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By Ross Tester Printing in the Third Dimension Imagine a colour printer that outputs images not just in the two dimensions we’re all familiar with – width and depth – but adds the third dimension, height, so that the “printed” images can be physically held, picked up, turned, inverted . . . just like any other 3D object. 12  Silicon Chip siliconchip.com.au A few months ago, a company called SOS Components placed a flyer in SILICON CHIP advertising their rapid prototyping bureau. It looked fascinating but, not being involved with anyone who needed or used such a service, I’d all but forgotten about it . . . until I came across the company’s stand at this year’s national manufacturing week exhibition. Centrepiece of the stand was a magnificent model boat. It would have been well over a metre long, 250mm wide and perhaps 350mm deep. I was informed that this boat was an exact scale model of a boat currently being built in Queensland for a (very!) well-heeled individual. Now prototypes or models are not exactly new – a lot of models, for all sorts of “products” are built before production begins. The client might want to make structural or cosmetic changes once they see how the “thing” actually looks. And it’s normally a lot cheaper to do it earlier than later. A lot of companies also make accurate models of proposed new products for evaluation, testing, checking and so on. But this was no ordinary model boat. It wasn’t carved from a block of balsa or modelling plastic by a skilled modelmaker, labouring away for perhaps several weeks. In fact, it wasn’t carved at all. It was printed, in the true sense of the word, layer after layer after layer – and in colour! Due to size limitations of the printer, (maximum build size is 250 x 350 x 200mm), it was “printed” in four sections which were then glued together. Because each section was extremely accurate, there were virtually no join edges – just some very minor retouching was all that was needed to hide the seams. That’s a photo of it at left, with the man who “printed” it, Jeff Condren, from SOS Components in Brisbane. To say it was impressive is at best an understatement. However, it wasn’t all that SOS were displaying. Across the back of the stand was a large (>2m x 2m) model of a proposed Brisbane motorway intersection. Note the word You better believe it: it’s a model of a Tupperware bowl, complete with removable lid moulded in “Superflex” – developed in Australia by SOS Components. “model”. It wasn’t just your usual flat “map” with a few cars and trucks added to make it look more realistic; this one had all the terrain in accurate scale, the cuts for the motorway lanes where required, the hills and landscaping alongside – it was just like looking down on the scene from a few hundred metres up. Then there were quite a number of “model” buildings, engineering samples, appliances, components, even soft plastic bottles (more on this innovation shortly) – all in accurate scale, most in colour. Because the layers are printed, any “internal” parts are formed exactly as they would be in the real thing – even movable parts. For designers and engineers creating a new product, this aspect is so valuable. They can actually see how the components fit into one another, how they react, if the clearances are correct and so on. But it takes a little bit to get your head around the fact that every one of these is printed, not carved, cast, stamped or any other, shall we say “conventional” method of producing models or miniatures. A sense of déjà vu? Regular SILICON CHIP readers may recall a story we published back in the September 1996 issue on a process Take a set of architect’s drawings, convert them to 3D . . . and print them! Just imagine how much more likely the sale would be when a potential buyer can see a real model of what they are being offered! siliconchip.com.au August 2008  13 for producing prototypes. At first glance, it might appear that the processes are the same. While they are, to some degree, similar, that’s like saying Minis and Maseratis are similar. Things have changed significantly in the last decade or so. For a start, the process we looked at in 1996 used a laser beam to “sinter” a layer of fine powder together. (Sintering is the amalgamation of material by heat, without melting). The article also discussed a process where a layer of adhesivebacked paper was laser-cut and stuck to a previous layer, building up one layer at a time. The process we are looking at here is true printing – in fact, four-colour (CMYK – cyan, magenta, yellow and black) printing, as used in this magazine. There aren’t many colours that CMYK printing can’t replicate reasonably well – fluoro colours and bright orange/bright green are the main exceptions. However, by combining various percentages of inks, the vast gamut of colours can be produced very successfully and is one of the reasons the CMYK process is used so extensively. However, unlike the offset (roller) printing used for most CMYK jobs, the 3D printer works in much the same way as an inkjet printer. First it deposits a very fine layer of tiny beads of powder, then sprays microscopic droplets of ink onto the powder in the required pattern as the head passes over. As the powder is “wet” by the ink, it effectively turns it into a glue which bonds to the layer immediately underneath. As the ink dries, the powder/glue hardens. Then the process is repeated – over and over – and every time the printer head makes a pass over a layer and it is completed, the whole thing drops down about 0.1mm, ready for the next layer. Thus the image is built up, layer by layer, until the 3D image is produced. Only the areas of powder hit by ink droplets are affected, so all of the other powder remains in its original condition and is available for re-use – in fact, it is collected for that very purpose. If the original had printing, colouring, texture mapping or labelling, so will the 3D-printed “image” Complexity is no problem – it takes exactly the same time to print a highly detailed, intricate image such as those shown on these pages as it does to print a brick the same size! Where does it get the image to print? Like any “conventional” printer, the 3D printer requires “driving instructions” to tell it where to deposit which ink The medical applications, particularly in a learning environment, are enormous: above is a human heart, printed from an MRI Scan. This heart, though, comes apart as seen top right so that all the chambers and valves can be seen exactly as they should appear. For good measure, lower right is a “slice” or cross-section of a human kidney, complete with colour-coding to show how it works. 