Porosity formation studies in high pressure die castings of Al-9Si-3Cu alloy based on Taguchi method

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
K. Ch Appa Rao ◽  
Anil Kumar Birru ◽  
Praveen Kumar Bannaravuri ◽  
E. Daniel Francis
Keyword(s):  
Molten Metal ◽  
Process Improvement ◽  
Die Casting ◽  
Injection Pressure ◽  
Light Weight ◽  
Grain Refiner ◽  
Porosity Formation ◽  
Content Type ◽  
Die Temperature ◽  
Casting Porosity

PurposeNowadays, ample industries are fascinated to look for high strength and light weight materials for the development of robust parts. Because of light weight and high stiffness to weight ratio; usage of aluminum parts is growing rapidly, especially in automotive engineering. Process improvement of Al alloys and their grain structure refinement is the current area of interest in casting companies. In this research work, an investigation has been carried out to enhance the process improvement of die casting by optimization of various significant parameters and their refinement of grains by the effect of Nb-C novel grain refiner.Design/methodology/approachL27 orthogonal array (OA) has been considered to optimize the preferred casting input parameters such as molten metal temperature (°C), die temperature (°C), injection pressure (bar), Al-3.5Nb-1.5 C novel grain refiner and Ni alloying additions as key process parameters in order to increase the quality and efficiency of Al-9Si-3Cu aluminum alloy die casting by reducing the porosity formation.FindingsIt was observed that the porosity values have significantly decreased from 0.88% to 0.25% particularly at 0.1 wt.% of new grain refiner and 0.5 wt. % of Al-6Ni master alloy. As per the ANOVA results, it was observed that Al-3.5FeNb-1.5 C grain refiner (F value 2609.22), Al-6Ni alloying addition (F value 1329.13), molten metal temperature (F value 1002.43) and, injection pressure (F value 448.06) are the factors that significantly affects the porosity, whereas die temperature was found to be insignificant. The results show that new grain refiner is one the most significant factor among the other selected parameters. The contribution of the new grain refiner to the variation of mean casting porosity is around 57.74%. confidence interval (CI) has also been estimated as 0.013 for 95% consistency level to validate the predicted range of optimum casting porosity of aforesaid alloy.Originality/valueTo the best of the authors' knowledge, no study has been conducted in the past to investigate the combined effect of these die casting parameters and composition factors for the development of Al-Si robust cast parts. The paper represents original research and provides new information for the fabrication of die casting parts.

Study on high-temperature wear and mechanism of Al-Si/graphite composites prepared by the die-casting process

2020 ◽  
Vol 72 (10) ◽  
pp. 1153-1158 ◽  
Author(s):  
Yafei Deng ◽  
Xiaotao Pan ◽  
Guoxun Zeng ◽  
Jie Liu ◽  
Sinong Xiao ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
Wear Rate ◽  
Peer Review ◽  
Die Casting ◽  
Casting Machine ◽  
Injection Pressure ◽  
Casting Process ◽  
Matrix Alloy ◽  
Content Type ◽  
The Matrix

Purpose This paper aims to improve the tribological properties of aluminum alloys and reduce their wear rate. Design/methodology/approach Carbon is placed in the model at room temperature, pour 680°C of molten aluminum into the pressure chamber, and then pressed it into the mold containing carbon felt through a die casting machine, and waited for it to cool, which used an injection pressure of 52.8 MPa and held the same pressure for 15 s. Findings The result indicated that the mechanical properties of matrix and composite are similar, and the compressive strength of the composite is only 95% of the matrix alloy. However, the composite showed a low friction coefficient, the friction coefficient of Gr/Al composite is only 0.15, which just is two-third than that of the matrix alloy. Similarly, the wear rate of the composite is less than 4% of the matrix. In addition, the composite can avoid severe wear before 200°C, but the matrix alloy only 100°C. Originality/value This material has excellent friction properties and is able to maintain this excellent performance at high temperatures. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-10-2019-0454/

Effects of shot sleeve filling in HPDC machine

2019 ◽  
Vol 15 (6) ◽  
pp. 1255-1273
Author(s):  
Korti Mohammed Choukri ◽  
Korti Abdel Illah Nabil ◽  
Abboudi Said
Keyword(s):  
Molten Metal ◽  
Transient Flow ◽  
Die Casting ◽  
Rest Period ◽  
Convergence Criterion ◽  
Shot Sleeve ◽  
Content Type ◽  
Filling Phase ◽  
Triangular Elements ◽  
Injection Phase

