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Muhammad Dilawer Hayat - One of the best experts on this subject based on the ideXlab platform.

  • Binder System interactions and their effects
    Feedstock Technology for Reactive Metal Injection Molding, 2020
    Co-Authors: Muhammad Dilawer Hayat
    Abstract:

    Abstract At present, the Binder’s properties for metal injection molding (MIM) are assessed by rheological measurements and thermal decomposition temperature of the backbone polymer. Although blend studies of common polymers are available in the literature, little attention has been paid to study specific interactions among the particular Binder System components and the effects of such interaction on reactive powders-MIM feedstocks are largely missing. This chapter aims to give readers some basic knowledge about polymer blends, their thermodynamics, and the possible interactions among individual components of common Binder Systems. In the last section, interactions between a Binder System and metallic powder are also explained. After going through this chapter, the readers should be able to identify the importance of such interactions and know-how these interactions can be used to improve the properties of a feedstock.

  • improving titanium injection moulding feedstock based on peg ppc based Binder System
    Powder Technology, 2018
    Co-Authors: Muhammad Dilawer Hayat, Pratik Prakash Jadhav, Hongzhou Zhang
    Abstract:

    Abstract Binder System is an integral part of metal injection moulding (MIM) process that holds the metal powder together until the first stage of sintering. In this research, a new Binder System was developed consisting of water soluble polyethylene glycol (PEG) as the main component, while poly (propylene carbonate) (PPC) and poly (methyl methacrylate) (PMMA) were used as the backbone components for titanium-MIM processing. The macromolecular interactions between various Binder components were evident from Fourier-transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) studies. The interactions between polymeric components in the Binder provided ample compatibility within the Binder System as revealed from the thermo-rheological properties of the titanium-MIM feedstock, which ensured suitability for thermal processing. Incorporation of PMMA in PEG/PPC Binder System significantly improved the green strength of the moulded parts especially after initial water debinding step and thereby facilitated the following thermal processing. In addition, the chemical interactions between the polymers in PMMA-containing Binder System enhanced the thermal stability of the as-moulded parts. Hence, the interactions between different polymeric materials showed a crucial role in developing suitable Binder System for the MIM processing. The oxygen, carbon and nitrogen impurity contents of thermally debound samples obtained from this new Binder System met the grade 1 ASTM standard, suggesting the potential applicability in the production of high quality titanium products.

  • Improving titanium injection moulding feedstock based on PEG/PPC based Binder System
    Powder Technology, 2018
    Co-Authors: Muhammad Dilawer Hayat, Pratik Prakash Jadhav, Hongzhou Zhang
    Abstract:

    Abstract Binder System is an integral part of metal injection moulding (MIM) process that holds the metal powder together until the first stage of sintering. In this research, a new Binder System was developed consisting of water soluble polyethylene glycol (PEG) as the main component, while poly (propylene carbonate) (PPC) and poly (methyl methacrylate) (PMMA) were used as the backbone components for titanium-MIM processing. The macromolecular interactions between various Binder components were evident from Fourier-transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) studies. The interactions between polymeric components in the Binder provided ample compatibility within the Binder System as revealed from the thermo-rheological properties of the titanium-MIM feedstock, which ensured suitability for thermal processing. Incorporation of PMMA in PEG/PPC Binder System significantly improved the green strength of the moulded parts especially after initial water debinding step and thereby facilitated the following thermal processing. In addition, the chemical interactions between the polymers in PMMA-containing Binder System enhanced the thermal stability of the as-moulded parts. Hence, the interactions between different polymeric materials showed a crucial role in developing suitable Binder System for the MIM processing. The oxygen, carbon and nitrogen impurity contents of thermally debound samples obtained from this new Binder System met the grade 1 ASTM standard, suggesting the potential applicability in the production of high quality titanium products.

  • Study of a Binder System for Ti-MIM: A Potential Low Temperature Backbone Polymer
    Key Engineering Materials, 2018
    Co-Authors: Hongzhou Zhang, Muhammad Dilawer Hayat, Pratik Prakash Jadhav, Xuanhui Qu, Xingang Wang
    Abstract:

    Impurity control remains to be a challenge to titanium metal injection moulding (Ti-MIM). Much attention has been paid to polyethylene glycol (PEG) based Binder Systems due to the eco-friendly and water-soluble feature of PEG. In this study, a new easy-to-debind PEG/polypropylene carbonate (PPC)-based Binder System (76% PEG+17% PPC+3% polymethyl methacrylate (PMMA)+2% stearic acid (SA)+2% polyvinyl acetate (PVAc)) was developed. The rheological properties of the feedstocks prepared with the Binder System in different proportions were assessed. Debinding behaviours of the moulded samples and impurity contents of oxygen (O), carbon (C), and nitrogen (N) of the thermal debound specimens were investigated as well.

