What are the challenges around using additive manufacturing for production? - TCT Magazine

2022-09-03 02:18:34 By : Mr. zhang jian

"There is a lot of opportunity for disruption."

In the 30-plus years since the introduction of the first additive manufacturing (AM) machines, 3D printers have gotten faster, materials superior, applications bigger, acceptance greater, and the ambition to deploy AM for production all the closer. 

From Carbon’s 3D printed adidas midsoles to Chanel’s laser sintered mascara brushes, examples of production are all around but challenges remain that prevent the technology from excelling as a true production process.

“There are new consumer demands at play— heightened by the impact of the pandemic—and they are completely reshaping the way we design, manufacture and mass produce goods that are not only highly personalised but built with sustainability in mind," Wayne Davey, Global Head of 3D Printing Solutions Go-to-Market for HP shared with TCT. “There is a lot of opportunity for disruption not limited to any one industry in particular. Brands across automotive, health and wellness, sports, and more are seeing the benefits of making the switch from traditional manufacturing methods in favour of additive technology. And they want to do it quickly, economically, and most importantly, at a mass scale.”

The effects of the pandemic on supply chains have only brought more attention to the advantages AM can provide. When HP, for example, surveyed a group of global digital manufacturing decision makers in late 2020, 89% said they were changing their business models. Some have already made the shift; As of December last year, the company had reportedly produced over 100 million parts with its Multi Jet Fusion technology for customers like Cobra Golf and Volkswagen, the latter of which has set itself a target of producing 100,000 additively manufactured components each year by 2025. While 100,000 parts might seem like small change compared traditional manufacturing volumes, the gears have certainly shifted.

“Five to ten years ago our greatest challenge was the cost to produce parts by AM – but this has changed significantly in recent years and the cost to print parts is frequently far lower than it was previously,” says Professor Neil Hopkinson, VP of Technology at Stratasys and inventor of the production-focused Selective Absorption Fusion (SAF) technology. “However, this leads to new challenges, most notably educating and informing people in industry, from design to procurement, about what AM can now bring.”

SAF, now under the Stratasys portfolio following the acquisition of Xaar 3D last year, has been designed to enable cost- competitive parts at production-level throughput. The technology has already been put to work by design company DQBD GmbH to produce personalised load-bearing parts for cycling saddles that boast a higher level of comfort, save thousands of euros in costs and cut lead times from months to days.

“If we can clearly articulate how far the AM industry has come in the last 5-10 years, and where the best opportunities lie, then the technology and economics are already there to radically change how we should manufacture many parts,” Hopkinson continued. “The most compelling way to educate the manufacturing user base about the capabilities of AM is through case studies – leading by example.”

One of AM’s biggest enablers is the range of materials now available. 3D Systems, for example, has introduced a variety of production grade materials for its Figure 4 platform along with technical data that validates their suitability for end-use parts. The launch of its fast SLA 750 stereolithography platform earlier this year came paired with a post-processing station and new Accura AMX Durable Natural resin which has been tested per ASTM D4329 and ASTM G194 standards for indoor mechanical performance for up to eight years, and outdoor weathering stability for up to one and a half years.

“Material formulators are increasingly designing production-grade materials,” Brent Stucker, Chief Scientist at 3D Systems said. “Over the coming year, I expect there will be new polymer and metal materials designed for more rigorous use-case environments. I believe we’ll also see new 3D printers designed for specific applications, part sizes, or material offerings. Unlike the more generic multi-material, multi- application prototyping machines of the past, these new application-specific printers have the potential to enable more cost-effective solutions for specific production applications.”

But Ilaria Guicciardini, Head of Marketing at Roboze, which develops machines for high performance polymers and composites, says there are still limitations in matching materials and hardware capabilities to the production standards we expect today.

Ilaria explained: “From our point of view, the greatest challenges of mass production with AM technology are linked to a range of materials and print sizes that are still too narrow and too limited connected to the quality standards required for the production of finished parts as well as to scalable and repeatable systems around the world.”

It's why Roboze is developing materials that correlate with specific market demands such as its Helios PEEK 2005 material, a PEEK-reinforced filament which features short ceramic fibres and offers strong mechanical, thermal and surface finish characteristics for applications in motorsport, aerospace and energy.

Further emphasising the onus on materials, Kristin Mulherin, President of Women in 3D Printing offered: “Materials are cost prohibitive when looking at higher-volume production and there is currently limited relief even with economies of scale. If we are to reach volumes supportive of real end-use production, the costs for materials need to come down many times over.”

Including materials, Mulherin argues there are a trio of factors limiting AM’s production potential: a lack of workflow automation, and a relatively low throughput compared to traditional manufacturing.

“The latter two topics are deeply intertwined,” Mulherin continued. “A lack of workflow automation is just one factor affecting the relatively low throughput of current AM technologies. But, relatively high maintenance requirements also leads to an untenably low uptime of the capital equipment. Until real and reliable automation can be integrated into the end-to-end workflow, serial production with AM technologies will be limited to relatively low-volume production.”

Automation comes up frequently. Additive is a complex, multi-step process with several touch points along the way from setting up process parameters to material handling to the often-manual task of support removal. But automation comes with its own challenges.

