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Li, Chen; Ji, Shi-Ming; Tan, Da-Peng
doi: 10.1007/s00170-011-3621-ypmid: N/A
Tiny scale mold structural surface finishing is of high difficulty. In allusion to the problem, a new no-tool precision finishing method based on solid–liquid two-phase softness abrasive flow (SAF) is brought forward. By setting restrained component for the structural surface machined, the restrained flow passage is constructed. Using the wall effect of SAF, no-tool precision finishing for tiny scale structural surface can be realized. According to the Nikuradse’s experimental principles, the motion regulars of SAF are studied, and the friction coefficient formulas suited for SAF finishing are obtained. Taking U-shaped restrained flow passage as instance, standard k-ε model and Euler multiple-phase model are used to describe the SAF flow field, and the kinetic model of SAF is established based on discrete phase model. Then, the variation trends of SAF turbulent parameters and flow passage pressure distribution with different inlet velocities are acquired by semi-implicit method for pressure-linked equations consistent algorithm. Numerical simulation results derived that pressure attenuation of solid phase in flow passage is inversely proportional to inlet velocity, and the motion trails are disordered and stochastic, which are the sufficient conditions of SAF finishing. By analyzing pressure distribution and turbulent characteristics of SAF, the best finishing area in restrained flow passage is gained. Observational experiment of particles motion had been carried out; experimental results showed particles’ motion satisfied requirements of SAF finishing, and feasibility of SAF could be proved theoretically. SAF experimental platform oriented to module structural surface finishing is constructed, and the nano-level finishing can be realized. Experiment results show that SAF method can increase mold structural surface precision more than ten times, and the roughness machined in Ra value is less than 62 nm.
Nazemi, Eslam; Tarokh, Mohammad; Djavanshir, G.
doi: 10.1007/s00170-011-3756-xpmid: N/A
Most of organizations have a “functional structure,” which is composed of various functional units. In some cases, each functional unit works towards their own goals and objectives, rather than the organizational goals. This is further aggravated because information flow is restricted by functions, and even when other functional units want to take a systemic view, they do not have the needed information to do so. These are the issues addressed by “Enterprise Resource Planning” (ERP) software solutions providing a common and consistent system to capture information organization-wide, with minimum redundancy. Today, many organizations acquire and implement ERP to improve their operational performance and create strategic value; however, they fail to achieve these objective due to lack of knowledge and better understanding of ERP and its lifecycle. Although, so far, hundreds of research article are published separately focusing on ERP and various issues related to its lifecycle and management, there is no survey and overview of the article published in different top-tier journals. We believe that a survey of the articles related to ERP provides better understanding of ERP and attempts to create an information bank of the published articles these in turn, contribute to improving the performance of an enterprise in terms of achieving its strategic value creation goals. In this study, we attempt to summarize our survey and review of the articles related to ERP.
Jain, V.; Kalia, Subodh; Sidpara, Ajay; Kulkarni, V.
doi: 10.1007/s00170-012-4088-1pmid: N/A
Electrochemical micromachining (ECMM) is an advanced machining process for the machining of electrically conducting materials. In the present work, an experimental setup has been designed and fabricated to machine micro-holes and micro-channels. Machining of these features is done using a sewing needle with 47 μm tip diameter as a tool. The effects of process parameters such as voltage, electrolyte concentration, pulse duty cycle, and feed rate on the machined hole diameter have been studied, and a mathematical model is developed. The fabrication of micro-tools is done on a different setup. A straight tool having a diameter of 80 μm is fabricated from a 1,000-μm steel wire using the ECMM process. Variations of wire diameter and the material removal rate with time are studied. Micro-feature measurements and photographic analysis are done using a digital microscope.