Purpose High-pressure die casting is one of the manufacturing techniques used for the rational mass production of metal parts. Due to the high velocity of the molten metal during the injection phase, the die casting of aluminum is so complex and it is almost impossible to calculate these exact performances. Numerical simulation is an effective way to optimize the injection phase and minimize air entrapment that causes porosity defects in the metal. Generally, the filling phase of the molten metal in the shot sleeve is neglected in most scientific work. This phase is followed by a rest period to allow the escape of the resident air bubbles (gravity effect). The paper aims to discuss these issue. Design/methodology/approach It is relatively clear that the model described poses a great challenge for numerical implementation, especially for 3D geometries. The governing transport equations are solved numerically using the commercial CFD solver Fluent and the equations are discretized using a pressure-based finite volume method. The coupling pressure–velocity was solved by the PISO algorithm. The PISO algorithm takes relatively more CPU time per solver iteration, but it significantly decreases the number of iterations required for the convergence of the transient flow problems. Laminar flow inside air and molten metal was assumed. In order to describe the behavior of the molten metal, a VOF model has been activated. The model makes it possible to account for the moving boundary due to the variation of the shot sleeve volume caused by the plunger displacement. The scheme used in the discretization of momentum equation was the first-order upwind scheme, and the scheme used for the pressure was the PRESTO. The profile of the plunger velocity, boundary conditions change with time and the physical properties change with liquid fraction were used by implementation of a user-defined function. For the discretization of the domain, an unstructured mesh with triangular elements is used. After conducting mesh sensitivity study, a mesh having 53,813 triangular elements has been chosen for the present study. The convergence criterion was set equal to 10–4 for all parameters. Findings The results show that the rest and global filling times increase by 2.5 and 8.57 percent with decreasing the pouring velocity by 10 percent. In addition, the rest and global filling times decrease by 5.77 and 8.12 percent with increasing the pouring velocity by 10 percent. Originality/value After the filling phase, it is necessary to offer a rest period before the injection phase. However, the rest and global filling times increase by 2.5 and 8.57 percent with decreasing the pouring velocity by 10 percent. In addition, the rest and global filling times decrease by 5.77 and 8.12 percent with increasing the pouring velocity by 10 percent. Increasing the pouring velocity by 10 percent leads increasing of the molten metal velocity in the shot sleeve and requires a delay of time of the beginning of the faster plunger movement by 7–10.5 percent. On the other hand, Figure 12 shows that increasing the pouring velocity requires increasing of the plunger velocity during the injection phase, thus increasing the pouring velocity. In order to overcome this problem, it is necessary to reduce the injection velocity and prolong the period of the slower plunger movement.

scholarly journals Analysis and Optimisation of High Pressure Die Casting Parameters to Achieve Six Sigma Quality Product Using Numerical Simulation Approach

2021 ◽  
Vol 11 (1) ◽  
pp. 97-109
Author(s):  
Suraj R. Marathe ◽  
Dr. Carmo E. Quadros
Keyword(s):  
Numerical Simulation ◽  
High Pressure ◽  
Molten Metal ◽  
Die Casting ◽  
Injection Pressure ◽  
Simulation Software ◽  
Holding Time ◽  
Simulation Approach ◽  
High Pressure Die Casting ◽  
Pressure Die Casting

A numerical simulation approach is proposed to predict the optimal parameter setting during high pressure die casting. The contribution from the optimal parameters, the temperature, showed more influence on the casting quality than the other parameters. This study’s outcome was beneficial for finding the solution for casting defects that occurs due to incorrect setting of process parameters in die casting. Thus, a combination of numerical optimisation techniques and casting simulation serves as a tool to improve the casting product quality in die casting industries. This paper aims to analyse and optimise critical parameters like injection pressure, molten metal temperature, holding time, and plunger velocity, contributing to the defects. In this research paper, an effort has been made to give optimal pressure, temperature, holding time, and plunger velocity parameters using ProCAST simulation software that uses finite element analysis technology. Numerical analysis for optimising the parameters by varying the temperature of molten metal, injection pressure, holding time, and plunger velocity,  concerning solidification time at hot spots, is an essential parameter for studying the defect analysis in the simulated model.