“Currently, it is more cost-effective for brands to mix and match production of parts between a number of big and small industry players,” Davey explained. “This makes automating the entire physical and digital flow much more difficult because integration can be complex. There are many nuances, such as geometries and post- processing requirements to name a few, that must be considered."

Ted Anderson, Industrialization Leader at GE Additive, a user and provider of several metal AM technologies, agrees that more attention should be paid to the steps that happen before and after a part comes out of the build chamber.

“One of the challenges is that even experienced users can get fixated on the additive manufacturing process and nothing outside of the process, particularly pre- and post-processing,” Anderson said. “It is just as important to understand what it takes to take the part out of the machine and remove powder from the part. Another challenge we still see all too regularly is that the wrong part or technology has been chosen for serial production. A part that doesn't take advantage of the additive process can drive up cost and drive down productivity, if the part requires lots of post-processing.”

DyeMansion is a company focused solely on addressing those post-printing steps, having released its next generation of automated depowdering and surface treatment technology last year with high volume production in mind.

“Reproducible quality at scale throughout the whole end-to-end process chain is the biggest challenge,” said DyeMansion CEO & Co-founder Felix Ewald. “Adapting every process to the needs of the application is already challenging but combining all process steps is where the complexity starts. Also, costs per part are in many cases far off the cost structure that other industries are used to. Costs are not the only limitation, but when we talk about scale it's the biggest accelerator.”

Cost is indeed a big one. It’s one of the reasons most automotive examples you see in additive are likely to be found on a Bugatti than a Ford Fiesta. In a report published by manufacturing service provider Hubs, 24% of those surveyed saw cost as the main hurdle to using 3D printing. Yet, on the flip side, price was also cited as the second biggest factor in choosing 3D printing, suggesting that where the application suits, combined with other benefits such as lead time reduction, flexibility and part complexity, the cost of additive makes sense.

“An endless commitment of everyone to focus on lowering the costs per part to finally enable economies of scale,” Ewald continued. “Having application- specific production lines where every single step is optimised to the specific application. Adoption in the different industries will only happen at scale if we as the industry solve the challenges and reduce the complexity for the customers. This will only happen if we collaborate.”

Daniel Leong, Product Marketing Manager at Markforged, believes we need to integrate additional steps such as inspection into the fabrication process. Back in April, the company acquired Teton Simulation to enable rapid validation of print parameters and part performance with its SmartSlice software and provide confidence that printed parts will perform as intended.

“3D printing has a unique opportunity to combine part creation and verification where other types of fabrication cannot,” Leong said. “Expanding this capability gives 3D printing another advantage over conventional manufacturing.”

As we move away from prototyping, managing process variation and establishing qualifications to ensure quality and repeatability are crucial. Mohsen Seifi, Director, Global Additive Manufacturing Programs at ASTM International, which has developed and published a range of standards focused on AM, believes in order to maintain these consistencies, we all need to be speaking the same language.

“A standardised procedure must be followed to maintain repeatability, consistency, and quality, which are critical attributes for serial production,” Seifi said, citing standards such as ISO/ASTM 52920 which specifies the requirements for industrial AM processes and production sites. "Whether you operate an AM facility in sectors like aerospace, energy, transportation, or even a hospital, one can map out different elements in the AM value chain with relevant standards to develop an internal quality framework to deploy AM for serial production successfully.”

While technological advancements are all well and good, the challenge to get AM accepted as a production process could also be of the industry’s own making. While AM has undoubtedly benefitted from the ‘cool’ factor thanks to 3D printed trinkets and buzzwords that were common back when the CES stands were still big and the Yoda busts still novel, Jeremy Pullin, Head of Additive Manufacturing at biopharmaceutical industry solutions specialist Sartorius thinks we need to be careful with weighty statements around ‘paradigm shifts in manufacturing.’

“Once you have stopped all these things, refocus your head and your approach by remembering the following ‘AM technologies are just a series of manufacturing processes’,” Pullin said. “They are not magical, they are not more advanced, better or cooler than so called conventional manufacturing. Once your head is in that space you need to benchmark each part objectively against alternative technologies. AM offers many potential advantages such as distributed manufacturing, flexible batch quantitates etc. If none of those add value to the particular part that you are looking at however then forget about them.”

Thankfully, AM vendors are taking note of this pragmatic approach, as Haim Levi, XJet VP Strategic Marketing, Europe, noted: “In my view AM will not replace mass production, even in the future. Even for ‘less massive’ production, AM still needs to overcome several obstacles. [...] The industry still needs to look at improving manufacturing speeds, reducing post- processing times and labour, reducing both equipment and material costs, automating processes and integrating AM onto the manufacturing floor if it is to seriously compete with true mass production.”

For those considering making the jump, Pullin offers the following: “In all, yes, AM as a technology is capable of making stuff but series production results from an entire system where the ability to make stuff is only one part. Don’t get too excited about the possibilities, don’t be too frustrated by the hurdles and be prepared to do an awful lot of convincing people who have worked long and hard to build a career based on the status quo.”

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