Multi-Constraint Optimization for Grinding Nickel-Based Alloys

2013 ◽  
Author(s):  
Radu Pavel ◽  
Xiqun Wang ◽  
Anil K. Srivastava
Keyword(s):  
Material Removal Rate ◽  
Surface Integrity ◽  
Material Removal ◽  
Large Scale ◽  
Model Building ◽  
Removal Rate ◽  
Optimal Combination ◽  
Sensor Data ◽  
Wheel Wear ◽  
Grinding Parameters

Nickel-based alloys (Ni-based alloys) are used on a large scale in military, aerospace, missile and defense applications with the aim of improving performance, life, and fuel efficiency. Grinding is extensively used for final finishing of these components. Due to their specific material properties, such as work-hardening and low thermal conductivity, the workpieces made of Ni-based alloys are difficult to grind. The difficulty consists in finding the combination of dressing and grinding parameters that generate the prescribed dimensions, finish, and surface integrity of the finished part with high productivity. Increasing productivity is generally associated with increasing the material removal rate. This, in turn, can create detrimental effects on the ground parts such as micro-cracks, high residual stresses, white layers, and thermal damage. This paper presents a novel methodology for determining an optimal combination of dressing and grinding parameters with respect to maximizing the material removal rate, while taking into account a number of process constraints including: grinding force, power, surface roughness, wheel wear, and surface integrity. According to this methodology, predictive models for grinding behavior are determined using a reduced number of experiments based on an in-process, fast sensor data acquisition system. The models are used as inputs for the multiple criterion optimization program based on a genetic algorithm approach. A CNC surface grinding machine was instrumented to allow process monitoring and data collection. The model building and the optimization methodology have been validated using specimens made of Ni-based alloys. The workpiece materials and the range of the grinding parameters were selected according to applications from aerospace industry. The results support the use of adopted methodology for finding the optimal combination of dressing and grinding parameters.

Wafer Scale Modeling and Control for Yield Improvement in Wafer Planarization

2002 ◽  
Author(s):  
Sutee Eamkajornsiri ◽  
Ranga Narayanaswami ◽  
Abhijit Chandra
Keyword(s):  
Material Removal Rate ◽  
Integrated Circuit ◽  
Material Removal ◽  
Large Scale ◽  
Removal Rate ◽  
Control Strategies ◽  
Elastic Half Space ◽  
Modeling And Control ◽  
Planarization Process ◽  
Curvature Control

Chemical mechanical polishing (CMP) is a planarization process that produces high quality surfaces both locally and globally. It is one of the key process steps during the fabrication of very large scale integrated (VLSI) chips in integrated circuit (IC) manufacturing. CMP consists of a chemical process and a mechanical process being performed together to reduce height variation across a wafer. High and reliable wafer yield, which is dependent upon uniformity of the material removal rate across the entire wafer, is of critical importance in the CMP process. In this paper, the variations in material removal rate (MRR) variation across the wafer are analytically modeled assumimg a rigid wafer and a flexible polishing pad. The wafer pad contact is modeled as the indentation of a rigid indenter on an elastic half-space. Load and curvature control strategies are investigated for improving the wafer yield. The notion of curvature control is entirely new and has not been addressed in the literature. The control strategy is based on minimizing a moment function that represents the wafer curvature and the height of the oxide layer left for material removal. Simulation results indicate that curvature control can improve wafer yield significantly, and is more effective than just the load control.

Optimization of EDM Process Parameters of Thixoformed A356-5TiB2 In Situ Composites

2020 ◽  
Vol 978 ◽  
pp. 271-276
Author(s):  
Sahini Deepak Kumar ◽  
Shailesh Dewangan ◽  
Joyjeet Ghose ◽  
S.K. Jha
Keyword(s):  
Surface Morphology ◽  
Process Parameters ◽  
Material Removal Rate ◽  
Surface Integrity ◽  
Material Removal ◽  
Removal Rate ◽  
Machining Parameters ◽  
In Situ Composites ◽  
Edm Process

The present work reports the influence of various Electric-Discharge Machining (EDM) process parameters on the surface morphology and EDM characteristics of thixoformed A356-5TiB2 in-situ composites. The important EDM parameters such as pulse current, pulse-on time, Duty Cycle, etc. on Surface morphology and Material removal rate of the thixoformed A356-5TiB2 in-situ composites have been investigated. Further, the machining parameters were optimized using Fuzzy-logic and grey relational analysis approach. The effect of EDM parameters and their interactions on the erosion behavior of A356-5TiB2 in-situ composites on various aspects of surface integrity and Material Removal rate (MRR) is reported. The surface integrity during EDM was characterized by Scanning Electron Microscope and analyzed from the machinability point of view. Thus, this work is an attempt to study the machinability behavior of thixoformed A356-5TiB2 in-situ composites.

