Euro PM2023 Proceedings

Authors:

Federico Simone Gobber (1), Chiara Monti (2,4), Matteo Turani (3,4), Markus Bambach (4), Marco Actis Grande (1)

1- Politecnico di Torino, Corso Duca degli Abruzzi 24, 10124 Turin, Italy

2- Materials Processes and Sustainability, inspire AG, Technoparkstrasse 1, CH-8005 Zürich, Switzerland

3- Innovation Center for Additive Manufacturing, inspire AG, Lerchenfeldstrasse 5, CH-9014 St. Gallen, Switzerland

4- Advanced Manufacturing Laboratory, Department of Mechanical and Process Engineering, ETH Zürich, Technoparkstrasse 1, CH-8005 Zürich, Switzerland

Abstract:

The need for spherical powders with enhanced flowability and tailored compositions have brought on new atomization techniques particularly suited for the lab-scale and highly competitive R&D activities. Among metal atomization techniques suitable for lab-scale development, those assisted by ultrasonic vibration are experiencing a notable diffusion at the R&D level. Gas-atomization is, however, the primary technique for producing spherical powders when larger batches are needed for production or R&D purposes. The present study analyses the characteristics of an innovative Al-Cu-Ti-Fe-Cr alloy obtained by the two powder production techniques. At first, the two atomization processes are compared in terms of yield in specific PSD ranges, a peculiarity of the AM technologies. Then, the main body of the study presents the characterization and comparison of the powders in terms of morphology and microstructure.

DOI:

https://doi.org/10.59499/EP235764662

Authors:

Raquel de Oro Calderon (1), Robert Steinlechner (1), Wolf-Dieter Schubert (1)

1-Technische Universität Wien (TU Wien), Austria

Abstract:

WC-Co cemented carbides alloyed with Ru are relevant for the hardmetal industry in spite of their high cost. These alloys are used in applications requiring very demanding thermal properties and good performance in aggressive and abrasive media. For some applications, it is difficult to find an alternative material that could offer a similar performance. WC-Co-Ru alloys are analysed in this work considering carbon contents covering the whole carbon window, and using an equivalent WC-Co alloy for comparison. Ru additions broaden the carbon window by increasing the solubility of W in the binder phase all over the carbon window. Thus, the addition of Ru modifies the chemical composition of the binder which has some slight effect on grain growth inhibition. However, the main factor determining the grain growth inhibition seems to be the carbon content, Ru playing only an indirect role.

DOI:

https://doi.org/10.59499/EP235765016

Authors:

Dr. Sebastian Boris Hein (1), Lea Reineke (1), Andrea Cogotti (1), Felix Gerken (1), Malte Sandmann (1)

1- Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM, Wiener Straße 12, 28359 Bremen, Germany

Abstract:

Metal Binder Jetting (MBJ) gains increasing industrial attention due to its serial production potential. In order to tap the full potential of MBJ, a deep process understanding is crucial. The aim of this work is to gain a deeper insight of the influence of process parameters on the powder spreading and powder bed heating by using in situ measurements, as a way to create a basis for real-time process control and optimization. This is achieved by generating images of the powder build-up in front of the spreading roller and thermal imaging of the powder bed for each layer. An automated image processing was developed to examine the powder build-up, and the green part properties were evaluated with different powder heating settings respectively. A proper control of the powder spreading and powder bed temperature positively influences powder binder interaction and green part properties, while minimizing the scrap rate.

DOI:

https://doi.org/10.59499/EP235762920

Authors:

Lars Wimbert 1; Bruce Lindsley 2; Kylan McQuaig 2 ; Rich Bon 3; Jeff Howie 4

1- Hoeganaes Corporation, Germany

2- Hoeganaes Corporation, NJ, USA

3- Alpha Precision Group, Ridgway, PA 15853

4- Alpha Precision Group, Wyandotte, MI 48192

Abstract:

Modern compaction lubricants must address a wide range of key properties through the entire powder metallurgical process flow. These include not only compaction density requirement but also the ability to mix uniformly at scale, good powder flow and fill in powder premixes, ejection, compaction as well as clean burn-off during sintering. Modern lubricant developments, such as AncorLube LV, provide excellent processability in all process steps and are far more clean-burning and environmentally friendly as previous materials. This lubricant has now been used in several production settings and new applications for an extended period with positive results. The benefits and opportunities of using advanced lubricants will be discussed in this paper for various parts geometries and powder compositions with respect to the whole PM process chain.

