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Xaar plc
Uses for the HSS technology range from industrial products to the FMCG market.
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Xaar plc
A selection of functional parts manufactured using the HSS process. Image courtesy Xaar
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Xaar plc
The internals of the HSS system
The team is also investigating materials. The envelope of materials for HSS appears to be greater than for laser sintering, but not as wide yet as injection moulding. FACTUM has discovered materials that are difficult or impossible to laser sinter, but can reliably high-speed sintered.
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Imagine picking up your groceries in the supermarket and loading your car with packaging that was once injection-moulded and is now additive-manufactured. Imperceptible as this may be for the average consumer, for additive manufacturing it would signal the maturing of a technology that was once the reserve of prototyping.
Additive manufacturing through advanced polymer sintering at high speeds is being explored by University of Sheffield spin-out FaraPack Polymers, as it investigates laser sintering for low-volume applications and high-speed sintering (HSS) for low and high volumes. The team is working alongside industry partners and with Loughborough University - which owns the patents for HSS - to exploit this manufacturing process with the aim to deliver a validated supply chain and a range of example products that show the time-saving, part properties and cost benefits of choosing this technique for high-volume orders.
Christened FACTUM, the project has been awarded £1.5 million in funding from the Technology Strategy Board (TSB) and industry partners. Leading the research is The University of Sheffield’s Professor Neil Hopkinson, of the Department of Mechanical Engineering, who was on the team that invented HSS at Loughborough University, where the intellectual property stayed when Hopkinson moved to Sheffield University.
“The HSS machine we’ve been using in this project to make parts is owned by Loughborough and loaned to Sheffield, as the research helps Loughborough to licence the technology, while Sheffield secures funds to develop new technology,” he explained.
Strong partners
“We have a really strong partner in the fast-moving consumer goods field with Unilever,” Hopkinson stated. “We believe this is the first time such a company has engaged in a publically-funded project in which they have invested substantial resources of their own, with a target of using additive manufacturing for end-use products. Fast-moving consumer goods are produced in high volume and thus far that’s not worked with additive manufacturing economically. The viability of additive manufacturing at high volume is one of the key unique features for this project.
“That’s one end of the production spectrum. BAE Systems and Cobham Antenna Systems represent the other side, with low-volume, high-added-value products more usually associated with additive manufacturing. BAE is an aerospace giant, while Cobham Antenna Systems works in the field of space telecommunications equipment. We are looking at working with them and exploring the design freedoms and material possibilities and working with the technology in terms of improved product performance.”
Christened FACTUM, the project has been awarded ££1.5 million in funding from the Technology Strategy Board (TSB) and industry partners.
FACTUM has also signed up Sebastian Conran Associates to master the design opportunities afforded by the technology. His team decided upon the name of the project, choosing the Latin for ‘to make’ to allow the significance the technology will have on manufacturing to speak for itself.
“It’s a bit of a coup for us,” Hopkinson admitted. “We think Sebastian Conran Associates is the first example of a long-established design brand that’s really embracing additive manufacturing technology.”
Maximum freedom of choice
FACTUM’s other industrial partner is inkjet technology leader Xaar, which is responsible for producing the inkjet heads that are “right at the core” of the HSS process.
David Chapman, who is responsible for developing Xaar’s inkjet technology as an advanced manufacturing process, said FACTUM has the potential to “radically change the way we think about manufacturing, introducing new designs and business models that we cannot even imagine today”.
“The fact that it has attracted the interest of the likes of Unilever and BAE Systems underscores this potential,” said Chapman. “Inkjet is at the heart of this technology and by working with our supply chain partners, Xaar is committed to bring this technology to market. The great thing is that it’s British technology and British manufacturing that is leading the way on this.”
Hopkinson added: “Xaar is really important because they are both integrating their systems into our machines and helping us with the supply chains for inks. We are trying to make the project more end-user focused, keeping supply chain companies outside of the core membership. This way we can create example products in these different sectors with maximum freedom of choice for materials.
“We have no material suppliers as core partners to this project, so there’s no opportunity for monopoly or control over the supply chain by any particular company.”
The long-term vision for HSS is for it to compete with injection moulding and CNC machining but to achieve this, HSS must have a similarly open supply chain.