Thanigaivelan, R.; Arunachalam, R.; Drukpa, Pelden
doi: 10.1007/s00170-012-4093-4pmid: N/A
Electrochemical micromachining (EMM) is one of the best micromachining techniques for machining electrically conducting, tough, and difficult-to-machine materials with suitable machining parameter combinations. For the micro-fabrication of components like nozzle plate for ink jet printer head and delicate 3D electronic circuit board components, EMM is predominantly used. In this paper, the effect of process parameters such as such as electrolyte concentration, machining voltage, frequency, and duty cycle on the material removal rate (MRR) and overcut were studied using copper workpiece. According to Taguchi’s quality design concepts, an L18 orthogonal array is used. ANOVA is also performed to determine the most significant parameter that influences the EMM process. The optimum process parameters for lower overcut and higher MRR are found out and confirmation tests were carried out to validate the prediction. The confirmation test results show 19 and 20.78 % improvements of overcut and MRR, respectively, with respect to the initial parametric setting.
doi: 10.1007/s00170-012-4094-3pmid: N/A
The paper presents the result of an experimental investigation on the micro machining of electrically non-conductive e-glass–fibre–epoxy composite during electrochemical spark machining using specially designed square cross section with centrally micro hole brass tool and different diameter round-shaped micro tools made of IS-3748 steel. A micro electrochemical spark machining (ECSM) setup has been designed, fabricated and used for conducting the experiments. According to the Taguchi method-based design, the specific numbers of experiments have been carried out to investigate the influence of the fabricated ECSM parameters on the material removal rate and overcut on generated hole radius. Test results show that the material removal rate is maximum when machining was performed at higher setting value of D.C. supply voltage (e.g. 70 V), moderate setting value of electrolytic concentration (e.g. 80 g/l) and 180-mm gap between electrodes. Taking significant machining parameters into consideration and using multiple linear regression, mathematical modes for material removal rate and overcut on hole radius are established to investigate the influence of cutting parameters during micro-ECSM. The influence of machining parameters on machined hole and special shape contour quality are also analysed through different scanning electron micrographs. Confirmation test results established the fact that the developed mathematical models are appropriate for effectively representing the machining performance criteria.
Shandilya, Pragya; Jain, P.; Jain, N.
doi: 10.1007/s00170-012-4095-2pmid: N/A
Unconventional machining like wire electric discharge machining/cutting (WEDM/WEDC) seems to be a better choice for machining/cutting the metal matrix composites (MMCs) because it offers easy control and has the capability of machining intricate complex shapes. But wire breakage in the WEDM/WEDC process decreases the machining accuracy and the quality of the machined surface. This paper describes the effect of four input process parameters (i.e., servo voltage, pulse-on time, pulse-off time, and wire feed rate) on wire breakage frequency and the microstructure of the cut surface during WEDC of SiCp/6061 Al MMC. An optimum range of input parameters has been bracketed as the outcome of this work for determining the effects of input process parameters on the average cutting speed, material removal rate, and surface roughness during WEDC of SiCp/6061 Al MMC. This range of input parameters can also be used for carrying out further research to develop the models for WEDC of SiCp/6061 Al MMC and to optimize the WEDC parameters for smooth cutting.
Somashekhar, K.; Mathew, Jose; Ramachandran, N.
doi: 10.1007/s00170-012-4096-1pmid: N/A
Due to the presence of large number of process variables and complicated stochastic nature, selection of optimum machining parameter combinations for obtaining higher material removal rate with minimum overcut and surface roughness is a challenging task in Micro Wire Electric Discharge Machining (μ-WEDM). The important parameters of Material Removal Rate (MRR), overcut and surface roughness are considered in this study of single pass μ-WEDM machining of aluminium. The system model is created with statistical based regression analysis using experimental data. This system model is employed to maximize the material removal rate and minimize the surface roughness and overcut using Simulated Annealing (SA) scheme. Finally consistency of the method is tested with trial values. The model is found as capable of predicting the response characteristics as a function of different control variables. Experiments are carried out to check the validity of the developed model and then optimal parametric combinations are searched out using an advanced optimization strategy.
S., Gopi; V. R., Raju; K., Ankit; P. V., Shashikumar
doi: 10.1007/s00170-012-4097-0pmid: N/A
This work presents the fabrication of micro threads of pitch less than 100 μm for micro components. The micro sized threading tool having a tool nose radius less than 40 μm is manufactured by micro wire electric discharge machining (μWEDM) process. This μWEDM process overcomes the difficulties in conventional machining process for production of threading tools and helps in achieving a corner radius as small as 15 μm with specialized wire tool path strategies. This method also helps in fabrication of special micro tools from commercially available or worn-out tungsten carbide tool inserts.
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