Posted on

Markforged Metal 3D Printing Replaces Obsolete Part for Legacy Race Car

Founded in 2013 by Greg Mark, Massachusetts-headquartered Markforged quickly became a powerful presence in the 3D printing industry, first with carbon fiber reinforced 3D printing and then developing a novel metal 3D printing technology.

With a range of end-to-end processing systems, Markforged offers its customers access to the boldest advantages in additive manufacturing—not only through rapid prototyping but also rapid speed in the fabrication of high-performance parts. Past the initial investment, industrialists are able to see substantial savings, along with a new ability to innovate upon casting aside the restrictions of older technology. These benefits drew the attention of Tecron, a European company known for its manufacturing and engineering services in the automotive industry.

In a recent case study, the Markforged team details how metal AM processes improved the production of high-performance parts needed for the vintage race cars Tecron has been working on lately. Metal 3D printing offered the opportunity for Tecron to make a shift, especially in working with one of their most important clients, Škoda Motor, to streamline the production of an original, discontinued racecar carburetor.

Tecron’s collaboration with Škoda Motor exemplifies one of the most exciting benefits in 3D printing—offering the ability to create parts that may have become obsolete and are nearly impossible to find. We have followed other projects too within automotive and railways applications, with 3D scanning of original parts allowing for better rebuilding and maintenance.

In the case of the missing design for the carburetor, the original die used in traditional die-casting methods was lost long ago. The Tecron design team not only made an affordable copy of the initial race-car component, but they also modified the structure for better optimization.

Tecron replica carburetor

In another study, Czech Aerospace Research Centre (VZLU) partnered with Tecron for prototyping and testing new parts. Engineers were tasked with creating a new wing design and challenged with finding a method that was not cost-prohibitive. Prototyping can require extensive (and expensive) measures for applications like aerospace, and VZLU realized the need for different, advanced technology in creating complex models like their innovative nozzle design.

“The narrow slit in the design improves overall wing performance, and was crucial to the success of the process. Deconstructing the design into several more manageable parts would have a negative impact on performance,” stated the Markforged case study.

The use of electrical discharge manufacturing (EDM) was another possible choice, but was not cost-effective and would have taken much longer than with metal 3D printing. In using the Metal X by Markforged, the engineers were able to complete their highly customized design, quickly and affordably.

After analyzing over 100 additive use cases, Markforged discovered that industrial users are concerned with the following:

  • Accessibility
  • Design freedom
  • Physical strength and durability
  • Reliability

Data was compiled from the 2020 Additive Trends Report by Markforged, also showing that 46 percent of companies expect to be using additive manufacturing within the next two years. Download the study here.

[Source / Images: Markforged]

The post Markforged Metal 3D Printing Replaces Obsolete Part for Legacy Race Car appeared first on 3DPrint.com | The Voice of 3D Printing / Additive Manufacturing.

Posted on

Investigating Properties of Virgin, Sieved, and Waste 316L Metallic Powder for SLM 3D Printing

We often see metal 3D printing used to make steel parts, so plenty of research is being done regarding the material properties. Researchers from VSB – Technical University of Ostrava in the Czech Republic published a paper, “Research of 316L Metallic Powder for Use in SLM 3D Printing,” about investigating Renishaw’s AISI 316L powder for use in Selective Laser Melting (SLM) technology.

“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.”

Fig. 2. Satellite illustration, magnification x900

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.

Discuss this and other 3D printing topics at 3DPrintBoard.com or share your thoughts below.

The post Investigating Properties of Virgin, Sieved, and Waste 316L Metallic Powder for SLM 3D Printing appeared first on 3DPrint.com | The Voice of 3D Printing / Additive Manufacturing.

Posted on

Czech Republic: Researchers to Support Ongoing Electronic Structures Work with nScrypt 3D Printer

The University of Pardubice is one of the top universities in the Czech Republic, and particularly excels in the chemical sciences. It originally opened in 1950, in answer to a local petition, as an Institute for Chemical Technology, and after years of expansion, was officially rechristened in 1994. The university’s overall vision is to always be contributing to developments in advanced technologies, creative human potential, and scientific knowledge. So it makes sense that is has chosen the 3Dn Tabletop Factory in a Tool (FiT) system from Orlando company nScrypt to help support its ongoing research in 3D printing electronic structures and materials.

nScrypt, a spin-out from research and development think tank Sciperio Inc., designs and manufactures accurate, flexible, high-precision microdispensing and Direct Digital Manufacturing solutions and equipment for industrial applications, and has also branched out into bioprinting as well. Its next-generation systems are used for multiple applications in the aerospace and defense fields, in addition to others.

