“Understanding the SLM process is extremely challenging, not only because of the large number of thermal, mechanical and chemical phenomena that take place here, but also in terms of metallurgy. The presence of three states (solid, liquid, gaseous) complicates the ability to analyze and formulate a model formula for proper simulation and prediction of part performance when printed,” they explained. “Since the SLM process operates on a powder basis, this process is more complicated by another factor compared to the use of other bulk material. The properties of the used printing powder define to a large extent the quality of the finished part.”
Because the material can impact an SLM 3D printed part’s final properties, powder research should be done ahead of time for best results. Particle size, shape, flowability, morphology, and size distribution are key factors in making a homogeneous powder layer, and using gas atomization to produce spherical particles helps achieve high packing density; this can also be improved with small particles.
The researchers investigated three phases of metallic powder present in the SLM process – virgin powder (manufacturer-supplied), test powder that had been sieved 30 times, and waste powder “that had settled in the sieve and was no longer being processed and disposed of.” They used a non-magnetic austenitic stainless steel, alloyed with elements like nickel and chromium and containing a low percentage of carbon.
Scanning electron microscopy (SEM) was used to investigate the powder morphology, which “affects the application of metal powder by laser in terms of fluidity and packing density.” First, the shape of the powder particles was measured and evaluated, and then a visual quality evaluation was completed to look at the spherical quality and satellite (shape irregularity) content. The team found that many particles had satellites, but that this number increased in over-sized powder.
Fig. 1. SEM image of virgin powder 316L, magnification x180
“The measurement of virgin powder (Fig. 1) reveals that the production of powder by gas atomization is not perfect and the shape of some particles is not perfectly spherical,” the researchers wrote. “It is also possible to observe satellites (small particles glued to larger ones, Fig. 2), which are again a defect of the production method.”
They found that the particle shape was “not always isometric,” and that cylindrical, elongated, and irregular shapes appeared alongside spherical particles in over-sized powders.
“Another interesting phenomenon was manifested in the sieved powder, where particles with a smoother and more spherical surface were observed than the original particles. This is most likely due to the melting and solidification process that is specific to AM,” they noted.
Fig. 3. Morphological defects – a) particle fusion; b) gas impurities; c) agglomeration – sintered particle; d) dendritic particle structure; e) spherical particle; f) particles with a satellite
An optical method was used to measure powder porosity. The 316L powder was embedded in a resin, and was “1 mm layer abraded” post-curing before the particles were cut in half and polished with diamond paste. The images captured via microscope were loaded into analysis software, which determined that the total density of the powder was 99.785%.
“In general, pores must be closed from 3/4 of their circumference to be considered pores,” the team explained. “Particles that do not comply with this rule are automatically considered irregular particles.”
Fig. 4. An example of open pores that correspond to the rule (L), and pores that do not conform (R)
The researchers also measured the size of all individual pores and recorded which ones began at 5 µm, though they noted that due to potential image resolution issues, “pore sizes of about 5-8 μm should be taken with some uncertainty.”
Fig. 5. Pore size measurement of 316L metallic powder
A histogram showed that, in the metallic powder particles, the “15 µm pore size was most present,” and that the largest was 30 µm.
Table 3. Measured values of porosity of powder particles
Finally, they used an optical method to measure and examine grain size distribution of the virgin and sifted powder. Using 200x magnification, measurements were taken at five random locations, each of which had roughly 200 particles on which they performed static analysis. The results were processed with statistical software, which created cumulative curves to indicate how many particles were smaller or larger than a certain size.
“Of these, the quantiles d10, d50 and d90 were obtained, which express the cut-off limit within which the size falls to 10, 50, 90 % of the measured particles,” they wrote.
The average particle size only increases a little by repeatedly sieving the metallic powder, but because of irregular particles, agglomerated or molten particles larger than 45 μm, they fall through the mesh. Results show that <10 µm particles are reduced, while larger particles are increased, in the sift powder. But, the team notes that the powder is still usable.
“The sift powder showed an increase in particle volume and surface area while circularity decreased, indicating that virgin powder generally has a higher sphericity,” the team explained.
They found defects like agglomeration, gas impurities, and particulate fusions at all three stages, but since the powder is still usable, they concluded that SLM is both an economic and ecological technology. The researchers listed several measures to take in order to “achieve the best possible consolidation,” such as high purity, fine surface, low internal porosity, tight particle distribution, and as few surface pores and satellites as possible.
