Expert Interview: Solvay’s Brian Alexander on Developing High-Performance Polymers for 3D Printing

With a number of patents for technologies like SLS and FFF having expired by 2016, Alexander explains that this also had an impact on Solvay’s perspective of the evolving market.
 
“The market opening up a lot more and new players emerging opened up key opportunities for the polymer side of things. Of course, along with the opportunity came a lot of hype as well — so it was important for us to take a pragmatic approach.”
 
Alexander notes how the industry has changed in just three short years.

“In our first year we interviewed many of our top customers to understand their needs and where they were with AM. Surprisingly, when we did this in 2016, hardly anyone believed in AM. ‘It’s interesting, but it’s not for mass production’ was the general sentiment. That’s all changed now, of course.”

AM requires a shift in mindset

Solvay Speciality Polymers is one of the business units within the Solvay Group and comprises around 3,500 employees. “Our value proposition is that we have one of the largest portfolios of high-performance materials on the market,” says Alexander. “We have around 35 different polymers to offer, all with unique properties.”
 
These polymers are high-value materials, sold in smaller volumes. This, in turn, complements additive manufacturing, where specialised, high-value applications can benefit from the economies of scale and complexity the technology requires.
 
However, developing materials specifically for the additive manufacturing process required a shift in mindset, Alexander notes.

“We soon realised that the whole mindset for AM is completely different from traditional manufacturing. You have to completely redesign your value chain. Pretty much everything needs to change, from materials to design — and of course optimising your equipment and processes.

“We knew that if we tried to sell our standard resins, some that have been around for 30 years, within the AM space, we weren’t going to succeed. So our goal was to become the leading supplier of customised high-performance AM-ready solutions.”
 
What does that mean in practice?
 
“Well, we need to know exactly what’s going into the machine,” says Alexander. “If we pollute the value chain with all sorts of different steps and have no idea what’s going into the machine, then we have no control over the process. And this is crucial if you’re trying to qualify materials to very high-value niche markets like medical or aerospace.”

The road to developing high-performance polymers for additive

“Additive manufacturing started with fairly low-performing materials, like PLA and ABS,” says Alexander. “These are great for making things like toys and gadgets. But to get the full benefits of the technology, you’ll need more industrial-grade materials, like PEEK, for example.”
 
The increasing need for industrial-grade materials can be tied into the industry-wide shift from using 3D printing for serial production, and not just prototyping.
 
As Alexander puts it: “If you’re just focusing on prototyping, you’re really not getting any of the benefits of additive manufacturing because these parts aren’t designed for AM. So you’ll never get the same properties.
 
“With series production, if you want to make a part in your material of choice, you’ve got to have a broad range of temperatures, mechanical performance, qualifications, approvals and so on. Only then can you bring all of these elements together to get the design you really want to obtain. So we were working on providing more high-performance materials than what was available on the market.”
 
Developing high-performance polymers specifically for the additive manufacturing would be no mean feat, not least because of the range of 3D printing technologies on the market and Solvay’s broad materials portfolio.
 
In the end, the company chose to start with Fused Filament Fabrication (FFF) — the most accessible 3D printing technology.
 
Solvay also had two key target markets in mind when testing these initial materials: healthcare, for its mass customisation applications, and aerospace for small series production.
 
“The key questions we were asking were: how are our materials being used in these markets currently and how can we enable them to be 3D printed? This would provide our customers with the opportunity to use our materials even further, as complementary to their traditional manufacturing.”
 
PEEK (Polyether ether ketone) and PPSU (Polyphenylsulfone) were chosen as the two polymers to start with.
 
PEEK is well-known for its exceptional stability, chemical and temperature resistance as well as its excellent strength-to-weight ratio. It’s used in demanding environments for applications that include aircraft components, automotive bearings, oil & gas and electronic components.
 
Similarly, PPSU possesses high heat resistance and exceptional chemical and impact resistance and elongation at break. It can be used for applications like medical devices, plumbing and food service applications, just to name a few.
 
“When it comes to AM, you have to understand your materials in terms of shrinkage, warpage and cohesion,” says Alexander “All of these properties are related to the material itself and can be predicted if you know your material well enough.”
 
Solvay also launched its Additive Manufacturing Cup in October 2017. The competition invited university students around the world to demonstrate their ‘aptitude for additive manufacturing’ by using its PEEK filament to produce complex parts. The results, Alexander says, were phenomenal.
 
