Gradient Temperature Heat Treatment of LPBF 3D-Printed Inconel 718

In order to tailor and improve the performance of microstructures, it helps with many 3D-printed alloys if the post-heat treatment process is carefully designed and executed for this purpose. Researchers Yunhao Zhao, Noah Sargent, Kun Li, and Wei Xiong with the University of Pittsburgh’s Physical Metallurgy and Materials Design Laboratory published a paper, “A new high-throughput method using additive manufacturing for materials design and processing optimization,” about their work on this subject, which was supported by a NASA contract.

They explained that post-heat treatment optimization and composite design are the central parts of materials development, and that “high-throughput (HT) modeling and experimentation are critical to design efficiency.” These aspects are even more important when it comes 3D printing, because the more processing parameters are used, the more the “microstructure-property relationships of the as-fabricated materials” will be effected.

“In this work, we couple the [laser powder bed fusion (LPBF) technique with the gradient temperature heat treatment (GTHT) process as an effective HT tool to accelerate the post-heat treatment design for AM components,” they explained.

They used the Ni-based Inconel 718 superalloy, which has excellent high-temperature mechanical properties, in order to evaluate their proof of concept, as the material is often fabricated with LPBF technology.

Figure 1. (a) Inconel 718 build printed by LPBF; (b) setup of temperature record and illustration of sample cutting for microstructure characterization; (c) setup of the furnace for the high-throughput experiment; (d) experimental temperature distribution inside the bar-sample.

The researchers created a high-throughput approach by using LPBF technology to print a cuboid long-bar sample out of Inconel 718 on an EOS M290. They designed the build with 23 evenly distributed holes, which not only increase the sample’s surface area and improve convection heat transfer, but also make it more flexible “when choosing monitoring locations.” The improved heat transfer also helped lower the variation in the sample’s temperature relative to the temperature of the air.

“As a result, the air temperature calibration became more representative of the real sample temperature, which allowed the preemptive selection of the monitoring locations in the sample according to the actual needs. Using this methodology, the current work significantly reduced the total time needed for heat treatment, and the flexibility of the setup of the high-throughput experiment was increased by adopting additive manufacturing methods for sample fabrication,” they explained.

Once the long bar sample’s microsegration and AM-related grain texture had been removed, it was submerged in ice water, and then conductive high-temperature cement was used to fix eight K-type thermocouples into equidistant holes. Finally, it was time for the 15-hour aging process of the heat treatment.

“The thermocouples were connected to a computer via a data acquisition system to record the aging temperatures at each location throughout the aging process,” the researchers wrote. “The aging heat treatment was then carried out in a tube furnace with one end open to introduce gradient temperatures at different locations in the sample, as illustrated in Fig. 1(c). The furnace temperature settings and the position of the sample inside of the furnace tube had been deliberately calibrated to acquire a temperature gradient of 600~800°C, within which the δ, γ′, and γ″ phases may precipitate during the aging processes [19]. The temperature gradient during the aging process is stable without fluctuation, and the distribution of temperatures achieved at each monitored location is illustrated in Fig. 1(d). From Fig. 1(d), the experimentally obtained temperature gradient was within 605~825°C, which agreed well with our expectation.”

Figure 2. Temperature diagram of heat treatment with corresponding sample notations.

The adjacent alloy to each thermocouple was individually sectioned to characterize the microstructure, and view the effect of the various aging temperatures. After the samples were polished, they were analyzed with SEM (scanning electron microscope), so the team could identify the phases, and EBSD (electron backscatter diffraction), for grain morphology observation.

Figure 3. (a) Results of microhardness and average grain size measurements. IPFs of the aged samples with (b) HT605; (c) HT664; (d) HT716; (e) HT751; (f) HT779; (g) HT798; (h) HT816; (i) HT825.

“Within the temperature range of 716~816°C, the hardness of the aged samples are higher than that in the wrought Inconel 718 (340 HV, AMS5662) [14], indicating the AM alloys could achieve higher strengthening effects when applied suitable heat treatment,” they wrote. “The highest hardness is 477.5 HV0.1 and occurs after aging at a temperature of 716°C. It is found that the temperatures above and below 716°C result in the reduction of hardness. The lowest hardness of 248.4 HV0.1 is obtained at 605°C, which is lower than that in the as-built alloy (338 HV0.1).”

The EBSD found that coarse grains formed in all of the aged samples, and while their diameters were “plotted as a function of the corresponding aging temperatures in Fig. 3(a),” their size is independent of the temperature. This likely means that the aging temperatures did not significantly effect either the grain size or morphology, and that “the relatively large grain size achieved after heat treatment in this study has little contribution to the microhardness variation.”