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Metal 3D printing solutions provider Sciaky, Inc., well known for its extremely popular Electron Beam Additive Manufacturing (EBAM) process, just announced that it has entered into a research and development initiative with metallurgist expert Aubert & Duval – a subsidiary of the Eramet group’s Alloys division – and Airbus, one of its previous 3D printing partners. The ambitious initiative, also called the Metallic Advanced Materials for Aeronautics (MAMA) project, is being driven by the Saint Exupéry Institute for Research in Technology (IRT), and the academic partner for the project is the Production Engineering laboratory of the National School of Engineering in Tarbes, France.
“Sciaky is proud to work with the Saint Exupéry IRT, Aubert & Duval and Airbus on this exciting project. Industrial metal additive manufacturing technology continues to break new ground every day, and Sciaky is committed to keeping EBAM at the forefront of this movement,” said Scott Phillips, the President and CEO of Sciaky, Inc., a subsidiary of Phillips Service Industries, Inc. (PSI).
In terms of work envelope, Sciaky’s exclusive EBAM technology is probably the most widely scalable metal AM solution in the industry. It’s the only industrial metal 3D printing process that has approved applications for air, land, sea, and space, with gross deposition rates up to 11.34 kg of metal an hour, and is able to manufacture parts from 203 mm to 5.79 meters in length. Rather than just melting the outer layer of the metal powder, the EBAM process completely liquefies the metal wire feed.
The fast, cost-effective EBAM process offers a wide range of material options, including titanium, for large-scale metal applications, and uses its adaptive IRISS (Interlayer Real-time Imaging and Sensing System) to combine quality and control, as the patented system can sense, and digitally self-adjust, metal deposition with repeatability and precision. It is mainly due to the IRISS system that the Chicago-based company’s EBAM 3D printing process is so good at delivering, as the company puts it, “consistent part geometry, mechanical properties, microstructure, and metal chemistry, from the first part to the last.”
The goal of its combined MAMA project with Airbus and Aubert & Duval is to combine traditional metallurgy (high-power closed die forging) with new wirefed metal 3D printing techniques, such as Sciaky’s EBAM process, in order to come up with new processes for manufacturing titanium alloys that can be used to make aircraft parts. Based on the caliber of its partners, Sciaky made a good decision in joining the R&D initiative – Airbus is a 3D printing pioneer in the aerospace industry, and Aubert & Duval creates and develops advanced metallurgical solutions for projects in demanding industries, such as nuclear, medical, energy, defense, and aeronautics.
The project’s first phase has global funding in the amount of €4.2 million. 50% of this funding is supported by the French State as part of its “Investing in the Future” program (Programme Investissement d’Avenir, or PIA), while the other half is funded by industrial partners of the initiative.
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Buckle your seat belts, because we’ve got a of news to share with you in today’s 3D Printing News Briefs, starting with more event announcements and moving on to several new partnerships, a workshop, and a 3D printing project. Nanogrande introduced its new 3D printer for nanometer metallic particles at Fabtech this week, while Sartomer and Nanoe are launching new 3D printing innovations at formnext. Creatz3D is working to accelerate ceramics 3D printing in Singapore, while partnerships were announced between Valuechain and Clad Korea, PostProcess and Rösler, and Additive Manufacturing Technologies and Mitsubishi Electric. Finally, two Fraunhofer Institutes are hosting an AM materials workshop, and a maker from YouTube channel Potent Printables is sharing a new project.
Nanogrande Introduced First 3D Printer for Nanometer Metallic Particles
At FABTECH 2018 in Atlanta this week, Nanogrande officially introduced its new 3D printer. The MPL-1, enabled with the company’s Power Layering Technology, is actually the first nanoscale 3D printer for metallic particles in the world, and could successfully open up new 3D printing horizons. Nanogrande has spent years working to develop the new 3D printer.
“Power Layering, while maximizing particle compaction, allows MPL-1 to use particles of all shapes, sizes and types. With this approach, we can easily print with particles as small as a nanometer, but also particles of 5 microns, what the industrial sector is currently seeking. At this size, the particles stick to each other, virtually eliminating the need for support structures typical to 3D printing. In this way, there is a considerable reduction in post- printing costs,” said Juan Schneider, the President and Founder of Nanogrande.
