Virtual Signal-Based Pulse Discrimination in Micro-Electro-Discharge Machining

2017 ◽  
Vol 139 (9) ◽  
Author(s):  
C. K. Nirala ◽  
D. R. Unune ◽  
H. K. Sankhla
Keyword(s):  
Material Removal ◽  
Virtual Instrumentation ◽  
Electro Discharge Machining ◽  
Wide Range ◽  
Innovative Idea ◽  
System Developer ◽  
Small Discharge ◽  
Virtual Signal ◽  
Discharge Gap

Owing to the contaminations in the small discharge gap of micro-electro-discharge machining (μEDM), generation of nonuniform nature of discharge pulses is more significant than in macro-EDM. To address the contribution in material removal of workpiece by each of these pulses, a pulse discriminating (PD) system which discriminates them into contributing and noncontributing types is generally used. Developing a PD system in μEDM is a time-consuming process that requires an availability of continuously running machine. Such requirement could be eliminated if virtual signals, similar to the actual once, are made available and provided continuously to the PD system developer. An innovative idea of generating such virtual signals, based on ni multisim, is, therefore, proposed and a robust PD system based on these signals is developed and validated. The strategy for discriminating the pulses in various types is developed through virtual instrumentation in ni labview. The robustness is validated in terms of its applicability over a wide range of parametric settings, acquisition length, and time.

EDM with USM Combination Process of Sintered NdFeB Permanent Magnet

2010 ◽  
Vol 44-47 ◽  
pp. 1066-1069
Author(s):  
Li Li ◽  
Li Ling Qi ◽  
Zong Wei Niu
Keyword(s):  
Permanent Magnet ◽  
Material Removal ◽  
Removal Rate ◽  
Surface Characteristics ◽  
Dielectric Fluid ◽  
Machined Surface ◽  
Combination Process ◽  
Electro Discharge Machining ◽  
Ndfeb Permanent Magnet ◽  
Machining Characteristics

This paper presents an experimental investigation of the machining characteristics of sintered NdFeB permanent magnet using a combination process of electro-discharge machining (EDM) with ultrasonic machining (USM). Concentration of abrasive in the dielectric fluid is changed to explore its effect on the material removal rate (MRR). MRR of EDM /USM, conventional EDM are compared, machined surface characteristics are also compared between them. It is concluded that the combination EDM/USM process can increase the MRR and decrease the thickness of the recast layer. In the combination process, an appropriate abrasive concentration can improve its machining efficiency.

A Mechanistic Approach to the Prediction of Material Removal Rates in Rotary Ultrasonic Machining

1995 ◽  
Vol 117 (2) ◽  
pp. 142-151 ◽  
Author(s):  
Z. J. Pei ◽  
D. Prabhakar ◽  
P. M. Ferreira ◽  
M. Haselkorn
Keyword(s):  
Material Removal Rate ◽  
Material Removal ◽  
Removal Rate ◽  
Diamond Particle ◽  
Machining Parameters ◽  
Ultrasonic Machining ◽  
Rotary Ultrasonic Machining ◽  
Stabilized Zirconia ◽  
Mechanistic Approach ◽  
Wide Range

An approach to modeling the material removal rate (MRR) during rotary ultrasonic machining (RUM) of ceramics is proposed and applied to predicting the MRR for the case of magnesia stabilized zirconia. The model, a first attempt at predicting the MRR in RUM, is based on the assumption that brittle fracture is the primary mechanism of material removal. To justify this assumption, a model parameter (which models the ratio of the fractured volume to the indented volume of a single diamond particle) is shown to be invariant for most machining conditions. The model is mechanistic in the sense that this parameter can be observed experimentally from a few experiments for a particular material and then used in prediction of MRR over a wide range of process parameters. This is demonstrated for magnesia stabilized zirconia, where very good predictions are obtained using an estimate of this single parameter. On the basis of this model, relations between the material removal rate and the controllable machining parameters are deduced. These relationships agree well with the trends observed by experimental observations made by other investigators.

Experimental studies on graphite powder-mixed electro-discharge machining of Inconel 718 super alloys: Comparison with conventional electro-discharge machining

2018 ◽  
Vol 233 (2) ◽  
pp. 384-402 ◽  
Author(s):  
Santosh Kumar Sahu ◽  
Saurav Datta
Keyword(s):  
Thermal Conductivity ◽  
Residual Stress ◽  
Wear Rate ◽  
Tool Wear ◽  
Inconel 718 ◽  
Material Removal ◽  
Graphite Powder ◽  
Tool Wear Rate ◽  
Machined Surface ◽  
Electro Discharge Machining