DOI:

https://doi.org/10.59499/EP235756908

Authors:

Michael Norda (1), Lea Reineke (1), David Wonn (2), Dr. Sebastian Boris Hein (1)

1- Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM, Wiener Straße 12, 28359 Bremen, Germany

2- ExOne GmbH, Daimlerstraße 22, 86368 Gersthofen, Germany

Abstract:

The metal binder jetting (MBJ) process is a powder bed-based Additive Manufacturing (AM) process, which is attracting growing interest. In this process, a liquid binder deposited by a print head is bonding the powder particles to create green parts, which are then consolidated by a subsequent sintering step. The parameters of this liquid deposition are crucial for high quality parts because the droplet impact influences the porosity of the parts. In this work, different droplet volumes are investigated by using two print heads in order to describe the influence of the size, weight and amount of the droplets on the parts quality. The experiments are conducted using 316L stainless steel in two different sizes and a titanium alloy Ti6Al4V. Several properties of powders and parts are analysed such as powder size distribution, green part density, powder bed density and bending strength. Furthermore, drop watcher analyses were conducted. The results show that the print head with lower drop volume introduces more porosity in the green part compared to the higher version. Also, they show higher strength values during the bending tests. The drop watcher analyses indicate that the drops can be very irregular in size, trajectory, and velocity. The fire frequency, voltage and pulse width needs to be adjusted accordingly. Further research can be carried out using optimized firing parameters for the print heads.

DOI:

https://doi.org/10.59499/EP235762850

Authors:

Francesco Marconcini (1), Francesco Tamburrino (1), Guido Giammarinaro (1), Fabrizio Paganucci (1), Armando Viviano Razionale (1)

1- Department of Civil and Industrial Engineering, University of Pisa, L.go L. Lazzarino, 56122 Pisa, Italy.

Abstract:

Material Extrusion Additive Manufacturing (MEAM) for metals is becoming increasingly appealing compared to other metal AM techniques, which are typically energy-intensive and require equipment expensive to install and maintain. In MEAM a polymeric feedstock filled with metal particles is extruded through a heated nozzle; subsequently, the 3D-printed green parts are debound and sintered. This study investigates the feasibility of producing functional Inconel-718 components with a commercial filament and a desktop printer, using a one-step thermal debiding and sintering procedure. To this purpose, the feedstock was extensively characterized, and optimal printing parameters were determined using the design of experiment technique and statistical analysis. Then tensile specimens were printed, debound, sintered and their mechanical and physical properties were measured. The specimens reached a maximum relative density of 83.4% and a maximum ultimate tensile strength of 223 MPa. A decrease in the debinding heat rate was required to avoid macro-void formation.

DOI:

https://doi.org/10.59499/EP235765215

Authors:

Rosito Michele (1), Vanzetti Matteo (1), Padovano Elisa (1), Gili Flavia (2), Dellacà Valentina (2), Tedesco Michele Maria (2), Bondioli Federica (1), Badini Claudio (1)

1- Department of Applied Science and Technology, Politecnico di Torino, Corso Duca degli Abruzzi, 24, 10129 Torino (TO)

2- Centro Ricerche Fiat S.c.p.A. (CRF) Stellantis, Corso Settembrini 40, Corpo 1, ingresso 109/A, 10135 Torino (TO)

Abstract:

The interest in laser powder bed fusion (L-PBF) has grown in the last decades because of the possibility to obtain near-net shapes parts with high performance. However, the main issue in this process is the limited availability of materials. For instance, A6061 alloy has a wide application range but it is hardly processable by L-PBF because of a severe solidification cracking. This critical issue can be overcome through the introduction of nucleants in the system, which induce an equiaxed solidification and avoid the solidification cracks. A6061 RAM2 is a mixture of A6061, Ti and B4C particles capable to react with each other to synthetise TiC and TiB2, grain refiners for Al alloys. A parameters optimization to produce dense samples was performed. Microstructural characterization of these specimens was carried out to investigate the evolution of the system in the processed material. Then, preliminary evaluation of mechanical properties was performed.

DOI:

https://doi.org/10.59499/EP235764682

Authors:

Emre Ozeren (1), Caglar Unver (1), Guney Mert Bilgin (1), Beyzanur Ertekin (1), Alican Tas (1), Akın Orhangul (1), Emre Dilektasli (1)

1- TUSAS Engine Industries Inc., Turkey

Abstract:

In L-PBF, metal powders are used as feedstock material and can be reused for successive productions. The reused powder usage requires attention in high-quality and reliable part production since the reused powder may effect flowability and built-part properties. In this study, Alloy 718 powder was used over a 40 series of L-PBF build cycles without rejuvenating the powder. The powder characterization was performed in order to investigate the flow behavior of reused powder using several methods. Besides, tensile tests, Archimedes and image processing density measurements were performed in order to investigate the behavior of built-part produced by reused powders. Furthermore, chemical composition analyses were carried out over the bulk samples built via L-PBF. The results showed that no major and meaningful difference was seen among 40 cycles in some powder characteristics and built parts behavior while there are prominent differences in some powder characterization methods and in metallurgical behavior.