Precision microdispensing, material extrusion, micro-milling, and pick-and-place toolheads can run on the nScrypt Factory in a Tool

The university will be using nScrypt’s 3Dn Tabletop Dual-Head, multi-material, precision ball screw motion platform for its research. In order to ensure automated in-process inspection and computer vision routines, the system, which includes a point laser height sensor for Z-tracking and mapping for conformal 3D printing onto objects of any surface shape, will come with nVision cameras for monitoring the multiple toolheads. Additionally, the 3Dn Tabletop will also feature a SmartPump microdispensing toolhead.

“This machine’s SmartPump can microdispense more than 10,000 commercially available materials, ranging from a few centipoise (like water) to millions of centipoise (much thicker than peanut butter),” explained nScrypt CEO Ken Church. “We have sold machines to many universities and labs around the world, but this is our first machine going to the Czech Republic. This machine is perfect for printing electronic materials, so we are proud to be able to support the University’s research and education efforts.”

The SmartPump toolhead has a pen tip with the smallest commercially available diameter at just ten microns, and can also get rid of “drooling” with pico-liter volumetric control.

Professor Tomáš Syrový, a member of the university’s Chemical Technology faculty, explained that nScrypt’s 3Dn-Tabletop machine is the perfect choice, as it can successfully print inks that have a wide variety of viscosity.

“The machine’s functionality is allowing us to prototype various functional structures using hundreds of commercial inks or our experimental ink formulations, which we are using in our labs for industrial oriented R&D and for education,” Professor Syrový continued. “This is a big advantage, because we can use identical inks which we in previous times optimized for conventional printing techniques, such as screen printing, gravure printing, or flexography, and which we are using for various large area material printing applications. This is the perfect tool to enable my group to do faster development of various applications like various sensory structures, battery electrode layers, or conductive paths on 3D shaped objects, which our industrial partners frequently request for their commercial applications. A big advantage of the nScrypt system is how it helps our educational mission, where the students are in contact with latest hi-tech printing technologies, which allow them precise material printing, 3D bioprinting of biologically compatible materials, or conformal printing on 3D objects.”

Discuss this and other 3D printing topics at 3DPrintBoard.com or share your thoughts in the Facebook comments below.

The post Czech Republic: Researchers to Support Ongoing Electronic Structures Work with nScrypt 3D Printer appeared first on 3DPrint.com | The Voice of 3D Printing / Additive Manufacturing.

Posted on

Researchers Compare Microstructure of As-Cast, Hot-Extruded, and 3D Printed Magnesium Alloy Samples

Fig. 1: SEM micrographs of the WE43 alloy powder

Alloys of the shiny gray chemical element magnesium (Mg) feature a high strength-to-weight ratio and a low density of about 1700 kg/m3, making them good options for technical applications in the automotive, aviation, and medical fields. But it’s been determined that their weight can be further decreased if porous structures are formed – which can be achieved with 3D printing. A team of researchers from the University of Chemistry and Technology Prague and the Brno University of Technology, both in the Czech Republic, wanted to study the microstructure of a particular magnesium alloy after it had been fabricated using three different methods: as-cast, hot-extruded, and 3D printed with SLM technology.

SLM 3D printing can achieve complex geometric shapes, but there are issues when it comes to fabricating magnesium alloys with this process, mainly high reactivity of magnesium powder, which can lead to unsafe oxide particles forming within 3D printed parts. Patrícia Krištofová, Jiří Kubásek, Dalibor Vojtěch, David Paloušek, and Jan Suchý recently published a study, titled ” Microstructure of the Mg-4Y-3RE-Zr (WE43) Magnesium Alloy Produced by 3D Printing,” about their work mapping an SLM 3D printed magnesium alloy’s microstructure.

