3D printing: the myths and the reality

That impression is only reinforced by the (necessary) hazard warning stickers on the device. While the printer is in operation, the extrusion head heats up to a searing 260°C – hot enough to cause third-degree burns in a fraction of a second while printing is in progress, and for a good minute or two afterwards. No wonder the device comes with a pair of heatproof gloves. You’re advised to wear safety goggles for various parts of the process, too.

What to print?

Once you’re ready to print, the next question is: what will you produce? The notion of bringing your own 3D designs to life sounds incredibly freeing, but your options are more limited than you might imagine.

The first thing to remember is that current print technology only works with plastic. It may not be long before more materials can be used – including conductive ones, opening up the possibility of printing functional electronic gadgets. At the moment, though, you can forget about printing anything that uses metal, rubber or any other substances: whatever you want to produce on your 3D printer will have to be made entirely from brittle plastic.

You’ll also have to take into account the physical capabilities of your printer. Our Afinia H-Series can produce items up to a maximum size of around five cubic inches, and because it uses a single spool of plastic, everything you produce comes out in one colour. These aren’t universal restrictions, however: more advanced devices such as the RepRapPro can create larger objects and use multiple spools to create objects of various colours.

Another potential obstacle is the fact that 3D printers need full digital 3D models to work with. If you want to produce original, bespoke items, rather than simply printing other people’s models, you’ll need to be familiar with a CAD package in order to design it. There are several free tools you can use to create and edit your own STL files, including SketchUp, OpenSCAD and Blender, but you shouldn’t underestimate how much work is involved in mastering these applications and learning the principles of 3D design.

It’s also possible to generate STL files by using a 3D scanner to capture the shape of an existing physical object, turning the printer into a sort of three-dimensional photocopier. The scanning hardware typically uses a combination of lasers and cameras to measure the external contours of its subject, and the technology is likely to become more mainstream as 3D printing gathers momentum. Indeed, MakerBot recently announced plans to release a 3D scanner in the near future.

However, 3D scanning technology has its own limits. The scanner can detect only the outsides of scanned objects, so any internal structures and cavities won’t be captured. It can’t account for moving parts or mechanisms, either – and even if it could, there’d be no way to reproduce such pieces using current 3D printing technology. As such, few really useful objects can be directly duplicated.

It’s also important to realise that not all shapes are amenable to 3D printing. Imagine attempting to print a hollow cube, for example: the printer would have no problem producing the base and sides of the shape, but it wouldn’t be able to print the top face, as the molten plastic would simply fall inside the cube. In short, you can’t directly print anything involving overhangs or empty shells (although there are workarounds, as we’ll discuss below).