While still young, 4D printing is making waves in the industry with its programmatic structures and reactions to stimuli. This opens up a lot of applications for many products, such as foldable and un-foldable structures or heat-sensitive materials. Sadly, one of the current problems facing 4D printing is that of a lack of materials. To […]
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Velo3D has recently launched its newest metal 3D printer with their trademark Sapphire System technology. The Sapphire System employs a Laser Powder Bed Fusion process using inconel 718 and titanium 6al-4v powders for processing. The company touts the system’s ability to create structures with complex geometric designs “once considered impossible“. The printer uses Velo3D’s intelligent fusion process […]
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A heat exchanger 3D printed with Velo3D.
Velo3D raised $22 Million in 2015 and was working in secret to revolutionize metal 3D printing. For the past years the company has been quiet as a mouse about its process and intentions. A lot of speculation abounded as to what Velo3D could unleash upon the world. Today we learn that the company has developed a metal printing process with more design freedom in metal. The company says that its systems can print complex geometries below 45 degrees. Which would make more 3D printed parts possible with their technology. The company has also developed its own software to acompany its process. And rather than just raising $22 million it turns out that they’ve raised over $90 million in funding. 3DPrint.com interviewed Stefan Zschiegner, Chief Product Officer at Velo3D, about the secretive start up now coming out of stealth mode. From their answers, their published work and patents we can conclude that this is a well captilalized start up with a lot of candle power that seems to have gotten quite far in controlling for many the important variables in metal 3D printing.
Acetabular Cups 3D printed on a Velo3D. We can see that in terms of the sheen and the look of this that it is very different from the usual output of metal 3D printers.
Why all the secrecy?
The model for Silicon Valley has typically been to announce and hype products long before they are commercially available. For a solution like the one we are bringing to market which aims to disrupt the $500 billion global manufacturing industry, we felt it was necessary to wait until we had a thoroughly vetted, customer tested product available for sale before announcing ourselves to the world.
Unpacking Acetabular cups (for giants) with the Velo3D.
What’s special about Velo3D?
We started Velo3D with a bold vision to enable additive manufacturing without design constraints. We are solving problems with deep insights and getting to the root cause. Based on that we build a solution from the ground up for high volume manufacturing consisting of our Sapphire System and Velo3D Flow print preparation software. Intelligent Fusion is the technology that powers the combination of Flow and Sapphire and enables an end-to-end integrated workflow.
While conventional systems often require supports for any geometry below 45 degrees, Velo3D’s Sapphire uniquely enables engineers to realize designs with overhangs lower than 5°and large inner diameters without supports.Some of our key benefites include
1st print success rates of 90%
Reduced part costs by 30-70%
Look at the teeny tiny blue windows, not sure what is going on in there but it is very powerful and plasma-y. Am I the only one getting a kind of DoD InQtel feel from this?
Is this a manufacturing technology?
Yes, Velo3D is a metal additive manufacturing solution company. Our customers are service bureaus who offer metal 3D printing services to end users, as well as leading OEMs for use in-house.
What kind of parts can be made with your technology?
We have removed design constraints by enabling overhangs below 5 degrees and large internal openings up to 40mm. Key applications include shrouded impellers, heat exchangers, pump housings and other turbomachinery components which are critical for the aerospace, energy and industrial applications. We also enable medical instruments and implants, such as orthopedic hip cups.
You state that more geometries can be made? How?
The ability to design and print complex geometries is enabled by our Intelligent Fusion technology. Intelligent Fusion is a Velo3D proprietary technology invented to free the conventional powder bed laser fusion approach from design constraints through process simulation, prediction, and closed loop control.
An impeller 3D printed by Velo3D.
Did you manage to correct for melt pool size in order to improve microstructure control?
Yes. Microstructure control is only one of Velo3D’s benefits. It allows us to build previously impossible designs and to improve part-to-part consistency.
What kind of reliability and repeatability are you getting?
We are meeting and exceeding reliability and repeatability tests by our customers. Currently we are testing with external labs and plan to publish the results soon.
A Shrouded Impeller Printed on the Velo3D, note the supports on the bottom.
How dense are parts?
