Tag Archives: PT2020 Program

SLM-XL project: Printing large-scaled parts with Laser Powder Bed Fusion process

LISBON, 31-May-2019 — /EPR INDUSTRIAL NEWS/ — Additive manufacturing technologies are increasingly used, as they allow the manufacturing of parts with geometries not achievable by traditional processes, leading to increasingly more efficient parts for the intended applications, but mostly for smaller build envelopes and rapid prototyping. In the case of Laser Powder Bed Fusion technology, the SLM-XL project has taken the parts size shortcoming head-on and it has managed to produce large stainless steel parts of over one meter compliant with the 316L specification (image 1). To achieve this milestone, the project included the development of a prototype machine for larger parts using LPBF technology with a new, breakthrough technology, tiled laser melting, that is paving the way for the seamless production of small to large parts for the most demanding usage scenarios. Printing large-scaled parts with laser powder bed fusion 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.

The project experiment has produced samples on the customized LPBF machine with relative densities above 99%, with the best result at 99,655%. This is a positive indicator towards the ultimate goal of zero-defect manufacturing in producing large components with LPBF. The SLM-XL projectwas led 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, INEGI – Institute of Science and Innovation in Mechanical and Industrial Engineering) and one end user (MCG – Manuel Conceição Graça).

There is a growing market demand for this type of machines and this specific prototype includes a unique TLM (Tiled Laser Melting) printing process technology developed by Adira. By being able to produce larger parts, the project has brought the broad utilization of Laser Powder Bed Fusion into the mainstream, with clear benefits in efficient resources utilization, cost effectiveness for customized smaller production runs and overall flexibility on the production. 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.

Empowering industry with large parts production capabilities

Laser powder bed fusion is one of the metal additive manufacturing technologies available. It is a layer by layer process in which a defined powder thickness is melted by the laser allowing the manufacture of functional complex-shaped objects, with high structural integrity for low volume and affordable costs in different materials. Being able to deliver parts produced through this technology is not a novelty, and has already been used, among other, for biomedical devices. But ensuring the production of larger parts, retaining the expected features of materials made from traditional subtractive manufacturing, has proven elusive so far. The consortium tested the ultimate ability to reach the highest possible density for a larger part, which in turn would reveal the type of potential applications.

By showing the capability of producing large build envelopes of 316L stainless steel samples, the project has paved the way for other materials to follow in the near future. To achieve the results of 99% plus density in all the part, it was required to adjust the parameters at the outer zones, and a methodology to perform this adjustment has also been proposed as an outcome of this project.

SOURCE: EuropaWire

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