scholarly journals New Feedstock System for Fused Filament Fabrication of Sintered Alumina Parts

Materials ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 4461 ◽  
Author(s):  
Dorit Nötzel ◽  
Thomas Hanemann
Keyword(s):  
Injection Molding ◽  
Material Selection ◽  
Flow Behavior ◽  
Ceramic Materials ◽  
Maximum Temperature ◽  
Powder Injection ◽  
Fused Filament Fabrication ◽  
Sintered Ceramic ◽  
Whole Process ◽  
Dependent Flow

Only a few 3D-printing techniques are able to process ceramic materials and exploit successfully the capabilities of additive manufacturing of sintered ceramic parts. In this work, a new two component binder system, consisting of polyethyleneglycol and polyvinylbutyral, as well stearic acid as surfactant, was filled with submicron sized alumina up to 55 vol.% and used in fused filament fabrication (FFF) for the first time. The whole process chain, as established in powder injection molding of ceramic parts, starting with material selection, compounding, measurement of shear rate and temperature dependent flow behavior, filament fabrication, as well as FFF printing. A combination of solvent pre-debinding with thermal debinding and sintering at a reduced maximum temperature due to the submicron sized alumina and the related enhanced sinter activity, enabled the realization of alumina parts with complex shape and sinter densities around 98 % Th. Finally the overall shrinkage of the printed parts were compared with similar ones obtained by micro ceramic injection molding.

Metal and Ceramic Micro Components Made by Powder Injection Molding

2007 ◽  
Vol 534-536 ◽  
pp. 373-376 ◽  
Author(s):  
Volker Piotter ◽  
G. Finnah ◽  
B. Zeep ◽  
Robert Ruprecht ◽  
Jürgen Haußelt
Keyword(s):  
Injection Molding ◽  
Large Scale ◽  
Ceramic Materials ◽  
Powder Injection Molding ◽  
Tungsten Alloy ◽  
Powder Injection ◽  
Scale Production ◽  
Large Scale Production ◽  
Scope Of Application ◽  
Tungsten Powders

To overcome the lack of micro manufacturing processes suitable for medium and large scale production as well as to process high resistive materials a special variant of micro injection molding is currently under development: micro powder injection molding (MicroPIM), which already enables the manufacturing of finest detailed components with structure sizes down to a few ten micrometer. In order to expand the scope of application of MicroPIM, tests are being conducted with pure tungsten powders or tungsten alloy powders. As further improvement, micro twocomponent injection molding allows, for example, the fabrication of micro components consisting of two ceramic materials with different physical properties.

Water Debinding for Zirconia Powder Injection Molding

2008 ◽  
Vol 368-372 ◽  
pp. 732-735 ◽  
Author(s):  
Zhi Peng Xie ◽  
Lin Lin Wang ◽  
Xian Feng Yang ◽  
Zhen Ting Zhang
Keyword(s):  
Polyethylene Glycol ◽  
Injection Molding ◽  
Powder Injection ◽  
Major Fraction ◽  
Zirconia Powder ◽  
Sintered Ceramic ◽  
Molecular Weights ◽  
Minor Fraction ◽  
Ceramic Injection Molding ◽  
A Minor

Water debinding is an important debinding technique for ceramic injection molding. However cracks or blisters usually generate during water extraction. In this paper, two types of multi-component binder systems were studied: (1) a major fraction of polyethylene glycol (PEG), and a minor fraction of polyvinyl butyra (PVB) and other additives. (2) a major fraction of PEG, and a minor fraction of polymethyl methacrylate (PMMA) and other additives. Mechanism of defects generation was investigated, and PEGs with various molecular weights were introduced to avoid cracks or blisters during the process. Further more, the compatibilities of PEG/PVB and PEG/PMMA were studied. The results showed that PEG and PMMA exhibited better compatibility, with the feedstock more homogeneous and sintered ceramic parts higher strength.

