed for the indentation and the scratching is not reduced. The processed surface is found to be smoother in the lubricated case. As expected, the lubrication has an important influence on the temperature field observed in the simulation.

High Precision Machine Based on a Differential Mechanism

2014 ◽  
Author(s):  
Alberto Borboni ◽  
Elisabetta Ceretti ◽  
Alessandro Copeta ◽  
Davide Moscatelli ◽  
Rodolfo Faglia ◽  
...  
Keyword(s):  
High Precision ◽  
Degrees Of Freedom ◽  
Static Friction ◽  
Micro Machining ◽  
Concept Design ◽  
Machining Processes ◽  
Precision Machine ◽  
Macro Scale ◽  
Differential Mechanism ◽  
Servo Drives

Micromachining processes deal with the production of parts characterized by features in the micro range (i.e., with dimension lower than 1 mm). Several works are present in literature analyzing the tool behaviors, the material influence on the process, and the machine design. In fact, the downsize of the process up to the microscale needs a full review of all the knowledge coming from the meso and macro scale. As a consequence, machines suitable for micromachining processes were recently introduced in the market. Usually, these machines are classified by the classical gantry layout structure supported by a granite frame and, in order to guarantee the needed requirements of precision and accuracy in the micro scale, they are based on fluid-supported axes and active and/or passive vibration control systems. This paper proposes a new concept design: a high precision machine (HPM) based on an innovative layout exploiting a differential mechanism with three motors for two degrees of freedom using pulleys and metal belts. This new layout exhibits relevant advantages. The most significant is that all the worktable servo drives, that moves along x and y axes, are ground-fixed. This allows to isolate the working area of the machine from the servo drives. The system of pulleys and belts holding the working table slides on air bearings in order to minimize the micro vibrations induced by all the drives. A further peculiarity of the machine consists of the double z-axis each of them is motorized by a micrometer slide with linear absolute encoder. The first z-axis is equipped with a spindle for performing micro machining processes (drilling and milling). The second z-axis is equipped with a laser head for micro ablation. The servo drives of the two z-axes are controlled by the same control system of the worktable. Another important feature of the proposed layout is that the differential configuration of the xy mechanism admits the use of a constant speed signal to each control reference with no output displacements. This allows to guarantee non-inversion of motion of the servo-drives and so the avoidance of problems due to backlash and/or static friction. Drives are controlled by position and speed control loops with PID architecture, anti-windup and feed forward strategies. Controllers have been tuned by the use of a genetic algorithm applied to a dynamic model of the system. As a general consideration, the quality of the investigated micro machining processes can be improved with the designed machine structure.

Prediction of Material Removal in Extrusion Honing of Hastelloy C22 Using Artificial Neural Network

2019 ◽  
Vol 895 ◽  
pp. 32-37
Author(s):  
V.R. Devadath ◽  
H.P. Raju
Keyword(s):  
Neural Network ◽  
Material Removal ◽  
Elevated Temperatures ◽  
Machining Process ◽  
Work Piece ◽  
Micro Machining ◽  
Machining Processes ◽  
Aqueous Corrosion ◽  
Feed Forward Back Propagation ◽  
Wide Range

The traditional finishing processes are incapable of producing required surface finish and other characteristics in difficult-to machine materials like Nickel based superalloys and also complex geometrical shapes of engineering components. Hence to achieve these goals non-traditional micro-machining processes have been developed. Extrusion honing (EH) is one of the non-traditional micro-machining process to debur, radius, polish, and remove recast layer of components in a wide range of applications. In this process material is removed from the work-piece by flowing abrasive laden medium under pressure through or past the work surface to be finished. Components made up of complex passages having surface/areas inaccessible to traditional methods can be finished to high quality and precision by this process. Hastelloy C22 offers resistance to both aqueous corrosion and attack at elevated temperatures and it is a difficult metal to machine using traditional techniques. In this study, micro finishing of internal surface of Hastelloy C22 material having predrilled passage diameters 7, 8, 9 and 10 mm have been performed in an indigenously built hydraulic operated one way extrusion honing setup. For the present EH process, patented polymer mixed with SiC abrasive at 35% volume concentration was used as carrier medium. The study was performed for 46, 54, and 60 grit sizes of SiC abrasive. The material removal in EH process varies with passage diameter and grit size of abrasives at each trial. A feed forward back propagation neural network model has been developed for the prediction of material removal and it has successfully predicted material removed in each trial of EH process.

