REJOINT Uses EBM, Sensors & IoT Data for Patient-Specific Knee Surgery

REJOINT is an Italy based medical device company specializing in Total Knee Arthroplasty operations that received 3 million Euro in EU Horizon 2030 funding in 2019. The firm is seeking US Food & Drug Administration, FDA 510(k) clearance for a new data-driven mass customization approach to patient-specific implants.

In total knee arthroplasty procedures, usually arthritic, knees have their surfaces completely replaced by implants. Total knee arthroplasty is becoming more prevalent as more people enter more advanced ages. More of those people also want to live active lifestyles compared to years ago, when more sedentary lifestyles were the norm. Increasingly people from developing and middle-income countries can also now have these procedures made available to them and younger patients (below 65) are increasingly getting them.

At the same time, these kinds of operations may become more prevalent due to increased obesity. Obesity affects over 1.9 billion adults and over 600 million are clinically obese which in turn can exacerbate osteoarthritis. For “every 5 kg increase in weight, the risk (of the development of knee osteoarthritis) increases by 30%.” Around 45% of TKA patients may have diabetes as well, which is a steadily rising condition in and of itself.

In the US alone some estimate that the prevalence of the procedure will increase by 143% by 2050, while, as of 2015, 7 million adults have had the procedure. In 2010, the prevalence was “1.52%….Prevalence was higher among women than among men and increased with age, reaching…10.38% for total knee replacement at eighty years. These estimates corresponded …. 4.7 million individuals (3.0 million women and 1.7 million men) with total knee replacement in 2010.” Other estimates predict 673% growth in the US until 2030 or even growth of 855%. In the US 790,000 procedures are performed annually, while even a small country as the Netherlands has over 28,000 procedures per year.

REJOINT’s approach puts the firm in the middle of several converging megatrends and the firm is also taking a very trendy approach to improving total knee arthroplasty. By extensively using data, IoT sensors, artificial intelligence, and 3D printing the company hopes to create better mass-customized implants for patients.

REJOINT uses GE’s Arcam EBM technology to make patient-specific implants. On the whole, we would expect that patient-specific implants would hasten procedures and perhaps shorten recovery time because the implants fit the patient better, reducing the length of the procedure and requiring less pushing and shoving by the doctors to make the implant fit.

Pushing and shoving is not used facetiously here. Orthopedic surgeries are a lot less delicate than one may assume. So patient-specific seems like a very logical choice that may be quite beneficial to the patient. Most studies on patient-specific implants have, however, been carried out at the behest of the manufacturers of these implants.

What we do know is that we can get good osseointegration through EBM implants and this is partially why the procedure has grown in popularity in recent years. EBM medical devices can also be comparatively easier to develop through making more iterations possible and are lower cost than conventionally manufactured implants.

Higher specificity of designs and more patient-specific options have been something that the medical device industry has been flirting with for quite a while now, but what should guide patient-specific designs? Can we create specific textures for osseointegration for specific patients or groups of patients? How many sizes of implants are optimal, and do we really need individualized implants? There are no hard and fast answers to these questions at the moment.

What REJOINT has done however is to look further at new data sources that could input implant design and individualization. The company maintains that, “For the patient, over- or under-sizing means constant awareness of the presence of an artificial joint, as well as leading to muscle and ligament decay.” The company also notes, “Patient feedback after an implant can sometimes reflect these issues and indicates that dissatisfaction can be felt by one in five patients and sometimes even to levels of one in four. Dissatisfaction is often largely related to the suboptimal sizing of the implanted prosthesis.

“To produce the additively manufactured prosthesis, REJOINT starts by 3D modelling the patient’s CT scan. Sophisticated Artificial Intelligence (AI) algorithms are then used to analyze the images and identify the most suitable size for each specific case.

AI is used to compare the unique anatomy of a patient on several thousand prosthetic dimensions, each with as many dimensional variables in specific areas of the implant.

The surgeon is then offered the optimal configuration, for positioning both the prosthetic components and for simulating the operation. This analysis forms the basis for the production of the prosthesis and for patient-specific tools for the planning of the intervention – which is carried out with the support of computer-aided surgery tools.”

In 3D printing for in-the-ear hearing aids, such configuration and placement decisions are still guided by the choice of the operator. By making the configuration step software-guided, the company is making it easier for surgeons to order and receive the right implants for the patient. The risk of choosing the right-sized implant is now also partially offloaded from the surgeon’s shoulders to the device manufacturer. This may reduce some hesitation to go patient-specific by some surgeons and administrators to a certain extent.

The fit system is based in part on Enhatch, a startup that was started by some of Rejoint’s founders. The implants are 3D printed on GE Additive Arcam EBM Q10plus systems in cobalt chrome. In modular hip systems specifically, designers are increasingly opting for cobalt chrome over titanium because, in some cases, the femoral neck portion of some total hip arthroplasty implants has fractured in titanium implants; however, in some very isolated cases, Co-Cr femoral necks have also reportedly failed. Having said that, the jury isn’t out on when which material delivers better results for patients.

Besides just 3D printing, Rejoint data-driven mass customization approach uses web-enabled sensors to provide feedback data to the company which will help it improve its products.

