Material Extrusion with filaments, Fused Filament Fabrication – FFF, is the most widespread addit... more Material Extrusion with filaments, Fused Filament Fabrication – FFF, is the most widespread additive manufacturing technology. This counts mainly for polymers, since the use of this technology for metal and ceramic powders is still in its early days. For several metals, filaments can be bought in the market. Aluminium has a low sintering temperature already in the range of the temperatures for thermal debinding of many feedstocks and needs special sintering regimes. To meet these special requirements, a feedstock for the production of highly filled aluminium filaments was developed. The printed parts are debinded by solvents. Here, the following results are presented: 1) rheological behaviour of the feedstock, 2) debinding behaviour with emphasis on the selection of solvents and 3) printing performance.
Fused filament fabrication (FFF) is a very popular additive manufacturing technique for the produ... more Fused filament fabrication (FFF) is a very popular additive manufacturing technique for the production of geometrically complex polymeric parts. FFF can also be used for the production of sintered magnetic parts, as part of the shaping, debinding and sintering (SDS) process. In order for sintering to be possible, it is recommended to prepare feedstock materials with 50 vol% or more filler content. However, when the filler content increases the properties required for FFF change. In this paper the mechanical properties of filaments, the viscosity of the molten feedstock, and surface properties of the solidified feedstock were investigated as a function of strontium ferrite powder content (53 to 60 vol%). In addition printing trials were performed. It was observed that mechanical properties significantly decrease, the viscosity increases and the surface tension showed no changes as a function of powder loading. All materials were in principle printable, but the printing temperature had to be adjusted to print the most highly filled material due to its lower mechanical properties and higher viscosity.
Over the last ten years several groups have been carrying out research into metal injection mould... more Over the last ten years several groups have been carrying out research into metal injection moulding (MIM) of neodymium-iron-boron (NdFeB) powders to produce isotropic or anisotropic rare earth magnets with higher complexity than in the conventional press and sintering approaches. However, difficult processability due to the high affinity of the powder to oxygen and carbon pickup remains problematic in terms of obtaining sufficient remanence and coercivity. In this paper, a new approach to MIM of NdFeB magnets is presented. It is based on the use of powder obtained from recycling of used rare earth magnets by the hydrogen decrepitation (HD) process. Different types of binder systems have been used for producing mouldable MIM feedstock. Influence of debinding and sintering conditions on interstitial contents and magnetic properties of sintered MIM parts are presented and discussed. Magnets with a remanence of 570 mT, a coercivity of 970 kA/m and an energy product of 57 kJ/m3 could be...
The current study presents the effect of the backbone as an important binder component on the mec... more The current study presents the effect of the backbone as an important binder component on the mechanical, rheological, and thermal properties of Aluminium (Al) alloy feedstocks. A thermoplastic elastomer (TPE) main binder component was blended with either polypropylene (PP), grafted-maleic anhydride-PP (PPMA), or grafted-maleic anhydride-PPwax (PPMAwax) plus PP, as the backbone. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) tests were performed to investigate the thermal properties of binder systems and feedstocks. Fourier-transform infrared (FTIR) spectroscopy was used to study the chemical interaction between the binder and the Al alloy. After making feedstock filaments, tensile tests, scanning electron microscopy (SEM), and fused filament fabrication (FFF) printing were done. The results showed that although the PP printability was acceptable, the best mechanical properties and printed quality can be achieved by PPMA. TGA test showed that all binder...
MAX phase, as a group of layered ternary carbides and nitrides exhibiting combined properties of ... more MAX phase, as a group of layered ternary carbides and nitrides exhibiting combined properties of metallic and ceramic materials, attracts increasing interest because they own exceptionally chemical, physical, electrical, thermal, and mechanical properties. In the present paper, a novel Ti3AlC2-based green part was manufactured by extrusion-based fused filament fabrication (FFF) and 3D printing technologies. The morphology, thermal/electrical conductivity, thermal stability, electromagnetic interference (EMI) shielding effectiveness (SE), and mechanical properties of Ti3AlC2/binder with the volume ratio of 1:1 were investigated. The tensile and compressive strengths and elongation are measured to be 8.29 MPa and 18.20%, 44.90 MPa and 33.76%, respectively. The morphology of the filament reveals that Ti3AlC2 powders are well bonded by the thermoplastic binder. More importantly, the composite shows good thermal and electrical conductivities together with the excellent EMI shielding effe...
IBEREO15 - Challenges in rheology and product development, Nov 30, 2015
Powder injection moulding (PIM) process is well established for production of small precision com... more Powder injection moulding (PIM) process is well established for production of small precision components with both metal and ceramic powders. In comparison to unfilled polymers, the PIM-feedstocks are highly filled multiphase systems, whose flow behaviour is very sensitive to composition of binder and powder loading. Furthermore, the rheology of highly filled multiphase systems is characterized by strain and temperature dependence and influenced by flow instabilities and yield stress. In this study, the rheological behaviour of 316L feedstocks with a polypropylene/wax binder system and different powder loadings was investigated. The experimental work was performed with a rotational and a high pressure capillary rheometer. The aim of this work was to evaluate mixing rules predicting the viscosity of the feedstock out of its composition taking into account the melt temperature rise due to dissipative heating. Hence, measured data were corrected with respect to temperature. Thus the influence of the temperature onto the viscosity and the related model was evaluated.
