Better colour, better texture, better prototyping

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Rapid prototyping, additive manufacturing, 3D printing - whatever the label, it amounts to the same thing; producing models quickly in one build.

Stratasys has been a vanguard of 3D printing for decades, pioneering Fused Deposition Modelling (FDM) technology in 1989 and establishing what is now a multi-million dollar, international additive manufacturing hardware, material-development and associated technologies business.

Multi-colour, multi-material rapid prototyping

As the industry matures, Stratasys is spreading its wings, with the introduction of sophisticated machines that can produce prototypes in multiple colours and multiple materials in a single build. Stratasys' Connex3 - which utilises PolyJet high-accuracy additive manufacturing technology - can 3D print models using three colour and material combinations, allowing for a wide range of colour options in rigid and flexible materials.

Speaking to EPPM at Interplas in October 2014, John Jones, Materials Business Manager, EMEA, explained: "We've taken the printer technology - which is the same as all PolyJet printers fundamentally - and we’ve provided a cabinet with up to 28 kg of material available at all times. We added this to the Connex1 platform, which is simultaneously giving them the same capabilities as an Eden machine.

"You can use two pure materials in the one part, but the difference is we can only talk about overmoulded material in the Connex1. We can't make digital layers yet but we can combine them to overmould with the Connex1, while we can only really talk about digital materials with the Connex2."

Jones explained that a good usage for this overmoulding rapid prototyping technology would be in the case of a car steering wheel, where there are rigid components that can be designed to resemble leather, while with a haptic steering wheel you can produce it so it has a softer grip for comfort. This softer material can, using Stratasys technology, be built onto the steering wheel in one go together with the more rigid material.

There are numerous benefits to rapid prototyping in this way, said Jones: "Time saving, first of all, and accuracy and the ability to use the technology on the Connex2 to give you more layers of Shore A value. For example, printing something simple like a prototype for a stapler where you need the perfect prototype so your design team decides whether the Shore A value will be optimised at 60, 50 or 40; the Connex2 allows you to print all three prototypes simultaneously because it's a PolyJet technology and prints everything on the X-axis, so you can produce all three in one pass with no additional time required. Each part will be built with a different Shore value, even though each part has a different value."

"Ultimately," he added, "this means we can do more prototypes and test more ideas, allowing companies to achieve better parts."

Before additive manufacturing arrived on the scene, Jones explained, prototyping would take days or weeks, when now it takes hours.

And now Stratasys can produce prototypes that are more resistant to their environment, as the company's ASA material is similar in its properties to ABS, but with greater resistance to UV light.

"Traditional ABS will discolour with time, becoming yellow if it's white. ASA provides UV stability and allows colour to remain constant even in an outdoor environment. The aesthetics of the part is also improved more generally because of the makeup of the material. During the layering process, the surface finish will look and feel better than any other FDM material. When you look at the part, there's an apparent smoothness of the surface, giving the impression the layer thickness is finer, but it's the same thickness, the same machine - it just gives the appearance of being finer," said Jones.

"During the build process, it looks smoother even without post-processing, but with post-processing, it looks even better."

Moving under the bonnet

Jones believes these more recent developments are just a continuation of where 3D printing is going.

"A few times a year we bring out the next generation of material. We have some of the highest quality technology available thanks to PolyJet in terms of layer thickness, but every time we bring out a new material capability, we're increasing the range of applications.

"Our challenge is to overcome limitations. With the Connex, the spectrum of possibilities grows even further. A range of material colour should be there - we're moving away from the black-grey-blue world - not to full colour - but we're simulating some colours fairly accurately, and importantly, the repeatability of those colours is very good. You don’t have to be calibrating the machine every time you use it, either.

"Most importantly the capabilities of the materials is being enhanced. One of the things we'll see in the future is increased high temperature technology. Today we're talking about 90 degrees Celsius and I'm sure one of the areas we'll see new developments thanks to this technology would be materials capable of withstanding - I hope - 120-130 degrees. This would be a major step for 3D printing in automotive because we could move under the bonnet."

Jones explained that meeting the needs of the design field is as important as achieving greater levels of functionality in prototyping. "You could probably go to all our customers and find our technology is being used but only covers a percentage of their needs. For the remaining 20, 30, 80 per cent, they have to use other technologies - conventional methods. Every incremental improvement in the material enables them to produce parts on the 3D printer they would not have been able to before."

Aside from what is going on at Stratasys' research and development facilities throughout the world, Jones says it's the customers who are showing the company how its technology is being used and inspiring the next steps for 3D printing.

"The most interesting thing is going to existing customers in automotive, aerospace, jewellery etc., and being shown what they've come up with based on what the technology can do. It's a never-ending journey of being given new tools and sharing this knowledge with customers."

So what next for Stratasys' material development? Jones, mirroring General Manager for EMEA Andy Middleton's sentiments, agreed that introducing a fourth colour capability to the Connex system would be "logical".

"It makes good sense. I come from HP and you need five or six colours [in 2D printing] to get a really rich Pantone. So why stop at four? From the colour perspective, to match Pantone colours to approach large corporates and allow them to produce better prototypes, that's the dream."

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