REJOINT CEO, Gian Guido Riva, said of the announcement:

“Having all this data made us realize that we could link it to the information recorded during the operation. And in turn, this data could still be further improved upon if we could collect through the use of wearable devices (such as sensorized headbands and socks), both pre- and post-operative measurements, on how the patient loads their limb or bends their knee, until post-operative evaluation questionnaires have been completed,”

“By 2022, we will have the complete data of thousands of cases available. This will provide us with an unparalleled wealth of application information, in terms of completeness, in the sector. Despite the sale of millions of pieces, there is little or no information on what happens post-sale,”

A real genius element of this is that, “The key element, is an increasingly close and direct relationship between company and patient. This will further increase the degree of post-operative satisfaction. We are at the beginning of a revolution in the field of knee implants. REJOINT’s work in adopting additive technology will allow for more personalized procedures and higher levels of long-term patient satisfaction.”

If REJOINT can strengthen its relationship with the patient and listen intently during the feedback phase, then better implants could result. What will of course most probably be the case is that the soliciting of direct feedback and the closer relationship with the patient that the company is seeking will result in better patient satisfaction. If patients feel more of a connection with the device manufacturer and feel listened to, we would expect them to have a better self-reported feeling towards this procedure and the company. Indeed, the company is now working on a host of mobile apps and web tools to connect it with doctors and patients. Actual listening to patients coupled with a data-driven approach to implant design could very well cause REJOINT to produce better and better-rated implants.

The post REJOINT Uses EBM, Sensors & IoT Data for Patient-Specific Knee Surgery appeared first on 3DPrint.com | The Voice of 3D Printing / Additive Manufacturing.

REJOINT is developing knee replacements with additive manufacturing and artificial intelligence

REJOINT, an Italian medical implant manufacturer, is introducing mass customization and therapy personalization through a combination of additive manufacturing technology with artificial intelligence.  Specifically, the company will be using GE Additive Arcam’s Electron Beam Melting (EBM) technology and computerized analysis of intraoperative and post-operative data collection through IoT-connected sensorized wearables. This will help REJOINT in […]

Inside GE Additive’s Arcam EBM Centre of Excellence, Gothenburg with CEO Jason Oliver

GE Additive invited 3D Printing Industry for a tour of the Arcam Electron Beam Melting (EBM) Center of Excellence, a new 15,000 square meter additive manufacturing facility in Gothenburg Sweden opened in August 2019.  Situated at the Mölnlycke Business Park, the new facility triples the floor space of Arcam’s previous site in Mölndal. It has capacity […]

3D Printing Will Power the New Space Race

Whereas the last space race was powered by ideology and meant to declare the superiority of one economic system over the other; this one is powered by 3D printing and will pit firms against one another for untold riches. The opportunities for satellite networks, planetary colonization, in-space manufacturing, mining and space tourism seem incredible. Incredibly optimistic, most of all.

Personally, space exploration and travel seems fantastic to me. The business models and long term profitability of these businesses seem tenuous, however. Yes, the opportunities are huge but if we look at investments in space the generally come from communications companies through television internet and phone communications, science projects such as ISS and defense. With the space companies themselves venturing into satellite networks it seems likely that there will be a few integrated satellite, tv, movies and music alliances that will win big, and a lot of losers. Science seems to be under threat in our modern world so I don’t see huge ISS-like projects getting started now unless they are prestige projects being done by China. This leaves investor optimism or defense spending to underpin the new space race. If we look at investments in space, launch vehicles, launch assignments and infrastructure then the space race really starts to look like a defense business with the occasional smiling space tourist. If investor optimism is available for the long term then this may make the new space race a reality. Barring this most of the money seems to be emanating from the defense community specifically parts of the US government such as the NRO and DOD.

Boeing’s reusable space plane demonstrator the X37 could function as a reusable satellite. This would be bad for dragons.

Beneath the PR space race with Virgin and SpaceX, there is jockeying for temporary satellites and new kinds of taskable satellites, offensive space systems and perhaps even systems capable of disruption or targeting of ground targets. At the same time, space junk risk and a constant need to replace satellite systems props up demand for launches, vehicles, and programs. Another way to describe the current space race is a desire by the broader US defense establishment to diversify its supplier base away from a select few companies to many more. Elon is not in the driving seat. Some committee at the NRO is. Rather than an ever-expanding universe of opportunities, therefore, I see the current space race as a defense business. These types of businesses are often very dependent on government initiatives and grand plans (Star Wars, the Moon in ten years, Total Information Awareness). Government spending strategies and procurement will further muddy the waters. With the US exhibiting greater arbitrary decisionmaking over the past years this may be a path fraught with difficulty. Also currently other countries are bit players in the funding of new space initiatives so this is a race with fewer competitors than it could have.

If we see the US government as laying the groundwork for the New Space Race everything makes more sense. Sandia and ORNL labs have been commercializing 3D printing technologies for many years now. Many of the Directed Energy Deposition, Laser cladding, EBM initiatives got huge boosts from the shuttle program. Under the radar, many billions have gone to funding materials, processes, machines, and technologies for a spy satellite race that has been a bit of a solo challenge with the US racing to beat its personal best. Space for the US was never about Tang or photo ops but a real effort to dominate the final high ground, the area around our planet. The NRO has a budget of, the has a budget of. These agencies you’ve never heard of are the main architects of the current space race.

A large scale EBM system at NASA.

In the middle between them and publicly available information and technology sits NASA. NASA has been working tirelessly to bring EBM to in-space manufacturing for years now. Many tests and NASA programs have worked out the technology kinks of 3D printing in space. A lot of attention goes to the MARS habitat challenge but NASA has done so much more. Currently, it is helping to develop bioprinting, circuit printing, plastics recycling, metal printing, polymer printing, printing of rocket engines, new 3D printing metals, magnetic 3D printing, printing of large scale space components in space and much more. If one single organization is responsible for the current 3D printed space race then it is NASA.   

