

One small slice of bread, one giant leap for toasters.



A few weeks ago, we rounded up a bunch of high tech toasters and wrote about about using a hot-air gun to draw designs, by hand, on fancy toast. We’ve now mounted the hot air gun to a computer-controlled X-Y control system so that we can use it to print arbitrary images on toast.

The hot air gun that we’ve used is actually intended to be the printing head of our 3D sugar printer, where it serves to selectively fuse the printing media together.

Recently we succeeded in mounting the hot air gun to the carriage of the printer. The next step was testing the XY motion control system without the Z axis installed.

It turns out that you can actually do some interesting things with just the print head and the X-Y gantry. Especially since, as one of our astute readers noted in a comment, “(3D printer – Z axis) + hot air rework station=completely digital toast imaging technology.” Our thoughts exactly.

We certainly aren’t the first ones to aim for true CNC toast– A group of students at Olin College apparently were working towards that goal a few years ago, but may have given up in favor of their laser cutter– which is (we think) cheating on building a CNC toaster. (Don’t get us wrong– We are of course very fond of laser cutters– they can be used to cut cake, or engrave matza, or just about anything else. Whether merely ablating away part of your bread with a high power CO2 laser should count as toasting is perhaps debatable, but it’s certainly an expensive way to make breakfast.)



Hello world!

To begin our 2D testing, we placed a cookie sheet where the Z axis of the printer would normally go. We had to stack a few pieces of bread on top of each other so that the top piece would be at the correct level to be printed on, just a few millimeters below the heat gun nozzle.

Our resolution for these tests was 10 dots per inch (2.5 mm pixel size).



Next, we tried out a photographic subject. When we thought about what face we’d expect to see staring out of a little rectangle, the clear choice was Ze Frank.

We pulled a great still from this article about small screen movies. (It is, of course, a still from The Show with zefrank.)





Getting an image to print correctly took several things going right: a good image, and adjusting the air flow rate, temperature, and the length of time spent on each pixel. Here is the actual image that we printed, 55 x 42 pixels:

Quite a bit of fine tuning was necessary to get the correct amount of darkening to show the image best.

We made a short movie of the toast-printing process, 1:18, no sound. You can watch the hot toasting action on YouTube or embedded here:





One of the other cool things that toast visibly is a papadum. It’s a nice round canvas. I drew a sunflower in Inkscape and scaled it down to make a good test subject. I used large dots in the middle (not a grey or a set of small dots) so that when it reduced, the pattern in the middle was still visible.

It even shows up nicely on the papadum.





Unfortunately, while the papadums toast very easily, they get flexible when heated and tend to curl. To counteract this tendency, we held them down to the cookie sheet with magnets. This was tricky– the papadums are brittle!



If you perform a Google search on the terms CNC and Toast, one of the top hits is our friends at Because We Can. Not that they are making CNC toast, but they score high on those terms because they make things with a CNC routing table and one of the cofounders is Jeffrey “Toast” McGrew. I adapted this photo and printed it on bread, so we made a piece of CNC Toast toast for Toast. (And yes, we gave this piece of Toast toast to Toast).

