Rubber Band Pen Mount Was Too Flexible

Now our Z-axis version 4 has a homing switch, I thought I would again repeat the pen plotting test that I performed with Z-axis version 3. And to do that, I will need a pen holder.

Our problem with the previous plotter test was that our pen was rigidly held. This meant it could not adjust for the uneven height of the drawing surface. We compensated for this by mounting the paper on squishy foam, but still the pen was borderline drawing in one part of the paper and on another part, it pushed so far into the foam to risk tearing the paper. I thought I should build a flexible (“compliant”) pen holding mechanism.

This first draft here had a vertical channel for holding the pen, and rubber band to keep the pen inside that V-shaped channel allowing for vertical movement. In theory the pen would only move within the channel vertically and the rubber band will prevent movement along any other axis. In practice, the rubber band did not constrain movement very much, the pen flexed along every axis. This will be a problem as the pen is drawing, as it needs to resist sideways bending forces.

Onward to the next draft.

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