The “Complex Barrel Cam Writing Machine” is an advanced project that demonstrates the mechanical potential of barrel cams to encode and generate complex movements.

See here for video: https://youtu.be/-QQxDgqsT68

See here for stable download: https://thangs.com/mythangs/file/42309

Included here Is a calibration cam that produces return movements along the y direction, x direction (inner and outer range) and diagonal.

See here for other compatible barrel cams:
Mechanical Cast Signing Machine: https://www.thingiverse.com/thing:4723372
F**K 2020: https://www.thingiverse.com/thing:4702239

The barrel cams are designed by plotting shapes from an xy plane onto a cylinder. Movement in the x direction is plotted helically along the length of the cylinder. Movement in the y direction is plotted along the radius of the sphere. When the cylinder is rotated, the follower and piston reproduce the shape back onto the xy plane.