The last couple of years have seen the price of 3D printers fall rapidly, but to a lot of people it still seems like an expensive item. After all when a basic laser printer costs less than £40 even £250 for an entry-level 3D model looks like a lot. Prices keep falling though, and a 3D printer that costs $100 (about £70) should be hitting the US market soon. Thanks to the mysterious way American prices convert into British ones that probably means it will cost £100 here, but that’s still a good price – and it’s a very interesting printer, too.
The Peachy Printer comes as a kit, but it’s very easy to assemble. Most of the parts just snap together, and there’s no soldering or anything else complicated involved. It’s also modular, so individual components can be upgraded in the future – or you can try out your own components without having to hack up the stock ones. At this price it definitely encourages experiments.
Filament-free 3D printer technology
What’s most interesting about this printer, however, is the way it works. Almost all lower-priced 3D printers use fused deposition modelling, but the Peachy is one of the rare exceptions. You won’t find any filament here. Instead it uses photolithography. Basically this works by shining a laser into a liquid resin, which hardens when the beam hits it. It’s used quite a lot in specialised high end devices, but the Peachy makes it affordable. At the same time it also lets you customise the build volume.
Instead of the usual print bed the Peachy creates objects in a tank. This doesn’t come with the kit; instead you have to supply two straight-walled containers, which can be pretty much whatever size you want. One of these is tilled with salt water, and placed on a stand so it’s higher than the other one. The printer clips on to it, above the second tank. The resin goes in the second, lower container, which doubles as the print area.
The printer contains the laser, which can be aimed in the X and Y axes to harden the surface of the resin. The really clever bit is how it handles the Z axis. It exploits the fact that the resin floats on salt water, which slowly drips down a tube into the lower tank. A sensor measures the drip rate and calculates how high the surface of the resin is (that’s why the containers have to be straight-walled) and feeds it back to the printer, which aims the laser at the points which need to be printed at that height. As the water level and resin – rises, the laser adds layers to the object.
Silent running, but great colour options
Resin for the Peachy Printer will cost about $60 a litre, and comes in eight colours. A big advantage is that these can be mixed together to create custom colours, or lightly swirled in the tank to give a tie-dyed effect to the finished model. The printer should handle resolutions down to around 1/000th of an inch, and unlike conventional designs it runs completely silently.
Photolithography is a new idea at the more affordable end of the market, and it will be interesting to see how it works out. Meanwhile the Peachy Printer is the cheapest kit available and seems quite economical to run, as well. If you want a 3D printer that’s a bit different this one could be worth a look.