Inconel 718 is a nickel-based super alloy widely applied in aerospace, automotive, and defense industries. Low thermal conductivity, extreme high temperature strength, strong work-hardening tendency make the alloy difficult-to-cut. In contrast to traditional machining, nonconventional route like electro-discharge machining is relatively more advantageous to machine this alloy. However, low thermal conductivity of Inconel 718 restricts electro-discharge machining from performing well. In order to improve the electro-discharge machining performance of Inconel 718, powder-mixed electro-discharge machining was reported in this paper. It was carried out by adding graphite powder to the dielectric media in consideration with varied peak discharge current. The morphology and topographical features of the machined surface including surface roughness, crack density, white layer thickness, metallurgical aspects (phase transformation, crystallite size, microstrain, and dislocation density), material migration, residual stress, microindentation hardness, etc. were studied and compared with that of the conventional electro-discharge machining. Additionally, effects of peak discharge current were discussed on influencing different performance measures of powder-mixed electro-discharge machining. Material removal efficiency and tool wear rate were also examined. Use of graphite powder-mixed electro-discharge machining was found to be better in performance for improved material removal rate, superior surface finish, reduced tool wear rate, and reduced intensity as well as severity of surface cracking. Lesser extent of carbon migration onto the machined surface as observed in powder-mixed electro-discharge machining in turn reduced the formation of hard carbide layers. As compared to the conventional electro-discharge machining, graphite powder-mixed electro-discharge machining exhibited relatively less microhardness and residual stress at the machined surface.

scholarly journals Feature Recognition for Manufacturability Analysis

1994 ◽  
Author(s):  
William C. Regli ◽  
Satyandra K. Gupta ◽  
Dana S. Nau
Keyword(s):  
Time Complexity ◽  
Material Removal ◽  
Feature Recognition ◽  
Solid Modeling ◽  
Cad Model ◽  
Worst Case ◽  
Machining Features ◽  
Automated Recognition ◽  
Wide Range ◽  
Complete Set

Abstract While automated recognition of features has been attempted for a wide range of applications, no single existing approach possesses the functionality required to perform manufacturability analysis. In this paper, we present a methodology for taking a CAD model of a part and extracting a set of machinable features that contains the complete set of alternative interpretations of the part as collections of MRSEVs (Material Removal Shape Element Volumes, a STEP-based library of machining features). The approach handles a variety of features including those describing holes, pockets, slots, and chamfering and filleting operations. In addition, the approach considers accessibility constraints for these features, has an worst-case algorithmic time complexity quadratic in the number of solid modeling operations, and modifies features recognized to account for available tooling and produce more realistic volumes for manufacturability analysis.

Probabilistic model of surface layer removal when grinding brittle non-metallic materials

2021 ◽  
Vol 23 (2) ◽  
pp. 6-16
Author(s):  
Sergey Bratan ◽  
◽  
Stanislav Roshchupkin ◽  
Alexander Kharchenko ◽  
Anastasia Chasovitina ◽  
...  
Keyword(s):  
Surface Layer ◽  
Contact Zone ◽  
Probabilistic Model ◽  
Material Removal ◽  
Brittle Materials ◽  
Grinding Wheel ◽  
Metallic Materials ◽  
Deformable Solid ◽  
Metallic Material ◽  
Wide Range

Introduction. The final quality of products is formed during finishing operations, which include the grinding process. It is known that when grinding brittle materials, the cost of grinding work increases significantly. It is possible to reduce the scatter of product quality indicators when grinding brittle materials, as well as to increase the reliability and efficiency of the operation, by choosing the optimal parameters of the technological system based on dynamic models of the process. However, to describe the regularities of the removal of particles of a brittle non-metallic material and the wear of the surface of the grinding wheel in the contact zone, the known models do not allow taking into account the peculiarities of the process in which micro-cutting and brittle chipping of the material are combined. Purpose of the work: to create a new probabilistic model for removing the surface layer when grinding brittle non-metallic materials. The task is to study the laws governing the removal of particles of brittle non-metallic material in the contact zone. In this work, the removal of material in the contact zone as a result of microcutting and brittle chipping is considered as a random event. The research methods are mathematical and physical simulation using the basic provisions of the theory of probability, the laws of distribution of random variables, as well as the theory of cutting and the theory of a deformable solid. Results and discussion. The developed mathematical models make it possible to trace the effect on material removal of the overlap of single cuts on each other when grinding holes in ceramic materials. The proposed dependences show the regularity of stock removal within the arc of contact of the grinding wheel with the workpiece. The considered features of the change in the probability of material removal upon contact of the treated surface with an abrasive tool and the proposed analytical dependences are valid for a wide range of grinding modes, wheel characteristics and a number of other technological factors. The obtained expressions make it possible to find the amount of material removal also for schemes of end, flat and circular external grinding, for which it is necessary to know the amount of removal increment due to brittle fracture during the development of microcracks in the surface layer. One of the ways to determine the magnitude of this increment is to simulate the crack formation process using a computer. The presented results confirm the prospects of the developed approach to simulate the processes of mechanical processing of brittle non-metallic materials.

