Linear rails for a Pen Plotter

[Fozzie55]

Hi
Hopefully you can help a noob with a design please. I have admired everyones work here and got the CNC bug (that golf trolley painting machine!)
I want to build a Pen/Brush Plotter. I presume it wouldn't have to be as heavily built as some of your CNC machines. The purpose of it is to draw outlines onto 40mm deep box canvases.
I have 3 steppers and the control electronics (Routout), I just need to sort out a frame and linears for it.

I want to base it on a 1m x 1m x 25mm thick piece of MDF with a stainless steel face. I could have it bigger or smaller but I have settled on a convenient size. My design would allow larger canvases to be drawn on if needed but 900mm x 900mm is average.

I have attached a sketch. Basically one large round fully supported fixed rail 25mm dia. for the X axis with 2 linear bushings which carry the Y axis of 2 supported 16mm round rails holding 2 bushings to hold the Z axis on. I am ignoring the Z axis for the time being as it will only be holding a pen. The other side of the Y axis will be supported by an idler wheel of different heights so it can ride on a canvas underneath if its bigger than the plotter or just ride on the bed if it's smaller.

Both axis will be belt driven. (I have a Roland A3 plotter and though if it's good enough for that?)

What do you guys think please?

Regards DF

[High Seas]

Cool - looks fairly low cost - because you keep the weight/loads on the y/z axis down to the pen/brush and drive. Looks like you've supersized one of the scanners I ripped for bits and pieces - and you know they are pretty accurate. Been looking at cheap methods for vinyl cutting and this could be one. Ought to be a quick build too. Thanks for the sketch! I'll be interested on your results - cost/time/precision/repeatability etc.
Jim
btw - remember, you'll be giving up a bit at both ends and width of the y axis so it might be a squeeze to get 900x900 worked edge to edge with only the 1 meter rail! 800x800 ought to fit nicely.

[cbass]

You'll probably want to attach the pen-holder to a seperate floating rail which will then attach to your z axis. This will allow you to compensate for irregularities in the flatness of your stock...

Carlo

[Fozzie55]

Cheers Jim, yes I realised about the size, but as the base is open sided, larger canvases can just hang over the edge a bit. When I get the stuff I will do photos and a write up.
Thanks Carlo, I have left the Z axis until I get the X and Y running, not thought about it much as I am only drawing on canvas. By stock do you mean the canvases or the plotter base?
David

[cbass]

Originally Posted by Fozzie55 Cheers Jim, yes I realised about the size, but as the base is open sided, larger canvases can just hang over the edge a bit. When I get the stuff I will do photos and a write up. Thanks Carlo, I have left the Z axis until I get the X and Y running, not thought about it much as I am only drawing on canvas. By stock do you mean the canvases or the plotter base? David

Yes, I mean the canvas. It will inevitably sit higher in some areas than others. Even the texture in the canvas may give you problems. The easy way to take care of it is to float your pen holder. This is something that can be designed after you have everything built.

Carlo

[Fozzie55]

Thanks again. I will let you know when I have X and Y working. Searching eBay at the moment but I may be ordering the rails this week.

[Enraged]

vxb.com may be a good source for the rails and bushings, they are an ebay store

[Fozzie55]

Well I have done the electrics bit in readiness. The controllers and steppers are all working fine. Ignore the connecting blocks they are only temporary.
Roll on the rollers!

[Robyn]

You should check out T.E.A. Machine Components, Inc. - www.teausa.net. They carry a wide variety of components.