“Magnesium alloys made in the form of 3D printing are relatively new production processes,” the researchers wrote. “The study therefore this process compared with current processes, which are now well known and mapped. It was therefore studied the microstructure produced by three different processes of production. The microstructure and chemical composition of present phases were studied using scanning electron microscopy (SEM) and energy dispersive xray spectrometry (EDS). Based on the microstructural examination, significant differences were found between the materials produced by different production processes. The microstructure of the as-cast alloy consisted of relatively coarse α-Mg dendrites surrounded by eutectics containing intermetallic phases rich-in alloying elements. During hot extrusion, the eutectics fragmented into fine particles which arranged into rows parallel to the extrusion direction. The 3D printed alloy was characterized by significantly refined microstructure due to a high cooling rate during the SLM process. It consisted of very fine dendrites of α-Mg and interdendritic network enriched-in the alloying elements. In addition, there were also oxides covering original powder particles and the material showed also some porosity that is a common feature of 3D printed alloys.”

The team used an SLM Solutions 280HL 3D printer to fabricate 15 × 5 × 60 mm rectangular samples of WE43 magnesium alloy, and used SEM and EDS to study their microstructures; then, these were compared to identical materials that had been manufactured through simple gravity casting and hot extrusion.

“The first sample was an as-cast ingot of 60×80×500 mm in size purchased from an industrial supplier. The second WE43 alloy sample was prepared by hot extrusion of the ingot. Cylinders with a diameter of 30 mm and a length of 60 mm were directly cut from the ingot and then extruded at 400°C, extrusion rate of 2 mm/s and extrusion ratio of 16. The resulting extruded rods had a diameter of 7.5 mm,” the researchers explained.

“The analysis revealed that 10% of the WE43 alloy powder particles had a size of 26.9 μm, 50% to 39.8 μm and 90% to 57.9 μm. Thus, the powder contains a sufficient amount of both larger and smaller particles. With respect to the particle size, the size of the building layer was 50 μm.”

The team conducted microscopic observations of the samples, and you can see the views of their microstructures in Figure 2.

Fig. 2: SEM micrographs of the WE43 alloy: a) as-cast, b) hot extruded, c) 3D printed by SLM, d) 3D printed by SLM – detail.

The as-cast alloy has a coarse microstructure, while the microstructure of the sample fabricated with hot extrusion was “considerably” modified. The microstructure of the 3D printed sample is completely different from the other two, featuring regions about 20-50 µm in size that are surrounded by thin boundaries.

“In addition, residual porosity is observed as dark areas between grey regions. The shape and size of grey regions indicates that these regions correspond to original powder particles, either totally or partly melted by laser beam,” the researchers explained. “A more detailed image in Fig. 2d shows very fine internal microstructure of these particles. It contains α-Mg dendrites (dark) surrounded by interdendritic regions (light) enriched in Y and RE elements. The average thiskness of dendritic branches is only approx. 3 µm, suggesting very high cooling rates during the SLM process. In literature focused on the SLM process, cooling rates of 103-106 K/s are often reported.”

The researchers also studied the distribution of elements in the material’s structure, which showed that both the hot-extruded and as-cast material samples had very low oxygen concentration. But the SLM 3D printed sample showed a different story, illustrated in Figure 5 and Table 4.

Fig. 5 Microstructure of the SLM WE43 alloy (SEM) and elements distribution maps (EDS).

“First, element maps and point analysis demonstrate an increased concentration of oxygen in the material which is located mainly in pores (point 1) and also at bondaries between melted powder particles. In the particle interior the O-concentration is very low (point 2),” the researchers wrote. “Second, element map in Fig. 5 also indicates increased content of Y at powder particle boundaries. It can be assumed, that partial oxidation of the powder occurred during the SLM process inside the building chamber. Most probably, the atmosphere contained traces of residual oxygen which reacted preferentially with yttrium due to a high chemical affinity of these elements. For this reason, imperfect connection between powder particles and porosity are observed.”

Results show that an SLM material’s microstructure is “extremely fine” because of high cooling rates, and will also feature a high oxygen concentration “due to a high affinity of the alloy to this gas.” This creates an “imperfect connection” between powder particles and porosity. The researchers plan further studies of this magnesium alloy in order to produce pore-free compact material and decrease the “harmful influence of residual oxygen.”

Discuss this research and other 3D printing topics at 3DPrintBoard.com or share your thoughts below.

The post Researchers Compare Microstructure of As-Cast, Hot-Extruded, and 3D Printed Magnesium Alloy Samples appeared first on 3DPrint.com | The Voice of 3D Printing / Additive Manufacturing.