To better understand structure-property relationships, the researchers chose three samples to undergo more microstructure investigation:

  • HT605 with the lowest microhardness of 248.4 HV0.1,
  • HT716 with the highest microhardness of 477.5 HV0.1, and
  • HT825 with the lowest microhardness of 332.2 HV0.1 in the high-temperature gradient

Other than a few NbC carbides, they did not see any other precipitates in the HT605 sample, but noted that 716°C-aging caused a little “of the δ phase to precipitate along grain boundaries” in the HT716 sample.

“However, a large number of plate-shaped γ″ particles are observed in the TEM micrographs,” the team wrote. “These γ″ particles are very fine with a mean particle length of 13.8±4.2 nm through image analysis. The typical γ′ phase with spherical shape is not found to precipitate in sample HT716. This indicates that the precipitation of γ″ preceded the formation of γ′ in the current study. Therefore, the strengthening effect is dominated by γ″ with fine particle size.”

Figure 4. Microstructures of HT605 characterized by (a) SEM-BSE; (b) bright-field TEM; (c) selected-area-electron-diffraction (SAED). Microstructures of HT716 characterized by (d) SEM-BSE; (e) bright-field TEM; (f) SAED. Microstructures of HT825 characterized by (g) SEM-BSE; (h) bright-field TEM; (i) SAED. The different γ″ variants in (f) and (i) are differently colored, and the corresponding zone axes are indicated.

Just like with the second sample, the researchers also did not observe the γ′ phase in HT825.

The team deduced that the phase transformation behaviors caused the varying microhardnesses in the aged samples, concluding that aging the 3D-printed Inconel 718 samples at 605°C for 15 hours is not ideal for precipitation-hardening.

“We developed a high-throughput approach by fabricating a long-bar sample heat-treated under a monitored gradient temperature zone for phase transformation study to accelerate the post-heat treatment design of AM alloys. This approach has been proven efficient to determine the aging temperature with peak hardness. We observed that the precipitation strengthening is predominant for the studied superalloy by laser powder bed fusion, and the grain size variation is insensitive on temperature between 605 and 825ºC.”

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VELO3D’s Metal Printer Tackles Design and Build Limitations

After working under the radar for many years, California-based VELO3D finally emerged as one of the most promising startups in August 2018 with the release of its Sapphire metal 3D printer. The company developed a metal printing process with more design freedom in metal, able to print complex geometries below 45 degrees, and reduce part costs by 30 to 70 percent, which would make more 3D printed parts possible. Based on the company’s Intelligent Fusion technology, the system comes with fewer constraints than other printers, becoming the only metal laser system with support-free capability and an end-to-end integrated workflow, which many consider will change metal 3D printing forever. 

Brian Spink

Now, thanks to a free webinar hosted this month by the company’s Applications Engineering Manager, Brian Spink, the firm is taking metal 3D printing engineers and specialists through the design process for VELO3D’s Sapphire System, discussing the considerations to keep in mind when selecting parts for their printer, including a deep understanding of angle and floating geometry guidelines, as well as their advanced non-contact recoater mechanism (a truly revolutionary invention).

 

“Designing parts for VELO3D‘s Sapphire printer has fewer restrictions than other systems. In fact, you may not need to redesign your parts at all since the technology can print support-free in a wider range of geometries and has overcome the 45-degree rule, with a first print success rate of 90 percent, and parts that meet and exceed metal manufacturing density requirements over 99.9 percent,” suggests Spink,

VELO3D‘s Sapphire printer is a next-generation laser fusion metal AM system designed for advanced 3D metal printing. While conventional 3D printing systems often require supports for any geometry below 45 degrees, VELO3D’s Sapphire uniquely enables engineers to realize designs with overhangs lower than 10 degrees, and large inner tubes up to 40 mm without supports. Some applications can even be printed free-floating in the powder bed, built layer by layer in Inconel 718 (IN718) or Titanium alloy (Ti6Al4V), using two powerful kW lasers and a patented non-contact recoater. The technology is designed from the ground up with high volume manufacturing in mind featuring a 315 mm diameter by 400 mm height build envelope. Additionally, and to maximize productivity, Sapphire also features integrated in-situ process metrology that enables first-of-a-kind closed loop melt pool control.

Sapphire laser fusion system

The development is truly a game-changer. Users typically had to go through an iterative redesign process in order to make parts that are suitable for additive manufacturing, meaning an extra design effort. During the webinar, the expert explained that there is no support needed for overhangs over 15 degrees for both materials: Inconel and Titanium. Usually, supports have to be designed up-front in order to keep the parts from warping, and then, once the part is built, they have to be removed, which leads to costly post-processing.

“In general, the way people address residual stress along the part is to just add support material. Supports help, but they are not the only way to build and they also introduce other issues, such as restraining or anchoring the part down to keep it from warping up and also acts as energy sync,” he said. “There are major drawbacks to these supports which is why VELO3D does not want to include them, allowing for some unique processes to run through,” Spink went on.

