13 December 2023

Being able to 3D print various products may change processes in various areas, from the manufacturing industry to healthcare. Some may think of the astronaut who forgot his wrench at home. Is it just to print a new one?

Three male scientist in laboratory Jinghao Xu, Anton Wibergand Joakim Holmberg collaborate in various ways in additive manufacturing.There are many challenges, involving everything from material strength to environmental impact. Thor Balkhed

But it is more complicated than that, according to Anton Wiberg, postdoc working in the field of additive manufacturing at Linköping University.
A 3D-printet part of a hip joint. Photo credit Thor Balkhed
“For instance, we have to qualify manufacturing, be able to repeat it, secure strength and study the material, costs and effects on the environment. There are many questions for us researchers,” says Anton Wiberg, who is project manager for part of this area.

Additive manufacturing is the term for what is often known as 3D printing. The manufacturing process is completely different from traditional manufacturing industry. There are plenty of advantages:

Accessibility is important. A ready-to-use product can be made in a relatively short time. Although this manufacturing may not be better for the environment, reducing transports can make a difference and lead to lower total cost. Objects can be manufactured one at a time, with individually tailored details.

It’s important to have a lab environment that can inspire others 
On the minus side, there are uncertainties as to quality, and a general scepticism. Additive manufacturing is on the increase, but has not yet matured.

“Traditional manufacturing processes are very mature. People know very well how to use a milling machine to get the right shape. With 3D printing, completely new methods are introduced. This becomes a huge uncertainty factor. But there are numerous indications that the new methods will mature too,” says associate professor Joakim Holmberg.

In the heat chamber in the 3D-printer for prints in metal. Photo credit Thor Balkhed There is a whirring sound in the laboratory, from the fans that help maintain temperature and air quality. Everything is connected to a system with special filters. A machine in the centre of the sound-proofed room is printing out materials in metal. The temperature in the building chamber needs to be about 1,000 degrees Celsius. The lab is closed but at the same time open. It has windows, with curious students peeking in now and then.
Male scientist checking 3D printer in laboratory.Research Engineer Jinghao Xu is checkning the metal 3D printer.
“You get used to that. It’s important to have a lab environment that can inspire others. We want this space to become available as a testbed for researchers, students and industry,” says Anton Wiberg.

The metal printer consists of a building chamber with an adjacent powder chamber from where thin layers of metal powder are successively applied to a build plate. The electron cannon shoots electrons at the metal powder bed. Its beam can be directed with very high precision and extremely quickly at various positions to melt the powder, layer by layer, according to the pre-set geometries. Electromagnets guide the beam to the right location.

In 3D printing, the material, the product and its geometry are created simultaneously. This places very high demands on the entire process, from metal powder to geometric shape.

The geometry, i.e., the shape of the product, impacts the entire manufacturing process, and also the quality of the final material. Anton Wiberg holds up a plate with examples of various shapes.

Samples of various prints in metal.Samples of various prints. The shape of the product affects both the manufacturing, the material and the strength. Photo credit Thor Balkhed “Look here, the square bit has better properties and a much finer surface, whereas the ones that vary in shape have less good properties. With a smaller detail, it’s faster and the temperature is higher, as you’re directing more energy in a shorter amount of time at the same location. This is one of the things we’re trying to take into account,” says Anton Wiberg.

Photo credit Thor Balkhed The researchers can see many uses for 3D printing, for instance new types of hollow metal structures that should be able to carry more in relation to their own weight than normal, massive metal. But also various types of polymers, i.e., plastics.

“In principle, all materials can be 3d printed if you choose the right technology. But the consequences of additive manufacturing span over the entire life cycle of a product, forcing us to reconsider the design, manufacture, use and recycling of products,” says Johan Moverare, professor and research leader in the area of additive manufacturing.

Medical applications is one of the areas they focus on. Anton Wiberg has worked on printing of hip bones, together with Joakim Holmberg and research engineer Jinghao Xu and orthopaedist Jörg Schilcher, researcher at the Faculty of Medicine and Health Sciences. This is done using a plastic material resembling the structure of a human skeleton. From CT scan images, they print a natural size model that looks very much like the hip joint to be operated on.

“The purpose of this is to train the surgeons on the procedure before the operation. We have developed a software that transforms the CT scan images, and is easy to use. You can print using a normal hobby printer. This keeps the costs down,” says Anton Wiberg.

In this way, surgeons can discuss the procedure beforehand. They can practice drilling and screwing into the printed “bone material”, as well as use screws to attach implants to it – before the actual operation. They can also practice new methods and more advanced procedures.

“Training can reduce surgery time and give better results,” says Anton Wiberg.

Photo of titan part of hip joint.On a 3D-printed hip joint in sized 1:1, orthopedists can practice pre-operative in a realistic manner. Photo credit Thor Balkhed This work is carried out in interdisciplinary collaboration between researchers and orthopaedists at Region Östergötland and the Faculty of Medicine and Health Sciences. The training was carried out in workshop format only, and not in connection with surgery. The research has been presented at scientific conferences, and will be compiled in articles for publication. Another collaboration project involves a medical company, Swemac, which manufactures titanium nails for hip and wrist joints. This project is about developing a completely new manufacturing process.

What scientific gains can collaboration with businesses and organisations bring?

“Huge gains, as we can ask questions in our research that are relevant to future applications,” says Anton Wiberg.

Johan Moverare summarises:
“There are many good examples of how additive manufacturing contributes to making products more effective, cheaper and more environmentally friendly. But this has to be done in the right way and there are pitfalls. There are still many challenges that we need to solve together with industry and other organisations in society.”

Photo credit Thor Balkhed

Facts

Additive manufacturing is an array of manufacturing methods that, compared to traditional methods, offer a flexible manufacturing process enabling the creation of advanced geometries and materials. 3D printing is one method.

Linköping University and its Department of Management and Engineering (IEI) are investing in strengthening competence and increasing available equipment for various methods of manufacturing metal, polymers and other materials.

The aim is an operation that involves both internal research and a possibility to collaborate with other parts of the university, as well as with the Region and industry.

Currently, collaboration takes place in the form of projects with, among others, the Innovative Materials Arena (IMA) and various industry actors, such as Saab, Siemens Energy and Region Östergötland.

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