Experimental Investigation and Numerical Simulation of Thermal Debinding and Sintering Processes in Powder Injection Moulding PDF Download
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Author: Belgacem Mamen
Publisher:
ISBN:
Category :
Languages : en
Pages : 171
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Book Description
Thermal debinding is one of the most important steps In Powder Injection Moulding process. Thermogravimetric analyses (TGA) are employed to analyze the physics and kinetics of thermal debinding behaviour under argon atmosphere. The Kissinger and Ozawa method have been used to estimate the kinetic parameters from thermogravimetric experiments. To set up the numerical simulations of thermal debinding stage using finite element method, a coupled mathematical has been developed. The basic steps of the proposed model consist to solve the following sequences of coupled problems: themal degradation of binder coupled with heat transfer and deformation phenomena by finite element method using Comsol Multiphysics software.In the second part of this thesis, sintering behaviour of tungsten powders injection moulded component, under pure hydrogen atmosphere at temperature up to 1700°C. The experimental tests are used to determine the material parameters in the parameters in the viscoplastic constitutive law, which is incorporated with the identified parameters in order to simulate the final shrinkages and densities of tungsten injection moulded components during the sintering process. Comparison between the numerical simulations results and experimental ones, in term of shrinkages and sintered densities, shows a good agreement.
Author: Belgacem Mamen
Publisher:
ISBN:
Category :
Languages : en
Pages : 171
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Book Description
Thermal debinding is one of the most important steps In Powder Injection Moulding process. Thermogravimetric analyses (TGA) are employed to analyze the physics and kinetics of thermal debinding behaviour under argon atmosphere. The Kissinger and Ozawa method have been used to estimate the kinetic parameters from thermogravimetric experiments. To set up the numerical simulations of thermal debinding stage using finite element method, a coupled mathematical has been developed. The basic steps of the proposed model consist to solve the following sequences of coupled problems: themal degradation of binder coupled with heat transfer and deformation phenomena by finite element method using Comsol Multiphysics software.In the second part of this thesis, sintering behaviour of tungsten powders injection moulded component, under pure hydrogen atmosphere at temperature up to 1700°C. The experimental tests are used to determine the material parameters in the parameters in the viscoplastic constitutive law, which is incorporated with the identified parameters in order to simulate the final shrinkages and densities of tungsten injection moulded components during the sintering process. Comparison between the numerical simulations results and experimental ones, in term of shrinkages and sintered densities, shows a good agreement.
Author: Bilon Lin
Publisher:
ISBN:
Category :
Languages : en
Pages : 239
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Book Description
Author: Ling Eng Khoong
Publisher:
ISBN:
Category : Powder injection molding
Languages : en
Pages : 202
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Author: Foad Haghniaz
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
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Author: Donald F. Heaney
Publisher: Elsevier
ISBN: 0857096230
Category : Technology & Engineering
Languages : en
Pages : 609
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Book Description
Metal injection molding combines the most useful characteristics of powder metallurgy and plastic injection molding to facilitate the production of small, complex-shaped metal components with outstanding mechanical properties. The Handbook of metal injection molding provides an authoritative guide to this important technology and its applications.Part one discusses the fundamentals of the metal injection molding process with chapters on topics such as component design, important powder characteristics, compound manufacture, tooling design, molding optimization, debinding, and sintering. Part two provides a detailed review of quality issues, including feedstock characterisation, modeling and simulation, methods to qualify a MIM process, common defects and carbon content control. Special metal injection molding processes are the focus of part three, which provides comprehensive coverage of micro components, two material/two color structures, and porous metal techniques. Finally, part four explores metal injection molding of particular materials, including stainless steels, titanium and titanium alloys, thermal management alloys, high speed tool steels, heavy alloys, refractory metals, hard metals and soft magnetic alloys.With its distinguished editor and expert team of international contributors, the Handbook of metal injection molding is an essential guide for all those involved in the high-volume manufacture of small precision parts, across a wide range of high-tech industries such as microelectronics, biomedical and aerospace engineering. - Provides an authoritative guide to metal injection molding and its applications - Discusses the fundamentals of the metal injection molding processes and covers topics such as component design, important powder characteristics, compound manufacture, tooling design, molding optimization, debinding, and sintering - Comprehensively examines quality issues such as feedstock characterization, modeling and simulation, common defects and carbon content control
Author: Jiupeng Song
Publisher:
ISBN:
Category :
Languages : en
Pages : 174
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Book Description
Author: Rong Zheng
Publisher: Springer Science & Business Media
ISBN: 3642212638
Category : Technology & Engineering
Languages : en
Pages : 194
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Book Description
This book covers fundamental principles and numerical methods relevant to the modeling of the injection molding process. As injection molding processing is related to rheology, mechanical and chemical engineering, polymer science and computational methods, and is a rapidly growing field, the book provides a multidisciplinary and comprehensive introduction to the subjects required for an understanding of the complex process. It addresses the up-to-date status of fundamental understanding and simulation technologies, without losing sight of still useful classical approaches. The main chapters of the book are devoted to the currently active fields of flow-induced crystallization and orientation evolution of fiber suspensions, respectively, followed by detailed discussion of their effects on mechanical property, shrinkage and warpage of injection-molded products. The level of the proposed book will be suitable for interested scientists, R&D engineers, application engineers, and graduate students in engineering.