VELO 3D controls the thermal/mechanical behavior of the geometry through proprietary hardware and advanced process controls. The system recognizes many more unique geometries, especially using angle based rules to apply unique processes to the geometries, to avert more control and have a fuller experience without breaking down. 

“Another added level of control that VELO3D has introduced is a closer control for certain process parameters. We have a couple of sensors that monitor the melt pool in real time, and using this data we can recreate a close loop that can adjust the laser parameters–also in real time–to help control the consistency of the melt pool and avoid breakdowns.”

A heat exchanger made in Inconel

“In some of these cases, we are taking something that couldn’s be done with any other AM process and enabling it on the VELO3D system, such as with dome closures where internal cavities have manifold type geometries that can be printed using the firm’s technology without adding support.”

According to Spink, being able to print the feature without supports is highly dependent on the angle normal to the surface, but also on other driving factors that determine angle-based rules, including the curvature of the leading-edge of growth of the part, the number of layers the geometric feature propagates, the laser angle of incidence relative to the angle of growth, and other local geometric characteristics that affect how the energy is being absorbed and how the melt pool is behaving locally.

“Every geometry is unique so its hard to generalize an exact rule for an infinite amount of parts, this is why we are attempting to give the users a couple of proxies and a handfull of rules on simple geometries so that they may interpolate them on other geometries they are experiencing with.”

The specialist explained how to deal with plane and conical geometrical shapes, suggesting, via a “Probability of Breakdown” graph, whether and when the geometry needs to be constrained. The angle guidelines for the conical shapes–which are simple proxy– reveal that an outward growing conical surface (convex) has a higher probability of breakdown once it goes above a full height of 5 mm, meaning it is quite risky, and at 10 mm it behaves at very high risk. Spink suggests that in this cases two basic forces are working together that may lead to breakdowns: global residual stress which is shrinking each layer by pulling the geometry inward towards the local mass, and the other is a skin process that forms a ring around the geometry that contracts and wants to pull it inward. 

Otherwise, an inward growing conical surface (concave) geometry at a 10-degree angle is very stable and does not require support because the probability of breakdown is very low.

Example: strut and impeller mock up

To better understand how conical geometries work in VELO3D, Spink suggests looking into a strut and impeller example, which has a critical internal flow path when it is oriented in an outward growing conical shape (convex) and if it is not supported, there is a high risk of breakdown. This conical shape is going to behave pretty unfavorably and put the user at a higher risk when he or she avoids adding supports. So by flipping it into a concave conical shape, the relatively high-risk downfacing surface keeps the same angle range but the general shape is an inward growing conical one that can maintain stability and avoid breakdowns in the process without having to add supports. 

VELO3D systems also have the ability to print floating parts, which means they are not attached to the build plate at all or any other surface in the build volume, which means no added support material.

“The build starts in powder and the main enabler here, aside from the process control, is the unique non-contact recoater mechanism (which applies a fresh layer of powder on the print bed, making it ready for a pass by the lasers for selective fusing). Because there is no interference between the part, which is now floating loose in the powder, you will find it very rewarding to open a build chamber and simply reach in to pull the part out, without having to remove any support material attached to it,” Spink explained.

There are a few rules for the floating geometries. They must originate from a small-cross section or point of geometry, meaning you can’t print a large flat plane because there will still be residual stress even with VELO3D’s unique processes. And the second main rule is that there must be one powder start and no connection with the build plate. 

VELO3D still has a strong process development team working on ongoing research and development, especially regarding stability on existing processes and spearheading other efforts, but most experts agree that the powerful 3D metal printing technology they have developed is groundbreaking. As you can see in the VELO3D images and videos, there is a lot of detail and accuracy in the geometries. These capabilities mean that the Sapphire System can now print objects that were impossible on other 3D printing systems. VELO3D says they can even achieve a 500:1 aspect ratio on structures, as opposed to the more typical 10:1 ratio on competing systems (or even less 4:1 or 5:1 on other powder bed fusion machines), but you should probably try it out for yourself and see what it is all about.

[Images: VELO3D]

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3D Printing News Briefs: June 27, 2019

In today’s 3D Printing News Briefs, we’re starting with a couple of stories from the recent Paris Air Show: TUSAS Engine Industries has invested in GE Additive technology, and ARMOR explained its AM materials partnership with Airbus. Moving on, Formlabs just hosted some live webinars, and PostProcess Technologies released a whitepaper on surface finishing metal 3D printed parts. Modix is sharing a lot of news, including four new 3D printer models, and finally, FormFutura has introduced sustainable packaging.

TEI Invests in GE Additive Technology

TUSAŞ Engine Industries, Inc. (TEI), founded in Turkey as a joint venture in 1985, has invested in GE Additive‘s direct metal laser melting (DMLM) technology. GE Additive announced at the recent Paris Air Show that TEI had purchased two of its M LINE factory systems and two M2 cusing machines. While the financial terms of the investment were not disclosed, the 3D printers will be installed at TEI’s Eskişehir headquarters, joining its current fleet of laser and Arcam EBM printers.

