Software Stack Overview
The programming system consists of three main layers: G-code generation (Python), motion control firmware (Arduino/C++), and a user interface for collecting dimension input.
Figure 1: Software architecture
Software Function
The CNC frosting printer is controlled through an Arduino UNO using a Python and C++ program. The purpose of the python program is displaying the GUI to receive user input on the cake dimensions. Those dimensions are then transmitted through a communication port to the C++ program so the proper extruded path can be calculated. Once the dimensions are received, the axes' limits are set first using the limit switches positioned at the bottom of the Y axis and the inner end of the X axis. After those are set, the extruder lowers to the height determined by user input and begins extruding frosting in an Archimedean spiral pattern till the set diameter input value is reached. When the pattern is complete, the frosting is back extruded for 3 seconds to minimize drip before returning to rest at the top of the Y axis. An additional Arduino program was coded to run the frosting extruder motor forward in order to fill the frosting tubing before use.
Design Process
Because the peristaltic pump motor used within the budget was not strong enough for thick frosting, we thinned out the frosting to extrude properly. Though this meant the frosting did not have enough structure to form a design. So, we did not have a design-drawing function to our final project, and stuck with our MVP of frosting the top of a cake.
Github
To find all of the code used for this project, see here: https://github.com/traiti77/PC-Frost