3D Printing

U of T researchers advance metal 3D printing technology for automotive, energy and biomedical applications

Christopher.Sorensen — Tue, 14 Mar 2023 22:26:54 +0000

U of T researchers advance metal 3D printing technology for automotive, energy and biomedical applications

Christopher.Sorensen Tue, 03/14/2023 - 18:26

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The metal 3D printers used by U of T Engineering Professor Yu Zou and his team are designed to specialize in both selective laser melting and directed energy deposition – two essential metal additive manufacturing techniques (photo by Safa Jinje)

Safa Jinje

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Our Community

3D Printing

Advanced Manufacturing

Faculty of Applied Science & Engineering

Graduate Students

Research & Innovation

A team of University of Toronto researchers, led by Professor Yu Zou in the Faculty of Applied Science & Engineering, is working to advance the field of metal additive manufacturing at the university’s first metal 3D printing laboratory.

The technology, which uses computer-aided design (CAD) to construct materials layer by layer, can improve manufacturing across aerospace, biomedical, energy and automotive industries.

“We are working to uncover the fundamental physics behind the additive manufacturing process, as well as improving its robustness and creating novel structural and functional materials through its applications,” says Zou, an assistant professor in the department of materials science and engineering.

Unlike traditional manufacturing, in which parts or components are made from bulk materials, the metal 3D printing process enables microstructure and materials constitutions to be locally tailored, meaning they can exhibit distinct properties.

“For example, medical implants require human bone-like materials that are dense and hard on the outside, but porous on the inside,” says Xiao Shang, a PhD candidate in Zou’s lab. “With traditional manufacturing, that’s really hard to accomplish – but metal printing gives you a lot more control and customized products.”

Subtractive manufacturing techniques generally involves removing material in order to achieve a desired end product. Additive manufacturing, by contrast, builds new objects by adding layers of material. This process significantly reduces production time, material cost and energy consumption when producing objects such as aerospace engine components, tooling parts for automotive production, critical components for nuclear reactors and joint implants.

Assistant professor Yu Zou, far left, and his 3D printing team conduct research in the Laboratory for Extreme Mechanics & Additive Manufacturing (photo by Safa Jinje)

Zou’s metal 3D printers are designed to specialize in both selective laser melting and directed energy deposition – two essential metal additive manufacturing techniques used in both academia and industry.

First, CAD software is used to create a 3D model of the object and its layers. Then, for each layer, the machine deposits a very thin layer of metal powder, which is subsequently melted by a powerful laser according to the geometry defined by the 3D model.

After the molten metal solidifies, it adheres to either the previous layer or the substrate. Once each layer is complete, the machine will repeat the powder doping and laser melting process until all layers are printed and the object is completed.

“Conventional manufacturing techniques are still well-suited for large-scale industrial manufacturing,” says Tianyi Lyu, a PhD candidate in materials science and engineering. “But additive manufacturing has capabilities that go beyond what conventional techniques can do. These include the fabrication of complex geometries, rapid prototyping and customization of designs, and precise control of the material properties.”

Three different geometries are fabricated layer by layer using the directed energy deposition process (video by Xiao Shang)

For example, dental professionals can use selective laser melting to create dentures or implants customized to specific patients via a precise 3D model with dimensional accuracy that is within a few micrometres. Rapid prototyping also allows for easy adjustments of the denture design. And since implants can require different material properties at distinct locations, this can be achieved by simply changing the process parameters.

The team is also applying novel experimental and analytical methods to gain a better understanding of the selective laser melting and directed energy deposition printing processes. Currently, their research is focused on advanced steels, nickel-based superalloys and high-entropy alloys, and they may expand to explore titanium and aluminum alloys in the future.

“One of the major bottlenecks in conventional alloy design today is the large processing times required to create and test new materials. This type of high-throughput design just isn’t possible for conventional fabrication methods,” says Ajay Talbot, a master’s student in materials science and engineering.

With additive manufacturing techniques such as directed energy deposition, the team is rapidly increasing the amount of alloy systems explored, altering the composition of materials during the printing process by adding or taking away certain elements.

“We are also working towards intelligent manufacturing. During the metal 3D printing process, the interaction between a high-energy laser and the material only lasts for a few microseconds. However, within this limited timeframe, multi-scale, multi-physics phenomena take place,” says Jiahui Zhang, a PhD candidate in materials science and engineering. “Our main challenge is attaining data to capture these phenomena.

“In our research, we have successfully customized specific machine learning methods for different parts of the metal additive manufacturing lifecycle.”

In the lab, high-speed infrared camera systems are integrated directly into the metal 3D printers. The team has also built an in-situ monitoring system based on the images taken by the printer to analyze and extract the key features of printed objects.