Professor Dr. Mahmut Faruk Akşit, President and CEO of TEI, said, “Today, we invest in TEI’s future by investing in additive manufacturing, ‘the future of manufacturing.’ Our longstanding partnership and collaboration with GE is now broadening with GE Additive’s machine portfolio.”

Armor and Airbus Partner Up for Aerospace 3D Printing

Air pipe prototype printed using the Kimya PLA HI (Photo: ProtoSpace Airbus)

Continuing with news from the Paris Air Show, ARMOR Group – a French multinational company – was also at the event, exhibiting its Kimya materials and a miniFactory printer, as well as its new aeronautics filament, PEI-9085. While there, ARMOR also met up with Airbus, which has frequently used 3D printing to create parts and prototypes, such as an air nozzle for the climate control system of its 330neo passenger cabin. The company has now requested ARMOR’s expertise in better qualifying its materials in order to standardize its own AM process.

“We have qualified the PLA-HI and PETG-S. We are currently testing more technical materials, such as the PETG Carbon before moving on to the PEI and PEEK. We have requested a specific preparation to make it easier to use them in our machines,” Marc Carré, who is responsible for innovation at Airbus ProtoSpace in Saint-Nazaire,

“We expect to be able to make prototypes quickly and of high quality in terms of tolerances, aesthetics and resistance.

“Thanks to ARMOR and its Kimya range and services, we have found a partner we can share our issues with and jointly find solutions. It is very important for us to be able to rely on a competent and responsive supplier.”

Webinars by Formlabs: Product Demo and Advanced Hybrid Workflows

Recently, Formlabs hosted a couple of informative webinars, and the first was a live product demonstration of its Form 3. 3D printing expert Faris Sheikh explained the technology behind the company’s Low Force Stereolithography (LFS) 3D printing, walked through the Form 3’s step-by-step-workflow, and participated in a live Q&A session with attendees. Speaking of workflows, Formlabs also held a webinar titled “Metal, Ceramic, and Silicone: Using 3D Printed Molds in Advanced Hybrid Workflows” that was led by Applications Engineering Lead Jennifer Milne.

“Hybrid workflows can help you reduce cost per part and scale to meet demand, while taking advantage of a wider range of materials in the production of end-use parts,” Formlabs wrote. “Tune in for some inspiration on new ways of working to advance your own process or to stay on top of trends and capabilities across the ever-growing range of printable materials.”

PostProcess Whitepaper on 3D Print Surface Finishing

PostProcess Technologies has released its new whitepaper, titled “Considerations for Optimizing Surface Finishing of 3D Printed Inconel 718.” The paper discusses a novel approach to help improve surface finish results by combining a patent-pending chemistry solution and software-driven automation. Using this new approach, PostProcess reports increased consistency and productivity, as well as decreased technician touch time. The whitepaper focuses on surface finishing 3D prints made with alloys and metals, but especially zeroes in on nickel superalloy Inconel 718, 3D printed with DMLS technology.

“With current surface finishing techniques used that are largely expensive, can require significant manual labor, or require the use of hazardous chemicals, this paper analyzes the benefits of a novel alternative method for post-printing the part’s surface,” PostProcess wrote. “Key considerations are reviewed including part density and hardness, corrosion (chemical) resistance, grain structure, as well as manufacturing factors including the impact of print technology and print orientation on the surface profile.”

You can download the new whitepaper here.

Modix Announces New 3D Printers, Reseller Program, and Executive

Israel-based Modix, which develops large-format 3D printers, has plenty of news to share – first, the company has come out with four new 3D printer models based on its modular design. The new models, which should be available as soon as Q3 2019, are the 1000 x 1000 x 600 mm Big-1000, the 600 x 600 x 1200 mm Big-120Z, the 1800 x 600 x 600 mm Big-180X, and the 400 x 400 x 600 mm Big-40. Additionally, the company has launched a reseller program, where resellers can offer Modix printers to current customers of smaller printers as the “best next 3D printer.” Finally, Modix has appointed 3D printing veteran John Van El as its new Chief Commercial Officer; he will help build up the company’s partner program.

“We are proud to have John with us,” said Modix CEO Shachar Gafni. “John brings aboard unique capabilities and experiences strengthening Modix’s current momentum on the path to become a global leader in the large scale 3D printing market.”