“So the supply of materials, the powders and the inks we use - even suppliers of machines themselves - we’ve intentionally kept them as non-core partners. We’ve developed a hinterland of supporting companies who are feeding into FACTUM. In this respect, it’s very helpful to have Xaar on board to help us find suppliers and very helpful to have Unilever and BAE because they are so influential when it comes to getting material suppliers to commit their resources.
A very profound first
In order to compete with a technology as ubiquitous as injection moulding the FACTUM team has been looking into using HSS for a wide range of products with diverse geometries, establishing how much it will cost to make each unit.
“Something interesting we found,” Hopkinson said, “we’re beginning to find some geometries where we expect it to be cheaper to use HSS than to injection mould for any production volume. To date, it’s been the case that it’s only cheaper to additive manufacture a product up to a certain production volume, thereafter it’s cheaper to injection mould. But we’ve found for some geometries this is no longer the case. With HSS, we predict for a substantial range of products it will always be cheaper than injection moulding, which won’t be able to compete on cost in these cases. We think this is a very profound first for additive manufacturing.”
The team is also investigating materials. The envelope of materials for HSS appears to be greater than for laser sintering, but not as wide yet as injection moulding. FACTUM has discovered materials that are difficult or impossible to laser sinter, but can reliably high-speed sintered.
“Even though the process is capable of making finger-sized parts at less than one second per part,” Hopkinson said, “there’s the paradox that the time the heat is applied to melt the powder is longer than when employing lasers. The sweeping lamp employed in HSS typically applies heat to adjacent particles for a period 10,000 times longer than a laser, so HSS gently heats materials that can minimise damage and improve sintering quality.
“We believe this elongated heating period is the reason why we get double the properties than laser sintering for some materials.”
The part doesn’t have to be metal
Hopkinson noted the system will open up more polymers to clients who perhaps overlooked plastics in favour of other materials such as aluminium, because they had to be manufactured using CNC machining.
“We can imagine lots of applications where products are currently made in CNC machining out of aluminium because the part is made in small quantities and moulding it is cost prohibitive, so the choice is to machine it and this dictates that the material should be metal. If you are going to use HSS and you don’t have to consider the cost of tooling, you don’t have to consider machining - therefore the part doesn’t have to be metal. So we see a lot of opportunities particularly in low production up to a few thousand where we think these technologies will displace the CNC machining market.”
HSS can also open up functionality horizons for parts, Hopkinson explained: “When we’re working with fast-moving consumer goods, appearance and tactile qualities are important. We’re working on ways of using the process to intrinsically improve the visual and the tactile aesthetic parts and the possibility of adding extra functionality into parts.
“We are working with our end-user project partners who send us geometries to make. We find this quite inspiring because they have really heavy demands. The demands for aerospace are obvious and challenging, but we find the challenges for products to be of a high enough quality to go on a supermarket shelf is equally demanding. These challenges we are being set are very real and there’s such a buzz in our lab now because the team working on this can really see the fruits of their labour thanks to this end-user drive.”
Hats off to the Technology Strategy Board
Hopkinson claimed FACTUM is unusual for a TSB-funded project. Due to restrictions surrounding funding allocation, FaraPack Polymers is leading the venture, but this means industrial partners have to invest more than they would usually be expected to in normal TSB-funded projects to cover the full cost.
“The input from industry partners is greater than you would normally see in a TSB project. This is relevant - it conveys how seriously these companies are taking this technology,” he remarked.
“Overall, it’s fair to say the TSB funding has been an enabler to help us pull together this really impressive consortium that has global appeal. I think it is going to be a critical factor in Loughborough University being open to licencing the technology. We can already speak to licensees and make parts and that’s all well and good, but now we have committed partners who are putting in more financial commitment than would usually be needed and this really increases the level of interest.”
Hopkinson had nothing but praise for the support of the TSB, without which, he does not believe FACTUM could have achieved so much.
“I think we’ll look back in two or three years’ time and take our hats off to the TSB on this one,” he acknowledged. “We will recognise that TSB funding was critical in bringing HSS technology to the market. That’s what it’s there to do and I’m certain in this case it’s going to deliver industry-changing results.”