Important work by NASA on the baby bantam and other rocket propulsion systems spread knowledge on the advantages of 3D printing for spacecraft, especially in propulsion. NASA showed that reducing part count works through 3D printing. NASA showed us that you could get significant weight savings through metal 3D printed propulsion units. NASA also showed us how 3D printed propulsion systems could be developed at lower cost and faster through 3D Printing.

A NASA and Virgin Orbit 3D printed combustion chamber test.

Due to NASA sharing their knowledge and findings it became public knowledge in the space community that 3D Printing was the best technology to make new rocket engines out of. With 3D Printing, you could cut development times in half, at the same time you could reduce costs by 40% or more. With the same process and technology, you could then reduce part count. In some cases, you could go from 80 parts to 3. This reduces your mold and tooling costs and means you have fewer parts to keep and keep on making as you go forward. The same development lets you iterate more quickly. Based on testing you can now make more parts and try more parts and do this more quickly. Also, at the same time, you can save weight which is supremely important in space exploration. It is NASA that time and time showed everyone that the built parts could be on par with or outperform conventionally manufactured parts.

Through sharing data NASA clued on a new generation of space companies to 3D printing. In propulsion, all of the major players are using metal 3D printing to create and power the next generation of spacecraft. 3D Printed propulsion systems are less expensive, quicker to make and lighter than previous propulsion systems. Through more iterations and weight-saving, it will be 3D printing that will power the new space race and push humanity further for a select few. 

The post 3D Printing Will Power the New Space Race appeared first on 3DPrint.com | The Voice of 3D Printing / Additive Manufacturing.

GE Additive champions lean manufacturing in new Arcam EBM Center of Excellence

Award-winning 3D printer OEM GE Additive has opened a new Center of Excellence dedicated to its Arcam electron beam melting (EBM) subsidiary. Located in Härryda, Sweden, the 15,000 square meter facility is approximately 22 km southeast of central Gothenburg. Compared to Arcam’s former headquarters in Mölndal, west of Härryda, the facility has three times the floor space. The extra area will be […]

Kiwi Companies Partner to Build Tailored 3D Printed Training Prosthetics for Female Para-Athletes

New Zealand-based Zenith Tecnica, which is the only company in the country using Electron Beam Melting (EBM) technology to make 3D printed titanium components, is teaming up with High Performance Sports NZ (HPSNZ) to give two inspiring Kiwi athletes a competitive edge for the Tokyo 2020 Paralympics. Through this collaboration, the two companies will produce tailored 3D printed prosthetics for esteemed para-athletes Anna Grimaldi and Holly Robinson to use while working out and training in the gym.

3D printing has been used multiple times to help disabled athletes get a leg up over their competition, with prosthetics and braces as some of the main applications. As Zenith Tecnica, headquartered in Auckland, has supplied EBM 3D printed titanium components to America’s Cup Regatta and Formula 1 teams, fabricated plenty of medical instruments and implants, and manufactured components in outer space, the company was more than up to the challenge of making advanced, tailored prosthetics for Grimaldi and Robinson.

“Zenith Tecnica 3D printed the new attachment for Holly and Anna to use in the gym,” said Dr Stafford Murray, HPSNZ Head of Innovation. “It’s providing them with something different that you can’t buy off the shelf, that enables them to be the best that they can be.”


The company utilizes the Arcam Q10 plus and Q20 plus systems to produce EBM parts for multiple industries. These 3D printers are built on breakthrough deflection electronics, which allow for extremely accurate, fast beam control so melting can occur simultaneously at more than one point, while still maintaining excellent speed, precision, and surface finish. In addition, its hot vacuum process means no residual stresses to distort the 3D printed components.

“Zenith Tecnica offers a freedom of design to a lot of engineers, so we are not constrained to classical manufacturing methods like machining and casting,” explained Peter Sefont, the Production Manager at Zenith Tecnica. “It allows us and the engineers to do whatever we want.”

Holly Robinson

HPSNZ is a leader in sports innovation, and works with National Sporting Organisations (NSOs) to identify athletes’ strengths and push them further with modern technology and sports science. By partnering with Zenith Tecnica and using its EBM titanium 3D printing expertise, the company is able to think about the possibilities of design in a new way and knock down any boundaries that would otherwise limit them.

“To have someone listen to what we need and be like, ‘Nothing is off the table, we can try and build whatever it is you need,’ that was really awesome,” Grimaldi said about the teamwork between HPSNZ and Zenith Tecnica.

These two fierce female para-athletes are simply amazing. Robinson won the silver medal in the Women’s Javelin F46 at both the Rio 2016 Paralympics and the 2018 Gold Coast Commonwealth Games. She’s already thrown her personal best – 45.73 m – which was good enough to break the world record in the event at the Australian Track & Field Championships in Sydney this past weekend.

Grimaldi won the gold in the Women’s Long Jump T47 at the Rio 2016 Paralympics and came in fourth in the Women’s 100m T47 at the same competition. This coming June, both women will have an optimal opportunity to see if their new 3D printed training prosthetics can help them win at the 2019 Oceania Area and Combined Events Championships.

Raylene Bates, Athletics New Zealand high performance coach, said, “This is a piece of equipment that would enable them to train like an able-bodied person; granting the use of both arms with a full range of movement, achieving a full body balance.”

Anna Grimaldi

Of course, all of these competitions are a precursor to the main event both Robinson and Grimaldi are working towards – the 2020 Paralympics in Tokyo. The hope is that through this partnership between Zenith Tecnica and HPSNZ, their new 3D printed titanium prosthetics will help them up their game while preparing for next year’s competition. Because these will be prosthetics tailored specifically to them, exercises and training methods that the para-athletes were previously unable to do because of previous off-the-shelf prosthetics should now be entirely possible…which means that gold medals are possible as well.