FormFutura Presents Recyclable Cardboard Packaging

Dutch filament supplier FormFutura wants to set an example for the rest of the industry by not only raising awareness about sustainability, but also by stepping up its own efforts. That’s why the company has moved completely to cardboard packaging – all of its filaments up to one kilogram will now be spooled onto fully recyclable cardboard spools, which will also come in cardboard boxes. All of FormFutura’s cardboard spools and boxes are manufactured in its home country of the Netherlands, which helps reduce its carbon footprint in terms of travel distance, and the material is also a natural drying agent, so it will better protect filament against humidity.

“Over the past couple of months we’ve been brainstorming a lot on how we can make FormFutura more sustainable and help renew our branding. As over this period we have received feedback from the market about helping to find a viable solution to the empty plastic spools, we started setting up a plan to reduce our carbon footprint through cardboard spools,” said Arnold Medenblik, the CEO of FormFutura. “But as we got to working on realizing rolling out cardboard spools, we’ve also expanded the scope of the project to include boxes and logistics.”

Because the company still has some warehoused stock on plastic spools, customers may receive both types of packaging during the transition.

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The AMOS Project is Investigating Repair and Maintenance Technologies for the Aerospace Industry

The Additive Manufacturing Optimisation and Simulation (AMOS) project

There has been enormous progress in terms of aircraft safety in the past two decades. However, last year, the Aviation Safety Network recorded a total of 15 fatal airliner accidents, resulting in 556 deaths. With an estimated worldwide air traffic of about 37,800,000 flights per year and over three million passengers flying on any given day, an aviation industry objective is to keep their aircraft from potential failures with faster on-demand repairs and lower costs. For the last few years, we have seen how 3D printing techniques have been well received in the aerospace industry; the technology is transforming prototyping, the manufacture and maintenance of end-use parts, as well as the production of custom pieces; even the FAA has been developing a comprehensive regulatory plan to deal with aerospace’s industry adoption of 3D printing technology. One international research project in particular has been carrying out an investigation to help the industry understand the pros and cons of how additive manufacturing technology can help with the repair of aircraft parts. Led by the University of Sheffield’s Nuclear Advanced Manufacturing Research Centre (AMRC), the Additive Manufacturing Optimisation and Simulation (AMOS) project focuses on additive technologies already being used in the aerospace industry. It also addresses the potential of different direct energy deposition (DED) methods, like a range of techniques which combine conventional welding tools with automated control to accurately deposit and melt metal powder or wire, or the wire-feed gas tungsten arc process used by Nuclear AMRC’s bulk additive cell. The project’s team is trying to see how these techniques can reduce the time and cost of regular maintenance and repair for aircrafts, while decreasing material waste and extending the life of expensive components. 

According to Yaoyao Fiona Zhao, a professor at McGill University’s Additive Design and Manufacturing Lab, “the project will provide a fundamental understanding of thermal and mechanical behaviour of powder and wire material during deposition, and also a simulation and optimisation platform for industrial partners to further develop their component-specific applications”.

McGill students study additive cell at Nuclear AMRC to feed into defect detection and process planning work

AMOS is a limited time project that began its research on February of 2016 and has an end-date on January, 2020. With over 2.9 million dollars invested, it is one of the first European-Canadian projects to be funded under the ‘Mobility For Growth’ collaboration in aeronautics R&D. The project focuses on several key Direct Energy Deposition AM processes that have great potential to be used as cost-effective and efficient repairing and re-manufacturing processes for aerospace components, such as turbine blades and landing gears. If successful, eventually the project will aid in reducing the weakness of aerospace components at the design stage and extend their life cycles.

The AMOS team

“There’s a host of additive manufacturing technologies available to aerospace manufacturers, but they tend to be focused on new production rather than repairing damaged parts; and the AMOS project is bringing together some of the world’s leading research organisations and companies to identify which additive technologies are best suited for repair and remanufacture, and develop them for commercial use,” explained Rosemary Gault, the European project coordinator at the University of Sheffield AMRC. 

The AMOS consortium includes nine partners from Canada, France, Sweden and the UK, including research organisations, top-tier aerospace manufacturers, and specialist technology developers. École Central de Nantes in France;  GKN Aerospace Engine Systems, McGill University of Montreal and jet engine manufacturer Pratt & Whitney are some of the partners. It is supported by the European Commission through the Horizon 2020 programme and by Canadian funding agencies CARIC and NSERC.

An AMOS team-member working on bulk-additive-cell

The project will involve a range of additive manufacturing technologies used at the participating centres and companies, including laser powder and robotic laser wire systems operated by Liburdi in Canada, a CNC laser powder facility at Ecole Centrale de Nantes in France, and robotic powder diode laser and wire-feed gas tungsten arc facilities at the University of Sheffield AMRC. At McGill University, AMOS is employing an additive machine which will be used to deposit Titanium. No surprise there, the use of Titanium has grown driven by needs in the aerospace industry, and according to a report by SmarTech, shipments of titanium powders grew by 32% in 2018, with the report predicting a 24% growth in titanium alloy revenues in 2019. As the metal AM market grows, so does the demand for metal powders. Material research will focus on three widely used aerospace alloys: Titanium 6-4 alloy (in wire and powder form), AerMet 100 highstrength stainless steel powder and the nickel-chromium superalloy Inconel 718.

