# Cnc Routing, 4'x8' sheet material, on a 4'x4' table



## Ehicks

Hi all,
I am looking for information on routeing 4'x8' sheet material (plywood, expanded PVC, etc) on a 4'x4' router table. I want to purchase a cnc router with a 4×8 table by I haven't founded one that meets my budget needs but have found a few quality 4×4 routers that say you can index the sheet and maintain quality. Has anyone ever done this?


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## DS

Generally speaking, the size of the table limits the size of the sheet. As for indexing, this would be difficult under most circumstances. You could use "tabbing" to keep all the cut parts connected long enough to index the sheet, but then you have a secondary process to release the all the parts.

Usually, one would cut down 4×8 sheets and nest all the parts on a 4×4 sheet.
At times we need to make parts from 5X5 Baltic Birch and have a 4×8 CNC table. In those cases we make two 30" X 60" sheets prior to cutting on the CNC. Sometimes a material may only come in 5X8 and we then optimize the nest for 4'x5' sheets.

The only reason you might need to index is if your parts are longer than 4', or the material yield, due to the part's sizes, is absolutely terrible otherwise. For much of of what you might do, you might find 4×4 sheets to be acceptable. 
(Still a pain to deal with) YMMV


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## Desert_Woodworker

The method is called "tiling the tool path". Here is a video on an example:






Also, Vetric software has a tutorial on this process. 
I have cut 8' in length, window valances, that was done with this method. My machine is a 24×36" Laguna IQ.
Perferably, the larger machine would be easier, yet the smaller ones can work for you.


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## DS

I suppose I allowed my preconceptions to get ahold of me. I assumed you would be cutting several small parts nested on one large sheet. DW's video shows a larger piece of artwork.
The principle is similar. The first half program makes the registration holes for the second half.

Still seems like a PIA. Some machines have other things on the ends that won't allow this to even happen. (Tool holders, rails, etc.)

If you can swing the larger machine, I say go for it. Anything else and you are just making do.

This quote from the 'CNC wish list' thread seems to apply;


> *"If you need a machine and don't buy it, you ultimately find that you have paid for it, but don't have it." *
> Henry Ford
> 
> The key is, IMHO, to really know your business, and to tailor the machine specs to your needs…. with a little room to grow.
> 
> - Mainiac Matt


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## Desert_Woodworker

I should add, that "tiling" is not a wiz bang process, for there are problems that can make you cry. I think that this is for small machines to make an occasional project or two. If I were to make continous 4×8 runs, then "tiling" would not be my choice, but the bigger machine.

Now when it comes to the "cost savings vs time savings = $$$; then then seek out LJock DS's help, he is in the actual business. Check out DS's forum topic on the "Dream CNC" 
http://lumberjocks.com/topics/235553

I would love to know more about you- Ehicks Do you have experience with CNC and the software?
If others want to get a start, then start with the software. Vetric.com Has free trial software with training video's
It doesn't cost a dime. You can practice, practice see you results.


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## Mike_D_S

Ok as a "tiler" I have a few suggestions (note not my original idea, but I can't remember who I originally got it from to give them credit).

This idea was originally passed to me as a way to reliably index jigs repeatably. I drilled holes and glued in brass tubes at specific points on my table. Then for my jigs they have brass pins which fit those tubes. I place the jig with the brass locator pins and set the offsets written on the jig, touch off the Z and cut my parts.

Then I needed to cut a piece that was 7 foot long. So I designed the cut as a tiled piece and as part of the last cuts on the first tile are to drill locator pin holes in the piece. The second tile is laid out assuming the locator pin hole are aligned with the brass tubes I use for the jigs. So I made the first cut, re-positioned the piece using the locator holes from the first cut and the brass tubes (which I know the position of) and then just made the second cut.

The biggest issue I've always found with tiling was getting an accurate position and applying the jig locating trick has made things a lot simpler when I need to do a bigger piece.

Mike


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## CherryWood

I made a 8'x2' long sign out of 1 piece of material quite easily using the Vectric software and tiling on my 24"x24" machine. Vectric is not the only software that does tiling. ArtCam and others as well are out there.

I have done a few others with tiling on .

I have since bought a 4'x4' machine and set it up in my shop with the idea in mind that I can tile a 12' sign.

So to answer the question - can you do a 4×8 sign on a 4×4 machine? YES - but be sure the machine is open and you can slide the 8' through-most machines are like this.


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