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

Interview With 3DInductors About 3D Printing Pure Copper Induction Coils With EBM

Recently we told you about 3DInductors. This is a new service that lets you 3D print pure copper induction coils. 3DInductors was developed by GH Induction which is a part of GH Group, based in Valencia Spain and one of the market leaders in induction heating. The company developed its own technology application for 3D printing copper based on EBM (Electron Beam Welding). This is a complex process to work with and dial in for manufacturing. In addition, copper 3D printing has been attempted before by many players only for them to find out that it is much more difficult than they think. Of the players that say that say can do it right now precious few are actually able to deliver parts at scale. What’s more, the 3DInductors team is the first to do this for EBM. Also, it is the first company able to 3D print pure copper. It’s incredibly innovative that the GH Group would go through the significant lengths to develop their own technology and then to launch a direct to customer “start up/separate brand/skunkworks” type of play to bring it to market. I think that this really shows a very fruitful path for staid and large companies to innovate.

A 3D Printed Pure Copper Induction Coil

Induction coils are used to heat conductive metals in order to harden them via induction heating. Traditionally they were made by hand but the design freedom was limited. With 3DCoil 3DInductors opens up the design space for these parts. Lower inventory and lower TCO are just some of the benefits. A very exciting thing, however, is that due to the 3D printing process the parts last up to four times longer than the traditionally made ones. The combination of these factors may see the induction heating industry forever changed.

The company uses 99.99% copper and has a very high 99.7% recycling rate. They’ve already shipped over 400 of these 3D printed coils to customers including large automotive firms such as Renault. They also 3D print quenches to go with your induction coils. The business case for this looks very solid indeed and I love innovation such as this. We reached out to the firm with more questions and Concepción (do call her Inma) Sánchez was kind enough to answer them.

Why did you turn to 3D printing?

In induction metal parts heating, coils and inductors are the core of the process. They are the end tool where the magnetic process affecting the part, or material to be heated, occurs.

After more than a century in which the dominant manufacturing process has been mainly based, upon joining technologies such as brazing or soldering, skilled coppersmithing has been the safeguard of the quality with unique knowledge and know-how. The use of fixtures, mandrels, and machined parts has improved the repeatability and quality of the produced elements but high volume, dimensional repeatability has always been a source of problems.

All manufacturers are working continuously on the improvement of such relatively artisanal methods to allow better lifetime, minimized production time and overall better quality.

GH Induction is always looking for new technologies that benefit directly to our customers. This is our main added value.

Why copper?

The raw material for inductors is copper because it is the ideal for induction heat treatment in metal parts.

Copper represents the best compromise between electrical conductivity, mechanical properties, and cost. Other material could be used but either do not match cost limitation or mechanical properties.

Was it difficult to develop a copper process?

It really was.

GH Induction performed tests and developments with the available technologies before taking a decision on LBM (Laser Beam Melting) or EBM (Electron Beam Melting). We obtained better results (melting rate, porosity level) with EBM while using copper powder than with LBM (beam reflection problem, Argon trapped). In addition, considering an industrial production approach, the EBM technology allows to stack parts one above the other.

Then we had to develop from scratch EBM with pure copper manufacturing method. That didn’t exist before with EBM (Electron Beam Melting) printing technology.

Only titanium and cobalt-chrome printing for demanding applications in mechanical properties like orthopedic implants and aerospace parts were developed so far.

GH Induction together with a research center took some years to develop the process with pure copper material.

The solution was so innovative that we have been able to patent it. We are working with it for 5 years now and we commercialize it for almost 3 years now.

It is a breakthrough in the industrial induction heating sector.

An EBM Build Plate with pure copper

What machines do you run it on?

We have several machines, all based upon Electron Beam Melting technology which utilize a high power electron beam that generates the energy needed for high melting capacity and high productivity. The electron beam is managed by electromagnetic coils providing extremely fast and accurate beam control that allows several melt pools to be maintained simultaneously (MultiBeam). The process takes place in vacuum and at high temperature, resulting in stress relieved components with material properties better than cast and comparable to forged material. Our method based on EBM is the only 3D printing method able to print pure copper. The service life is much longer, the density is higher minimizing leakages and the mechanical and electrical properties are better. LBM techniques use copper alloys and they present intrinsic drawback when considering the manufacturing of coil with pure copper:

  • · Limited transformation of the energy into efficient melting due to the refraction of the beam on copper

  • · Post treatment needed due to created stress within the part

  • · Risk of pollution of the element (no vacuum)

  • · Use of an additional element to improve powder bonding remains as one important question mark.

Do you use pure copper? Other materials?

Only pure copper at the moment but we are always researching.

Copper alloys are not suitable because the alloy elements must be removed in order to avoid rusting creation of inclusion or compound which makes the manufacturing process more complex.

A Flame Brazing Coil

What are the advantages of 3D printing copper for your parts?

The inductor is an end effector where take place the creation of the magnetic field required for the induction heating effect. That means it follows the contour of the part we want to heat. The advantage of printing copper is that we can manage complex design that before were extremely or impossible to do with a more classical method (brazed elements).

In addition, we translate directly into the printer the CAD deign we have engineered. It includes shape changes that we believe allow to obtain the best efficiency in terms of pattern and magnetic precision.

We should not forget that an inductor is a tube shaped into the form we want to give it. Tubular section variation is needed since high power density flows onto the surface and requires cooling in most cases and we are in the vicinity of a part which can top at more than 1000 deg C.