“With the development of computer vision, a well-trained deep learning model could automatically accomplish some basic tasks that human visual systems can do, such as classification, detection and segmentation,” adds Zhang.

One of the problems with current additive manufacturing processes is building a robust and reliable 3D printer that can deliver consistent high-quality parts. To this end, the team is actively working to apply machine learning and computer vision to develop a fully autonomous closed loop-controlled 3D printing system that can detect and correct defects that would otherwise emerge in parts made via additive manufacturing. Implementing these systems could greatly widen the adoption of metal additive manufacturing systems in the industry, says Zou.

Since building up the lab’s metal printing capabilities, Zou and his team have established partnerships with government research laboratories, including National Research Council Canada (NRC) and many Canadian companies, including Oetiker Limited, Mech Solutions Ltd., EXCO Engineering and Magna International.

“Metal 3D printing has the potential to revolutionize manufacturing as we know it,” says Zou, who offers an additive manufacturing course that is available to both undergraduate and graduate students. “With robust autonomous systems, the cost of operating these systems can be dramatically reduced, allowing metal additive manufacturing to be adopted more widely across industries worldwide.

“The process also reduces materials and energy waste, leading towards a more sustainable manufacturing industry.”

U of T Engineering launches 3D-printing course to prepare students for booming field

Christopher.Sorensen — Tue, 05 Jan 2021 14:23:45 +0000

U of T Engineering launches 3D-printing course to prepare students for booming field

Christopher.Sorensen Tue, 01/05/2021 - 09:23

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(photo by Neil Ta)

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Faculty of Applied Science & Engineering

Graduate Students

Mechanical & Industrial Engineering

Students at the University of Toronto now have access to a course focused entirely on 3D printing, a fast-growing $13-billion industry.

The graduate-level course, which is open to all U of T students, is being offered by the department of mechanical and industrial engineering (MIE) in the Faculty of Applied Science & Engineering. MIE1724: Additive Manufacturing in Engineering Applications focuses specifically on the rapidly evolving and lucrative field, which has applications for numerous sectors of the economy.

The course is the creation of alumnus Ali Radhi, who wanted to provide a graduate-level specialized class that looks at the process of designing and building cost-effective and timely products using novel materials and hardware.

Radhi recently spoke to writer Kendra Hunter about the new course and the importance of preparing today’s students for the design and fabrication of complex structures.

What inspired you to create this course?

At MIE, I have been involved in the design of lightweight structures and saw there was room to further bridge the fields of materials and manufacturing through a new course. A recent trend in 3D printing is to produce complex structures using materials with properties not usually found in nature, such as invisibility cloaks, and I wanted to address this while giving singular focus to the field of additive manufacturing, 3D printing and their respective applications. Associate Professor Tobin Filleter’s MIE1744: Nanomechanics of Materials provided inspiration in expanding this area of knowledge. From there, MIE1724 took shape.

 What can students expect from this course?

The course introduces various types of additive manufacturing approaches, including multi-material 3D printing, micro/nano additive manufacturing and 3D bioprinting. MIE1724 is also designed to show the limitation of selected additive manufacturing methods. Characterization of additive manufacturing parts is included as a major course outcome. It helps students to integrate design for additive manufacturing aspects in industry product fabrication.

Students get to learn about new 3D printing technologies and how they are applied to solve problems in security, automation and more.

The course will first introduce the concept of 3D printing and then will move into computer-aided design (CAD) for additive manufacturing. Currently, students can request parts to be 3D printed through the Myhal Centre’s fabrication facility. Once it is safe to do, they will be able to receive training to use the facility for their own education and research.

How does this course benefit degree and career options?

3D printing is now the primary method of prototyping. More recently, it became the sole method for end-use part production for highly complex structures and/or material content. Dedicated post-secondary education in 3D printing helps fill the talent gap in additive manufacturing as global revenue from these technologies has jumped from $4 billion to $13 billion between 2014 to 2018.

Additive manufacturing shortens design and production processes by enabling companies to streamline prototyping activities, alter supply chains and evolve end-product manufacturing. The market is growing at a rapid pace and people with a specialization in additive manufacturing will be in demand.

Did you design MIE1724 strictly as an engineering course for engineering students?

No, in fact this course is open to all U of T students. 3D printing is of great interest to many fields such as medicine, architecture and dentistry. The course is structured to highlight the technology’s potential, process and applications in those fields and much more. The course also addresses unique fields, such as textiles and cosmetics, and how this technology can be applied. Additionally, the areas of information science, education and graphic design also benefit with over 250 applications of additive manufacturing that can be incorporated into their daily use of technology.