According to AMOS, results for Inconel proved that wire-deposited materials showed better tensile properties than the powder-deposited material, for both the as-built material and the interface region. For titanium wire, yield stress, ultimate tensile strength and elongation are comparable with the standard reference material. However, when using powder, the results were below those of the reference standard. The investigation into Aermet 100 is ongoing but the majority of the tests have been completed, although work is also continuing on low-cycle fatigue and crack propagation.

AMOS Project: the machine used to deposit Titanium, located at McGill University in Montreal

The Nuclear AMRC’s research for Amos has generated huge amounts of metallurgical data for quantifying the variations between conventional, as-built and repaired materials, while investigating the interface integrity, performance and predictability of the alloy materials in different orientations, and how this data can facilitate the development of DED repair standards. The Nuclear AMRC team is now working with samples featuring a series of intentional defects, produced by GKN Aerospace. The samples have been scanned using an innovative inspection process developed by Canadian partners Liburdi and McGill University, and the Nuclear AMRC’s non-destructive testing specialists are benchmarking the new technique against current practice. Looking into automated processes for detecting defects to facilitate DED repairs. According to the specialists, they can now identify certain types of defects such as voids and tool marks relatively easily, while cracks are more challenging.

Aerospace manufacturing companies are trying to make their aircraft fully sustainable and 3D printing technology is helping with that by making parts lighter, which in turn saves the companies money from less fuel consumption, emissions, and increased speed. Most commercial aircraft makers are racing towards additive manufacturing technology to cut costs in repair and maintenance as well. Aircraft maintenance companies are under a lot of financial pressure from carriers, who demand these low cost repairs using high quality processes and spare parts. Other projects, like RepAir, are also tackling this issue with additive manufacturing, engaging in research on future repair and maintenance for the aerospace industry and proving that the technology adds new opportunities for onsite maintenance and repair. With 3D printing taking center stage in aircraft repair and maintenance, as well as becoming the protagonist in many projects worldwide, perhaps we can expect better built structures, higher safety features on planes and even fewer fatal airliner accidents thanks to maintenance efforts on site.

3D Printing News Briefs: January 26, 2019

We’re starting with business first in this edition of 3D Printing News Briefs, and then moving on to design software and 3D printing materials. Mimaki USA is getting ready for the grand opening of its LA Technology Center next month, and a Sartomer executive has been elected to the RadTech board of directors. A startup will soon be offering a new cryptotoken for additive manufacturing, and the 3D Printing Association will cease operations. A simplified Blender user interface will make 3D printing easier, and Protolabs is introducing some new materials for its DMLS 3D printing.

Mimaki USA Opening Los Angeles Technology Center

Not long after Japanese company Mimaki Engineering launched its first full-color inkjet printer in 1996, it established Mimaki USA, an operating entity that manufactures digital printing and cutting products around the world. Mimaki USA began preparing to enter the 3D printing market in 2015, and installed its first 3DUJ-553 3D printer in the Americas last winter. Now, it’s preparing for the grand opening of its Los Angeles Technology Center next month.

The event will take place on Friday, February 22nd from 10 am to 4 pm at the new technology center, located at 150 West Walnut Street, Suite 100, in Gardena, California. Attendees will have the chance to meet the company’s industry experts, along with Mimaki Engineering Chairman Akira Ikeda, Mimaki USA President Naoya Kawagoshi, and the regional sales managers from all seven technology centers. Live demonstrations of the company’s printers and cutters will commence after lunch, and attendees will also enjoy tours of the center and a traditional Japanese Kagami Biraki ceremony.

Sartomer’s Jeffrey Klang Elected to RadTech Board

Sartomer, an Arkema Inc. business unit and developer of UV/EB curing technology products, has announced that Jeffrey Klang, its global R&D Directer – 3D Printing for Sartomer, has been elected to the board of directors for RadTech, a nonprofit trade association that promotes the use and development of UV and EB processing technologies. Sartomer is part of Arkema’s commercial platform dedicated to additive manufacturing, and Klang, an inventor with over 20 US patents who was previously the manager for Sartomer’s Coatings Platform R&D, has played an important role in helping the company develop and commercialize many of its oligomers and monomers.

“Jeff’s strong leadership of Sartomer’s innovation and R&D initiatives supports the evolving needs of UV and EB processors in diverse industries, such as 3D printing, coatings, graphic arts, adhesives, sealants, elastomers and electronics. His deep understanding of UV/EB technologies, markets and regulatory requirements will make him an asset to RadTech’s board of directors,” said Kenny Messer, the President of Sartomer Americas.

erecoin Startup to Offer New Cryptocurrency for Additive Manufacturing

A startup called erecoin, which is a product of CAE lab GmbH, is on a mission to change the world of 3D printing by combining the benefits of blockchain with future demands of the ever expanding AM community. After a year of preparation, erecoin has completed the registration of its ICO (Initial Coin Offering), and people can begin purchasing its new cryptotoken on the Ethereum public trading infrastructure starting February 18, 2019.