Analysis of Residual Stress Induced by Hand Grinding Process

2011 ◽  
Vol 681 ◽  
pp. 327-331 ◽  
Author(s):  
Sawsen Youssef ◽  
O. Calonne ◽  
Eric Feulvarch ◽  
P. Gilles ◽  
Hédi Hamdi
Keyword(s):  
Residual Stress ◽  
Experimental Study ◽  
Crack Initiation ◽  
Residual Stresses ◽  
Material Removal Rate ◽  
Surface Integrity ◽  
Material Removal ◽  
Removal Rate ◽  
Grinding Process ◽  
Cup Wheel

Grinding cup wheel is often used in the case of hand grinding which allows an important material removal rate but with secondary concern of surface integrity. Integrity is strongly affected by the process and consequently influences the surface behaviour in terms of resistivity to stress corrosion and crack initiation. This operation is difficult to master in terms of results on the surface and subsurface due to its manual nature. The paper presents results of an experimental study to investigate the residual stresses induced by this hand grinding process.

Material removal rate for nanocomposite ceramics in ultrasound-aided electrolytic in process dressing

2016 ◽  
Vol 231 (21) ◽  
pp. 3987-3998 ◽  
Author(s):  
Fan Chen ◽  
Bo Zhao ◽  
Xiaofeng Jia ◽  
Xiaobo Wang
Keyword(s):  
Material Removal Rate ◽  
Material Removal ◽  
Removal Rate ◽  
Ductile Failure ◽  
Processing Parameters ◽  
Depth Of Cut ◽  
Grinding Parameters ◽  
Brittle Rupture ◽  
Ductile Machining ◽  
Optimal Setting

Nanocomposite ceramics possess beneficial mechanical and physical characteristics over traditional engineering ceramics; however, there is currently no effective method of machining nanocomposites ceramics. This paper proposes a new ultrasound-aided electrolytic in-process dressing machining method. There are many factors influencing the material removal rate in the ultrasound-aided electrolytic in-process dressing grinding. In order to optimize the processing parameters and guide practice, the material removal models are developed to simulate the material removal process based on ductile failure and brittle rupture models, and the influence of grinding parameters on material removal rates is obtained. With the model, the influence of grinding parameters on the material removal rate is analyzed by MATLAB. The analysis results are verified by the ultrasound-aided electrolytic in-process dressing grinding test: the material removal rate increases with the increase of grinding parameters; depth of cut significantly improves material removal rate, followed by axial feeding speed, wheel speed, and workpiece speed that are less important; considering the comprehensive processing effect, depth of cut is the key parameter with the optimal setting at about 3.73 µm. The ultrasound-aided electrolytic in-process dressing grinding test not only proves the reliability of the model, but also proves that the ultrasound-aided electrolytic in-process dressing grinding can improve the ductile machining effect, when compared to electrolytic in-process dressing grinding, which is suitable for mirror machining of the nanocomposite materials.

scholarly journals OPTIMASI KINERJA PROSES FINE SODICK A 350 SS WIRE-EDM PADA PEMOTONGAN BAJA SKD 11

2019 ◽  
Vol 1 (01) ◽  
pp. 40
Author(s):  
Yon Haryono
Keyword(s):  
Response Surface Methodology ◽  
Response Surface ◽  
Material Removal Rate ◽  
Surface Integrity ◽  
Material Removal ◽  
Removal Rate ◽  
Inequality Constraint ◽  
Wire Edm ◽  
Dual Response

Performansi yang diharapkan dari proses pemesinan Wire-EDM adalah laju pembuangan material (material removal rate) yang tinggi dan kualitas permukaan (surface integrity) yang baik. Akan tetapi kondisi tersebut  tidak mudah untuk dilakukan karena banyaknya variabel yang mempengaruhi kinerja proses pemesinan Wire-EDM.             Salah satu upaya untuk mencari solusi dari problem diatas adalah dengan menentukan hubungan antara kinerja proses dengan variabel proses, kemudian dicari kombinasi level variabel proses yang dapat memberikan performansi proses optimum. Penelitian ini dilakukan untuk mengembangkan model dari proses Wire-EDM dengan mengadopsi Response Surface Methodology (RSM). Durasi pulsa, kuat arus, tegangan mekanik  kawat dan kecepatan kawat dipilih sebagai variabel proses, sedangkan laju pembuangan material/material removal rate  (MRR) dan kekasaran permukaan sebagai respon. Proses optimasi dual response dilakukan dengan bantuan paket program aplikasi Quantitative System untuk kasus inequality constraint.             Hasil yang didapatkan menunjukakan bahwa variabel proses yang dipilih memberikan pengaruh yang signifikan terhadap respon. Laju pembuangan material dan kekasaran permukaan mancapai kondisi optimal secara bersamaan pada kombinasi durasi pulsa 3.83  ms,  kuat arus 2,74 amper, tegangan mekanik kawat 998,93 gr/mm2, dan kecepatan kawat 1419,29 cm/min. Pada seting variabel proses seperti tersebut diatas dihasilkan MRR sebesar 11,48 mm3/min dan kekasaran permukaan 1,86 mm.