Estimating performance from capabilities in business process improvement

2016 ◽  
Vol 22 (6) ◽  
pp. 1099-1117 ◽  
Author(s):  
Boyd A. Nicholds ◽  
John P.T. Mo
Keyword(s):  
Process Improvement ◽  
Business Process ◽  
Expected Improvement ◽  
Management Decision ◽  
Published Data ◽  
Performance Gain ◽  
Data Set ◽  
Business Process Improvement ◽  
Improvement Project ◽  
Content Type

Purpose The research indicates there is a positive link between the improvement capability of an organisation and the intensity of effort applied to a business process improvement (BPI) project or initiative. While a degree of stochastic variation in applied effort to any particular improvement project may be expected there is a clear need to quantify the causal relationship, to assist management decision, and to enhance the chance of achieving and sustaining the expected improvement targets. The paper aims to discuss these issues. Design/methodology/approach The paper presents a method to obtain the function that estimates the range of applicable effort an organisation can expect to be able to apply based on their current improvement capability. The method used analysed published data as well as regression analysis of new data points obtained from completed process improvement projects. Findings The level of effort available to be applied to a process improvement project can be expressed as a regression function expressing the possible range of achievable BPI performance within 90 per cent confidence limits. Research limitations/implications The data set applied by this research is limited due to constraints during the research project. A more accurate function can be obtained with more industry data. Practical implications When the described function is combined with a separate non-linear function of performance gain vs effort a model of performance gain for a process improvement project as a function of organisational improvement capability is obtained. The probability of success in achieving performance targets may be estimated for a process improvement project. Originality/value The method developed in this research is novel and unique and has the potential to be applied to assessing an organisation’s capability to manage change.

scholarly journals Molten metal flow through multiple gates in the runner of die casting.

1986 ◽  
Vol 36 (9) ◽  
pp. 577-581
Author(s):  
Yasushi IWATA ◽  
Yoshiaki YAMAMOTO ◽  
Motoshi NAKAMURA ◽  
Haruo SUZUKI ◽  
Hiroshi SAWADA ◽  
...  
Keyword(s):  
Molten Metal ◽  
Die Casting ◽  
Metal Flow ◽  
Flow Through ◽  
Molten Metal Flow

Credit card account opening excellence using six sigma methodology

2016 ◽  
Vol 7 (3) ◽  
pp. 294-323 ◽  
Author(s):  
Samsul Islam
Keyword(s):  
Process Improvement ◽  
Six Sigma ◽  
Credit Card ◽  
Current Knowledge ◽  
Case Study Methodology ◽  
Content Type ◽  
Study Results ◽  
Six Sigma Methodology ◽  
Six Sigma Approach ◽  
Opening Process

Purpose This study aims to expand the current knowledge of the Six Sigma approach in a period of time when there is little direct evidence of the need to improve the credit card account opening process. This is an important but neglected area of focus in the Six Sigma literature. This study explores the extent to which process improvement practices are extended to the credit card department. Design/methodology/approach A case study methodology is adopted in this study to facilitate an exploration of the implemented Six Sigma approach in the credit card department of a leading commercial bank. The process improvement tool used is the define, measure, analyze, improve and control (DMAIC) cycle. Findings The study’s results confirm that the Six Sigma approach improves the quality of the credit card account opening process. So, the Six Sigma approach can account for a reduced number of keying-in errors, resulting in better data accuracy and improved customer satisfaction. Research limitations/implications The authors, in an attempt to render the study results more feasible for data collection, have chosen to focus on the process of the new accounts unit of the credit card department. Therefore, the authors have not taken into account the other units (e.g. transaction processing) of the same department. Practical implications The results of this study will be useful in persuading bank management to evaluate and implement the Six Sigma approach. Hence, this research will assist bank managers with replies to questions, such as: “What impact will Six Sigma have on process-centric improvement, such as the new accounts opening process of a credit card department?” Originality/value Within the literature on the Six Sigma practice, there is little research that focuses on the implementation of this particular toolset especially for credit card departments. This indicates a gap in the field. A new contribution to bridging that gap comes from the analysis of the results for the Six Sigma concept, which addresses the new accounts opening process.

Numerical investigations on the hydrogen jet pressure variations in a strut based scramjet combustor

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Jeyakumar Suppandipillai ◽  
Jayaraman Kandasamy ◽  
R. Sivakumar ◽  
Mehmet Karaca ◽  
Karthik K.
Keyword(s):  
Shock Wave ◽  
Supersonic Flow ◽  
Pressure Loss ◽  
Total Pressure ◽  
Injection Pressure ◽  
Total Pressure Loss ◽  
Normal Shock ◽  
Content Type ◽  
Normal Shock Wave ◽  
Scramjet Combustor