The parts meet and exceed metal manufacturing density requirements of over 99.9%.
What kind of Ra are you getting off the machine?
The surface properties are geometry dependent and customer application defined. We are demonstrating below < 3 SA.
Both Impellers.
What post processing typically needs to be done?
The Velo3D solution minimizes the need for supports reducing typical support volume 3-5 times. It avoids internal supports that prevents the manufacturability or causes laborious post processing with conventional approaches.
Who are your target customers?
Service Bureaus and OEMs with expertise in additive manufacturing.
A stator ring and impeller
What are your target applications?
Aerospace, energy and Industrial applications, as well as medical applications (i.e., orthopedic implants). Applications include engine parts such as impellers, heat exchanges, and other critical turbomachinery parts, as well as assembly simplifications but also spare parts and spine implements, and larger implements such as hip cups.
Velo3D has come out of nowhere to seem quite the contender. If their estimates and performance claims pan out in the real world then this is a very interesting technology indeed. Simulation is very difficult to do in metal 3D printing and its a key element of getting prints right. Finding out $5000 and three days later that your parts don’t work kind of holds the technology back. This opens up new applications for 3D printing. Especially if they can have a sucess rate of 90% on the first time printed parts. Sometimes in Powder Bed Fusion you have to come up with different support strategies and print a part four or five times to get it right if it is a new geometry. Powder Bed Fusion in metals is great at making a million different hip cups but if we’d throw a radically different shape in the printer for the first time than this will most likely fail. Many applications are being held back because of this. Think of “draw your own jewlery” as a start up idea for example. Reducing supports will also make this much cheaper in terms of overal part costs and may save time as well. Supports are still manually removed on, nearly all, Metal Powder Bed Fusion 3D prints. You can see how parts are being unpacked on the Velo3D here. Manual removal of supports adds considerable cost to the final part so any gain here would be very beneficial. The increased design space could open up new applications, especially in new customers that have thusfar been unable to make their parts with metal 3D printing.
3D printing is very much a testing and data game if you want to take on manufacturing. You’ll need hundreds of kilos of a powder to make sure it works well for example. There are also many geometries that can have significant effects on how and if the part builds. Thermal stresses can cause parts to get ripped apart as well. By developing simulation software the 100 strong Velo3D team has really focussed on getting the repeatability right through lowering their testing cost and increasing their dataset. This is a smart move and will bring dividends to them and their customers. The company has a number of patents including a skillfull 3D printing one, an accurate 3D printing one and an adept 3D printing one. Also the first time I’ve ever seen cute patent names. Going by those patents the company has developed a real time melt pool monitoring technology that works in concert with material dosing and laser control and builds closed loop using, probably, a plasma beam.The company seems to also to be able to correct on the fly with cooling to reduce deformation and may use an FPGA or similar to do this. So depending on errors it seems to be able to reduce the insensity of the laser or actively cool a part. Given the teams previous work and published articles they may also be using a MOSFET or Field Effect Transistor to do this.
Also given that velocity fields play an important role in metal 3D printing and the name of the company is Velo 3D, I’m taking a guess here to say that they probably are managing to control velocity fields in some way which would then allow them to have more of a grip on the final part and how it is built. If they then are able to monitor melt pool size and shape in real time using the FPGA and then have influence on the cooling rate of areas of the part while being able to adjust the plasma beam also on the fly then they may have just come close to cracking this metal printing thing. They certainly have the candle power to do it, they’ve hired very bright people who have over the years written some very interesting papers on real time monitoring, modeling and control of metal 3D printing. During my research for this I was actually at one point surprised to learn that Brent Stucker didn’t work at Velo3D now given the overlap.
The patents also seem to disclose that parts can be polished and post processed in part by lasers on the build machine, perhaps in concert with building the part. Another patent seems to point to active cooling or producing multiple layers at once using a preheat step or process. Can’t wait to find out how this actually works. All in all the value propostion seems a solid one and they’re certainly ticking the right goals. They’ve also got a lot of air which they can use to iron out the kinks in the chain. I like the fact that the company seems down to earth and isn’t all “startuppy” about everything. But, first impressions are first impressions and we work in an industry where an awful lot of machines and dreams have caught fire. We’ll have to wait to find out what the performance is as tested or experienced by the customer, it will cost me some beers at a trade show but I’ll find out for you guys.