  • a new lubricant based Binder System for feedstock formulation from hdh ti powder
    Advanced Powder Technology, 2016
    Co-Authors: Muhammad Dilawer Hayat
    Abstract:

    Abstract This study reported the preparation of homogeneous hydride–dehydride (HDH) titanium metal injection moulding (Ti-MIM) feedstocks using solvent mixing. The research emphasis was on the development of a Binder System for producing higher solid loadings for the irregular HDH titanium powder feedstocks. Homogeneous mixing and solid loading are the factors that strongly influence the final product properties. Solvent mixing provides an excellent alternative to the commonly used hot mixing and emulsion mixing. Due to its natural irregular shape of HDH-Ti powder, the feedstock, which is injection mouldable, usually has a lower solid loading than that of spherical powder. In this study, Ti-MIM feedstocks were prepared using polyethylene glycol (PEG) as the primary Binder component, polymethyl methacrylate (PMMA) as the backbone component and a new lubricant. The Binder and metal powders were mixed in acetone and then vacuum dried. Scanning electron microscopic (SEM) analysis, rheometry tests and torque measurements were performed subsequently.

Janis E. Swan - One of the best experts on this subject based on the ideXlab platform.

  • analysis of rheological behaviour of titanium feedstocks formulated with a water soluble Binder System for powder injection moulding
    Powder Technology, 2015
    Co-Authors: G. Thavanayagam, Kim L. Pickering, Janis E. Swan
    Abstract:

    Abstract Binder selection and formulation are critical in powder injection moulding. Binders play a key role in controlling the rheological properties of a feedstock and influence whether the resulting feedstock can be successfully injection moulded, debound and sintered without defects. A four-step process was used to mix hydride-dehydride titanium alloy (processed) powder (Ti–6Al–4V) with a polyethylene glycol (PEG) based water soluble Binder System. The rheological properties, including flow behaviour index, flow activation energy, fluidity and melt flow index of the homogeneous feedstock, were determined with a capillary rheometer. All feedstock formulations exhibited shear thinning flow behaviour. The optimum feedstock consisting of 60 vol.% powder content, 32 vol.% PEG, 6 vol.% polyvinyl butyryl and 2 vol.% stearic acid was suitable for titanium injection moulding.

G. Thavanayagam - One of the best experts on this subject based on the ideXlab platform.

  • analysis of rheological behaviour of titanium feedstocks formulated with a water soluble Binder System for powder injection moulding
    Powder Technology, 2015
    Co-Authors: G. Thavanayagam, Kim L. Pickering, Janis E. Swan
    Abstract:

    Abstract Binder selection and formulation are critical in powder injection moulding. Binders play a key role in controlling the rheological properties of a feedstock and influence whether the resulting feedstock can be successfully injection moulded, debound and sintered without defects. A four-step process was used to mix hydride-dehydride titanium alloy (processed) powder (Ti–6Al–4V) with a polyethylene glycol (PEG) based water soluble Binder System. The rheological properties, including flow behaviour index, flow activation energy, fluidity and melt flow index of the homogeneous feedstock, were determined with a capillary rheometer. All feedstock formulations exhibited shear thinning flow behaviour. The optimum feedstock consisting of 60 vol.% powder content, 32 vol.% PEG, 6 vol.% polyvinyl butyryl and 2 vol.% stearic acid was suitable for titanium injection moulding.

  • rheological properties of feedstock composed of titanium alloy powder and polyethylene glycol based Binder System for metal injection moulding
    PRICM: 8 Pacific Rim International Congress on Advanced Materials and Processing, 2013
    Co-Authors: G. Thavanayagam, Deliang Zhang, Kim L. Pickering
    Abstract:

    Metal injection moulding (MIM) has been widely recognized as a route for cost effective production of titanium alloy parts with complex shapes. In this study, feedstock was prepared by mixing HDH Ti-6Al-4V alloy powder with polyethylene glycol (PEG) based Binder System. Feedstock formulation was homogeneous with a combination of dry mixing by a planetary mixer and a roller mixer, as well as melt mixing by a twin blade compounder and a twin screw extruder. Investigations were done using a capillary rheometer to understand the effects of key parameters such as powder loadings and Binder formulations on the rheological properties of feedstock. Results showed that all feedstock formulations exhibited pseudoplastic flow behaviour. A feedstock consists of 86 wt.% powder loading was found to be more suitable for MIM with the feeding screw speed of 200rpm, injection pressure of 20MPa and the feed to nozzle temperature of 130°C to 145°C.