Purpose This paper aims to study the influences of hydrogen jet pressure on flow features of a strut-based injector in a scramjet combustor under-reacting cases are numerically investigated in this study. Design/methodology/approach The numerical analysis is carried out using Reynolds Averaged Navier Stokes (RANS) equations with the Shear Stress Transport k-ω turbulence model in contention to comprehend the flow physics during scramjet combustion. The three major parameters such as the shock wave pattern, wall pressures and static temperature across the combustor are validated with the reported experiments. The results comply with the range, indicating the adopted simulation method can be extended for other investigations as well. The supersonic flow characteristics are determined based on the flow properties, combustion efficiency and total pressure loss. Findings The results revealed that the augmentation of hydrogen jet pressure via variation in flame features increases the static pressure in the vicinity of the strut and destabilize the normal shock wave position. Indeed, the pressure of the mainstream flow drives the shock wave toward the upstream direction. The study perceived that once the hydrogen jet pressure is reached 4 bar, the incoming flow attains a subsonic state due to the movement of normal shock wave ahead of the strut. It is noticed that the increase in hydrogen jet pressure in the supersonic flow field improves the jet penetration rate in the lateral direction of the flow and also increases the total pressure loss as compared with the baseline injection pressure condition. Practical implications The outcome of this research provides the influence of fuel injection pressure variations in the supersonic combustion phenomenon of hypersonic vehicles. Originality/value This paper substantiates the effect of increasing hydrogen jet pressure in the reacting supersonic airstream on the performance of a scramjet combustor.

Process improvement project failure: a systematic literature review and future research agenda

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Jiju Antony ◽  
Bart A. Lameijer ◽  
Hans P. Borgman ◽  
Kevin Linderman
Keyword(s):  
Literature Review ◽  
Process Improvement ◽  
Systematic Literature Review ◽  
Future Research ◽  
Research Directions ◽  
Improvement Project ◽  
Project Failure ◽  
Content Type ◽  
Future Research Directions ◽  
Research Propositions

Purpose Although scholars have considered the success factors of process improvement (PI) projects, limited research has considered the factors that influence failure. The purpose of this paper is to extend the understanding of PI project failure by systematically reviewing the research on generic project failure, and developing research propositions and future research directions specifically for PI projects. Design/methodology/approach A systematic literature review protocol resulted in a total of 97 research papers that are reviewed for contributions on project failure. Findings An inductive category formation process resulted in three categories of findings. The first category are the causes for project failure, the second category is about relatedness between failure factors and the third category is on failure mitigation strategies. For each category, propositions for future research on PI projects specifically are developed. Additional future research directions proposed lay in better understanding PI project failure as it unfolds (i.e. process studies vs cross-sectional), understanding PI project failure from a theoretical perspective and better understanding of PI project failure antecedents. Originality/value This paper takes a multi-disciplinary and project type approach, synthesizes the existing knowledge and reflects upon the developments in the field of research. Propositions and a framework for future research on PI project failure are presented.

Optimization design of drive system for industrial robots based on dynamic performance

2017 ◽  
Vol 44 (6) ◽  
pp. 765-775 ◽  
Author(s):  
LianZheng Ge ◽  
Jian Chen ◽  
Ruifeng Li ◽  
Peidong Liang
Keyword(s):  
Optimization Model ◽  
Optimization Problem ◽  
Industrial Robot ◽  
Dynamic Performance ◽  
System Optimization ◽  
Drive System ◽  
Industrial Robots ◽  
Mixed Integer ◽  
Light Weight ◽  
Content Type

Purpose The global performance of industrial robots partly depends on the properties of drive system consisting of motor inertia, gearbox inertia, etc. This paper aims to deal with the problem of optimization of global dynamic performance for robotic drive system selected from available components. Design/methodology/approach Considering the performance specifications of drive system, an optimization model whose objective function is composed of working efficiency and natural frequency of robots is proposed. Meanwhile, constraints including the rated and peak torque of motor, lifetime of gearbox and light-weight were taken into account. Furthermore, the mapping relationship between discrete optimal design variables and component properties of drive system were presented. The optimization problem with mixed integer variables was solved by a mixed integer-laplace crossover power mutation algorithm. Findings The optimization results show that our optimization model and methods are applicable, and the performances are also greatly promoted without sacrificing any constraints of drive system. Besides, the model fits the overall performance well with respect to light-weight ratio, safety, cost reduction and others. Practical implications The proposed drive system optimization method has been used for a 4-DOF palletizing robot, which has been largely manufactured in a factory. Originality/value This paper focuses on how the simulation-based optimization can be used for the purpose of generating trade-offs between cost, performance and lifetime when designing robotic drive system. An applicable optimization model and method are proposed to handle the dynamic performance optimization problem of a drive system for industrial robot.

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