Backscattered electrons images to observe oxidation regions of (a) T6 heat-treated, and not in (b) as-built, selective laser melting samples, (c) magnification of (a).
While many aluminum alloy components are still fabricated using traditional casting technologies, there’s been plenty of research and development into 3D printed aluminum alloys as well. For metallic 3D printing, the selective laser melting (SLM) method is typically used to produce Al alloys; however, AlSi10Mg alloys made with SLM technology must set up different post-printing treatments. This is due to a rapid cooling rate during the solidification process, which causes the microstructure and mechanical properties of the part to be vastly different from conventional cast or forged metal alloys.
Additionally, high heat transfer, high reflectivity to the laser beam, and easy oxidation to a tenacious oxide film make SLM-produced AI alloys more difficult than those of steel or titanium.
A pair of researchers recently published a paper, titled “T6 heat-treated AISi10Mg alloys additive-manufactured by selective laser melting,” in the Procedia Manufacturing journal about tailoring the mechanical properties of SLM-fabricated AlSi10Mg alloys with a two-stage T6 heat treatment.
The abstract reads, “A two-stage T6 heat treatment has been proposed to tailor mechanical properties of the selective laser melting fabricated AlSi10Mg alloy. The process included solid solution at 535 ºC and artificial aging at 158 ºC for 10 h. The densification, hardness and oxidation behavior have been investigated after T6 heat treatment. The results demonstrate that the hardness of the T6 heat-treated samples are lower than untreated ones. This is because a fine-grained recrystallization microstructure develops during solid solution. Oxides aggregation and dimple distribution occurred due to sufficient diffusion at the artificial aging of the second stage.”
Optical microscopy images of (a) as-built selective laser melting, and (b) magnification; (c) T6 heat-treated, and (d) magnification, samples perpendicular to building direction of selective laser melting.
The T6 heat treatment is most often used to increase the strength of Al-Si components with Cu and/or Mg in conventional manufacturing, which uses a high-temperature solution treatment to both dissolve larger intermetallic particles and homogenize the alloying elements. Then, lower temperature artificial aging is used to form fine precipitates.
New studies show that T6 heat treatment can actually cause cast alloys to soften, instead of harden, when they’re annealed at either 300 ºC or 530 ºC, which contrasts earlier research. In addition, SLM-fabricated AlSi12 post-solution had a 25% increase of ductility.
“However, most research so far focuses on how to increase the tensile strength during selective laser melting processing, only a few can refer to balancing plasticity and the resistance to facture by post heat treatment. Furthermore, only limited comprehensive work has currently been done to study heat treatment processes specific for selective laser melting-fabricated AlSi10Mg alloys, particularly on their influence on the mechanical properties,” the researchers wrote. “Thus, this raises the need to verify conventional T6 heat treatments when it comes to selective laser melting materials, and what would be the influence of these heat treatments on the specific mechanical properties of selective laser melting-produced AlSi10Mg alloys.”
Hardness measurement of as-built selective laser melting and T6 heat-treated samples.
The paper’s proposed thermal treatment uses a solid solution at 535 ºC and artificial aging at 158 ºC for 10 hours on gas-atomized AlSi10Mg powder provided by Renishaw. Then, the researchers investigated the impact of their two-stage T6 heat treatment on both the mechanical and microstructural properties developed in SLM 3D printed samples.
The samples’ mechanical properties depend on the densification mechanism of the parts, and their microstructure during SLM processing.
“In AlSi10Mg alloys, the theoretical bulk density usually is 2.68 g/cm3. After the selective laser melting processing, the densification of the as-built samples was 96%. By contrast, after T6 heat treatment, the mean value of the densification of the samples is 96.52% and the maximum densification is 98.13%,” the researchers wrote.
