Half-tone CNC with man-powered Z axis

We think this is an intriguing take on half-tone art. It’s a CNC machine that uses an Arduino and two stepper motors to draw on a paper-covered drum. But you’re not just going to set it and forget it. To simplify the device, the Z-axis is not mechanized, but requires the dexterous opposing digit of a person to actuate.

The first prototype used a frame cut from plywood, but the developers moved to some attractive laser-cut Lexan for the final version. The rotating drum was inspired by observing the off-set printing process. It greatly simplifies the build when compared to a flat CNC bed. But including a Z-axis solution that could account for differently sized dots really opens a can of worms. Because of this, the choice was made not to automate that task, but to leave it up to the user. A clickable Sharpie does the marking. When the pen is in place, you click the plunger to hold the felt tip against the paper until a dot of the appropriate size has leeched onto the paper.

It’s not a bad solution to the problem. Especially if you don’t have the high-end milling equipment necessary to do this on a piece of plywood.

[Thanks Dron]

Comments

  1. Jan says:

    Hmm, isn’t this type of “CNC machine” more customarily known as a drum plotter?

    Let’s not go overboard with all that CNC stuff …

  2. Chris says:

    It would be so simple to add a Z axis actuator, I wonder why one wasn’t added.

  3. Ames says:

    Using a human hand as an actuator is a great idea; but I think it could be brought a step further. With a few properly placed electrodes, you could probably automate the plunger-clicking using only existing hardware. You’ll have to check the specs for proper voltages, etc.

  4. gman says:

    Considering the z axis is binary, relying on time to create a larger dot, i’d suggest using a solenoid. The amount of time should be short enough that you won’t burn out a coil.

  5. Ben says:

    OK, maybe I’m missing something here. Does the operator really have to press down the pen separately for EACH PIXEL? Presumably while reading off a list of how big each pixel should be?

    If so, wouldn’t a simpler, cheaper, and overall better solution be just a piece of plastic with a grid of pen-nib-sized holes, to use as a stencil?

  6. jarfil says:

    So… the only benefit of this, is that you don’t have to choose where to place the pen, just how long to hold it. It still takes you almost the same amount of time to draw a picture. I’d call it useless.

    Unless you automated the pen action, then it might make some sense. Like some kind of printer… could be fun to print in “weird” inks like silver, copper, or raspberry.

    On the other hand, if the creators wanted an “artsy” interpretation of how we people interact with machines… you could forget the motors, and have someone manually move the pen and drum. Reading the positions off a screen would be a plus, too.

  7. Jim says:

    Pretty cool. It would be really cool to see designs like this created for reprap printers to print the parts. It would be a snap to build more of them.

  8. echodelta says:

    I quess laser cutters are not high end, but two pieces of wood clamped together and drilled with a hand electric drill is.

  9. Hirudinea says:

    If you used thermal paper you could replace the pen with a piece of heated wire.

  10. Renee says:

    Ugh, that was a pretty sparse write up between tons of advertisements.

    I’d like to know more about how they constructed the frame and what hardware they used but I can’t find any details about that.

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