“We are glad and proud that we, as a young startup, managed to master the necessary steps for a functioning utility token,” said erecoin Co-Founder Konstantin Steinmüller. “At the same time we are curious to see how the community supports our crowdfunding.”

Steinmüller told fellow co-founder Jürgen Kleinfelder about a concrete 3D prototype optimization project that CAE-lab was working on, which is how the idea to combine blockchain and 3D printing came about. The startup’s goal is to get rid of many of the uncertainties in the AM process chain, and blockchain can be used to conclude smart contracts to solve legal and technical questions in the industry. Because data exchange is integrated into the blockchain, a secure and efficient relationship of trust is created between the parties in the chain. Time will only tell if erecoin can achieve its goal and help accelerate additive manufacturing or if it is just hopeful hype or an inefficient way to do something no one needs.

3D Printing Association Closes

The 3D Printing Association (3DPA) is the member-funded, global trade association for the 3D printing industry in Europe. In 2015, the 3DPA moved its base of operations to The Hague in order to develop an independent professional B2B platform for European AM industries. As the 3D printing landscape continues to grow and mature, the association has decided to permanently terminate its operations beginning February 1st, 2019. But this isn’t necessarily bad news – in fact, 3DPA is glad that CECIMO, the European Association of the Machine Tool Industries and related Manufacturing Technologies, has been able to set itself up as a leading 3D printing advocate in Europe.

“3DPA’s goal, derived from an online survey and a business summit at the beginning of 2015, was to provide an independent B2B platform for standardisation, education and industry advocacy. Although there are still important steps to be taken to reaching full maturity, meanwhile the landscape has become less fragmented and volatile, and additive manufacturing has been embraced as strategic pillar by well-established umbrella organisations in sectors like manufacturing, automotive, aerospace and medical appliances,” said 3DPA’s Managing Director Jules Lejeune.

“CECIMO for example, is the long standing European Association of the Machine Tool Industries and related Manufacturing Technologies. It represents some 350 leading AM companies that play a significant role in a wide variety of critical sections of the AM value chain – from the supply of all different types of raw materials for additive manufacturing and the development of software, to machine manufacturing and post-processing. In recent years, it has successfully claimed a leading role in bringing relevant topics to the regulatory agenda in Brussels.”

Simplified Blender User Interface

While the free 3D design and modeling software application Blender is very handy, it’s only helpful if you’re able to learn how to use it, and by some accounts, that is not an easy feat. But, now there’s a new version of Blender that includes a simplified user interface (UI) that’s so easy, even kids as young as 10 years old can figure out how to work it. FluidDesigner has used a new Blender 2.79 feature called Application Templates, which makes it possible to add a library of parametric smart objects and reduce the menu structure and interface.

“Application Templates allows for the simplification of the UI but with the whole power of Blender in the background. You can access nearly all of Blender commands from the Spacebar or by switching panels. Another way to look at it is that it is an Application Template is an almighty Add-On,” Paul Summers from FluidDesigner said in an email.

“All objects are either Nurbs or Bezier (2D) Curves for ease of editing. Nurbs objects in particular can be joined together to create personalised jewellery or artwork quickly and simply.

“There is no need to go to the trouble of joining objects using Boolean modifiers, instead you simply overlap Nurbs objects and then run the *.obj file through Netfabb Basic to repair any issues created with Blender objects. With its much simplified interface, created by Andrew Peel, FluidDesigner for 3D Printing with its parametric smart objects (Nurbs curves) is suitable for even the novice user. The current version runs under Blender 2.79 and can be accessed from the File menu.”

Protolabs Adds New DMLS Materials

Protolabs, a digital manufacturing source for custom prototypes and low-volume production parts, has announced that it is enhancing its direct metal laser sintering (DMLS) offering with two new materials. Nickel-based Inconel 718 is a heat- and corrosion-resistant alloy with high creep, fatigue, rupture, and tensile strength, is able to create a thick, stable, passivating oxide layer at high temperatures, which protects it from attack – making it an ideal material for aerospace and other heavy industries for manufacturing gas turbine parts, jet engines, and rocket engine components.

Maraging Steel 1.2709 is a pre-alloyed, ultra-high strength steel in the form of fine powder. It’s easy to heat treat with a simple thermal age-hardening process, and offers high hardness and high-temperature resistance, which makes it perfect for high performance industrial and engineering parts and tooling applications. These two new Protolabs materials additions help reinforce the company’s enduring reputation as one that can offer an impressive range of metals.

