A nifty cam tracking plotter can draw many shapes

A nifty cam tracking plotter can draw many shapes

Arduino Team — December 30, 2022

Before the advent of CNC (Computer Numerical Control), automated machines used mechanisms such as cams and cones to act as guides. They are precisely contoured physical components intended to guide the tool, like an artist tracing lines with a pantograph. Such mechanisms are rare today, because the CNC is much more versatile and much easier to implement. But Mr Innovative turned to these traditional techniques to build this cam plotter that can draw many shapes.

A "cam" is a rotating or pivoting component in a mechanism, which has an irregular profile to control the actuation of something. Internal combustion engines, for example, often contain rotating cams that open and close the valves at the right time. In this case, the plotter cam controls the movement of the stylus in the X axis. The wider parts of the cam push the stylus further to the right, while the narrower parts of the cam allow the stylus to move to the right. left. A rubber band pulls the stylus arm cam follower against a cam. The paper moves at a constant speed on the Y axis, and its speed combined with the shape of the cam determines the shape of the resulting plot.

This machine will look familiar to those of you who have seen a Mr Innovative project in the past. It uses an Arduino Nano board combined with Mr Innovative's control board design to control the two motors. One stepper motor controls the rotation of the cam and a second stepper motor controls the paper feed. The user can set the number of cam rotations using a Nextion touch screen LCD panel. Mr Innovative 3D printed the mechanical parts and mounted them on a small sheet of wood, with a standard linear rail and a bearing limiting movement of the pen arm to the X axis. She can't draw any< /em>shape, but this machine is quite versatile and can produce quite a few interesting plots.