For the production of complex shaped titanium parts huge advances have been made by powder metallurgy (P/M) during the last years. However, when it comes to miniaturized parts with intricate inner structures like closed channels without entrapped powder and high aspect ratios conventional P/M methods are stretched to their limits. To remedy this shortcoming, Fraunhofer IFAM Dresden uses 3D screen printing, a modified screen printing process based on a powder-binder mixture which is printed layer-by-layer to the desired shape followed by debinding and a conventional sintering step. Especially for small parts a productivity of several million parts per year is achievable. The objective of this work is to demonstrate the possibility to manufacture complex designs based on titanium including thin walls down to 120 μm. Therefore, pre-alloyed gas atomized Ti-6Al-4V powder was used. Analysis of part accuracy, resulting porosity, impurity level and mechanical properties were performed.

Additive manufacturing (AM) of metals is stimulating the tool making industry. Moreover, besides the production of lost forms, AM processes are now being used to directly generate tools, molds or parts, leading to massive time savings. In the case of material development for AM, the challenge is to operate with carbon-containing iron-based materials distinguished by high strength and hardness, as well as high corrosion resistance and thermal conductivity. Often, those materials are susceptible to crack formation during processing. Using Electron Beam Powder Bed Fusion (PBF-EB), the challenge of crack formation can be overcome by using high process temperatures in the range 800–900 °C. In this paper, results on the processing of a cold-working tool steel (X65MoCrWV3-2) and a hot-working steel (X37CrMoV5-1) will be presented. These include the processing window, processing strategies to minimize the density of cracks and properties with respect to microstructure and hardness.

Due to the small variety of materials, the areas of application of additive manufacturing in the toolmaking industry are currently still limited. In order to overcome these material restrictions, AM material development for high carbon-containing iron-based materials, which are characterized by high strength, hardness, and wear resistance, must be intensified. However, these materials are often susceptible to crack formation or lack of fusion defects during processing. Therefore, these materials are preferentially suited for electron beam powder bed fusion (PBF-EB). In this paper, an Fe-Cr-V alloy with 10% vanadium is presented. Investigations were carried out on the PBF-EB system Arcam A2X. Specimens and demonstrators are characterized by a three-phase microstructure with an Fe-rich matrix and VC and M₇C₃ reinforcements. The resulting microstructures were characterized by scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD). Furthermore, mechanical and physical properties were measured. A final field test was conducted to evaluate durability in use.

Powder bed fusion of difficult-to-weld-steels such as the 42CrMo4 applied in this study is a challenging task. These materials are often susceptible to crack formation. To minimize thermal gradients and residual stresses, laser beam technologies generally require preheating of the substrates. Selective Electron Beam Melting (SEBM), on the other hand, is based on preheating the powder bed and, thus, enables crack-free printing even at greater heights. The present study demonstrates the processing of 42CrMo4 by SEBM. Besides parameter optimization, powder analysis, microstructural characterization as well as mechanical testing were carried out both for the as built and heat-treated conditions. The results indicate that the mechanical properties are comparable to those of conventional manufacturing technologies. Furthermore, a generic demonstrator with complex structures shows the high potential of SEBM for these particularly challenging steels.

In addition to the production of lost moulds, additive manufacturing (AM) is increasingly used for the direct manufacture of tools, inserts, or parts thereof. Depending on the material and tool geometry, the combination of additive and conventional technologies (hybrid production) are advantageous. Commercially available AM tool inserts have their limits on the kinds of the materials that can be used. High‐carbon, particle‐reinforced, or crack‐prone materials are indispensable for many areas of tool making but so far can hardly be processed using the common laser‐based AM methods, as rapid solidification in these brittle materials results in high residual stresses, which may lead to crack formation. In contrast, selective electron beam melting (SEBM) is working under elevated temperatures of up to 1100 °C and, thus, minimizes thermal stresses. This study shows how such materials can be processed by SEBM. Results are presented for the first‐time production of high‐carbon iron–chromium alloy. Herein, powder properties and their reusability are focused upon, as well as process parameters and their influence on part quality. Investigations on density, microstructure, and hardness are shown to illustrate the potential of the SEBM process. Final heat treatments reveal that a further increase in hardness is possible in this alloy.

In the present state of the art, highly spherical alloy powders are employed as feedstock in powder bed fusion processes. These powders are characterized by high flowability and apparent density. Their elaborate fabrication process is reflected in high powder price, adding a significant fraction to the cost of additively manufactured parts. Thus, the use of non-spherical powders, such as water atomized material, can lower costs significantly. Here, the electron beam powder bed fusion (PBF-EB) of standard water atomized iron powder used for press-and-sinter is studied. Despite raking problems, using the coating mechanism in standard configuration samples with densities exceeding 99% were fabricated. In a further step, the addition of alloying elements by powder blending is explored. Important powder properties of feedstock blended from irregular and spherical powders are characterized. The PBF-EB processing of two alloys is presented. The first represents a low carbon steel. Samples were characterized by metallographic cross-section, energy dispersive X-ray (EDX) mapping, and mechanical testing. The second alloy system is a FeCrAl. After PBF-EB processing of the powder mixture, chemical homogeneity was achieved. Besides the low cost, this approach of using water atomized powder mixed with master alloy offers the advantage of high flexibility for potential application.