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The SLM-XL – 3D project consortium was tasked with the production of 316L stainless steel materials with a prototype SLM machine developed by ADIRA

The SLM-XL – 3D project puts together leading research and industrial organizations to develop a prototype capable of coping with the most demanding real-life scenarios

LISBOA, 9-May-2019 — /EPR INDUSTRIAL NEWS/ — Utilization of laser powder bed fusion (LPBF) technology has been confined to the production of small parts with up to 99,9% relative density and with clear economic benefits, yet the difficulty to increase parts size while keeping its mechanical and other properties have prevented its utilization for large scale parts production. This is the challenge addressed by the SLM-XL project lead by an equipment manufacturer (Adira Metal Forming Solutions) with the collaboration of research organizations (Instituto Superior TécnicoUniversidade Nova de Lisboa – Faculdade de Ciência e Tecnologia) and end user (MCG – Manuel Conceição Graça). The consortium was tasked with the production of 316L stainless steel materials with a prototype SLM machine developed by ADIRA, and the project’s outcomes included a methodology for selection of parameters to fabricate large metal parts in stainless steel 316L, as well as contributing for the development of the final prototype machine.

Laser powder bed fusion (LPBF9 also known as selective Laser Melting (SLM) or direct metal laser sintering (DMLS), is a layer by layer process in which a defined powder thickness is melted by the laser allowing the manufacture of functional complex shaped components, with high structural integrity for low volume and affordable costs in different materials. Printing large-scaled parts with selective laser melting process provides a fast and efficient way to create low volume parts of any length and height allowing flexibility in design and overcoming disadvantages of traditional manufacturing technologies as eg. casting where modifying casting molds when the component design is changing is time consuming and cost-intensive. Especially in case of prototyping, additive manufacturing enhances the flexibility of manufacturers in design iterations.

The challenges are due to the microstructure and mechanical properties of additive manufactured parts, which can show anisotropy and position-depending properties. For large-scaled LPBF machines the position depending changes in microstructure and mechanical properties are more pronounced as compared to LPBF machines with reduced build volume. There is a market demand for this type of machines and as such several manufacturers are commercializing equipment with increased build envelopes.

Adira is addressing this market and has moved from design to prototype. The machine, used to produce the samples for the SLM-XL project, has been displayed in several exhibitions and is gaining market recognition, including being awarded on the Product Innovation category by COTEC-ANI in 2017, due to its unique TLM (Tiled Laser Melting) printing process technology.

Bringing the machine design into real-world usage scenarios

The present investigation has focused on the influence of an enlarged build envelope on porosity, and mechanical properties of 316 L stainless steel samples.

There is still significant lack of knowledge and understanding about the correlations between process parameters and mechanical properties and for high-power LPBF systems with increased build rates. As a result of extended laser powers of up to 1 kW the solidification conditions significantly affect the resulting microstructure in terms of size of dendrites and grains. Consequently, the SLM-XL project focused on the investigation and correlation of process parameters (e.g., laser power, scan speed, layer orientation, hatch distance, vector length, etc.) on the density of the samples (Archimedes, imaging technique), microstructure (scanning electron microscopy) and resultant mechanical properties (hardness, tensile and compression tests) for 316 L stainless steel parts with different geometrical characteristics and produced in different areas of the powder bed.

The results show that to assure 99% plus density in all the building envelop of a system with 1 m3 of volume, the user needs to adjust parameters as the outer zones are reached. A methodology to perform this adjustment is proposed.

The microstructure analysis indicates a preferential elongation of the grains in certain directions which leads to anisotropy of the mechanical properties relative to the direction of build. The mechanical tests resulted in hardness, elongation, tensile strength characteristic of 316L full hardened stainless steel.

SOURCE: EuropaWire

Prometheus project to bridge the existing gap between niche and mainstream applications for high power ultra-short pulse laser surface processing

PORTO SALVO, 4-Apr-2019 — /EPR INDUSTRIAL NEWS/ — Prometheus’ project will bridge the existing gap between niche and mainstream applications for high power ultra-short pulse laser surface processing. This advanced technology enables the production of materials with advanced properties such as non-stick, low wear/friction, oleophobic or hydrophobic, but through this unique project will deliver a broad range of surface functionalities onto metals, polymers and ceramics by way of high throughput, high spatial resolution Direct Laser Interference Patterning (DLIP) surface processing. It is expected to deliver unprecedented surface texturing speeds of up to 5 m2/min and enable high resolution features down to 1 μm to be produced with minimal heat impact on work pieces. This ambitious project represents a pan-European EU consortium of world leading organizations, from industrial and research partners to four manufacturers – Maier, Johnson and Johnson, Fiat Chrysler Automobile group and Arcelik – that will be able to assess the project’s outputs against current industrial processes. Wrapping up the thee-year project, and through breakthrough developments in laser sources, optics, process setup, control and monitoring, the consortium will deliver an integrated laser processing demonstrator system to showcase its capabilities according to the established goals.

Beyond the expected improvement on accuracy, the Prometheus project qualitative objectives include better resources utilization from raw materials to energy and waste. It is also expected a quantum leap on the speed of materials’ processing, as mentioned, by reaching 2-5 m2/min, while also minimizing heat impact on sensitive materials. The project aims to achieve improved flexibility and allow for a simpler product customization – all of this at a fraction of existing solutions’ cost. The case studies being developed include a dishwasher, a tumble dryer, a cylinder piston liner, and high strength aluminium pressing for automotive.

The unique ability of this technology to deliver precise periodic arrays of surface features at an unprecedented processing rate will contribute to its entrance into mainstream manufacturing processes, from its current usage in niche ultra-high value applications. The DLIP (Direct Laser Interference Patterning) technology enables the full utilisation of the high-power laser systems delivering profound productivity gains versus current technologies. Also, by being digital by default, the system enables rapid reconfiguration to deliver customised surface functionalities and patterns on a component by component basis.

Keeping Europe at the core of innovation and environmental leadership

This unique project will bring to light a high potential high power ultra-short pulse laser processing system. Prometheus will address some of the key European 2020 societal challenges, both by ensuring that European companies and research organizations stay at the leading edge of the new
manufacturing technologies and by creating new jobs opportunities. At the same time, the project will minimize environmental impacts.

Prometheus will also contribute to support the goal of increasing investment in innovation up to 3% of the EU’s GDP. The new approaches to surface engineering made possible by this technology will have an impact on the increase in R&D spending, both in photonic component development
necessary to control the increased power densities and in widespread application development.

The exceptionally high processing rate enables cost-effective processing to price-sensitive industrial sectors such as the consortium partners, spanning automotive, fast-moving consumer goods (FMCG), white goods and consumer durables. The effect will also be felt on the overall value chain, given the expected technology transfer and training across manufacturing sectors, as it becomes mainstream.

SOURCE: EuropaWire