The hype behind additive manufacturing technologies shows no sign of abating. While there continues to be broad interest, the same question is still being asked: ‘where to apply it and how?’ Given the flexibility of 3D printers, it is unsurprising that application of the technology has been far and wide across industrial processes from prototyping to production.
Not all 3D printers are created equally, however, and there are some broad brush trends between technologies. Plastic based machines have found steady and successful application in prototyping, and metal 3D printers are increasingly finding favour in production environments. Here, end-use parts can be made considerably lighter, using a mesh like internal lattice structure that doesn’t compromise overall part strength.
Mark Forth, industry strategy and business development manager at Autodesk, said: “It used to be, the only way to make these advancements was if you start doing it yourself so you understand the processes and problems, and then sympathetically design parts for particular manufacturing processes.”
Here lies the problem with metal 3D printers: a general lack of both understanding and experience. The nature of the fast moving and relatively new technology means that most are still trying to familiarise themselves with it. The reality though, is that no one has quite figured it out.
To help foresee problems Autodesk is developing its software to give design engineers the ability to understand the constraints of additive processes, and perhaps exploit some of the process freedoms.
“There is a school of thought that additive can make anything you want,” said Forth. “Even if you can make something using additive processes, that doesn’t always mean it’s the best way to do it.”
For all its flexibility, metal based additive manufacturing is still, for the moment, a novelty. Its slow processing times, high purchase cost, design complexity and relatively high energy consumption makes it an impractical option for most.
“At the moment, [metallic] additive machines are nice tools to have but that’s going to change, and is already changing,” said Forth. “We are seeing the technology increasingly move from being used to prototype to something that is able to actually make components that are going to be used through the life of a product.”
Forth knows all too well about developing tools to aid the practicalities of manufacturing processes, having worked with Delcam since the late 90s. The Birmingham based outfit built up a global reputation for its CAD/CAM software and was brought by Autodesk in 2014 to bridge the ever closing gap between design and manufacture.
“What we’re trying to do is that fuzzy area between design and manufacture,” said Forth. “When you start with a concept, how do you rationalise that into a design that would be able to actually outperform traditional casting and milling? You might, for example, be able to make the part lighter and use geometry you’d never normally be able to use.”
As the relationship between design, engineering and manufacture continues to become increasingly symbiotic, so to are additive and subtractive manufacturing technologies. Design for manufacture is a philosophy that has long been used to optimise parts or assemblies for certain processes, like casting then milling then finishing. Autodesk wants to take this a step further and use additive manufacturing technology to enable step-change lightweighting and customisation opportunities, more complex geometry creation and of course more cost effective parts. This has led to Autodesk acquiring NetFabb, a developer of software for industrial additive design and manufacturing.
“This really allows us to merge the design and manufacturing,” continued Forth. “The part builder technology that is now part of NetFabb allows you to understand how a part is going to be manufactured, so you can design how it is going to look. The metadata is then able to define a host of attributes about how the part will be made. So that could be making a certain wall thicker, to give better cutting conditions when you finish the part by milling.”
For established manufacturers, 3D printers are just tools that they can call on, alongside lathes and mills. Here, the terminology for parts that utilise both additive and subtractive processes is known as hybrid manufacturing. Here a number of techniques and technologies are emerging including the use of near net shape (NNS) where instead of using a solid cubic billet, a metallic 3D printer lays down material in the rough dimensional shape of the final part, drastically reducing the machining required. For more expensive metals like titanium, it can reduce more than two-thirds of the production costs in some industries.
“Increasingly, we are going to see the use of hybrid manufacturing to produce better parts and components,” Forth said. “We see additive manufacturing technologies as complementary to subtractive manufacturing processes and we want to enable engineers to be able to use all of these tools, as we believe in many cases it is the most effective way to get the job done.”
Hardware leading software
A common gripe by many is additive manufacturing hardware is evolving much quicker than the software. It means that the software tools needed to produce an optimised part are far from intuitive and engineers may well have to port designs and information between five or six different packages from modelling to simulation to production. Each time, the incumbent STL files can lose information adding an extra riddle to an already difficult design engineering puzzle.
However, Forth believes this too is changing. “There’s lots of silos of software that you can use to design and build a part,” he said. “But it’s connecting the dots and that knowledge, and at the moment for the most part we continue to do this manually. We need to increasingly automate this grey area, learn from it and utilise it.
“Those that are best able to integrate the different manufacturing technologies, with the best design technologies, are the companies that will be most innovate and successful going forward.”
Pull quote: “There is a school of thought that additive can make anything you want. Even if you can make something using additive processes, that doesn’t always mean it’s the best way to do it.”