Advice on Making a Plotter

[Al]

I'm after making a very strange sort of plotter and need some device for lifting a pen on and off a piece of paper, I'm guessing I could do it by buying a second hand plotter, any other ideas?

[Case]

second hand would work or you can build your own CNC with a pen head...i actualy have servo controllers here for a un started mill project.

[micsaund]

If the pen is riding on a slide-rail across the paper, you can attach a motor to one end of the rail and rotate it slightly, thus lifting the pen off the paper.

I'd have to know more details about the existing setup you've got to suggest anything specific as there are various shortcuts you can take (like the above) depending on the mechanics. If your pen is simply suspended on a belt/chain, then the rotation technique would not work.

Mike

[Case]

rotation what?

XYZ movement thats all you need right? basic 3 axis CNC movement...

[micsaund]

Al was asking how to lift a pen from paper. If the pen slides across the paper on a rail, you can "tilt" the rail "back" (rotate it slightly) to life the pen from the paper. This is not a full blown CNC setup you'd use to machine something, but might do the trick for the pen and paper mentioned and very simple.

[Case]

I dont see the diffrence.... what makes it not like a cnc?

Incoming super sized image :)

http://engraving.majosoft.com/bestanden/plotter_of_an_old_printer/Dscf0018.jpg

[micsaund]

Because lifting a pen from paper is mostly a "binary" operation. It's either on or off the paper. With a full-blown CNC setup (as "CNC" is usually thought of) you have a Z axis which you can usually control with more than "on" or "off" precision.

By needing a simple on/off state, the mechanics can be simplified significantly over designing and constructing a fully variable Z axis head. Simple is good.

Mike

[Case]

1 servo in Y and the vertical Z can be controlled by a solnoid or a servo with a on or off theres no limit on how to program it i mean going a full servo route vs converting a old printer would give you more flexabulity to do other things as well as in a multi tool...

really if you think about it you have two options... strip a old inkjet printer and convert it (Lots of DIY tutorials on that on the net) or go the CNC like route

[Johan]

Phidgets! Couple of servos, some strings, quick bit of code and you're done.

[Case]

pft use rubber bands

[nafi]

I like the solonoid solution. If it's on it up, if its off its down.

If your pen moves on the x axis by means of a threaded guide, lifting the pen by rotating the rod would be impossible.

Rubber bands break much easier than steel thread...

[Al]

Thanks guys, I like the solonoid and will check out phidgets. I'm very new to all this so need it to be very simple, a plain on or off is ideal for my needs.

[Case]

Wel if you want simple id sugest hacking apart a old inkjet to do it