  • A Study of Polyvinyl Butyryl Based Binder System in Titanium Based Metal Injection Moulding
    Key Engineering Materials, 2012
    Co-Authors: G. Thavanayagam, Kim L. Pickering, Deliang Zhang, Stiliana Rousseva Raynova
    Abstract:

    Metal injection moulding (MIM) is an innovative injection moulding technique widely used to produce complex shaped components from feedstock composed of metal powders and thermosetting or thermoplastic Binders. In MIM, Binder selection and formulation are considered as critical processes since Binder characteristics dictate the success of MIM. The purpose of this study is to determine the feasibility of polyvinyl butyryl (PVB) based Binder System in Ti-6Al-4V(wt.%)/Binder feedstock, as well as to understand the effects of key parameters, such as powder loading and mixing conditions on the rheological properties of a feedstock. In this study, PVB, polyethylene glycol (PEG), and stearic acid (SA) were chosen to formulate a multi-component Binder System to prepare Ti-6Al-4V based feedstock with the aid of three types of mixers: a compounder, a modified mechanical mixer and a twin screw extruder. Further, morphological analysis was performed using optical microscopy and scanning electron microscopy. Thermal analysis was performed using simultaneous differential thermal analysis and thermogravimetric analysis. Results showed that Binder formulation was reasonably successful with the aid of both mechanical mixer and a twin screw extruder under certain mixing conditions, and the critical powder loading was 68 vol.%, resulting in an optimum powder loading of 63 vol.% .

Muhammad Hussain Ismail - One of the best experts on this subject based on the ideXlab platform.

  • Rheological characterizations of copper - palm stearin based Binder System for metal injection moulding
    Materials Science Forum, 2016
    Co-Authors: Nor Amalina Nordin, Mohammad Dahar Kamal Bahrin, Nor 'aini Wahab, Afian Omar, Muhammad Hussain Ismail
    Abstract:

    This research paper reports the findings of feedstock establishment works for Metal Injection Moulding (MIM) of copper parts employing palm stearin based Binder System. The main objective of this study is to explore an appropriate formulation of palm stearin-polyethylene (PSPE) Binder System of copper feedstock that enabling the MIM process. Two formulations; 60%wt PS and 70%wt PS with constant powder loading of 60 vol. % Cu has been prepared. The mixing process of copper powder and Binders was performed at the speed of 50 rpm at 160°C. Scanning Electron Microscope (SEM) has been used for the microstructural study of starting materials and mixtures. The rheological characterizarions for both formulations that were carried out using Rosand RH2000 Capillary Rheometer exhibited the pseudo plastic flow and in good agreement with previous findings.

  • COMPRESSIVE MECHANICAL PROPERTIES OF POROUS TI-6AL-4V WITH PALM STEARIN Binder System
    Jurnal Teknologi, 2015
    Co-Authors: Juri Saedon, Muhammad Hussain Ismail, Nur Atikah Abu Kasim, Hazran Husain
    Abstract:

    Most Ti-6Al-4V implant used today are often much stiffer than human bone. However, the young modulus of those Ti-6Al-4V implants can be reduced through the formation of porous structure. Palm stearin Binder System with an addition of sodium chloride as space holder has been established in the fabrication of porous Ti-6Al-4V. Thus, this paper focuses on the compressive mechanical properties of porous Ti-6Al-4V with utilization of palm stearin Binder System along with sodium chloride (NaCl) as the space holder. The evaluated compositions consist of the powder volume fraction of 63vol% and 65vol%. The samples were compacted by thermal compacting machine at temperature of 160oC. Two different debinding processes involved, which are heptane solvent and water leaching. Then the samples were sintered up to three different temperatures, which are 1200oC, 1250oC and 1300oC. Mechanical properties of the porous Ti-6Al-4V were characterized by axial compression testing. The maximum compressive stress and Young’s modulus of the samples were determined to be 403.87MPa and 9.92GPa.

