Pen Lift [with suspension]
This pen tool head addresses one of the most frustrating challenges of using a pen plotter: drawing on uneven surfaces. After experimenting with numerous solutions, I found an effective and simple answer—an elastic band!
Parts List
The components for this tool head can be 3D printed individually and assembled using:
2x M3 screws
2x small springs
2x LM8UU linear ball bearings
2x 54mm lengths of 8mm metal rod
1x rubber band
This combination creates a flexible and adaptable tool head capable of handling minor surface irregularities. See below for assembly:
Start by checking that the metal rods fit smoothly into the bearings. You may need to sand them slightly. Tip: bring the bearings with you when buying rods to test the fit.
Slide the bearings into the printed clips. These parts can be fragile, so slide them in carefully. Once seated, they should not move.
Attach the pen holder clip to the bottom of the bracket using the screws. It should feel firm, with some resistance on both sides.
Install one or two of the springs. The tension should be enough to hold a pen or brush securely without slipping. The spring I used here was overkill, so I only used the one.
Assemble the carriage plate and pen-lift bracket. If you’re using a NEMA-17 motor for lifting, mount it here. Make sure the screw heads sit flush or recessed—any protrusion will interfere with movement.
Snap the rods into place. The motion should be smooth with minimal resistance.
Finally, loop an elastic band around the clip and the bottom of the bracket. This provides the slight flex needed to adapt to uneven surfaces. You’ll likely need to replace the band periodically as it wears out. Happy Plotting!
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