Powder Metallurgical Near-Net-Shape Fabrication of Porous NiTi Shape Memory Alloys for Use as Long-Term Implants by the Combination of the Metal Injection Molding Process with the Space-Holder Technique

2009 ◽  
pp. NA-NA ◽  
Author(s):  
Manuel Köhl ◽  
Tim Habijan ◽  
Martin Bram ◽  
Hans Peter Buchkremer ◽  
Detlev Stöver ◽  
...  
Keyword(s):  
Injection Molding ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Metal Injection Molding ◽  
Injection Molding Process ◽  
Molding Process ◽  
Space Holder ◽  
Near Net Shape ◽  
Niti Shape Memory Alloys

scholarly journals Application of Potassium Carbonate as Space Holder for Metal Injection Molding Process of Open Pore Copper Foam

2016 ◽  
Vol 19 ◽  
pp. 552-557 ◽  
Author(s):  
A. Noorsyakirah ◽  
M. Mazlan ◽  
O. Mohd Afian ◽  
M. Ahmad Aswad ◽  
S. Muhammad Jabir ◽  
...  
Keyword(s):  
Injection Molding ◽  
Potassium Carbonate ◽  
Metal Injection Molding ◽  
Injection Molding Process ◽  
Molding Process ◽  
Space Holder ◽  
Copper Foam

Feedstock Formulation of Open-Pore Cell Copper Foam via Metal Injection Molding

2016 ◽  
Vol 1133 ◽  
pp. 290-294
Author(s):  
Noorsyakirah Abdulah ◽  
Mazlan Mohamad ◽  
Mohd Afian Omar ◽  
Muhammad Jabir Suleiman @ Ahmad ◽  
Ahmad Aswad Mahaidin ◽  
...  
Keyword(s):  
Injection Molding ◽  
Metal Injection Molding ◽  
Injection Molding Process ◽  
Molding Process ◽  
Powder Morphology ◽  
Space Holder ◽  
Copper Foam ◽  
Vertical Injection ◽  
Injection Molded ◽  
Feedstock Preparation

Feedstock preparation is one of the most crucial steps that will influence the metal injection molding process. In this study, the properties of Cu and space holder powder were determined. Powder morphology was captured using Scanning Electron Microscopy (SEM). Three different ratios of feedstocks were premixed with potassium carbonate as space holder using Turbulence Shaker mixer prior to mixing with constant binder system consist of waste rubber (WR). Mixes of three feedstocks with from 40, 50 and 60 wt. % were carried out in Brabender Plasticoder. All feedstocks were mixed at constant powder loading. The feedstocks were successfully injection molded using Vertical Injection Molding machine at 200°C.

The Characterization and Flow Behavior of 316L Stainless Steel Feedstock for Micro Metal Injection Molding (μMIM)

2010 ◽  
Vol 44-47 ◽  
pp. 2872-2876
Author(s):  
Pei Li Haw ◽  
Norhamidi Muhamad ◽  
Hadi Murthadha
Keyword(s):  
Stainless Steel ◽  
Injection Molding ◽  
316L Stainless Steel ◽  
Flow Behavior ◽  
Palm Stearin ◽  
Metal Injection Molding ◽  
Injection Molding Process ◽  
Binder System ◽  
Molding Process ◽  
Rheological Characterization

The rheological behaviors of the Micro Metal Injection Molding feedstock are important for the stability of the feedstock during micro injection molding process and quality of the final micro-components. Homogeneous feedstocks are preferable for MIM process to ensure the dimensional consistency of molded components and prevent the defects of powder-binder separation or particle segregation. In this work, feedstocks with various formulations of 316L stainless steel and binder system were prepared by using Brabender Plastograph EC Plus mixer. The binder system comprises of palm stearin, polyethelene (PE) and stearic acid. In order to obtain the viscosity, activation energy, flow behavior and mold ability index, the rheological characterization of the feedstocks were investigated in numerous conditions by using Shimadzu 500-D capillary rheometer The study showed that all of the 316L stainless steel feedstocks are homogenous with pseudo-plastic behaviors.