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Protolabs adopts high-performance metal alloys for aerospace-grade 3D printed parts

Protolabs, an award-winning on-demand manufacturing provider, has announced the addition of Inconel 718 and Maraging Steel 1.2709 to its collection of Direct Metal Laser Sintering (DMLS) 3D printing materials. With its high strength and corrosion resistant properties, such materials as Inconcel 718 will further enable the Minnesota-based company to create functional end-use 3D printed parts […]

Study Shows Anisotropic Properties of 3D Printed Nickel Super Alloy K418 (713C)

3D printing materials don’t just suddenly appear and get put to use without further thought – there is a great deal of study that goes into them, particularly metal materials. Their behaviors and properties must be known in order to make sure they perform. Especially now that our technology is being used in high-value applications such as aero-engines and medcine research about material properties and performance is growing in both volume and importance. In a new study entitled “Anisotropy of nickel-based superalloy K418 fabricated by selective laser melting,” a group of researchers used 3D printed samples to study the anisotropic mechanical behavior of one particular material – K418, a nickel-based superalloy.

K418 was developed in the 1960s and has been used on a widespread basis in aerospace engines, hot end turbocharger impellers, turbine blades the automotive industry, and more. It has excellent mechanical properties, excellent ductility and fatigue strength, good oxidation resistance at high temperatures, making it a stable and reliable material. It is difficult to machine by conventional methods at room temperature, however, due to excessive tool wearing, high cutting temperature, and other issues. Components made from K418 are often complex, with inner chambers, thin walls, and overhangs, making them difficult to fabricate through one single method such as machining. This alloy is also known as 713C Alloy, 713C,or Inconel 713C Alloy and many derivatives thereof. Inconel is actually a superalloy that was developed in the 60″s but became a catch-all name for the many superalloys developed around the same time frame. Inconel 713LC was a proprietary alloy made by the INCO (INCO was a global Canadian mining company that was the world’s largest producer of nickel, bought by Vale in 2006) and this term plus all of the derivatives are used interchangeably. 713C or as it is also known K418 has been used extensively in rocket engines, turbo stages and in the space and defense industries since the 60’s. SpaceX, NASA, Rocketdyne and others are all using this material to 3D print rocket engines.

Selective laser melting (SLM, also called powder bed fusion, DMLS, Direct Metal Laser Sintering, PBF) has shown itself to be more effective than conventional techniques like machining at manufacturing complex metal components. Thanks to its high temperature and rapid cooling, it also offers better mechanical properties than casting.

In this study, the researchers looked at the anisotropic properties of the K418 alloy. Anisotropy is defined as a difference in physical or mechanical properties when measured along different axes – in other words, a material’s properties could be different along the vertical axis than along the horizontal axis. In FDM (material extrusion) printed parts for example parts are weaker in between layers than laterally.

The researchers used a self-developed SLM 3D printer to produce several cylinders from the K418 material. The samples were manufactured both horizontally and vertically, or transverse and longitudinal. Microstructural anisotropy analysis was performed on both the horizontal and vertical samples.

“The microstructural anisotropy analysis was performed by optical microscopy (OM) and scanning electron microscopy (SEM),” the researchers explain. “Electron backscatter diffraction (EBSD) analysis was used to identify their crystallographic preferred orientation (texture) and to correlate the anisotropy of the mechanical strength with the texture of the material. The results showed that the transverse specimens had slightly higher yield strength, but much significantly higher ductility than that of the transverse specimens with the elongated columnar grains along the building direction.”

SEM micrographs of (a and b) the horizontal samples and (b and c) the vertical samples.

The extremely high thermal gradient and rapid cooling rate during the SLM process led to strong non-equilibrium solidification of the molten pool and the formation of ultrafine grain structure, which resulted in anisotropic microstructures and mechanical properties in different directions.

“The presence of textures renders the SLM processed K418 samples anisotropic in their mechanical properties, indicating that the transverse specimens display a ductile-brittle hybrid fracture mode with a slightly higher yield strength, while the vertical specimens show a ductile fracture mode with a significant increase in ductility,” the researchers continue.

The fact that SLM-produced K418 has anisotropic properties is an interesting finding. The finding may mean that engineers will feel more comfortable using and designing K418 parts using 3D printing. Metal 3D printing is an extremely effective method for producing components from this material, particularly complex structures. Given the performance envelope of this material and its space applications, this is sure to be an article that many will take an interest in. For some more reading on Inconel this article discusses cooling rates and their effects on Inconel 718 and in this article, we look at how Inconel 718 is being used by Launcher.

Authors of the paper include Zhen Chen, Shenggui Chen, Zhengying Wei, Lijuan Zhang, Pei Wei, Bingheng Lu, Shuzhe Zhang, and Yu Xiang.

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