It's someone's birthday, which means making a cake, preferably with some kind of design drawn onto it with icing. But drawing accurate and to-scale shapes in icing is very difficult. You can't erase any mistakes, which can make for a very poorly made design. So what is the solution? Well just like with cutting plywood, a CNC machine makes everything more accurate. This project demonstrates how to create a CNC machine that can extrude icing to draw shapes onto a cake with ease.
On August 14, 2018 I published a project the featured a DIY Universal CNC machine. Its tools could be interchanged easily. Building the machine is quite complex, so see this project for further instructions.
Improving the Machine
My initial project did have some flaws, however, as brought to my attention in the comments section of it. For one, the X axis belt had uneven tension. This could cause the movements to not be as precise. The X axis carriage also didn't fit onto the rail tightly enough, causing the entire assembly to tip over and grind against the rail. To fix this I completely redesigned the X axis carriage block by moving where the timing belt fits in and moving the V slot wheels to better locations, as well as adding another wheel to the back to prevent tilting.