Pen Plotter

I designed all parts in SolidWorks, leveraging additive manufacturing to iterate on designs and prototype metal components. I used a combination of CNC machining and 3D printing for the final parts and designed accordingly with manufacturability in mind.

To achieve fast rapids and zippy accelerations, I used belts in a coreXY configuration (having learned the pains of non-stationary motors in my claw machine project). The only moving motor is a micro servo driving a cam for pen retraction, a speedy, lightweight, and reliable solution elegant in its simplicity.

My first personal project was a success! It moves fast and draws accurately, with a spacious 11” x 16” drawing area.

Through the many iterations, not all was perfect, and much was learned:

• Lower is better for the belt path to minimize the moment arm from belt tension. The high belt path in the current design required me to strengthen pulley mounts more than anticipated.
• Bearings work best in pairs, and linear carriages are no exception. Fortunately, this had little impact on my pen plotter, given the negligible forces during drawing. Conversion into something like a desktop router would demand more stability.
• Belt tensioning and cable management are best integrated into the initial design.