“Today we are witnessing the culmination of a long process of research and development that has given us the chance to set up a team that generates many innovative ideas. Alone, it is possible to have excellent ideas; but, as a team, we can bring these ideas to life. I am very pleased to highlight the success of the efforts of the people who work for Nanogrande.”
Sartomer Europe Introducing New UV-Curable Resins
At formnext in Frankfurt next week, the European division of specialty chemical supplier Sartomer, a business unit of Arkema, will be launching new products in its N3xtDimension line of UV-curable engineered resins as part of its new commercial 3D printing-dedicated platform. The new materials will help companies fulfill performance and regulatory requirements for multiple industrial applications, thanks to their excellent tunability and mechanical properties. At its booth H58 in Hall 3.1 at formnext, Sartomer will introduce N3D I-2105, with impact resistance for manufacturing functional parts; N3D-F2115, which can achieve varying levels of flexibility depending on post treatment; and N3D P-2125, which is perfect for prototyping with its homogeneous network and limited evolution of mechanical properties after post-curing is complete.
“We are addressing the needs of demanding and innovative 3D printing markets by partnering with global leaders to deliver custom material solutions for end-use applications. Through our range of products and services dedicated to additive manufacturing, we are supporting the 3D printing sector as it grows and continues to develop new applications,” said Sumeet Jain, the Global Director for 3D Printing Business at Sartomer.
Nanoe Launches Ceramic and Metal 3D Printer
In other formnext news, French company Nanoe, which is a leader in high-tech raw materials and also specializes in ceramics 3D printing, will be introducing its new Zetaprint system for desktop 3D printing of ceramic and metal materials. The team will perform a live demonstration of the 3D printer at the event, and explain the full 3D printing, debinding, and sintering process.
Additionally, the company will be launching its new stainless steel 16L Zetamix filament. These filaments, made up of a ceramic or metal powder and a polymer matrix, can be used to make high density parts in any FDM 3D printer. Nanoe, which is also developing materials in Inconel and titanium, will also soon be launching a complete line of adapted FDM 3D printers. Visit the company at booth A74 in Hall 3.0 next week at formnext to see a live Zetaprint demonstration and 3D printed parts in various Zetamix materials.
Creatz3D Accelerating Ceramics 3D Printing in Singapore
Speaking of ceramics, Creatz3D Ceramics Service Bureau is dedicated to 3D printing ceramics parts. Founded last year, its parent company is Singapore-based 3D printer and AM software solutions seller Creatz3D, which partnered with 3DCeram Sinto in Limoges to create the service. This partnership, signed in 2016, facilitated the first installation in Singapore of 3DCeram Sinto’s Ceramaker 900 Ceramic 3D printer, at the Advanced Remanufacturing Technology Centre. The Creatz3D Ceramics Service Bureau, which offers diverse material options and a hassle-free experience, is the first, and only, ceramics-focused 3D printing service in the country, and is helping to increase awareness and adoption of ceramics for 3D printing.
“The addition of ceramics to Creatz3D’s portfolio ensures that they stay ahead of the pack in the competitive 3D printing landscape, and their expertise can demonstrate the game-changing capabilities that the technology has to offer to help advance design, engineering, and manufacturing,” said Sean Looi, the General Manager of Creatz3D.
Valuechain Signs Strategic Partnership with Clad Korea
British technology company Valuechain reports that it has signed a strategic partnership with manufacturing company Clad Korea, in order to digitalize 3D printing in East Asia. Both companies will be able to grow their association together in the initial agreement, in addition to bringing Valuechain’s solutions, including its flagship DNA am production control software, to the East Asian AM marketplace. This software addresses 3D printing production process niche requirements, like powder traceability and managing AM build plans.
“Valuechain’s DNA am technology is a unique offering to the market, with great potential to enable rapid and mass production of additive manufactured parts. As we look to enter the additive manufacturing market ourselves, we believe this product will give us a competitive advantage in the industry, and we’re excited to be able to contribute to the growth of this technology in Asia by helping to deliver this solution throughout South Korea,” said Brandon Lee, the CEO of Clad Korea Co. Ltd.
PostProcess Technologies Partnering with Rösler
Moving on with strategic partnerships in the 3D printing world, PostProcess Technologies Inc., a pioneer of software-drive 3D post-processing solutions, is working with Rösler Oberflächentechnik GmbH, which sells finishing systems for traditional manufacturing, to bring automated, intelligent post-print solutions to Europe. Rösler will provide PostProcess’ data-driven support removal and surface finishing solutions for 3D printing to the European market, making it the only surface finishing supplier that will be providing solutions tailored to the needs of both traditional and additive manufacturing. The two companies will debut their partnership next week at formnext, with PostProcess’ technology on display in its booth H68, as well as Rösler’s booth E20, both of which are in Hall 3.0.