How did your PhD studies at MIE help you develop the skills to create MIE1724?

The PhD program provided a lot of exposure to state-of-the-art fabrication technologies. 3D printing was one of those avenues and I took part in design projects and competitions that employed such technologies within the facilities at U of T. Furthermore, the teaching assistant and instructor opportunities from the university helped me to identify the knowledge gap in 3D printing from U of T’s broad list of advanced courses. During my PhD studies, collaboration with fellow research groups aided my own research through sharing of knowledge with my network as well as training in high- tech research facilities.

MIE1724 was inspired by Associate Professors Filleter’s and Eric Diller’s research – both were helpful and supportive in providing insights for a proper scope and delivery for the course. Professor Murray Thomson, who is associate chair of graduate studies for MIE, provided support to address student expectations and Maximiliano Giuliani, senior facility supervisor at the Myhal Centre for Engineering Innovation & Entrepreneurship, provided input on expected knowledge and training for students before using his facilities for 3D printing.

U of T researchers turn McDonald's deep fryer oil into high-end 3D printing resin

Christopher.Sorensen — Thu, 30 Jan 2020 21:40:45 +0000

U of T researchers turn McDonald's deep fryer oil into high-end 3D printing resin

Christopher.Sorensen Thu, 01/30/2020 - 16:40

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Rajshree Biswas, a PhD student in the lab of U of T Scarborough Professor Andre Simpson, shows off biodegradable plastic butterflies made using a 3D printer and resin derived from McDonald's waste cooking oil (photo by Don Campbell)

Don Campbell

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Our Community

3D Printing

Physical and Environmental Sciences

Graduate Students

Research & Innovation

Sustainability

U of T Scarborough

Researchers at the University of Toronto Scarborough have, for the first time, turned waste cooking oil – from the deep fryers of a local McDonald’s – into a high-resolution, biodegradable 3D printing resin.

Using waste cooking oil for 3D printing has significant potential. Not only is it cheaper to make, the plastics made from it break down naturally unlike conventional 3D printing resins.

“The reasons plastics are a problem is because nature hasn’t evolved to handle human-made chemicals,” says Andre Simpson, a professor at U of T Scarborough’s department of physical and environmental sciences who developed the resin in his lab.

“Because we’re using what is essentially a natural product – in this case fats from cooking oil – nature can deal with it much better.”

The plastic butterfly printed from the researchers’ cooking oil-derived resin showed features down to 100 micrometres and was structurally and thermally stable (photo by Don Campbell)

Simpson first became interested in the idea when he got a 3D printer about three years ago. After noting the molecules used in commercial resins were similar to fats found in cooking oils, he wondered whether one could be created using waste cooking oil.

One challenge was finding old cooking oil from a restaurant’s deep fryers to test in the lab. Despite contacting several major national fast food chains, the only one that responded was McDonald’s. The oil used in the research was from one of the hamburger chain’s Scarborough restaurants.

Simpson (left) and his team used a straightforward one-step chemical process in the lab, using about one litre of used cooking oil to make 420 millilitres of resin. The resin was then used to print a plastic butterfly that showed features down to 100 micrometres and was structurally and thermally stable, meaning it wouldn’t crumble or melt above room temperature.

“We found that McDonald’s waste cooking oil has excellent potential as a 3D printing resin,” says Simpson, an environmental chemist and director of the Environmental NMR Centre at U of T Scarborough.

Used cooking oil is a major global environmental problem, with commercial and household waste causing serious environmental issues, including clogged sewage lines caused by the build-up of fats.

While there are commercial uses for waste cooking oil, Simpson says there’s a lack of ways to recycle it into a high value commodity such as a 3D printing resin. He adds that creating a high value commodity could remove some of the financial barriers with recycling waste cooking oil since many restaurants have to pay to dispose it.

Conventional high-resolution resins can cost upwards of US$525 per litre because they’re derived from fossil fuels and require several steps to produce. All but one of the chemicals used to make the resin in Simpson’s lab can be recycled, meaning it could be made for as low as US$300 per tonne, which is cheaper than most plastics. It also cures solid in sunlight, opening up the possibility of pouring it as liquid and forming the structure on a work site.

Another key advantage is biodegradability. The researchers found that burying a 3D-printed object made with their resin in soil lost 20 per cent of its weight in about two weeks.

“If you bury it in soil, microbes will start to break it down because essentially it’s just fat,” Simpson says.

“It’s something that microbes actually like to eat and they do a good job at breaking it down.”