Another aspect of that technology is the high reproducibility which allows the end-user to swap inductors with no or limited setting. That brings a clear gain in time.

Schematic of the EBM Process.

How does 3D printing extend the service life of the components?

The traditional method to manufacture copper coils is to join empty copper tubes segments by brazing. These coils must be cooled to withstand the high currency flowing through them. Mechanical fatigue results with the contraction and retraction cycles due to the magnetic forces onto the copper surface during the heating phases. Then the brazed joints in a coil/inductor assembly are often the weakest points and the initiation point of the coil destruction. Using 3D printing the coil is created as a single 3D piece without brazed joints increasing dramatically the lifespan.

We have seen improvements of over 400%. However, we see an average increase higher than 100% in most cases

In addition, the design is modelled through the 3D CAD software optimizing both outer and inner design:

  • reducing the points with higher current density (hot spots)

  • improving coil cooling by changing the geometric characteristics of the inductors

  • Manufacturing process carried out in a vacuum atmosphere in order to avoid porosity and rusting.

  • High dimensional accuracy process that allows identical coil copies.

  • These inductors can be repaired just like the traditional ones.

How many parts do you make?

We have already hundreds of 3D inductors in-field. Depending on the induction application, meaning type of part to heat and process, we can reach different results but always better. For instance, in an automotive driveline case we get 400% more lifespan.

Imagine the operational savings for the customer:

  • Dramatic decrease of their part production cost

  • Extreme reduction of production stoppages

  • Less inventory

How does geometric freedom help your part performance?

There are cases where the main benefit is the ability of adaptation to the part to be heated. In these cases the conventional brazed coils for mechanical reasons cannot fit to the part for optimum heat treatment. Another big benefit is the capability to improve continuously an original coil design once it is under production. Depending on production results, inner or outer coil modifications can be introduced to improve them.

Why is this such a good fit with inductors?

  • No brazed joints and total design coil flexibility

  • Total adaptation to the part to be heated

  • Design continuous improvement

  • High dimensional repeatability

  • Assembled inductors cost is sometimes more economic due to the reduction of the labor needed.

Who uses your products?

  • Industrial manufactures from any sector using heating processes like heat treatment (hardening, tempering, …), brazing, welding, straightening, etc.

  • The GH 3D inductors are highly recommended to high volume productions as automotive industry and when complex parts need to be treated.

What is the goal of your business?

To be a reference in our induction heating sector and to become a global 3D inductor provider for any induction machine or system.

What kinds of companies would you be interested in working with?

With any that can clearly benefit from our technology and experience because upgrading the traditional inductors to 3D is more than printing. Experience in induction and in 3D coils is mandatory.

Singapore: Researchers Test Potential of High Entropy Alloys in EBM Metal 3D Printing

Metal 3D printing is becoming invaluable for many manufacturers today worldwide, and the research regarding processes and materials continues as researchers from both Singapore Institute of Manufacturing Technology and Nanyang Technological University explore metal powders being used in electron beam melting (EBM) technology today in ‘Additively manufactured CoCrFeNiMn high-entropy alloy via pre-alloyed powder.’

Most studies regarding serious manufacturing practices and their interest in 3D printing with metal center around the best ways to produce strong, complex geometries. Here, the authors review whether CoCrFeNiMn high entropy alloy (HEA) parts produced through EBM—very similar to the popular selective laser sintering (SLS) process—is a realistic improvement over conventional casting techniques.

CoCrFeNiMn is known as an equiatomic alloy powder made through vacuum induction via atomization with argon gas. As a single face-centered-cubic (FCC) crystal structure, CoCrFeNiMn has been the focus of a wide variety of research throughout the years due to:

  • Strong mechanical properties
  • Corrosion resistance
  • Wear resistance
  • Excellent ductility

The scientists point out that while HEAS like CoCrFeNiMn perform well in cryogenic temperatures, melting, casting, and mechanical alloying are the ‘dominant preparation methods,’ often leading to issues with both voids and porosity. Powder bed fusion additive manufacturing (PBFAM) offers potential for fabricated HEAs due to the following features:

  • Short processing time
  • Geometrical accuracy
  • Reduced waste
  • Customization possibilities

EBM relies on high energy preheating up to 1100 °C, offers reduced stress on reactive parts, and has been known to be successful in production of HEA parts previously. Along with evaluating CoCrFeNiMn in terms of its microstructure and mechanical properties, researchers were able to produce it through gas atomization for this study, producing further analysis in powder flow, particle size, density, defect, printability, and more. For better ease in 3D printing, the atomized powder was separated into four different categories: ≤25 μm, 25–45 μm, 45–105 μm and 105–300 μm. Respectively, this allows for spark plasma sintering/injection molding, selective laser melting (SLM), EBM, and laser-aided AM.

Flowability is one of the important features in PBFAM, and can be determined in different ways, but for this study was evaluated through the Hall flowmeter funnel and pronounced excellent. Particle size was evaluated, with good printability proven, and parts were inspected for defects based on Archimedes principle and OM observation. Further, microhardness was evaluated as follows:

“The microhardness was examined on the polished specimen by using Matsuzawa MMT-X3 Vickers hardness tester at 1 kg for 15 s. Dog-bone specimens with a cross-section of 1 × 3 mm2 and a gauge length of 5 mm were cut from the cuboid sample. An Instron 5982 universal tensile testing machine with a 10 kN load cell was used for the tensile test with an initial strain rate of 3.3 × 10−4 s−1 at room temperature. A video extensometer was applied to record the strain. Three specimens were examined to obtain the yield strength (YS), ultimate tensile strength (UTS), and elongation to failure.”

