The Plotter Project

1.) What was the intent?

The intent of this project was to fully design, build and program a plotter.  A plotter is a machine that sketches out line drawings, and it also runs off of the principle of CNC.  This was meant to be the next step up after assembling a CNC Router from a kit to the level of building a CNC Router from scratch, as the plotter is programmed identically to a CNC Router and is built similarly.  This plotter would also have me practicing manufacturing the majority of the parts with the manufacturing knowledge I had gained from the Battery Carrier project, .and it would be more practice with more complex CAD assemblies than what I was used to.

2.) How would the intent manifest?

At first, I did research on a system to turn the rotation of the motors into linear action to move the pen of the plotter.  Inspired by my Shapeoko, I decided to go with a timing belt system.  I also chose to use Nema 17 Stepper Motors, common motors used for such a project.  A Stepper Motor breaks down every motor revolution into small angles called steps, so it can move at high precision angles instead of full revolutions like a standard DC motor.  CNC Routers use Stepper Motors.  With the linear motion figured out, I created a CAD model where every part was meant to be created by a CNC Router, 3-D printer, or simply wooden dowel.  The plan was to then take these online models, create them, purchase the Nema Motors, and assemble the plotter.  Then, the plotter would be optimized to the point of where it functions together, and it would be wired to an Arduino where it then would be programmed.  Due to the COVID-19 pandemc and the school being shut down, I was only able to create the virtual model of the plotter.

All parts are bespoke except for the motors, which are NEMA 17's taken off of https://grabcad.com/library/nema-17-stepper-motor-22. 

3.) What issues were resolved?

As the project progressed, I had trouble making it mimic the motion that would be present in the final motion, specifically the carriages alongside the axis.  This was resolved with a very simple "joint" command in Autodesk Inventor with the wheels that ride alongside the linear slide to the linear slide.  As mentioned earlier, at the moment the biggest issue is that I have no access to the CNC Router or 3-D printer in the school to actually create this project as the result of the COVID - 19 pandemic.  Most of the issues lay ahead, as this project is suspended until I have the means to make it.

4.) What was gained? 

Much of the gains from this project lie in the future.  For now, the gain is largely practicing patience while I wait for this pandemic to flush out.  Additionally, with over 100 parts in the assembly, this was the largest CAD model that I have ever completed, if not also the most complex.  I practiced and fine tuned my CAD skills.