Tool-Based Micro/Nano Machining: Development of Innovative Machine and Machining Processes

2020 ◽  
Author(s):  
Mustafizur Rahman ◽  
Keng Soon Woon ◽  
Wee Keong Neo
Keyword(s):  
Surface Finish ◽  
Continuous Production ◽  
Current Trend ◽  
Cutting Tools ◽  
Dimensional Accuracy ◽  
Machining Process ◽  
Successful Implementation ◽  
Micro Machining ◽  
Machining Processes ◽  
Ultra Precision

Abstract It is an unarguably fact is that the current trend in manufacturing is miniaturization of products with extreme surface finish. I addition, the surface finish and dimensional accuracy requirements of products as well components are getting remarkably stringent, especially in the areas of vision, information, biotech, environmental, measurement and medical industries. Moreover, these products need to accommodate increased number of functions. Production of such products and parts of micron level size with very high dimensional accuracy of nano meter level is getting more importance because of a steadily increasing demand for such industrial products. To satisfactorily meet these challenges micro/nanomachining technology must be developed. Such machining is usually performed either using techniques based on energy beams (beam-based micro-machining) or using solid cutting tools (tool-based micro/nanomachining). Some of the limitations of beam-based micro-machining are due to poor control of 3D structures, low aspect ratio of products and also low material removal rate. In addition, special facilities are required to perform these processes and the maximum achievable dimensions are relatively small. However, with the application of tool-based micro/nanomachining technology some of these limitations can be satisfactorily overcome using ultra precision machine tools and solid cutting tools to produce the micro-features with well-controlled shape, features and tolerances. In many cases, compound or hybrid or simultaneous machining process is required for effectively performing micromachining. To meet the challenges, multi-process machines are required and unfortunately such machines are not available. Consequently, the author will present the development of a first-of-its-kind multi-process machine tool and the innovative approaches to develop various compound, hybrid and simultaneous machining processes for the successful implementation of micromachining. Recently, nanomachining of difficult-to-machine materials is also getting more importance with the pervasive demand for fabrication of miniature, thinner and lighter products, intricate micro-shapes and structures on such materials. In addition, the products also require nano meter level surface finish. The author would like to present his contribution especially in the area ductile mode machining of brittle materials. This paper also presents the recent developments in the areas of deeper understanding of the mechanisms and machining technologies to generate nano-finish surface by machining processes. In this paper, the basic understanding of nanomachining mechanism, ‘extrusion-like’ chip formation metal cutting is briefly discussed. With the emergence of hybrid freeform surfaces to increase the optical performance and to provide new functions. To fulfill these objectives, the author and his team have carried out ultra-precision machining using fast tool servo (FTS) and slow slide servo (SSS) mechanisms. Some typical examples of the development of innovative nano machining processes and products have been presented in this paper. Finally, the development of a rotating tool for continuous production of radial Fresnel lenses has been presented.

scholarly journals Performance Analysis of Electrochemical Micro Machining of Titanium (Ti-6Al-4V) Alloy under Different Electrolytes Concentrations

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 247
Author(s):  
Geethapriyan Thangamani ◽  
Muthuramalingam Thangaraj ◽  
Khaja Moiduddin ◽  
Syed Hammad Mian ◽  
Hisham Alkhalefah ◽  
...  
Keyword(s):  
Sodium Chloride ◽  
Citric Acid ◽  
Process Parameters ◽  
Removal Rate ◽  
Machining Process ◽  
Micro Machining ◽  
Machining Processes ◽  
Machined Surface ◽  
Response Characteristics ◽  
Taguchi Design Of Experiments

Titanium alloy is widely used in modern automobile industries due to its higher strength with corrosion resistance. Such higher strength materials can be effectively machined using unconventional machining processes, especially the electro-chemical micro machining (ECMM) process. It is important to enhance the machining process by investigating the effects of electrolytes and process parameters in ECMM. The presented work describes the influence of three different combinations of Sodium Chloride-based electrolytes on machining Titanium (Ti-6Al-4V) alloy. Based on the ECMM process parameters such as applied voltage, electrolytic concentration, frequency and duty cycle on response, characteristics are determined by the Taguchi design of experiments. The highest material removal rate (MRR) was achieved by the Sodium Chloride and Sodium Nitrate electrolyte. The combination of Sodium Chloride and Citric Acid achieve highest Overcut and Circularity. The optimal overcut was observed from the Sodium Chloride and Glycerol electrolyte due to the presence of glycerol. The better conicity was obtained from Sodium Chloride and Citric Acid in comparison with other electrolytes. A Sodium Chloride and Glycerol combination could generate better machined surface owing to the chelating effect of Glycerol.