These similar values are an indication that the two-stage T6 heat treatment had very little effect on the SLM 3D printed parts’ densification. Additionally, post-T6 heat treatment, the hardness of the as-fabricated sample in a building direction significantly decreased as well. Evidence also shows that the T6 heat treatment can spheroidize oxidation regions to even further enhance the mechanical properties of SLM 3D printed samples.
The researchers concluded, “This heat treatment aims to tune the mechanical behavior of selective laser melting-produced AlSi10Mg alloys. The effects of the T6-like heat treatment on the densification, hardness, and oxidation behavior have been investigated. Similar densification of 96% in the as-built samples and of 96.52% in the heattreated samples indicates that the T6 heat treatment has no importance to the densification. Decrease by about 20% in the hardness of heat-treated samples compared with the selective laser melting as-built samples. The T6 heat treatment can spheroidize oxidation regions and thereby form dimple structure. This finding can offer an intriguing insight into explore oxidation behavior and mechanical properties of selective laser melting-fabricated AlSi10Mg alloy using a two-stage heat treatment.”
Co-authors of the paper are Xianglong Yu with the CAS Key Laboratory of Mechanical Behavior and Design of Materials (LMBD) at the University of Science and Technology of China and Lianfeng Wang with Shanghai Aerospace Equipment Manufacturer.
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Metal 3D printing is constantly under study to improve its quality and repeatability. A new research paper focuses on direct metal laser sintering (DMLS), also known as selective laser melting (SLM) and Powder Bed Fusion for Metal. DMLS still has its shortcomings, which include delamination between base plates and inaccuracy among various orientations. The paper, entitled “Characterization of acoustic signals during a direct metal laser sintering process,” points out that sintered parts tend to still be relatively large, soft and porous, hampering their widespread use, so improving part quality and repetability is crucial, especially for industries like aerospace and medicine.
The researchers look at acoustic signal processing as a way to monitor the build quality of a 3D printed part while in progress.
“This paper reports the relationship between acoustic signals, laser power as well as its laser scanning speed,” the researchers state. “The variety of acoustic signal power spectrum density (PSD) is presented and then the mechanism of acoustic signal formation is elaborated. A good mapping between acoustic signals and laser parameters has been found during the DMLS process. This lays a good foundation for monitoring the process and quality by acoustic signal and will enhance the part quality during the powder-based laser sintering and melting processes in the future.”
Several methods of in-process monitoring exist, such as optical, thermal, ultrasound and acoustic signals. Each has its drawbacks, but acoustic signals have been found to be an effective method as long as they are not disrupted by environmental noise. In this study, acoustic signals generated during the DMLS process were sampled and utilized for online monitoring.
Acoustic signals in a DMLS process are generated by several factors, mostly by the vibration from the friction of flow medium with liquid or solid matter, as well as flow motion. The signals in this study were sampled by an electret condenser microphone and processed with MATLAB 2015b.
The results of the experiment showed that there was a good correlation between the laser frequency and laser power as well as the laser scanning speed and acoustic signals.
“Through the investigation of the acoustic signal, information on the laser scanning characteristics can be extracted,” the researchers explain. “The second frequency peak is more promising for detecting the laser scanning attributes.”
The study showed that there was a good mapping between the acoustic signals and laser scanning status as well as the resulting laser sintering quality. These results, according to the researchers, will lead to future monitoring techniques for DMLS and provide a strong foundation for real-time control of metal printing processes.
“Future studies will be carried out on part qualities such as surface roughness, porosity, density and composition of the powder mixture interpreted via acoustic signals,” they conclude. “Defects can be predicted automatically for quality monitoring and feedback control.”
Studies like this one are important steps toward understanding what is happening during the metal 3D printing process, so that defects can be caught and avoided. Metal 3D printing is far from a perfect process, but the more technology is applied to understanding it, the more effective it will be.
Authors of the paper include Dongsen Ye, Yingjie Zhang, Kunpeng Zhu, Geok Soon Hong and Jerry Fuh Ying His.
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Out of the modern marvels of scientific world, none is arguably more iconic than CERN’s Large Hadron Collider. The massive compound runs for 27 kilometres, making it the largest single machine on the planet. Sadly, this means repairs can be an onerous task. Luckily, researchers are now looking to alleviate their repair woes with 3D […]
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