odd question

[mdreitzusa]

this may be an odd question but has anybody tried to us a live roler table to replace the x axis on a cnc router.
my thought is that it would give a limited y axis but an unlimited x axis.that way the length of the x axis wouldn't matter any more.
length could be ajusted for with the software.

[ToyMaker]

what is a "live roller table" ?

robotic regards,

Tom
= = = = =
"'If wishes were horses, beggars would ride.' But if horses had wishes, riders would beg."
- - Dennis R. Ridley

[murphy625]

I would think the cost of building it that way would make the cost go up exponentially. Trying to save money in doing something like that could make for a sloppy and unstable axis..
Am I to understand you want to make your axis like a looping conveyor?
How would you secure the piece??

Murphy (who knows nothing about cnc machines) LOL

[mdreitzusa]

this idea is for a portible sign machine.
the idea was to use 6 to 8 rollers that would be chained together and
driven by the x axis stepping motor.(most of the parts could be salvaged from old printers) the board would be held down to the table by 2 rollers. one placed each side of the y axis cutting path. there would be 8 small ajustable wheels to keep it centered and to position the board on the table. i'm not an engineer just a tinker. so it seemed logical to me.it may be complitly unworkable but it is just a wild idea.
(the only dumb question is the one you didn't ask)

[ynneb]

I understand what you mean, similar to a pen plotter, where the paper is fed back and forth except its not paper, its timber and the the rollers drive the timber back and forth.
As murphy says, it would be sloppy and totally unworkable. If you were to cut parts out of a sheet, you ar expecting them to move back and forth in harmony with the sheet. I just cant see how that could happen. What about doing 3d work. What sort of roller is going to ride on the top of the rough terain youve cut? You couldnt just have the material just driven by bottom rollers, it would need a top clamping rollers too.
I am all for re inventing the wheel, as you will see from some of my previous posts, but this wheel will offer no advantages and lots of potential problems.
Please post any other ideas you have because I really believe there are thousands more ideas for this world to have. Good effort on the thinking though.

EDIT: I just noticed you mentioned a portable sign machine. Well yes they do have what you are suggesting. They cut out vinyl letters. But the cuts are only partially through and it is on a flexable material.

[murphy625]

I think I know what he wants to do...

Im betting he's trying to create a machine that is small, but is capable of doing long X axis runs.. This way, the machine stays small (just large enough to make a single letter) yet it can feed x axis to the next letter.
What material would be used ????????? How big is the Y axis??

Murphy

[Cyclone]

mdreitzusa...don't let these guys pop your ballon! lol I think is a great idea!
It is true about the work piece, as long as you have a constant surface and no 3d cutting it should work great. there is only one way to find out.....
Just do it! build it!
If it does not work you can always go back to a normal setup and by then you already have built 75% of the machine.

Inovate! The earth is not flat!

[Bloy2004]

Is this idea similar to a feed planer? .... where the wide planing blades are replaced with a moveable axis (Y) and the rollers are reversible? and the height adjustment is the Z axis but separate from the gripper rollers? I can see it...somewhat... those wide rollers would grip the material even if some was cut out, and roller guides on the edges of the material would keep it tracking inline. Material debris would have to be handled different than a planer where it throws it up and away..to keep the rollers clean.

[Fred in NC]

This got me thinking . . .

If the workpiece has to travel back and forth along the x axis, it might eventually lead to error.

However, if it could cut along the y axis, and then move, the piece would only travel once along the x axis. More accurate, errors would be unnoticeable.

G codes would have to be generated to cut this way.

[murphy625]

Originally Posted by Fred in NC This got me thinking . . . If the workpiece has to travel back and forth along the x axis, it might eventually lead to error. However, if it could cut along the y axis, and then move, the piece would only travel once along the x axis. More accurate, errors would be unnoticeable. G codes would have to be generated to cut this way.

Here's the thing...
Now that we know he's making signs, is the traditional cnc machinining accuracy really an issue? Will something that is .01 inches off make any difference? I would think that the required accuracies and repeatabilities in this case would be totally dependant on the size of the smallest detail in the sign..
If this is indeed the case as stated above, then I would think his idea of a continous feed on one axis would work out just fine..

Lets face it, if your cutting a 12 inch circle that is part of a sign, and that shape is .1 inches off in shape or size, no person is ever going to see it..

Murphy

[ynneb]

Originally Posted by Cyclone mdreitzusa...don't let these guys pop your ballon! lol I think is a great idea! It is true about the work piece, as long as you have a constant surface and no 3d cutting it should work great. there is only one way to find out..... Just do it! build it! If it does not work you can always go back to a normal setup and by then you already have built 75% of the machine. Inovate! The earth is not flat!

mdreitzusa, I am definately not about popping your bubble. I am merely pointing out potential difficulties. I would prefere your bubble to be examined b4 you spent time on making the machine, and then finding it doesnt work, and abandoning it alltogether. If after taking all suggestions into consideration, you still feel it is worth trying, then go for it.
As I said b4 I love new ideas.

[mdreitzusa]

thanks everybody for the help.i think with a bit of figuring it might work.the machine was originaly just designed for letering and not to be used for cut outs.maybe adding a vacum hood on the bit could help clear the chips.thanks again for the nudge in the rite direction.
when my mind gets going sometimes it takes a brick wall to change direction,so please keep nudging.
(sorry for not explaining better.it would have a max y axis of 12in. and most run pine or other soft wood. good for name & address numbers plates)