Chemical composition analysis revealed ‘spherical morphology’ and only a few irregular particles, with all particles overall created as solidifying droplets collided in the ‘turbulent flow’ of atomization.

“In addition to the satellites, the spherical pores corresponding to entrapped gas during the atomization process was revealed by cross-sectioned observation. In contrast to the occasional appearance in the fine powder, these spherical pores prevailed in the coarse powder. These entrapped gas pores not only influence the true density but also cause defects in the AM parts.”

“A relative narrow ranged powder was obtained after the sieving process. The average particle size is 10.3, 36.2, 63.3 and 129.8 μm for the P1, P2, P3, and P4, respectively. The size distribution overlap is caused by non-perfect sieving process, such as plugged mesh by spherical powder, which can be improved by modifying the sieving process.”

SEM images showing typical HEA powder morphology with different magnifications. (a) and (b) for powder size ≤25 μm (P1); (c) and (d) for powder size ranged from 45 to 105 μm (P3).

The scientists agree that while previous processes may have led to obstacles in using HEA powder, gas optimization makes such materials a definite consideration for mass production, stating that the powders offered all the following:

  • Desirable and apparent density
  • Tapped density
  • Flowability
  • Particle size distribution

The researchers do point out, however, that there could be safety issues due to the ‘high density of satellites,’ although it does not seem to affect the EBM printing process. Porosity is a concern however, and the researchers tentatively suggest the hot isostatic press process for elimination of such issues in additive manufacturing, but it is costly and can be limiting for most applications.

“It is suggested that powder with low porosity, for example, produced by plasma rotated electrodes process, would be an ideal choice for critical industrial parts that needs to be exposed in high operating temperature,” said the researchers.

Ultimately, the team concluded that all important features of the process studied here deem it suitable for PBFAM technology and new materials, further stating:

“… the EBM-built CoCrFeNiMn HEA parts had comparable mechanical properties (microhardness and tensile properties) to their conventional cast counterparts.”

As 3D printing with metal in a variety of different methods begins to infiltrate industries focused on intense manufacturing processes, the study of the materials and powders that accompany this technology continues to grow, as exemplified in the automobile industry, aerospace, military and ammunitions endeavors—and far more. Find out more about the PBFAM process and the use of new materials in 3D printing here.

What do you think of this news? Let us know your thoughts! Join the discussion of this and other 3D printing topics at 3DPrintBoard.com.

[Source / Images: ‘Additively manufactured CoCrFeNiMn high-entropy alloy via pre-alloyed powder’]

(a) Image of EBM-built part. (b) SEM of the rough surface from the side view. (c) Typical top surface appearance of the cuboid samples with different extent of swelling and lack of fusion. The yellow and red arrows reveal the swelling and lack of fusion, respectively. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)

 

 

 

 

 

 

 

Will GEFERTEC’s 3DMP Metal 3D Printing Process Make 3D Printing Large Metal Structures Affordable?

German company GEFERTEC’s 3DMP process is a very interesting metal 3D printing technology. We profiled the company and its wire fed 3D printing technology a few months ago. Rather than focus on inexpensive parts (inkjet) or fine mechanical small parts (DMLS, SLM) their wire arc based technology is focused on large 3D printed metal parts. How large? Well, how about 1 meter or five-meter parts made out of various metals? What’s more, the industrial firm is committed to making its process affordable by opening up the process to let people use traditional low-cost wire arc feedstock. By positioning the technology in this way the company is trailblazing into the construction of airframes, wing spars and large structural components in aircraft.

Welding based technologies such as Trumpf’s, Sciaky‘s and Optomec as well as the various other Directed Energy Deposition technologies are much less well known than DMLS/SLM/LPBF powder bed fusion technologies. Developed during the cold war they were extensively used on the Shuttle and other space programs before people decided to do something brilliant and make a wire arc or other welding technology go up a layer. They often are used for defense-related applications such as satellite, missile or experimental aircraft structural components. Indeed a number of these technologies were specifically developed for such defense applications.

At the moment aerospace companies are very publicly focusing on tiny components. This means that they can gain from the advantages of 3D printing with these small components quickly while qualifying technologies. In my mind, the huge leap in design capabilities will also happen once full airframes, rockets, warheads and other large several meters in size components are qualified for aviation. At the moment this is being done on the down-low but the move towards civil aviation is happening behind the scenes. We now can see the market split into three in what I’ve termed the Goldilocks Moment. Essentially we’re seeing distinct segments in low cost, fine mechanical and large metal printing technologies emerge. One of the companies vying for a prize of the large-scale printing of metal parts for aerospace and other applications is the German firm GEFERTEC. We asked Tobias Röhrich the CEO of GEFERTEC to tell us about his firm and the 3DMP technology.

What is 3DMP? What kind of parts are ideal for the technology?

“3DMP stands for 3D Metal Print. It is the most economic additive manufacturing process for big metal part based on wire and arc. There are a lot of different interesting application scenarios for 3DMP. Once the parts must be made from metal, 3DMP is an economically and technically viable option for parts of a certain size, which are expensive or difficult to manufacture with conventional methods. In case you are looking at substituting milling it is of interest when expensive or difficult to machine materials are being processed. Especially when you look at parts with high cutting volume. 3DMP can be also an economically and logistically alternative to casting or forging in particular in case of low quantity lots, where you could save on the tooling cost and gain delivery time advantages.

“Furthermore, there is a list of functional and structural benefits of parts made by 3DMP that would be unthinkable using conventional methods. It is possible to generate inner structures like closed hollow parts, cooling channels etc.. For many applications for example in tool manufacturing, it is of great interest of combining different material layers in one part, like having a mild steel body and a hardfacing on top.”