DOI:

https://doi.org/10.59499/EP235761708

Authors:

S. Riecker (1); R. Teuber (1); T. Studnitzky (1); T. Weißgärber (1,2)

1- Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM

2- Technische Universität Dresden, Faculty Mechanical Engineering, Institute of Materials Science, Chair Powder Metallurgy, 01062 Dresden, Germany

Abstract:

Developments in the sinter-based additive manufacturing (AM) of metal components are progressing rapidly and the quality of the AM parts is steadily increasing. However, there are always process-related limitations with regard to surface roughness, which may make post-processing necessary. Within this context, the hybrid process chain of gel casting with AM molds can offer advantages, as the surface quality of the mold is transferred to the metal part and smoothing of the polymer mold is possible without effort. In this study, surface roughness was evaluated using different mold qualities. The surfaces in the green and sintered states were investigated and related to the mold surface quality. It is found that the surface roughness values Ra and Rz can range below the mean particle size of the powder used, which saves post-processing of the metal component in relevant applications.

DOI:

https://doi.org/10.59499/EP235763845

Authors:

Connor Quilter (1), Michael Head (1), Aurélien Neveu (2), Kate Black (1), Filip Francqui (2)

1- University of Liverpool, Liverpool, United Kingdom

2- Granutools, Rue Jean-Lambert Defrêne, 107, 4340 Awans, Belgium

Abstract:

Powder bed-based methods are common in additive manufacturing (AM), where successive thin layers are created using a ruler or rotating cylinder. The homogeneity of the layers determines the mechanical quality of the built parts. However, the layer quality is directly related to the spreading properties of the feedstock, which relies mainly on the cohesiveness and rheology of the powder. Despite wide availability, iron ore has never been considered a suitable feedstock material for AM. If a viable iron ore feedstock could be produced for AM, it would enable the manufacture of bespoke agglomerates which could be used in blast furnaces to produce steel. This could reduce the thermal budget and considerably lower CO2 emissions in the steel sector. In this study, the spreadability of iron ore powders has been evaluated in a binder jet printer and correlated with its flowability and rheological properties evaluated with a rotating drum method[1].

DOI:

https://doi.org/10.59499/EP235765118

Authors:

J. Trapp (1), G. Walther (1), M. Fries (2), M. Hoffmann (3), S. Böhme (4), T. Weißgärber (1,5)

1- Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM, Branch Lab Dresden, Germany

2- Fraunhofer Institute for Ceramic Technologies and Systems IKTS, Dresden, Germany

3- Ostec GmbH, Am Bahndamm 3, 01665 Klipphausen, Germany

4- PolyMIM GmbH, Am Gefach, D-55566 Bad Sobernheim

5- Technische Universität Dresden, Institute of Materials Science, Chair Powder Metallurgy, Dresden, Germany

Abstract:

The demand for small, spherical powders for additive manufacturing as well as for metal injection molding increases. For particles ≤ 10 µm, mainly two production routes exist: atomization and the carbonyl process. The production of such powders is costly, so alternatives are needed. We present developments in a solid-state processing route using iron ore from the steel steeping process that otherwise might end up as waste. To scale up the production to hundreds of kilograms per day, granules obtained by wet spraying are reduced and sintered in a rotary kiln to form porous but stable agglomerates, and post treated in a NARA hybridizer mill to form dense particles. Pure iron particles with < 0.2 m% oxygen, an apparent density of ≈ 3 g/cm³, and a purity of > 98 % are obtained at an expected cost level of less than 3 €/kg

DOI:

https://doi.org/10.59499/EP235765094

Authors:

Kai Zissel (1,2), Elena Bernardo Quejido (1), Sankhya Bhattacharya (1), Pierre Forêt (1), Eduard Hryha (2)

1- Linde GmbH, Germany

2- Chalmers University of Technology, Sweden

Abstract:

Binder Jetting (BJT) of metals is a multi-step process that relies on the sintering of printed parts to reach the intended material properties. A crucial but often overlooked step after printing is debinding, which is impacted by the processing atmosphere and strongly determines the efficiency of the following sintering process. A tailored processing atmosphere composition and flow can facilitate removal and decomposition of the binder as well as efficient removal of the decomposition products. The success of debinding and sintering is closely correlated, and both require a specific but often different processing atmosphere in terms of purity and composition in order to achieve the required material properties and tolerances of the sintered component. In this study, different atmospheres for the debinding and sintering of 17 4 PH stainless steel manufactured via BJT were studied utilizing chemical analysis and microstructural examination to determine the effectiveness of the debinding and sintering processes.

DOI:

https://doi.org/10.59499/EP235761118