Author: Shahrooz Sadeghi Borujeni
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
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Book Description
Debinding failure, sintering distortions are two of the main challenges in manufacturing of intact and dimensionally precise components with metal binder jetting technology. In the current research, the challenges are addressed by developing physics-based data-driven numerical simulations. Using thermos-optical observations it is demonstrated that debinding failure occurs when the binder is burnt-off from the green parts which lead to the strength reduction of the components. Through a design of experiment on self-stressing samples, it is resulted that stress on the specimens and the print direction are important factors which may affect debinding failure. A simulation-based Weibull model is developed to consider stress and print direction of the samples to predict he failure probability of green parts during debinding. The collected data from the design of experiment are used to fit the parameters of the simulation-based Weibull model. Validation evidence shows that the developed model is able to predict the failure probability of green parts. Furthermore, the model is detect the failure-prone zones with an acceptable accuracy. The creep-like behavior of sintering deformations can be captured by a rate-dependent material model. Therefore, a phenomenological thermo-elasto-viscoplastic material model in the scheme of finite element method can simulate the thermal, elastic and viscoelastic deformations of sintering bodies in a component scale. The aforementioned material model is calibrated for metal binder jetting technology with dilatometry, Dynamic Differential Calorimetry, Laser Flash Analysis, metallographic analysis, and thermos-optical measurements. The validation studies reveals that without considering the characteristics of MBJ green parts such as density variations and anisotropy, the required industrial-acceptable tolerances cannot be achieved by simulations. Using a data-driven approach and with a wider range of experimental data, the material model is developed in a generic format with the ability to adopt for new manufacturing parameters. The experimental study enabled the estimation of porosity-dependent anisotropy, thermal expansion coefficient, and viscosity. Moreover, with the data-driven approach, the green part properties such as density variations and dimensions can be predicted and fed into the material model. The predicted deformations from the data-driven material model have a good agreement with the validation data. Taking advantage of the data-driven numerical simulation and by introducing a compensation algorithm, sintering deformations of a given geometry are iteratively calculated and reversed to prepare a compensated configuration of the geometry. The presented approach results in manufacturing of MBJ parts with international tolerance grade of 14. Moreover, an experimental-based compensation technique is developed which takes use of previously calculated deformation vectors from numerical simulations and scan data of as-sinter configuration. Measuring the deviation between the as-sinter and the target geometry with the help of the normalized deformation vectors from simulations considers the physics of deformation and enables manufacturing of MBJ parts with a higher accuracy, achieving an international tolerance grade of 13.
Author: Rui Igreja
Publisher:
ISBN: 9783656649243
Category :
Languages : en
Pages : 126
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Book Description
Master's Thesis from the year 2007 in the subject Engineering - Mechanical Engineering, language: English, abstract: (Thesis in pdf available here: http: //goo.gl/EZzlT6 and here: http: //hdl.handle.net/10773/2419) Commonly used methods for injection moulding simulation involve a considerable number of simplifications, leading to a significant reduction of the computational effort but, in some cases also to limitations. In this work, Reaction Injection Moulding (RIM) simulations are performed with a minimum of simplifications, by using the general purpose CFD software package Ansys CFX, designed for numerical simulation of fluid flow and heat and mass transfer. The Ansys CFX's homogeneous multiphase flow model, which is generally considered to be the appropriate choice for modelling free surface flows where the phases are completely stratified and the interface is well defined, is shown to be unable to model the filling process correctly. This problem is overcome through the implementation of the inhomogeneous model in combination with the free-slip boundary condition for the air phase. The cure reaction is implemented in the code as a transport equation for an additional scalar variable, with a source term. Various transient and advection schemes are tested to determine which ones produce the most accurate results. Finally, the mass conservation, momentum, cure and energy equations are implemented all together to simulate the simultaneous filling and curing processes present in the RIM process. The obtained numerical results show a good global accuracy when compared with other available numerical and experimental results, though considerably long computation times are required to perform the simulations.
Author: Randall M. German
Publisher:
ISBN:
Category : Technology & Engineering
Languages : en
Pages : 282
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Book Description