14  Silicon Chip siliconchip.com.au and in which quantities to reproduce the colours required in the places required. Most printers simply need X and Y co-ordinates but the 3D printer also needs Z – the depth. The image might come from a 3D laser scan, an architect’s or engineer’s drawing in a CAD program or even, as we saw earlier, scaled down plans of a ship, a building, a spacecraft . . . in fact, just about anything that can be plotted in all three dimensions can be used to print the solid object. Where did the process come from? The 3D printing process was invented by Dr Jim Bredt and Tim Anderson, students at the Massachusets Institute of Technology during the early 1990s. Part of Dr Bredt’s PhD thesis involved the use of low-cost printer technology to produce 3D images. They formed ZCorporation which, with a licence from MIT for the 3D printing process, has now grown to an organisation with distribution and service in 61 countries and over 160 employees. SOS Components are the Australian distributors of ZCorporation products. The can produce elastometric parts, direct casting moulds, investment cast patterns and snap-fit parts directly off the printer with no machining required. These take hours instead of the traditional prototype days – and in fact are generally much more accurate than a hand-made (machined) prototype. Superflex However, SOS has taken the ZCoporation idea another step further with Superflex. By using a compound they developed themselves, SOS can produce flexible parts in a 24-bit colour process. Complexity is no problem, as this highly-detailed model of a machine demonstrates. This would have taken exactly the same time to print as a brick of the same size! (Right): Complete with obligatory “Save $XXXX” show stickers, one of the ZCorporation 3D printers – in this case the Spectrum Z510 – on display at the Manufacturing Week exhibition. Below is a close-up of the business end of the printer. On the extreme right is the movable print head which sprays microscopic ink droplets onto the powder in the well at left. As each pass is made, the bin containing the powder drops down a miniscule amount and a fresh layer of powder is laid down, ready for the next ink spray. The size limitation of this particular printer can be seen; hence the need for the model boat at left to be printed in four sections and then glued together. Because the printing process is so precise, the complete model appears virtually seamless. siliconchip.com.au August 2008  15 Want to know how a turbine works? The students can see “inside” the turbine with this exploded view of a turbine. Printed with all components already in place (and again colour-coded to aid understanding) this model would take hours to produce instead of weeks in a model-making shop. A “plastic” bottle printed with Superflex. As you can see, it behaves just like a “real” plastic bottle would behave. This enables the customer (and therefore evaluation and market research groups) to not only touch and feel a prototype product, they can squeeze it and flex it – just like the real thing would behave. Prototype squeeze bottles or extrusions that can be squeezed or flexed make a world of difference when it comes to product evaluation. Because they are printed and the (non-hardened) inside sections removed, empty bottles can be just that. If the design has movable internal parts , the model will have movable internal parts. And parts in the design that move with respect to other parts can move with respect to other parts in the model – and be checked that they do move! Who uses this service? Just about anyone who needs a highly accurate model of just about anything – for just about any purpose! The obvious users are in product design and development, advertising agencies, architects, real estate developers, colleges and universities . . . and then there are the not-so-obvious such as demonstrated by the model boat photograph. 16  Silicon Chip As a sales aid, it is without peer. You can just imagine how much more impressive is a scale model of a multimillion dollar bridge or freeway than even the best aerial photos. It’s more than likely that the 3D printing process has used those same aerial photographs, added data from topographic maps and voila! – a 3D “map” where everyone can see heights and relativities. Similarly, product prototypes: Proctor and Gamble’s Tim Smith said “We’ve handed people pictures, we’ve even handed them 3D glasses to watch a screen. But I never saw jaws hit the floor until I handed them a part in full colour!” Motorola’s V70 phone was extensively designed using the ZCorp 3D printing process. Many different models were made to be market-tested as well as in-house evaluation, with the final design achieving the design goals simply because it was so close to the “real thing”. Then there are all the people who use the process to produce extremely accurate moulds with no costly machining to worry about. It’s suitable for a wide range of moulding processes including direct casting moulds in metal or polyurethane and investment cast pattern moulds, sand casting, RTV moulding and thermoforming, among others. In fact, the system is now being used by most of the big names in the industry, simply because it cuts so much time out of the production equation. Investment casting, by the way, means a (usually) metal part produced from a mould that was created by surrounding an expendable pattern with a ceramic slurry. It offers a very smooth surface finish with intricate design and detail possible. The dimensional accuracy is very high – in the order of ±.002cm/cm. More information? SOS Components offer a free CD which contains an extensive library of 3D models as well as explanation on how the processes work. They are located at 30 Paradise St, Banyo, Qld (on Brisbane’s northside, not far from Brisbane airport). Phone no is (07) 3267 8104. Website is www.3dprinting.com.au SC siliconchip.com.au