“The additive space is rapidly growing, especially in Europe, and as such, the demand for an automated post-printing solution is accelerating. Rösler is a unique partner for PostProcess, bringing expertise in finishing systems with a broad European footprint, thousands of existing customers, and a strong presence across a range of industries that will greatly benefit from PostProcess’ proprietary and integrated software, hardware, and chemistry solution,” said Bruno Bourguet, the Managing Director for PostProcess Technologies.
Additive Manufacturing Technologies Announces Partnership with Mitsubishi Electric
Sheffield-based Additive Manufacturing Technologies Ltd (AMT) has entered into a partnership with Mitsubishi Electric in order to further develop its PostPro3D system with an integrated automation solution, which could provide a major productivity boost for 3D print post-processing. This new solution is based on Mitsubishi Electric’s MELSEC iQ-F Series compact PLC, HMIs, SCADA and MELFA articulated arm robots. While PostPro3D is already pretty impressive, with its ability to automatically smooth an object’s surface to 1μm precision, AMT wanted to further develop the system with certified automation products so it would be suitable for Industry 4.0. Now, PostPro3D is equipped with a Mitsubishi Electric power supply and low voltage switchgear, servo drives and motors, FR-D700 frequency inverters and the optional six-axis robot arm.
“To realise our concept, we needed an automation partner that could provide the whole range of machine control systems, as well as the actual robotics. This is fundamental to truly integrate our machine into the production line of the future as well as to benefit from a lean, single vendor distribution model,” explained Joseph Crabtree, CEO at AMT.
“Mitsubishi Electric was the clear choice because it offers a one stop shop for state-of-the-art automation solutions. In this way, we can be sure that the different components are compatible and can share data. Overall, the company can offer us products that adhere to UL, CE as well as Industry 4.0 requirements.”
Fraunhofer AM Materials Workshop
On November 29 and 30 in Dresden, Germany, Fraunhofer IKTS and Fraunhofer IWS are holding a workshop called “Hybrid materials and additive manufacturing processes.” The two institutes are working together to organize the workshop, which will be held in English and discuss innovative technologies for 3D printing metallic and ceramic components, in addition to application-specific manufacturing of material hybrids. Participants in the workshop’s practical insight sessions will be able to see diverse AM devices for multimaterial approaches live and in action.
“Why is that interesting? Additive manufacturing technologies for material hybrids open up new possibilities in production for diverse industrial branches,” Annika Ballin, Press and Public Relations for Fraunhofer IKTS, told 3DPrint.com. “It is not only possible to realize complex geometries, but also to functionalize components (sensors, heaters), to individualize production (labeling, inscriptions) and to combine different materials properties in one component (conductive/insulating, dense/porous etc.).”
The workshop, which costs €750, will be held at Fraunhofer Institute Center Dresden, and registration will continue until November 22.
DIY 3D Printed Linear Servo Actuators by Potent Printables
A maker named Ali, who runs the Potent Printables YouTube channel, recently completed a neat design project – 3D printed linear actuators. Ali, who was partly inspired by a Hackaday post, said that the project has received a great response on both Twitter and Instagram. He designed the parts in SOLIDWORKS, and controls them with an Arduino Uno. The simple rack-and-pinion design, perfect for light loads, comes in two sizes for different space constraints and force outputs.
“Each design has a pinion that has to be glued to a servo horn, and a selection of rack lengths to suit your needs,” Dan Maloney wrote in a new Hackaday post about Ali’s project. “The printed parts are nothing fancy, but seem to have material in the right places to bear the loads these actuators will encounter.”
Check out the video below to see the 3D printed linear actuators for yourself:
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“Understanding the SLM process is extremely challenging, not only because of the large number of thermal, mechanical and chemical phenomena that take place here, but also in terms of metallurgy. The presence of three states (solid, liquid, gaseous) complicates the ability to analyze and formulate a model formula for proper simulation and prediction of part performance when printed,” they explained. “Since the SLM process operates on a powder basis, this process is more complicated by another factor compared to the use of other bulk material. The properties of the used printing powder define to a large extent the quality of the finished part.”