Development of Recycled TiH2 Feedstock for Powder Injection Molding

2011 ◽  
Vol 291-294 ◽  
pp. 3024-3027 ◽  
Author(s):  
Bermha Cha ◽  
Jin Man Jang ◽  
Won Sik Lee ◽  
Jung Sik Seo ◽  
Se Hyun Ko ◽  
...  
Keyword(s):  
Injection Molding ◽  
Flow Behavior ◽  
Cost Effective ◽  
Powder Injection Molding ◽  
Powder Injection ◽  
Temperature Synthesis ◽  
Good Shape ◽  
Attrition Milling ◽  
High Temperature Synthesis ◽  
Processing Step

Powder Injection molding (PIM) is a cost-effective process for the fabrication of complex shaped parts, and has a great potential in many applications. In this work, an improved wax-based binder was developed for the powder injection molding of TiH2 powder fabricated by recycling of Ti chip. Fine TiH2 powders of about 350 nm in particle size were produced by attrition milling of Ti chip in less than five minutes, resulting from simultaneous self-propagating High temperature Synthesis (SHS) and fracturing. TiH2 feedstock, a mixture of binder and powders, was fabricated with critical powder loading of 68 vol.%. The rheological characteristics of the feedstock were investigated for subsequent processing step. Viscosity of the feedstock showed pseudo-plastic flow behavior and to optimize injection molding parameter, in-mold rheology curve was generated. The results indicated that the recycled TiH2 feedstock can be used for the fabrication of the complex shaped parts with good shape.

Effect of Particle Size in Feedstock Properties in Micro Powder Injection Molding

2007 ◽  
Vol 534-536 ◽  
pp. 349-352 ◽  
Author(s):  
Eung Ryul Baek ◽  
Sugen Supriadi ◽  
Chul Jin Choi ◽  
Byong Taek Lee ◽  
Jae Wook Lee
Keyword(s):  
Injection Molding ◽  
Flow Behavior ◽  
Average Diameter ◽  
High Viscosity ◽  
Metal Injection Molding ◽  
Powder Injection ◽  
Powder Size ◽  
Powder Metal ◽  
Mixing Behavior ◽  
Effect Of Particle Size

Micro powder metal injection molding has received attention as a manufacturing technology for microparts. Small powder size is very useful in achieving detailed structures. STS nanopowders with an average diameter of 100 nm and STS micropowders with an average diameter of 5 micron were utilized to produce feedstock. The mixing behavior of the feedstock was indicated that the nanoparticle feedstock produce highest mixing torque at various powder_loading than the micropowder feedstock. Ares rheometer was utilized to examine visco-elatic flow behavior. The nanoparticles feedstocks showed that elastic properties are dominant in flow behavior and high viscosity. Whereas the micropowders feedstocks, viscous properties are dominant in flow behavior and less viscosity.

scholarly journals Flow Behavior of Cu/CNTs Feedstocks for Powder Injection Molding

2011 ◽  
pp. 199-202 ◽  
Author(s):  
Ali Samer Muhsan ◽  
Faiz Ahmad ◽  
Norani Muti Mohamed ◽  
M. Rafi Raza
Keyword(s):  
Injection Molding ◽  
Flow Behavior ◽  
Powder Injection Molding ◽  
Powder Injection

scholarly journals Experimental Investigation of Comparative Process Capabilities of Metal and Ceramic Injection Molding for Precision Applications

2016 ◽  
Vol 4 (3) ◽  
Author(s):  
Aminul Islam ◽  
Nikolaos Giannekas ◽  
David Marhöfer ◽  
Guido Tosello ◽  
Hans Hansen
Keyword(s):  
Experimental Investigation ◽  
Injection Molding ◽  
Comparative Study ◽  
State Of The Art ◽  
Ceramic Materials ◽  
Metal Injection Molding ◽  
Powder Injection ◽  
Ceramic Injection Molding ◽  
Metal Ceramic ◽  
The Right

The purpose of this paper is to make a comparative study on the process capabilities of the two branches of the powder injection molding (PIM) process—metal injection molding (MIM) and ceramic injection molding (CIM), for high-end precision applications. The state-of-the-art literature does not make a clear comparative picture of the process capabilities of MIM and CIM. The current paper systematically characterizes the MIM and CIM processes and presents the process capabilities in terms of part shrinkage, surface replication, tolerance capability, and morphological fidelity. The results and discussion presented in the paper will be useful for thorough understanding of the MIM and CIM processes and to select the right material and process for the right application or even to combine metal and ceramic materials by molding to produce metal–ceramic hybrid components.