Reconfigurable Virtual Instrumentation Based on FPGA for Science and High-Education

2016 ◽  
pp. 99-123 ◽  
Author(s):  
Maria Liz Crespo ◽  
Andres Cicuttin ◽  
Julio Daniel Dondo Gazzano ◽  
Fernando Rincon Calle
Keyword(s):  
High Education ◽  
Theoretical Physics ◽  
Virtual Instrumentation ◽  
Industrial Sectors ◽  
Wide Range ◽  
Software Platforms ◽  
The Subject ◽  
Electronic Instrumentation ◽  
Technical Challenges ◽  
The Right

In this chapter we will show how modern FPGA offers the possibility of implementing Reconfigurable Virtual Instrumentation, a new kind of electronic instrumentation which generates interesting opportunities for regular users but that also poses several technical challenges for advanced users and instrument developers. We will analyze some of the main problems and we will give some ideas and possible strategies to deal with them. In order to put the subject in the right context we will review some general concepts regarding instrumentation in general and we later proceed with some more specific concepts and definitions. The chapter also describes two hardware/software platforms for science and high-education developed at the International Centre for Theoretical Physics (ICTP) where the concept of RVI proposed in this chapter was applied. Although we mainly adopt a scientist's prospective to define and analyze instrumentation, most of the conclusions drawn along this chapter can be easily generalized for a wide range of applications in commercial or industrial sectors.

scholarly journals Micromachining of Biolox Forte Ceramic Utilizing Combined Laser/Ultrasonic Processes

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3505
Author(s):  
Basem M. A. Abdo ◽  
Syed Hammad Mian ◽  
Abdualziz El-Tamimi ◽  
Hisham Alkhalefah ◽  
Khaja Moiduddin
Keyword(s):  
Surface Roughness ◽  
Material Removal ◽  
Thermal Damage ◽  
High Surface ◽  
Dimensional Accuracy ◽  
Ultrasonic Machining ◽  
Rotary Ultrasonic Machining ◽  
Machining Time ◽  
Laser Beam Machining ◽  
Wide Range

Micromachining has gained considerable interest across a wide range of applications. It ensures the production of microfeatures such as microchannels, micropockets, etc. Typically, the manufacturing of microchannels in bioceramics is a demanding task. The ubiquitous technologies, laser beam machining (LBM) and rotary ultrasonic machining (RUM), have tremendous potential. However, again, these machining methods do have inherent problems. LBM has issues concerning thermal damage, high surface roughness, and vulnerable dimensional accuracy. Likewise, RUM is associated with high machining costs and low material-removal rates. To overcome their limits, a synthesis of LBM and RUM processes known as laser rotary ultrasonic machining (LRUM) has been conceived. The bioceramic known as biolox forte was utilized in this investigation. The approach encompasses the exploratory study of the effects of fundamental input process parameters of LBM and RUM on the surface quality, machining time, and dimensional accuracy of the manufactured microchannels. The performance of LRUM was analyzed and the mechanism of LRUM tool wear was also investigated. The results revealed that the surface roughness, depth error, and width error is decreased by 88%, 70%, and 80% respectively in the LRUM process. Moreover, the machining time of LRUM is reduced by 85%.

Contact Zone Force Profile and Machining Performance of Filamentary Brush1

2005 ◽  
Vol 127 (1) ◽  
pp. 217-226 ◽  
Author(s):  
R. J. Stango ◽  
V. Cariapa ◽  
M. Zuzanski
Keyword(s):  
Contact Zone ◽  
Material Removal ◽  
Removal Rate ◽  
Contact Region ◽  
Force Sensor ◽  
Surface Finishing ◽  
Production Environment ◽  
Machining Performance ◽  
Wide Range ◽  
Force Profile

Filamentary brushing tools are used in a wide range of surface finishing processes, such as deburring, edge radiusing, polishing, and surface decontamination applications. Moreover, these tools are easily adapted to automation because the filament tips, which perform the machining operation, readily conform to the workpart surface without the need for sophisticated control systems technology. However, little is known about the material removal mechanics of filamentary brushes and, therefore, trial-and-error experimentation is often necessary before the tool is implemented in a production environment. This uncertainty of performance can be traced to a lack of understanding of the actual forces that are generated within the contact zone, that is, along the interface of the filament tip and workpart surface. Although previous experimental research has focused on the overall (i.e., resultant) brush force exerted onto the workpart, no information exists in the literature regarding the variation of force within the contact zone. Such information is essential for understanding the material removal profile within the contact zone, and could provide valuable information regarding the most active machining site along the contact surface. In this paper, a novel experiment is proposed for evaluating the force profile of filament tip forces that are generated within the contact region of a brushed surface. A specially designed workpart fixture is constructed and used in conjunction with a multiaxis force sensor for measuring the detailed force variation within the contact zone. The experiment is conducted using a wire brush at several different rotational speeds, which enables one to ascertain the role of filament inertia in the material removal process. Findings are reported which suggest that a significantly enhanced material removal rate can be achieved at a selective location within the contact zone at moderately elevated spindle speeds.

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