An Experimental Study on Grinding Fir-Tree Root Forms Using Vitrified CBN Wheels

2014 ◽  
Vol 1017 ◽  
pp. 55-60 ◽  
Author(s):  
Zhong De Shi ◽  
Amr Elfizy ◽  
Helmi Attia
Keyword(s):  
Experimental Study ◽  
Material Removal Rate ◽  
Material Removal ◽  
Removal Rate ◽  
Turbine Blades ◽  
Wheel Wear ◽  
Part Quality ◽  
Grinding Conditions ◽  
Vitrified Cbn ◽  
Maximum Material Removal Rate

An experimental study was undertaken to explore the conditions and performance on rough and finish grinding fir-tree root forms of turbine blades made of a nickel-based alloy using vitrified CBN wheels and water-based grinding fluid. This work was motivated by switching the grinding of fir-tree root forms from grinding with conventional abrasive wheels to vitrified CBN wheels for reducing overall production cost and enhancing productivity. Grinding experiments were conducted to measure grinding forces, power, surface roughness, and stress near the blade roots under various dressing and grinding conditions. Wheel re-dressing life in terms of the total number of good parts ground between dressing was tested with the condition producing the maximum material removal rate while satisfying preset part quality and process requirements. It was found that the maximum material removal rate achievable in rough grinding was restricted by the stress limit and the wheel re-dressing life was dominated by the radial wheel wear limit. The targeting part quality and process requirements were achieved. It was proved that vitrified CBN grinding process is feasible and very promising to machine fir-tree root forms.

Optimization of Process Productivity for Multi Phase Carbon Nanotubes (CNT) Reinforced Nanocomposites Using Taguchi-Fuzzy Model

2018 ◽  
Vol 24 (8) ◽  
pp. 5566-5569
Author(s):  
Kuwar Mausam ◽  
Kamal Sharma ◽  
Pradeep Kumar Singh ◽  
Aniruddha
Keyword(s):  
Carbon Nanotubes ◽  
Wear Rate ◽  
Process Parameters ◽  
Material Removal Rate ◽  
Material Removal ◽  
Removal Rate ◽  
Optimal Combination ◽  
Performance Characteristics ◽  
Tool Wear Rate ◽  
Process Productivity

The present work is focused on the processing and machining of multiphase carbon nanotubes reinforced nanocomposites. In this work the author has performed electric discharge machining on multiphase carbon nanotubes reinforced nanocomposites. Optimal combination of different process parameters have been decided determined for maximum material removal rate and minimum tool wear rate which results the improvement in productivity of the complete process. In this study four different process parameters (Peak current, gap voltage, pulse on time and duty cycle) are used and the most significant parameter is illustrated. In the present work, the factor material removal rate has been considered as productivity measure. The goal is to determine the best process condition for maximizing material removal rate and simultaneously for minimizing the tool wear rate values, which may be considered as multi-response optimization problem. Taguchi method is a well known optimization technique used for optimizing the single objective function. Consequently the conversion process of objective functions invites ambiguity, uncertainly etc. into the computation. These implications always arises the need to correlate various responses. Hence to overcome these implications a fuzzy reasoning of multiple performance characteristics has been developed. This results in the transformation of multi performance characteristics in single multi-performance characteristics (Productivity) and can be optimized using Taguchi method. Using Taguchi’s design of experiment methodology optimal combination of process parameters will be obtained for various performance measures. Process productivity Optimize using the Fuzzy logic approach and the optimal results were also validated.

scholarly journals A New Cutting Tool Design for Cryogenic Machining of Ti–6Al–4V Titanium Alloy

Materials ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 477 ◽  
Author(s):  
Alborz Shokrani ◽  
Stephen Newman
Keyword(s):  
Titanium Alloy ◽  
Titanium Alloys ◽  
Tool Life ◽  
Material Removal Rate ◽  
Surface Integrity ◽  
Material Removal ◽  
Cutting Tool ◽  
Removal Rate ◽  
Cutting Speed ◽  
Cryogenic Machining

Titanium alloys are extensively used in aerospace and medical industries. About 15% of modern civil aircrafts are made from titanium alloys. Ti–6Al–4V, the most used titanium alloy, is widely considered a difficult-to-machine material due to short tool life, poor surface integrity, and low productivity during machining. Cryogenic machining using liquid nitrogen (LN2) has shown promising advantages in increasing tool life and material removal rate whilst improving surface integrity. However, to date, there is no study on cutting tool geometry and its performance relationship in cryogenic machining. This paper presents the first investigation on various cutting tool geometries for cryogenic end milling of Ti–6Al–4V alloy. The investigations revealed that a 14° rake angle and a 10° primary clearance angle are the most suitable geometries for cryogenic machining. The effect of cutting speed on tool life was also studied. The analysis indicated that 110 m/min cutting speed yields the longest tool life of 91 min whilst allowing for up to 83% increased productivity when machining Ti–6Al–4V. Overall the research shows significant impact in machining performance of Ti–6Al–4V with much higher material removal rate.

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