What sizes can you print parts? 

“3DMP, especially comparing with laser and powder, is a very economical 3D printing process for bigger parts. The maximum size of the built structure reaches in the standard machines almost 3m³. Besides that the process is scalable, meaning it is technically possible and economically viable to use 3DMP for even bigger parts. In a joint effort, GEFERTEC and AIRBUS are driving a project looking at the possibility of printing titanium parts of 7 to 8 m size.”

What materials are possible? 

“Basically, you can use all of the conventional welding wire usable for this process, whereby one has to say that there are materials that are easier to handle and there are those with special challenges. We already control the process for about 30 different metals, amongst them tooling steels, stainless steels, high alloy steels, nickel-based alloys, titanium, copper based alloys, different aluminum alloys and many more.”

How are you positioning the technology vis a vis DMLS and DED?

“If you compare the different printing methods it is notable that there are different properties and applications coming along with them. 3DMP is an economical, easy to handle and robust technology for printing of big metal parts. Instead of powder and laser, 3DMP uses the wire and the arc. This has consequently a lot of advantages comparing it. One is the build rate, that compared with for example the DMLS is about 10-15 times higher. Another advantage is the easy handling of the wire instead of the complexities one has to deal with using metal powder. Furthermore, the wire is significantly less costly, there is a great variety of proven and certified materials available in the market for a technology that has essentially been used for about a 100 years.”

Is using wire feedstock cheaper than using powder? 

“Yes. Using wire is significantly cheaper than using powder. Having said that, it is also more efficient. Meaning with a wire you have almost a 100% of a material to part conversion. Using powder you, unfortunately, have a significant percentage of lost material.”

What kind of surface roughnesses can you achieve? Densities?

“The aim of 3DMP is to produce near net shape parts which will be milled afterwards. There will always be kind of a wavy surface due to the welding beads. The best you can achieve is about 0,3mm roughness, but again the purpose is not to produce finished parts. You have to mill afterwards and therefore it doesn´t matter to much if you have 0,3 mm or 1mm as roughness. Most of DMLS and DED parts need the milling as a finishing process as well, even though the reachable roughness would be finer. The relative density is 100%.”

What are the part costs when compared to inkjet metal, DED and DMLS? “This depends on the part, its geometry and its size. Generally speaking, the build rate, which is a big factor of the cost, is compared to DMLS 10 – 15 times higher. Big parts are not economically built up with DMLS, but are with 3DMP.”

What does a machine cost? 

“Machine cost varies between 300 and 750 thousand Euro.”

Who are your target customers?

“We are targetting job shops, aerospace companies, the shipbuilding industry, the power plant industry, general machine builders and many more verticals.”

3D Printing News Briefs: August 24, 2018

We’re sharing some business news in today’s 3D Printing News Briefs, followed by some interesting research and a cool 3D printed statue. Meld was listed as a finalist in the R&D 100 Awards, and Renishaw has introduced 3D printed versions to its styli range, while there’s an ongoing Digital Construction Grant competition happening in the UK. A researcher from Seoul Tech published a paper about in situ hydrogel in the field of click chemistry, while researchers in Canada focused on the Al10SiMg alloy for their study. Finally, an Arcam technician tested the Q20plus EBM 3D printer by making a unique titanium statue of Thomas Edison.

Meld is R&D 100 Awards Finalist

The global R&D 100 Awards have gone on for 56 years, highlighting the top 100 innovations each year in categories including Process/Prototyping, IT/Electrical, Mechanical Devices/Materials, Analytical/Test, and Software/Services, in addition to Special Recognition Awards for things like Green Tech and Market Disruptor Products. This year, over 50 judges from various industries selected finalists for the awards, one of which is MELD Manufacturing, an already award-winning company with a unique, patented no-melt process for altering, coating, joining, repairing, and 3D printing metal.

“Our mission with MELD is to revolutionize manufacturing and enable the design and manufacture of products not previously possible. MELD is a whole new category of additive manufacturing,” said MELD Manufacturing Corporation CEO Nanci Hardwick. “For example, we’re able to work with unweldable materials, operate our equipment in open-atmosphere, produce much larger parts that other additive processes, and avoid the many issues associated with melt-based technologies.”

The winners will be announced during a ceremony at the Waldorf Astoria in Orlando on November 16th.

Renishaw Introduces 3D Printed Styli

This month, Renishaw introduced a 3D printed stylus version to its already wide range of available styli. The company uses its metal powder bed fusion technology to provide customers with complex, turnkey styli solutions in-house, with the ability to access part features that other styli can’t reach. 3D printing helps to decrease the lead time for custom styli, and can manufacture strong but lightweight titanium styli with complex structures and shapes. Female titanium threads (M2/M3/M4/M5) can be added to fit any additional stylus from Renishaw’s range, and adding a curved 3D printed stylus to its REVO 5-axis inspection system provides flexibility when accessing a component’s critical features. Components with larger features need a larger stylus tip, which Renishaw can now provide in a 3D printed version.

“For precision metrology, there is no substitute for touching the critical features of a component to gather precise surface data,” Renishaw wrote. “Complex parts often demand custom styli to inspect difficult-to-access features. AM styli can access features of parts that other styli cannot reach, providing a flexible, high-performance solution to complex inspection challenges.”