scholarly journals Study on Stability of a Novel Binder System Based on Palm Stearin in Metal Injection Moulding Application

2007 ◽  
Vol 4 (2) ◽  
pp. 1
Author(s):  
Muhammad Hussain Ismail ◽  
Norhamidi Muhamad ◽  
Aidah Jumahat ◽  
Istikamah Subuki ◽  
Mohd Afian Omar
Keyword(s):  
Injection Molding ◽  
Flow Characteristics ◽  
Injection Pressure ◽  
Palm Stearin ◽  
Steel Powder ◽  
Metal Injection Molding ◽  
Injection Molding Process ◽  
Binder System ◽  
Molding Process ◽  
Flow Activation Energy

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.

Manufacturing and High Temperature Mechanical Properties of Inconel 713C by Using Metal Injection Molding

2012 ◽  
Vol 602-604 ◽  
pp. 627-630 ◽  
Author(s):  
Kyu Sik Kim ◽  
Kee Ahn Lee ◽  
Jong Ha Kim ◽  
Si Woo Park ◽  
Kyu Sang Cho
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Injection Molding ◽  
Room Temperature ◽  
Tensile Tests ◽  
Metal Injection Molding ◽  
Injection Molding Process ◽  
Molding Process ◽  
High Temperature Mechanical Properties ◽  
Inconel 713C

Inconel 713C alloy was tried to manufacture by using MIM(Metal Injection Molding) process. The high-temperature mechanical properties of MIMed Inconel 713C were also investigated. Processing defects such as pores and binders could be observed near the surface. Tensile tests were conducted from room temperature to 900°C. The result of tensile tests showed that this alloy had similar or somewhat higher strengths (YS: 734 MPa, UTS: 968 MPa, elongation: 7.16 % at room temperature) from RT to 700°C than those of conventional Inconel 713C alloys. Above 800°C, however, ultimate tensile strength decreased rapidly with increasing temperature (lower than casted Inconel 713C). Based on the observation of fractography, initial crack was found to have started near the surface defects and propagated rapidly. The superior mechanical properties of MIMed Inconel 713C could be obtained by optimizing the MIM process parameters.

scholarly journals In Search of the Optimal Conditions to Process Shape Memory Alloys (NiTi) Using Fused Filament Fabrication (FFF)

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4718
Author(s):  
Pedro Carreira ◽  
Fábio Cerejo ◽  
Nuno Alves ◽  
Maria Teresa Vieira
Keyword(s):  
Additive Manufacturing ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Sintering Temperature ◽  
Production Costs ◽  
Layer By Layer ◽  
Secondary Phases ◽  
Fused Filament Fabrication ◽  
Near Net Shape ◽  
Niti Shape Memory Alloys

This research was performed so as to investigate the additive manufacturing of NiTi shape memory alloys, which is associated with direct processes, such as selective laser melting. In addition to its expensive production costs, NiTi readily undergoes chemical and phase modifications, mainly as a result of Ni loss during processing as a result of high temperatures. This research explores the potential usefulness of NiTi as well as its limitations using indirect additive processes, such as fused filament fabrication (FFF). The first step was to evaluate the NiTi critical powder volume content (CPVC) needed to process high-quality filaments (via extrusion). A typical 3D printer can build a selected part/system/device layer-by-layer from the filaments, followed by debinding and sintering (SDS), in order to generate a near-net-shape object. The mixing, extruding (filament), printing (shaping), debinding, and sintering steps were extensively studied in order to optimize their parameters. Moreover, for the sintering step, two main targets should be met, namely: the reduction of contamination during the process in order to avoid the formation of secondary phases, and the decrease in sintering temperature, which also contributes to reducing the production costs. This study aims to demonstrate the possibility of using FFF as an additive manufacturing technology for processing NiTi.

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