International Journal of Manufacturing Research (10 papers in press)
Reliability Assessment of the Centrifugal Compressor Impeller Based on Monte Carlo Method
by Yifan Wang
Abstract: Abstract: Reliability assessment of centrifugal compressor impellers has been a critical issue in industrial practice and application. In this paper, cycling life of the impeller obtained by the fatigue test is substituted into the S-N formula to calculate a group of parameter b in the formula. Then b is fitted by a three-parameter Weibull distribution. After that, Monte Carlo method is used for random sampling from the three-parameter Weibull distribution. Every b acquired by the sampling is substituted back into the S-N formula, by which a large group of values of the cycling life are calculated to fit its distribution. The reliability of the impeller under operating condition is then obtained to provide a critical reference for the health monitoring of the centrifugal compressor impeller online.
Keywords: Key words: Impeller failures; Fatigue life; Life prediction; Reliability analysis.
Analysis of process parameters in Wire Electric Discharge Machining of gear cutting process using Entropy Grey Relational Analysis approach
by Kasinath Das Mohapatra
Abstract: The present paper focuses on optimization of response parameters in a gear cutting process by wire EDM using a hybrid Entropy GRA approach. The objective of the present work is to analyse the process parameters and to study the effects and optimize the process in order to produce high quality gears. The experiment was conducted in wire EDM machine by full factorial Design of Experiments having 64 numbers of combinations. Titanium was taken as the work-piece material with brass as the tool electrode and distilled water as Dielectric. The experiment was carried out by taking three process parameters at four different levels each. Four response parameters i.e. MRR, Kerf width, Wire wear rate and Tooth width error (TWE) were obtained from the experiment and the outputs were optimized by using the hybrid approach to get an optimum setting from these combinations. The optimum settings obtained endorses to produce high quality gears in near future.
Keywords: Brass; Distilled water; Entropy; Factorial design; Gear; Kerf; Wear rate; Wire EDM; Titanium; Tooth width.
An integrated cost model for metal cutting operations based on engagement time and a cost breakdown approach
by Jan-Eric Ståhl
Abstract: In all manufacturing processes it is important to determine the costs and their distribution between different sequential processing steps. A cost equation based directly on the losses during manufacturing, such as rejection rate, stops and waste of workpiece materials, also provides a valuable aid in giving priority to various development activities and investments. The present work concerns how a cost model presented earlier for calculating part costs can be developed to describe part costs as a function of the cutting data and tool life time T selected. This enables a tool life model to be a directly integrated into the cost model by use of tool engagement time. The model presented also takes into account the part costs for scrap incurred in connection with forced tool changes. Examples are also given of how the model developed can be used in the economic evaluation of various cutting tools and workpiece materials.
Keywords: Cost model; cost breakdown approach; metal cutting; Colding equation; tool life; cutting data.
A Process Analysis of Resistance Spot Welding on the Inconel alloy 625 Using Artificial Neural Networks
by Mohammadreza Farahani
Abstract: In this article the influence of the important resistance spot welding process parameters on the shear-tensile strength of the welded joints of Inconel alloy 625 was investigated. Experimental study using full factorial design of the electrode force, welding current, welding time parameters were conducted. In order to identify the effects of each factor and their interaction, the artificial neural network was employed. The R2 equal to 98.11% of the model confirmed the effectiveness of the ANN model for describing the correlation between the welding parameters and joint strength. It was observed that the welding current was most influential process parameter on the joint strength and in return the welding time had the least influences. Interaction between the welding parameters occurred only at very high welding currents. It was observed that the ANN model provides a lucrative reference for RSW strength characterization of Inconel alloy 625.
Keywords: Inconel alloy 625; Artificial Neural Network; Resistance Spot Welding; Shear Tensile Strength.
Chatter prediction in boring process using machine learning technique
by Saravanamurugan Sundaram
Abstract: Chatter is the main reason behind the failure of any part in the machining centre and lowers the productivity. Chatter occurs as a dynamic interaction between the tool and the work piece resulting in poor surface finish, high-pitch noise and premature tool failure. In this paper the chatter prediction is done by active method by considering the parameters like spindle speed, depth of cut, feed rate, and including the dynamics of both the tool and the workpiece. The vibration signals are acquired using an accelerometer in a closed environment. From the acquired signals Discrete Wavelet Transformation (DWT) features are extracted and classified into three different patterns(stable, transition and chatter) using Support Vector Machine(SVM).The classified results are validated using surface roughness values(Ra).
Keywords: Chatter; Boring; Discrete Wavelet Transformation (DWT); Support Vector Machine (SVM); Surface Roughness.
