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3D Printing – A Revolution?

3D Printing

You cannot have failed to have heard stories in the press and media recently about 3D Printing, and how it  is going to revolutionise the world. Many are likening it to the desktop-printing revolution that began in the late 1980’s with the advent of affordable, desktop, high quality printers that started to appear on the market.

There’s no doubt that ‘3D Printing’ is going to be a revolution – I myself have been banging on about it for some years now. I also have first hand experience of using 3D Printers and of using products built on 3D Printers.

However the stories that we hear in the press and media are often very poorly researched, and more often than not they are based on some particular companies’ most recent press release, more than they are based on fact.

I think it’s time we looked a bit more closely at ‘3D Printing’ and see what all the fuss is about.

Almost every affordable 3D Printer on the home and hobby market, and the small-medium business (SME) market today is a variation of just one type of machine. They are all what’s known as Fused Deposition Modeling (FDM) machines. In turn FDM machines are just one small sub-category of the three main categories of rapid prototyping systems, which are: i) Liquid Based Rapid Prototyping Systems, ii)Solids Based Rapid Prototyping Systems and iii)Powder Based Rapid Prototyping systems.

Here are some examples of home/hobby/SME based 3D Printers:

Velleman K8200.


The Velleman K8200 is sold as a kit of parts, with every part you need to assemble the working printer. Some semi-professional tools are required for assembly, such as a Soldering Iron, Digital Vernier Guage, Circlip Pliers, Multi-meter and so on. The build manual runs to over 690 Pages and that’s before you even switch the thing on. You also need to do some pretty technical stuff like measuring and trimming the motor drive current, and calibrating the extruder head temperature sensor. Some of the instructions are pretty scary, with a risk of damaging components. A good technical head and an ability solder some very fine ribbon cables is required. I’d expect to see a lot of ‘unfinished projects’ on ebay for this kit. It’s available from Maplin for £699 incl VAT.

RS Ormerod

The RS Ormerod is Available trade-only in the UK From RS Components at £499 +VAT, bringing it in slightly cheaper than the Velleman. It is also a build-at-home kit, but requires a bit less fettling and no soldering. It looks more professional and I believe is actually from the RepRapPro range of printers.

HP DesignJet 3D

The HP DesignJet 3D is a monster of a printer, costing in excess of £10,000, and aimed at the manufacturer who wants to reduce their time to market, and prototyping costs. It’s not for the home user!

 

 

 

 

 

All of these are additive, FDM (Fused Deposition Modelling) systems and work by extruding a plastic filament, either ABS (Acrylonitrile butadiene styrene) or PLA (Polylactic Acid). Heating it to a semi-liquid state and extruding it through a nozzle to form a pliable, almost molten string of the filament.  The extruder head is free to move in the X-Y direction, and deposits a thin layer of the plastic onto a build table which itself is free to move in the Z direction. To build something, a computer model of the object is created and fed through a ‘slicer’ software package which splits the virtual object into many hundreds, or even thousands, of thin horizontal layers to define an outline and in-fill. The data is sent to the 3D Printer’s controller and it re-produces each thin layer, after each layer is laid down (“printed”) the build table descends (or the extruder rises) and the next layer begins.

Since the machines are laying down molten ABS or PLA there can be no unsupported parts of the model. Any overhanging, or otherwise unsupported, parts must have support structures built under them which must be hand removed later. In the case of the HP DesignJet 3D the support structures can be printed with a soluble plastic which can be washed away later – with an optional, expensive, chemical bath machine. The plastic goes through a rapid cooling process when it exits the extruder and the stresses induced by this are evident in the model in the form of distortion and shrinkage. The amount of distortion and shrinkage is incalculable in advance and therefore it often takes several attempts to get the model printed correctly, after tweaking various machine parameters each time, such as extrusion temperature, head XY Speed and the pre-heating of the build table.

Above are just three examples – there are many more, and I’ll leave it as an exercise for the reader to ask Mr Google about these: RepRap, MakerBot, Thing-O-Matic and so on. However many you care to find, you’ll find that they are all basically the same extruded filament FDM machines. They vary in only small details such as build area.

Expensive toy with excessive running costs.

One very small variation on the theme is the ‘Fabbster’ from Reichelt which uses small plastic rods rather than filament on a reel. It looks like a toy and costs €1499 (About £1280). Since it uses a proprietary rod system you have to buy supplies from the manufacture, and can’t just buy ABS/PLA filaments from anywhere. Running costs are therefore higher and I’d worry about long term supply.

They all take a long time, a very long time, to actually build a model. Think in terms of 6 Hours to produce something about 10cm wide and tall.

All of the above, from the Ormerod at £600 to the £10K HP DesignJet 3D are suitable only for producing small quantities of prototypes. They cannot be used to produce production quality, or production quantity, end products. You could not set up a business knocking out, say, Smart Phone covers using any of these machines.

Pros and Cons
PROS 
– The machines are readily available, they are reasonably cheap, they are easy to operate. A whole universe of models is available to download online from numerous sites such as ThingyVerse.
CONS – The molten plastics (ABS at least) give off fumes, and need ventilation and health considerations. The machines are twitchy and need almost constant tweaking. A 6 Hour build can go horribly wrong after 5 ½ hours if your belt drive tension just happens to be slightly out. They are slow.

Comment
Like I’ve said before, there is definitely a revolution in home manufacturing coming, in the same way that there was a revolution in photo quality printing, everyone has a good photo quality printer now, something which was unheard of 20 Years ago, but we are not there yet. There are better rapid prototyping systems out there, such as Selective Laser Sintering (SLS) which is one of the Powder Based Rapid Prototyping systems. It is faster, cleaner and can use a much wider range of materials including ceramics, metals, plastics and polymers – including things like nylon. It produces near production quality articles and could easily be scaled to home/hobby and SME use. If only the media and companies like MakerBot would widen their scope, then the true home based manufacturing revolution could begin.

 

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