Rheological Analysis of Microminiature Powder Injection Molding (μPIM) Feedstock

2011 ◽  
Vol 52-54 ◽  
pp. 238-243 ◽  
Author(s):  
Haw Pei Li ◽  
Norhamidi Muhamad
Keyword(s):  
Activation Energy ◽  
Injection Molding ◽  
Power Law ◽  
Flow Behavior ◽  
Powder Injection Molding ◽  
Powder Injection ◽  
Flow Activation Energy ◽  
Rheological Analysis ◽  
Power Law Exponent ◽  
Flow Activation

A rheological analysis has been performed to evaluate the characteristics and behaviors of Microminiature Powder Injection Molding (μPIM) feedstocks. The feedstocks comprised of 316L stainless steel powder and water-based binder components. Feedstocks formulations with powder loading of 59% to 63% were prepared and investigated. In these formulations, the binder system consists of 65% Polyethelena Glycol (PEG), 25% Polymethyl Methacrilate (PMMA) and 10% Cellulose Acetate Butyrate (CAB) based on the weight fraction. The influences of rheological behaviors such as flow activation energy (E), Power-Law exponent (n), viscosity (η) and temperature (T) of the SS316L/PEG/PMMA/CAB feedstocks are analyzed and discussed. Results show that all of the feedstocks exhibited the pseudo-plastic flow behavior. The homogenous feedstock at 61 vol. % demonstrated the most satisfactory rheological properties for μPIM with the lowest flow activation energy, Power-Law exponent, n < 1 and moderate viscosity values. It was chosen to perform the injection molding process. Micro components have been replicated successfully by using this selected feedstock.

scholarly journals Rheology of Highly Concentrated Suspensions with a Bimodal Size Distribution of Solid Particles for Powder Injection Molding

Polymers ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2709
Author(s):  
Anton V. Mityukov ◽  
Vitaly A. Govorov ◽  
Alexander Ya. Malkin ◽  
Valery G. Kulichikhin
Keyword(s):  
Injection Molding ◽  
Solid Phase ◽  
Powder Injection Molding ◽  
Solid Particles ◽  
Powder Injection ◽  
Concentrated Suspensions ◽  
Sintered Ceramic ◽  
Technological Practice ◽  
Practical Limit ◽  
Poly Ethylene

Powder injection molding (PIM) is one of the modern and prospective technologies in processing different materials. We proposed to use bimodal compositions of particles for increasing their content in the final products. A set of model suspension of Al with low-molecular-weight poly (ethylene glycol) as a binder based on theoretical arguments concerning the filling capacity of bimodal suspensions was prepared. Studying the rheological properties of these compositions showed that they demonstrate elasto-viscous behavior with significant plasticity that is favorable for the technological process. Using compositions with bimodal distributions allows for increasing the content of the solid phase up to 75 vol. % for PIM technology, which is significantly higher than the standard practical limit. This rheological approach developed for model formulations was applied to processing compositions containing aluminum oxide as typical ceramics and polyolefines as a binder widely used in technological practice. The obtained sintered ceramic samples have quite acceptable mechanical properties of the usual corundum articles.

scholarly journals Development of Hypereutectic AlSi Alloy Powder Injection Molding Feedstocks by Rheological Analysis

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Jiaqi Ni ◽  
Keqing Han ◽  
Muhuo Yu
Keyword(s):  
Injection Molding ◽  
Alloy Powder ◽  
Flow Behavior ◽  
Powder Injection Molding ◽  
Rheological Parameters ◽  
Powder Injection ◽  
Homogeneous Distribution ◽  
Constant Density ◽  
Flow Activation Energy ◽  
Comprehensive Properties

The comprehensive properties of a feedstock have a critical influence on the powder injection molding process. Proper feedstock with homogeneous structure, favorable flow characteristic, and moldability is the prerequisite for obtaining a final part with excellent comprehensive properties. The objective of the present work was to develop an optimal feedstock for fabrication of hypereutectic AlSi (20 wt.%) alloy parts by the powder injection molding technique. For this purpose, micron-sized hypereutectic AlSi (20 wt.%) alloy powder was mixed with different amounts of a binder which consisted of 35 wt.% high-density polyethylene, 62 wt.% carnauba wax, and 3 wt.% stearic acid. The binder contents of the feedstocks were in the range from 13 wt.% to 21 wt.%. The influences of binder content, shear rate, and temperature on the rheological behaviors of feedstocks have been investigated via a capillary rheometer. The feedstock with 21 wt.% binder exhibited a variable flow behavior and was culled. The rest of the feedstocks showed a pseudoplastic behavior. Comprehensive analysis of rheological parameters such as the flow behavior index, yield stress, flow activation energy, and the general moldability index, the feedstock with 17 wt.% binder exhibited the best rheological performance and favorable moldability. The molded part with 17 wt.% binder had constant density, good shape retention, and stiffness as well as homogeneous distribution of the powder and binder. After solvent debinding, the debound item showed a homogeneous porous structure which is suitable for the subsequent thermal debinding and sintering processes.

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