Extraction of Dispatching Rules for Single Machine Total Weighted Tardiness using a Modified Genetic Algorithm and Data Mining
by Mohamed HABIB ZAHMANI
Abstract: This paper introduces novel heuristics for the resolution of the Single Machine problem with Total Weighted Tardiness by combining Data Mining and Genetic Algorithms. The aim of this approach is to use data mining techniques in order to explore, analyse, and extract knowledge from solutions for single machine scheduling problems. A hybrid genetic algorithm coupled with Dispatching Rules from literature is proposed to find near-optimal solutions for the single machine problem with total weighted tardiness. Using these solutions, data mining extracts knowledge which is then employed along with three proposed heuristics to solve unprecedented problems. The experiments show the superiority of the proposed approach over other well-known dispatching rules, mimicking the genetic algorithm behaviour while retaining heuristics
Keywords: single machine scheduling; total weighted tardiness; genetic algorithm; data mining; decision trees; heuristics; dispatching rules.
Experimental Investigation of Cutting Parameters Influence on Surface Finish during Turning of Steel using Taguchi Approach
by Gurpreet Singh
Abstract: Surface finish of the machined parts is one of the important criteria by which the success of a machining operation is judged. The value of optimum machining parameters (for better surface finish) can be either decided on the basis of a large number of experimental trails or design of experiments (DoE) can be used to predict the same with significantly lesser number of experimental trails. The purpose of this study was to demonstrate the application of Taguchi method to optimize the machining/cutting parameters for surface finish during turning of AISI 1018 steel under different cutting environments. Using MINITAB software, other statistical techniques such as analysis of variance (ANOVA) and test for equal variances were also performed to confirm results of Taguchi analysis and compare surface roughness under different cutting environments respectively. In addition to surface roughness, effect of different cutting parameters was also observed on workpiece-tool interface temperature.
Keywords: Machining; Turning; Steel; Surface finish; Taguchi; ANOVA; MINITAB.
Investigation of machining rate and roughness for rotary ultrasonic drilling of Inconel 718 alloy with slotted diamond metal bonded tool
by Dipesh Popli
Abstract: Super alloy has extensive engineering applications in nuclear industries owing to its outstanding performance characteristics at elevated temperature. More than 30 percent of consumption in nuclear industries is super alloy. A number of holes are required to be drilled into super alloys for their final stage assembly. During conventional machining process an excessive heat is generated, which is the cause of heat treated zone that further affect the life and performance of the product. To overcome this difficulty a Rotary Ultrasonic Machining method came into existence to machine super alloys by hybrid cutting action (vibratory and rotary) of diamond impregnated core drill. This study focuses on the machining characteristics of super alloy by RUM process. Material removal efficiency of RUM and surface topography of the machined material has been studied. The results reported that for quality and productivity aspect the feed rate in RUM is found a most critical factor.
Keywords: RUM; Ultrasonic; Machining; Roughness; ANOVA.
Surface Grinding of CFRP Composites using Rotary Ultrasonic Machining (RUM): Design of Experiment on Cutting Force, Torque, and Surface Roughness
by Hui Wang
Abstract: Carbon fiber reinforced plastic (CFRP) composites provide excellent properties, including high strength-to-weight ratio and high corrosion resistance, etc., which make them attractive in many industries. However, due to the properties of high stiffness, the anisotropy, and high abrasiveness of carbon fiber in CFRPs, they are regarded as difficult-to-cut materials. Many problems are caused in traditional surface grinding processes. In order to find an efficient surface grinding process for CFRP, this paper conducts an investigation using rotary ultrasonic machining (RUM). Design of experiment (DOE) is of great importance in evaluating effects of input variables on output variables in machining processes. However, there are no investigations on DOE in such a process. This investigation firstly tests the effects of three input variables, including tool rotation speed, feedrate, and ultrasonic power, on output variables, including cutting force, torque, and surface roughness, at two levels. This investigation can provide guides for future research.
Keywords: Surface grinding; CFRP composite; Rotary ultrasonic machining; DOE.
ANALYSIS OF THE TWIST OF RULED SURFACES. APPLICATION TO STRIP MACHINING
by Walter RUBIO
Abstract: Flank milling of ruled surfaces is commonly applied to obtain rotating machine parts as defined using ruled surfaces. To this purpose, a wide range of positioning strategies have been studied to reduce interference between the cutting tool and the surface. Indeed, modelled ruled surfaces are non-developable meaning that they cannot be machined without interference. In order to minimise such interference, the positioning strategies studied tend to become increasingly complex, involving software programming using a dedicated language. To simplify matters and apply developed methods using standard software applications, it is proposed here to reduce interference by breaking the machined surface down into a number of subsurfaces. The aim with this breakdown is to reduce the twist on each portion. A study of the global twist is presented showing non-linearity with the length of the rule so that cutting methods can be demonstrated.
Keywords: ruled surface; flank milling; 5-axis machine; twist angle; strip machining.