Material Extrusion with filaments, Fused Filament Fabrication – FFF, is the most widespread addit... more Material Extrusion with filaments, Fused Filament Fabrication – FFF, is the most widespread additive manufacturing technology. This counts mainly for polymers, since the use of this technology for metal and ceramic powders is still in its early days. For several metals, filaments can be bought in the market. Aluminium has a low sintering temperature already in the range of the temperatures for thermal debinding of many feedstocks and needs special sintering regimes. To meet these special requirements, a feedstock for the production of highly filled aluminium filaments was developed. The printed parts are debinded by solvents. Here, the following results are presented: 1) rheological behaviour of the feedstock, 2) debinding behaviour with emphasis on the selection of solvents and 3) printing performance.
Fused filament fabrication (FFF) is a very popular additive manufacturing technique for the produ... more Fused filament fabrication (FFF) is a very popular additive manufacturing technique for the production of geometrically complex polymeric parts. FFF can also be used for the production of sintered magnetic parts, as part of the shaping, debinding and sintering (SDS) process. In order for sintering to be possible, it is recommended to prepare feedstock materials with 50 vol% or more filler content. However, when the filler content increases the properties required for FFF change. In this paper the mechanical properties of filaments, the viscosity of the molten feedstock, and surface properties of the solidified feedstock were investigated as a function of strontium ferrite powder content (53 to 60 vol%). In addition printing trials were performed. It was observed that mechanical properties significantly decrease, the viscosity increases and the surface tension showed no changes as a function of powder loading. All materials were in principle printable, but the printing temperature had to be adjusted to print the most highly filled material due to its lower mechanical properties and higher viscosity.
Over the last ten years several groups have been carrying out research into metal injection mould... more Over the last ten years several groups have been carrying out research into metal injection moulding (MIM) of neodymium-iron-boron (NdFeB) powders to produce isotropic or anisotropic rare earth magnets with higher complexity than in the conventional press and sintering approaches. However, difficult processability due to the high affinity of the powder to oxygen and carbon pickup remains problematic in terms of obtaining sufficient remanence and coercivity. In this paper, a new approach to MIM of NdFeB magnets is presented. It is based on the use of powder obtained from recycling of used rare earth magnets by the hydrogen decrepitation (HD) process. Different types of binder systems have been used for producing mouldable MIM feedstock. Influence of debinding and sintering conditions on interstitial contents and magnetic properties of sintered MIM parts are presented and discussed. Magnets with a remanence of 570 mT, a coercivity of 970 kA/m and an energy product of 57 kJ/m3 could be...
The current study presents the effect of the backbone as an important binder component on the mec... more The current study presents the effect of the backbone as an important binder component on the mechanical, rheological, and thermal properties of Aluminium (Al) alloy feedstocks. A thermoplastic elastomer (TPE) main binder component was blended with either polypropylene (PP), grafted-maleic anhydride-PP (PPMA), or grafted-maleic anhydride-PPwax (PPMAwax) plus PP, as the backbone. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) tests were performed to investigate the thermal properties of binder systems and feedstocks. Fourier-transform infrared (FTIR) spectroscopy was used to study the chemical interaction between the binder and the Al alloy. After making feedstock filaments, tensile tests, scanning electron microscopy (SEM), and fused filament fabrication (FFF) printing were done. The results showed that although the PP printability was acceptable, the best mechanical properties and printed quality can be achieved by PPMA. TGA test showed that all binder...
MAX phase, as a group of layered ternary carbides and nitrides exhibiting combined properties of ... more MAX phase, as a group of layered ternary carbides and nitrides exhibiting combined properties of metallic and ceramic materials, attracts increasing interest because they own exceptionally chemical, physical, electrical, thermal, and mechanical properties. In the present paper, a novel Ti3AlC2-based green part was manufactured by extrusion-based fused filament fabrication (FFF) and 3D printing technologies. The morphology, thermal/electrical conductivity, thermal stability, electromagnetic interference (EMI) shielding effectiveness (SE), and mechanical properties of Ti3AlC2/binder with the volume ratio of 1:1 were investigated. The tensile and compressive strengths and elongation are measured to be 8.29 MPa and 18.20%, 44.90 MPa and 33.76%, respectively. The morphology of the filament reveals that Ti3AlC2 powders are well bonded by the thermoplastic binder. More importantly, the composite shows good thermal and electrical conductivities together with the excellent EMI shielding effe...
IBEREO15 - Challenges in rheology and product development, Nov 30, 2015
Powder injection moulding (PIM) process is well established for production of small precision com... more Powder injection moulding (PIM) process is well established for production of small precision components with both metal and ceramic powders. In comparison to unfilled polymers, the PIM-feedstocks are highly filled multiphase systems, whose flow behaviour is very sensitive to composition of binder and powder loading. Furthermore, the rheology of highly filled multiphase systems is characterized by strain and temperature dependence and influenced by flow instabilities and yield stress. In this study, the rheological behaviour of 316L feedstocks with a polypropylene/wax binder system and different powder loadings was investigated. The experimental work was performed with a rotational and a high pressure capillary rheometer. The aim of this work was to evaluate mixing rules predicting the viscosity of the feedstock out of its composition taking into account the melt temperature rise due to dissipative heating. Hence, measured data were corrected with respect to temperature. Thus the influence of the temperature onto the viscosity and the related model was evaluated.
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Papers by Christian Kukla