  • rheological properties of hydroxyapatite synthesized clamshell mix with palm stearin Binder System
    International Conference Key Engineering Materials, 2014
    Co-Authors: Istikamah Subuki, Muhammad Hussain Ismail
    Abstract:

    This study investigated the flow behavior of feedstock containing hydroxyapatite (HAp) powder with palm stearin (PS) based Binder System. The HAp was synthesized via chemical precipitation method with the use of waste of clamshells. The result showed that single phase synthesized HAp was successfully formed at annealing temperature and pH solution of 850°C and 6.5, respectively. The synthesized HAp with a volume fraction of 65% was then mixed with PS and and Polyethylene Binder at 160°C to prepare a feedstock. From the rheological test result, it was found that the feedstock exhibited a pseudoplastic behavior with low values of shear sensitivity in comparison with commercial HAp.

  • phase transformation temperatures ppts and microstructure of moulded niti alloy using a water soluble Binder System
    Sains Malaysiana, 2013
    Co-Authors: Muhammad Hussain Ismail, H A Davies, Martin Bram, Ana Paula Cysne Barbosa, Manuel Kohl, I Todd
    Abstract:

    In this work, the effects of backbone polymer in the Binder System mixed with pre-alloyed NiTi powder, on impurity contents, phase transformation temperatures and microstructures were investigated. A spherical gas-atomised pre-alloyed NiTi powder (50.3 at. %Ni) with a mean particle size of less than 22 μm and powder loading of 69.5 vol. % was used. The Binder consisted of a water soluble Binder System, mainly polyethylene glycol (PEG), with two different backbone Binders, namely polyethylene 520 (PE 520) and poly-methyl- methacrylate (PMMA). The latter was used in the form of a powder and as an emulsion. Green parts were prepared by warm-press the feedstock into a cylindrical shape. The samples were then leached in warm water, thermally debound in Argon and finally, vacuum sintered at 1240°C for 10 h. The experimental results indicate that the oxygen content in the as-sintered condition increased to almost double than that of the powder state (from 0.08 to 0.14 - 0.16 wt. %) and the carbon increased by one third to half (from 0.06 to 0.08 - 0.09 wt. %). This consequently resulted in a shift of the phase transformation temperature to lower values and consequently broadened the reversible austenite to martensite transformation. The uptake of oxygen and carbon during the process led to the formation of the well-known Ti4Ni2Ox and TiC precipitate phases which were evident from grey-scale images of back-scattered SEM.

  • Study on Stability of a Novel Binder System Based on Palm Stearin in Metal Injection Moulding Application
    Scientific Research Journal, 2007
    Co-Authors: Muhammad Hussain Ismail, Norhamidi Muhamad, Istikamah Subuki, Aidah Jumahat, Mohd Afian Omar
    Abstract:

    Metal Injection Molding (MIM) is a wellestablished technology for manufacturing a variety of complex and small precision parts. In this paper, fundamental rheological characteristics of MIM feedstock using palm stearin are theoretically analyzed and presented. The feedstock consisted of gas atomized 316L stainless steel powder at three different particle size distributions and the Binder System of palm stearin (PS) and polyethylene (PE). The powder loading used was 60vol % for all samples (monosize 16 µm, monosize 45 µm, and bimodal 16 µm + 45 µm) and the Binder System of 40vol %(PS/PE = 40/60). The viscosity of MIM feedstock at different temperatures and shear rates was measured and evaluated. Results showed that, the feedstock containing palm stearin exhibited suitable rheological properties by increasing the fluidity of feedstock in MIM process. The rheological results also showed a pseudoplastic flow characteristics, which poses higher value of shear sensitivity (n) and lower value of flow activation energy (E), that are both favourable for injection molding process. The green parts were successfully injected and exhibited adequate strength for handling by optimizing the injection pressure and temperature.

Shu Beng Tor - One of the best experts on this subject based on the ideXlab platform.

  • Effects of debinding parameters on powder injection molded Ti-6Al-4V/HA composite parts
    Advanced Powder Technology, 2001
    Co-Authors: Eng San Thian, N.h. Loh, Khiam Aik Khor, Shu Beng Tor
    Abstract:

    —Titanium alloy– hydroxyapatite (Ti-6Al-4V/ HA) composite powders produced by a ce-ramic slurry were mixed with a multi-component Binder System in the powder injection molding process. The Binder System comprises mainly of natural wax, fatty acid wax, stearic acid, poly-oxi-alkyen-ether and ole After molding, the Binder System was removed by conventional thermal debinding. The effects of heating rate and gas rate on the quality of the debound part in terms of defects, mass of Binder removed and residual carbon level were discussed. A slow heating rate (20 ± C/ h) at the beginning stage of the debinding step and a higher gas rate (250 cm 3 /min) were required for the production of defect-free parts with minimal carbon level.