Home built pen plotter

[amomar]

Dear Friends

This is my first time in this great site.

I have no background in the field of electronics and computer, however, I promise to do my best to learn. I've longtime dream of building my own pen plotter to be used to plot architectural drawing made using autodesk 2002 on my PC running window XP. After months of googling on the net ,I start to have an idea of the scale of the project. My questions is :

1- With regard to step motors, is there a specific type or speed to chose for such project.

2- Any Idea regarding the controller(electronic) and the driver (software).

3- I’ve seen a lot of plotter project on the net but no one explained how the pen gets up and down on the paper. Some of the project seems using same CNC engraver and converted it to plotter, but I cant understand how the Z-axis will control the pen (i.e. the pressure of up and down) since the range of movement in this axis will be just two (up-down)??


I know that these questions look stupid, but I am sure you will forgive my naivety. I really will appreciate your guidance and help, guys. If any one have been through similar project, that will be a dream.


Thanks

[High Seas]

I'll take a crack at #3:

Haven't done one yet - but am considering a 24 volt (12volt continuous duty) Push Solenoid for the Z axis. Energize and it goes down, 12 volts off - back to up position. Tollerences will need to be spot-on else maybe some spring loading to allow for difference in thicknesses of materials....

Anybody else got any ideas here?
Jim

[epineh]

Welcome to the zone amomar !

I don't want to sound negative but have you looked for a second hand plotter ? They are a few kicking around these days and even if it isn't working it might give you a good start.

But having said that if it the actual making of the plotter you are really interested then this is the right place to ask questions

I will have a go at your questions...

1. Because there isn't a great deal of load on the motors you won't need particularly large motors, compared to a milling table, but you may consider reasonable sized ones and use a ballscrew or acme thread leadscrew with high pitch, so the steppers don't have to turn huge amounts to make the pen move, maybe 2 turns per inch - this will help you with getting that pen movin !

2. Machine controllers and electronics has a pretty vast selection to pick through. Mach 3 is probably the most popular machine control program being used by the hobby guys, it has a free version, limited to 1000 lines of code.

There is also EMC which is linux (ubuntu) based and very good, and also FREE !!! This is what I am going to try for my router retrofit next, but linux isn't for everyone, though the new versions have seamless install's and in my opinion anyway whallop Windows for 6 !

Another option is to use TurboCNC, again this is free and runs on good old DOS, I used it initially and really liked it, the new version is reportedly going to have constant contouring, which will be very nice.

Electronics is really something you will have to research and pick to suit your needs, best advice I can give is to read through the DIY router logs and see what people use and get a "feel" for what might suit you.

3. For pen height you can go a couple of ways, first you could use a solenoid type of setup to simply have the pen up or pen down, the up/down signal can simply be a relay output from the machine controller, similiar to a spindle on/off, you will probably need some kind of adjustable spring pressure to get the pen just right.

Otherwise you can have a third axis, and simply have that controlled the same fasion as the X-Y axis's, I would probably go the path of the solenoid just to make things simpler.

Good Luck !

Russell.

[amomar]

Thanks guys

These are good suggestions to start with, thanks. I shall keep you informed about my progress. I will also welcome any new ideas.

Thanks

[kreutz]

I’ve seen a lot of plotter project on the net but no one explained how the pen gets up and down on the paper. Some of the project seems using same CNC engraver and converted it to plotter, but I cant understand how the Z-axis will control the pen (i.e. the pressure of up and down) since the range of movement in this axis will be just two (up-down)??

small solenoid, spring and lever.