Digital Construction Grant Competition

Recently, a competition opened up in the UK for organizations in need of funding to help increase productivity, performance, and quality in the construction sector. As part of UK Research and Innovation, the organization Innovate UK – a fan of 3D printing – will invest up to £12.5 million on innovative projects meant to help improve and transform construction in the UK. Projects must be led by a for-profit business in the UK, begin this December and end up December of 2020, and address the objectives of the Industrial Strategy Challenge Fund on Transforming Construction. The competition is looking specifically for projects that can improve the construction lifecycle’s three main stages:

  • Designing and managing buildings through digitally-enabled performance management
  • Constructing quality buildings using a manufacturing approach
  • Powering buildings with active energy components and improving build quality

Projects that demonstrate scalable solutions and cross-sector collaboration will be prioritized, and results should lead to a more streamlined process that decreases delays, saves on costs, and improves outputs, productivity, and collaborations. The competition closes at noon on Wednesday, September 19. You can find more information here.

Click Bioprinting Research

Researcher Janarthanan Gopinathan with the Seoul University of Science Technology (Seoul Tech) published a study about click chemistry, which can be used to create multifunctional hydrogel biomaterials for bioprinting ink and tissue engineering applications. These materials can form 3D printable hydrogels that are able to retain live cells, even under a swollen state, without losing their mechanical integrity. In the paper, titled “Click Chemistry-Based Injectable Hydrogels and Bioprinting Inks for Tissue Engineering Applications,” Gopinathan says that regenerative medicine and tissue engineering applications need biomaterials that can be quickly and easily reproduced, are able to generate complex 3D structures that mimic native tissue, and be biodegradable and biocompatible.

“In this review, we present the recent developments of in situ hydrogel in the field of click chemistry reported for the tissue engineering and 3D bioinks applications, by mainly covering the diverse types of click chemistry methods such as Diels–Alder reaction, strain-promoted azide-alkyne cycloaddition reactions, thiol-ene reactions, oxime reactions and other interrelated reactions, excluding enzyme-based reactions,” the paper states.

“Interestingly, the emergence of click chemistry reactions in bioink synthesis for 3D bioprinting have shown the massive potential of these reaction methods in creating 3D tissue constructs. However, the limitations and challenges involved in the click chemistry reactions should be analyzed and bettered to be applied to tissue engineering and 3D bioinks. The future scope of these materials is promising, including their applications in in situ 3D bioprinting for tissue or organ regeneration.”

Analysis of Solidification Patterns and Microstructural Developments for Al10SiMg Alloy

a) Secondary SEM surface shot of Al10SiMg powder starting stock, (b) optical micrograph and (c) high-magnification secondary SEM image of the cross-sectional view of the internal microstructure with the corresponding inset shown in (ci); (d) the printed sample and schematic representation of scanning strategy; The bi-directional scan vectors in Layer n+1 are rotated by 67° counter clockwise with respect to those at Layer n.

A group of researchers from Queen’s University and McGill University, both in Canada, explain the complex solidification pattern that occurs during laser powder bed fusion 3D printing of the Al10SiMg alloy in a new paper, titled “Solidification pattern, microstructure and texture development in Laser Powder Bed Fusion (LPBF) of Al10SiMg alloy.”

The paper also characterizes the evolution of the α-Al cellular network, grain structure and texture development, and brought to light many interesting facts, including that the grains’ orientation will align with that of the α-Al cells.

The abstract reads, “A comprehensive analysis of solidification patterns and microstructural development is presented for an Al10SiMg sample produced by Laser Powder Bed Fusion (LPBF). Utilizing a novel scanning strategy that involves counter-clockwise rotation of the scan vector by 67° upon completion of each layer, a relatively randomized cusp-like pattern of protruding/overlapping scan tracks has been produced along the build direction. We show that such a distribution of scan tracks, as well as enhancing densification during LPBF, reduces the overall crystallographic texture in the sample, as opposed to those normally achieved by commonly-used bidirectional or island-based scanning regimes with 90° rotation. It is shown that, under directional solidification conditions present in LPBF, the grain structure is strictly columnar throughout the sample and that the grains’ orientation aligns well with that of the α-Al cells. The size evolution of cells and grains within the melt pools, however, is shown to follow opposite patterns. The cells’/grains’ size distribution and texture in the sample are explained via use of analytical models of cellular solidification as well as the overall heat flow direction and local solidification conditions in relation to the LPBF processing conditions. Such a knowledge of the mechanisms upon which microstructural features evolve throughout a complex solidification process is critical for process optimization and control of mechanical properties in LPBF.”

Co-authors include Hong Qin, Vahid Fallah, Qingshan Dong, Mathieu Brochu, Mark R. Daymond, and Mark Gallerneault.

3D Printed Titanium Thomas Edison Statue

Thomas Edison statue, stacked and time lapse build

Oskar Zielinski, a research and development technician at Arcam EBM, a GE Additive company, is responsible for maintaining, repairing, and modifying the company’s electron beam melting (EBM) 3D printers. Zielinski decided that he wanted to test out the Arcam EBM Q20plus 3D printer, but not with just any old benchmark test. Instead, he decided to create and 3D print a titanium (Ti64) statue of Thomas Edison, the founder of GE. He created 25 pieces and different free-floating net structures inside each of the layers, in order to test out the 3D printer’s capabilities. All 4,300 of the statue’s 90-micron layers were 3D printed in one build over a total of 90 hours, with just minimal support between the slices’ outer skins.

The statue stands 387 mm tall, and its interior net structures show off the kind of complicated filigree work that EBM 3D printing is capable of producing. In addition, Zielinski also captured a time lapse, using an Arcam LayerQam, from inside the 3D printer of the statue being printed.

“I am really happy with the result; this final piece is huge,” Zielinski said. “I keep wondering though what Thomas Edison would have thought if someone would have told him during the 19th century about the technology that exists today.”

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