New Machine Build- Home made large xy plotter

[lewanski]

Hi group. I'm new to CNC. I am an artist making what is essentially a giant plotter. I want to feed an array of x,y values into a program, and for specific values, the machine will go to the x, y position and perform action (spray) From what I've read, I think I need to program this myself. Question: What kind of controllers/drivers/hardware should I use that will let me write my own program to move the motors? I will need x,y and z axis control. I need to input several values defining the width and height of a matrix of points. Does anyone get the jist of what I'm trying to do? Can anyone offer suggestions on what hardware/software will work?
Thanks!

[doorknob]

What you are asking for is somewhat vague.

Just how big is "giant"? How much precision do you want or need?

I'm unsure of what you mean by, "I need to input several values defining the width and height of a matrix of points."

How complex is the source image that you want to plot? Would it be simple enough to program point by point, or do you need to start with a drawing program of some sort and then convert the output to work with the plotter?

In theory, what you are talking about could be accomplished by modifying a CNC router table to handle a paint spraying assembly in place of the router. So, you could likely repurpose a lot of fairly standard parts and software to do what you want.

[lewanski]

Hello, thanks for taking the time, I know my post was a little vague. Here's what I'm trying to do: I have software that breaks any picture down into a specified number of pixels and assigns each pixel a numeric value based on a color palette of my choosing. An example output of this program is an excel cell that might look like this:
(1,1,1,1,1,2,2,3,4,3,2,2,2,2,1,1,1,1,1,1,1,1,1,2,3,2,1,1,1,3,6,7,9,9,9,9,3,1,1)
Each number represents a color. Imagine y rows of these kinds of cells that would stack up to form an entire picture.
I want to write a code that will tell my motors to go to each location of the matrix and test if a certain color value resides there or not. If so, it sprays a color, if not it goes to the next one, etc. Like a giant dot matrix printer, or plotter. I plan to make it 4x8 ft. The variables I need to input are the size of the picture and spacing between dots. I don't need very high precision at all. After reading some posts, I believe this could be written entirely in excel. What do you think? Thanks!

[doorknob]

The problem with writing it in Excel is that I am unaware of any CNC driver software that can directly read and interpret an Excel file.

It seems to me that what you would want to do is write a script (for example, in VB or Python) that would parse your encoded lines and spit out multiple gcode programs or callable routines (one for each color) that you could then feed directly to Mach3 or EMC2. The gcode would have X, Y, and possibly Z coordinates for each paint spray operation for a specific color, with perhaps custom "M codes" for initiating/stopping the paint spray, for changing spray colors, and the like.

That way, you could more easily make use of existing CNC infrastructure rather than inventing everything.

[Mudpuppy]

Originally Posted by lewanski Hi group. I'm new to CNC. I am an artist making what is essentially a giant plotter. I want to feed an array of x,y values into a program, and for specific values, the machine will go to the x, y position and perform action (spray) From what I've read, I think I need to program this myself. Question: What kind of controllers/drivers/hardware should I use that will let me write my own program to move the motors? I will need x,y and z axis control. I need to input several values defining the width and height of a matrix of points. Does anyone get the jist of what I'm trying to do? Can anyone offer suggestions on what hardware/software will work? Thanks!

What i would start out with is an old Graphtec or HP pen plotter these sell for less than $50.00 now. sizes from 9x11 inch up to about 4ft wide. drivers are standard in win 98 you just choose which model you have. XP Sp3 still
shows 1 model in hp printers. these held multiple pens and would pick colors
and replace pens as the blueprint drawing indicated. use coreldraw to draw
your art work. all .eps vinyl cutter files will open in coreldraw. No designing
on your part less than $100.00 for everything required and your up and printing art!
Also i saw three machines converted to airbrush t-shirts, at Walt Disney World
these were amazing they changed paint bottles cleaned the guns and painted
anything you wanted on the shirts, have a vid someware and some picts

[vger]

Lewanski,

Sounds like a project I have been thinking about from time to time. One of my ideas was to take an older 9 pin dot matrix printer and take the stepper drive outputs (carriage and platen) and boost them up to run larger steppers. Those steppers would be attached to a cable or timing belt driven XY assembly carrying the "print head" made up of 9 small air brush heads with small solenoid valves controlling the air to them. The original leads to the print head would control the valves. The idea was to set the thing up on a frame with suction cups at the corners so that it could be attached to a store front window. Using color separations and painting one color at a time, you could then paint a window with almost any photo or text you wanted.

I think you could use VB macro's in excel to indirectly generate the G-code to run a machine like you are describing. I suppose you could use one of outputs (coolant on/off) to control the spray on/off. Perhaps using the G4 dwell function to control the spray time.

Sounds like a fun project

Steve

[lewanski]

Hello, if anyone is still monitoring this post: I've figured out the gcode generating portion of my design with a handy little program I somehow managed to write. Thanks for all the input, I got really busy the last few months and had to table the project. Anyone know what software will take a 2d black and white image, like clip art, and allow a pen to trace the outline, slowly working toward the middle until it's filled in?