“We were amazed by the results we got. The students were able to innovate very quickly. It showed that the capabilities to make a change were there if someone could help enable the change. This gave us the confidence to try something different.”

A new business model emerges

The results from its Additive Manufacturing Cup led Solvay to develop a new way of engaging customers: through a new e-commerce platform.
 
“Instead of going the traditional route, operating on a closed model, we decided to make our materials available at a fair price to anyone with a credit card,” says Alexander.
 
“It makes it fast, transparent and easy to buy polymer materials — and it’s the first of its kind on the market from a major chemical company. Our end goal is to inspire the next generation to use our materials.”
 
When it comes to serving its industrial clients, for Solvay, data is key. “When you looked at the data sheets of other chemical companies, they were simply sheets of data from injection moulded parts,” Alexander explains. “That’s why we decided to make all of our data on additively manufactured parts available. It’s a matter of giving our industrial clients confidence in our materials.”

Why process control is important

Alexander puts the importance of process control clearly. “Without a good process or good equipment, you’ll end up with a terrible part. That’s why we’re working a lot on developing partnerships. For example, we’re trying to work with 3D printer manufacturers to help them understand how to process our polymers and the print profile we require from the machines. 
 
“The majority of our industrial users want to have a plug and play solution: a material they can put into the machine and have the part comes out the same way every single time. At Solvay, we understand that that is eventually where we want to go.”
 
Alexander further explains why being able to control the additive manufacturing process is so important. “What we learnt between 2017 and 2018 is that how you print the part is crucial. If you get high porosity and micro and macro voids in the material, your strength and strain at break won’t be consistent at all. The only way to do that is to learn how to process your materials and adapt the process to get a fully homogeneous part.

“If you want to get the full benefits of AM — lattices, lightweighting, part consolidation and so on — you need to understand how to process your material and see how your material will perform with a lattice structure, perimeter edge, and how you can optimise an existing design to make it suitable for AM.”

The role of materials simulation

Solvay is continuing its aim to expand its AM materials capabilities.
 
Last year, the company announced its partnership with e-Xstream engineering, a provider of simulation software. The partnership sees Solvay’s high-performance polymers being added to the company’s Digimat-AM platform for material simulation.
 
3D printing simulation is on the rise, as it becomes increasingly important to be able to predict how a part will behave before a design is sent to print.
 
Digimat-AM enables users to simulate the 3D printing process. Its partnership will Solvay means that users will now be able to predict the thermomechanical behaviour of Solvay’s polymers during the design stage. By digitally recreating the physical conditions and part behaviour, much of the trial-and-error common to the AM process can be eliminated.
 
Alexander explains the goal of the partnership.
 
“The aim was to allow users to get a digital twin of their material. With Digimat-AM, you can now design with and simulate with all of the Solvay AM ready materials on the market.
 
“When designers want to test a concept, they can spend up to 24 hours printing a part that may not work and may even be the wrong design. But if you can take the guesswork out of the equation and predict how a part will behave before you print, you’re adding significant value for the customer, as well as accelerating speed to market.”

The future of AM polymers

As far as the future of additive manufacturing, Alexander has a rather philosophical outlook.
 
“Honestly, I’m most excited by the promise of AM. Larger companies are more motivated to make that promise happen by moving away from an application or qualification approach to recognising the need for process qualification. That’s the most exciting trend. If you don’t have a process that works, you don’t have a successful part. It’s that simple. Also, I don’t think AM will ever fully replace traditional manufacturing methods but it can certainly be complementary and create new ideas and opportunities.”
 
As for the cost of materials, Alexander is positive. “Certainly, economies of scale are a current challenge and prices still remain fairly high. That’s how it is at the moment. We have to create the market. So I’m confident that as volumes increase and applications broaden, prices will come down.”
 
2019 is set to be a busy year for Solvay, as it continues to work on qualifying the additive process. “We’re trying to apply our print profile applications to a number of print suppliers,” Alexander explains. “Our aim is to have 10 -15 commercial printers capable of printing our polymers consistently.
 
“We’re also looking towards more partnerships, particularly on the Advanced Materials side and moving to other technologies and other materials. These will include powder-based technologies like SLS and Multi Jet Fusion. Finally, we’re working with our key OEMs that have the mentality and ability to invest in something that will be very disruptive.”
 
To learn more about Solvay, visit: https://www.solvay.com/en

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