Studying The Effect of a New Mixed Cutting Fluid on Surface Roughness

2020 ◽  
Vol 38 (11A) ◽  
pp. 1593-1601
Author(s):  
Mohammed H. Shaker ◽  
Salah K. Jawad ◽  
Maan A. Tawfiq
Keyword(s):  
Surface Roughness ◽  
Stainless Steel ◽  
Cutting Parameters ◽  
Machining Process ◽  
Cutting Fluid ◽  
Depth Of Cut ◽  
Cutting Fluids ◽  
Machining Processes ◽  
Dry Cutting ◽  
Cutting Speeds

This research studied the influence of cutting fluids and cutting parameters on the surface roughness for stainless steel worked by turning machine in dry and wet cutting cases. The work was done with different cutting speeds, and feed rates with a fixed depth of cutting. During the machining process, heat was generated and effects of higher surface roughness of work material. In this study, the effects of some cutting fluids, and dry cutting on surface roughness have been examined in turning of AISI316 stainless steel material. Sodium Lauryl Ether Sulfate (SLES) instead of other soluble oils has been used and compared to dry machining processes. Experiments have been performed at four cutting speeds (60, 95, 155, 240) m/min, feed rates (0.065, 0.08, 0.096, 0.114) mm/rev. and constant depth of cut (0.5) mm. The amount of decrease in Ra after the used suggested mixture arrived at (0.21µm), while Ra exceeded (1µm) in case of soluble oils This means the suggested mixture gave the best results of lubricating properties than other cases.

Challenges and Issues in the Design of Micro-Machined Antennas - A Review

2020 ◽  
Vol 13 ◽  
Author(s):  
Ashish Kumar ◽  
Amar Partap Singh Pharwaha
Keyword(s):  
Patch Antenna ◽  
Ground Plane ◽  
Substrate Material ◽  
Review Article ◽  
High Index ◽  
Performance Characteristics ◽  
Machining Process ◽  
Patch Antennas ◽  
Micro Machining ◽  
The Impact

Background: Patch antennas are composed of the substrate material with patch and ground plane on the both sides of the substrate. The dimensions and performance characteristics of the antenna are highly influenced by the choice of the appropriate substrate depending upon the value of their dielectric constant. Generally, low index substrate materials are used to design the patch antenna but there are also some of the applications, which require the implementation of patch antenna design on high index substrate like silicon and gallium arsenide. Objective: The objective of this article is to review the design of antennas developed on high index substrate and the problems associated with the use of these materials as substrate. Also, main challenges and solutions have been discussed to improve the performance characteristics while using the high index substrates. Method: The review article has divided into various sections including the solution of the problems associated with the high index substrates in the form of micro-machining process. Along with this, types of micro machining and their applications have discussed in detail. Results: This review article investigates the various patch antennas designed with micro-machining technology and also discusses the impact of micro-machining process on the performance parameters of the patch antennas designed on high index substrates. Conclusion: By using the micro-machining process, the performance of patch antenna improves drastically but fabrication and tolerances at such minute structures is very tedious task for the antenna designers.

scholarly journals Temperature monitoring in the subsurface during single lip deep hole drilling

2020 ◽  
Vol 87 (12) ◽  
pp. 757-767
Author(s):  
Robert Wegert ◽  
Vinzenz Guski ◽  
Hans-Christian Möhring ◽  
Siegfried Schmauder
Keyword(s):  
Cutting Parameters ◽  
Drill Hole ◽  
Machining Process ◽  
Hole Drilling ◽  
Drilling Process ◽  
Deep Hole ◽  
Machining Processes ◽  
Deep Hole Drilling ◽  
Feed Force ◽  
Cutting Zone

AbstractThe surface quality and the subsurface properties such as hardness, residual stresses and grain size of a drill hole are dependent on the cutting parameters of the single lip deep hole drilling process and therefore on the thermomechanical as-is state in the cutting zone and in the contact zone between the guide pads and the drill hole surface. In this contribution, the main objectives are the in-process measurement of the thermal as-is state in the subsurface of a drilling hole by means of thermocouples as well as the feed force and drilling torque evaluation. FE simulation results to verify the investigations and to predict the thermomechanical conditions in the cutting zone are presented as well. The work is part of an interdisciplinary research project in the framework of the priority program “Surface Conditioning in Machining Processes” (SPP 2086) of the German Research Foundation (DFG).This contribution provides an overview of the effects of cutting parameters, cooling lubrication and including wear on the thermal conditions in the subsurface and mechanical loads during this machining process. At first, a test set up for the in-process temperature measurement will be presented with the execution as well as the analysis of the resulting temperature, feed force and drilling torque during drilling a 42CrMo4 steel. Furthermore, the results of process simulations and the validation of this applied FE approach with measured quantities are presented.

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.

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