International Journal of Manufacturing Research (13 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.
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.
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.
Dynamic Mathematical Model and Stability Limits Computation in the Chatter system of Hard Turning.
by Guang Jun Chen, Xianli Liu, Zhenzhong Mi, Renping Guo
Abstract: The chatter in cutting process has a significant influence on production efficiency, processing quality, machining environment, costing and the lifetime of machine and cutting tools. The mathematical models of dynamic cutting force and cutting system dynamics in the cutting process were established by analytical method; The prediction of system stability limit in the multi-parameter hard turning process were made in the way of numerical simulation. The parameters taken into consideration include the spindle speed, the cutting width, the feed rate, the corner radius and the hardness of work-pieces; The critical condition of the stable cutting in experimental high speed precision hard cutting system were computed; The results of predictions about stability limits were verified, which conform to actual measurement. The cutting chatter appears more easily, when the hardness of the workpieces is higher, the corner radius is bigger or the feed rate is smaller.
Keywords: Hard turning; Dynamic mathematical model; Stability limits computation; Numerical simulation; Chatter system.
Comprehensive Investigation on the Mechanical Properties of Friction Stir Composite Joint from Polyethylene - Polypropylene
by Mohammadreza Farahani
Abstract: The widespread application of polymers has motivated researchers to improve their forming and joining processes. In this category, friction stir welding (FSW) proposed as an alternative for the traditional joining processes. In this paper, FSW with a threaded cylindrical tool was employed for dissimilar joining of sheets of polyethylene and polypropylene. In order to control the material flow, the used tool was equipped with a hot shoe. In the following, the influences of important process parameters such as tool rotation speed, tool traverse speed and tool tilt angle on the joint mechanical properties were investigated. In the optimum joining condition, composite welded joint with defect-free uniform microstructure, with strength equal to 99% of polyethylene and with higher elongation and hardness than the polyethylene was obtained. The optimum rotational speed equal to 1,860 rpm with the highest travel speed equal to 12.5 mm/min provide the welded joints with best mechanical properties.
Keywords: Friction Stir Welding; Thermoplastic; Polyethylene; Polypropylene.
Identification and Prioritization of Managerial Tools and Techniques in Impact on Quality Improvement
by Amir Amini
Abstract: Knowing the mechanisms that allow organisations to detect environmental changes and being able to adapt and offer the proper response to them becomes especially relevant, because this knowledge might lead firms to attain a greater success by exploiting emerging opportunities and new sources of competitive advantages. Given the importance of organisational excellence and superior performance, this study aimed at the identification and prioritisation of managerial tools and techniques in impact on quality improvement. The statistical population consisted of management and industrial engineering professors of the Iranian universities and managers and experts of Urmia Tractor Manufacturing Company in the national context. First, by using the Delphi method and wrapping up experts' views 25 managerial tools and techniques were identified. Then by responding to the secondary questionnaire, experts prioritised the tools and techniques. Finally, to promote the quality of company's products and services, some strategies and guidelines are presented.
Keywords: Quality; Quality Management and Improvement; Organizational Excellence; Quality improvement plans and Methods; Urmia Tractor Manufacturing Company.
Research on measurement of cutting area temperature and its prediction model
by Cui Yunxian
Abstract: In this paper, the temperature measuring tool based on NiCr/NiSi thin film thermocouple is developed. 6,061 aluminium alloys is selected as the experiment object. Based on the cutting area temperature result during field test, the central composite design is utilised, which contains the parameters of cutting speed, feed rate and cutting depth. Regarding each parameter, three levels are selected and then the second-order regression equation between cutting area temperature and three cutting parameters is established. The data of experimental measurement corresponds well with the mathematical prediction, which confirms that the experimental and mathematical methods are valid in the research on cutting area temperature. [Received: 14 August 2017; Accepted: 7 October 2017]
Keywords: temperature measuring tool; cutting area temperature; thin film thermocouple; response surface methodology.
Force and energy considerations on the face grinding of flat surfaces
by Eleonora Atzeni
Abstract: Face grinding is a process that is capable of meeting both the productivity and flexibility demands of industry, with acceptable manufacturing costs. Efficient grinding is the result of an optimisation process that considers detailed knowledge of the interaction between a grinding wheel and the material of the workpiece, but which should also consider energy aspects. The face grinding process of flat surfaces has been analysed in this work through an experimental campaign, in an attempt to relate the grinding parameters to the forces and energy. Thus, a grinding apparatus was instrumented with a force measuring device in order to monitor the grinding forces applied during the removal of the material. The applied power and energy were also evaluated. The experimental results are discussed in this paper, and are related to the analytical relationships that were found to develop for the specific face grinding operation.
Keywords: face grinding; energy; grinding forces; modeling; Design of Experiment.
The determination of instantaneous uncut chip thickness for non-uniform helix angle tools with complex tool path in ultrasonic milling process
by Mingyang Zhang
Abstract: Ultrasonic milling is used more and more common in fields such as aerospace, mould and so on. Whereas, there are few literatures studying the ultrasonic milling. In consequence, focus on one of important skills for the ultrasonic milling process, instantaneous uncut chip thickness (IUCT) model for the cutter with non-uniform helix angle and complex toolpaths, is built and then a calculation theory is introduced to compute the IUCT using a numerical method. Subsequently, two examples of the toolpath are taken to show the validity of the presented method, the first one is the line toolpath and the second one is circle. The results is shown that the method in this paper can compute the IUCT values for the complex tool path, also, the method in this paper can be used by the cutter with non-uniform helix angles.
Keywords: cutter with non-uniform helix angle; ultrasonic milling; complex toolpaths; instantaneous uncut chip thickness; cutting forces.
An investigation on measurement and evaluation of tool wear based on 3D topography
by J.F. Sun
Abstract: Tool wear and its service life have great influence on machining quality, production efficiency and cost. Tool wear is a three-dimensional phenomenon accompanied by physical and chemical factors. However, the tool wear model and evaluation standard characterised by two dimension are still widely used today. In order to explore the use of three-dimensional topography to track the tool wear trend and measure the tool wear condition, relatively high speed cutting experiments were done for cutting three kinds of materials. Laser scanning confocal microscope was used to measure the worn tool topography at different cutting times. After that, the deficiency of two-dimensional indicators and validity of three-dimensional topography in evaluating tool wear were analysed. Besides, some improved tool wear evaluation methods were proposed.
Keywords: tool wear; three-dimensional topography; wear measurement; wear evaluation.
Effects of the comprehensive stiffness performance of the impeller processing system on the machining error
by Shi Wu
Abstract: During the machining of the complex surface of impeller-type parts, the processing system together with the quality of the machined surface could be affected by the overall stiffness of the machine-cutting tool and the stiffness distribution of the workpiece. In this paper, the system stiffness field model and three-dimensional force ellipsoid are proposed and constructed. In particular for the five-axis NC machining centre, the corresponding sampling points are set on the workpiece surface by applying the matrix operations to the multibody deformation theory. Moreover, an integrated stiffness field of the processing system is developed via different tool spatial gestures. It is concluded from the experiment that the stiffness of the blade top is weak with strong vibrations and low machining precisions, which means deformations could easily arise in this region and influence the machining precision significantly. Ultimately, the blade processing techniques could be developed to minimise the machining error.
Keywords: impeller; complex surfaces; force ellipsoid; stiffness field; machining system.