The results of the research are published in the journal ACS Sustainable Chemistry & Engineering. Simpson received funding from the Natural Sciences and Engineering Research Council of Canada, the Canada Foundation for Innovation, the Government of Ontario and the Krembil Foundation.

A local #ScarbTO @McDonaldsCanada gave the researchers the old oil to test it out—and it WORKED! https://t.co/524Vhxx9WV #UTSC #UofT pic.twitter.com/XRFNSOSLZn
— University of Toronto Scarborough (@UTSC) January 30, 2020

Pumped up: These 3D printers create perfect models of life-sized human hearts, spines and other body parts

noreen.rasbach — Mon, 28 Oct 2019 13:59:56 +0000

Pumped up: These 3D printers create perfect models of life-sized human hearts, spines and other body parts

noreen.rasbach Mon, 10/28/2019 - 09:59

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A 3D printed model of a heart (photos by Hamin Lee)

Topic

Faculty of Information

Faculty of Medicine

Research & Innovation

In a small, windowless room at Toronto General Hospital, a bank of seven 3D printers runs day and night, patiently laying down layer after layer of coloured plastic. When the printing is done, the pieces are trimmed and fitted together into perfect models of human hearts, life-sized and correct down to the smallest detail.

The 3D printers are part of the Lynn & Arnold Irwin Advanced Perioperative Imaging Lab at the University Health Network’s Peter Munk Cardiac Centre. Combined with advances in medical imaging and computer modelling, they are allowing doctors to get a better look at heart defects before they go in to repair them, as well as providing better training methods.

The models of the hearts use extremely detailed data from MRIs, CT scans, ultrasounds or other imaging techniques. Normally, doctors are working with two-dimensional images on a printout or a flat screen. As anyone who has ever tried to see their baby on a prenatal ultrasound can appreciate, this isn’t always easy. By turning the data from those images into three-dimensional computer models, and using those models to make solid printed hearts, the lab gives the doctor something that can be held in the hand and examined in detail.

With the printers whirring away in the background, Josh Qua Hiansen, the biomedical industrial designer at the lab, shows how the model will be used by doctors. This particular patient has a malformation of a part of the heart called the superior vena cava, which is allowing blood to mix with blood from pulmonary veins. Doctors want to fit an implant to close the malformed area, and they will use the model to make sure the implant is sized and positioned appropriately to close the area.

The lab was created in collaboration with Matt Ratto, a University of Toronto associate professor in the Faculty of Information and the head of the university’s Critical Making Lab. Co-founders are Dr. Massimiliano Meineri, a U of T professor of anesthesia, and Dr. Azad Mashari, an anesthesiologist at Toronto General Hospital and a U of T lecturer who heads the imaging lab. The mandate is to evaluate, refine and translate 3D imaging, modelling and micromanufacturing techniques into clinical and educational practice.

Mashari says that the new techniques provide an inexpensive and flexible way to create all sorts of learning aids. These include medical “phantoms” – printed hearts, spines and other body parts. For instance, heart phantoms are used to train ultrasound technicians. And a phantom spine in flesh-like gel can be used to instruct on how to give spinal injections.

With the capability provided by in-house 3D printing, along with 3D computer models and even virtual reality, Mashari thinks that training and medical visualization will continue to become less expensive and more effective.

Close-up picture of a model of a human heart created with a 3D printer, with numbers 1-5 associated with various parts of the model

1. Left atrium and aorta. 2. Superior vena cava and right atrium. 3. Artifical conduit connecting the right ventricle to the pulmonary arteries (also green). 4. Pulmonic ventricle. 5. Systemic ventricle.

The 3D printed model of the heart above is taken from the scan of a patient with dextrocardia and transposition of the great arteries. The patient has had many surgeries in order to create a normal circulation.

This picture shows the top of the heart, so it is as if you were looking down at it from above the person’s head.

The model shows the spaces inside – as if the walls of the chambers, arteries and veins had been removed, and only the blood they contain was visible. This allows doctors to get a good look at the connections between the chambers of the heart.

To make the heart, images from CT scans were converted into 3D computer models, and then rendered into thousands of “slices.” The printer used these image slices to build up the pieces one layer at a time.

The models are fairly cheap to make, but they do take time. It took a technician about three hours to convert the CT scan for this one into a computer model. Total printer time was 30 to 40 hours.

3D Printing

U of T researchers advance metal 3D printing technology for automotive, energy and biomedical applications

U of T Engineering launches 3D-printing course to prepare students for booming field

U of T researchers turn McDonald's deep fryer oil into high-end 3D printing resin

Pumped up: These 3D printers create perfect models of life-sized human hearts, spines and other body parts

This story first appeared in the University of Toronto Magazine. Read the most recent issue