Lining Up Our Board.....

[Unckdecamp]

Hi everyone!

We have had our shopbot for a few years now and it is running great! I feel as if we are going about things all wrong though.....Here's the deal:

We print designs onto vinyl and then mount them on a board to be cut out. The tricky part of our process is lining up the board on the table to get the cut paths to line up with the print.

We print bomb marks in all 4 corners of our print. We then make a drilling cutpath that goes around and touches 4 points on the board. We adjust accordingly and run it again and again and again....

There has got to be a better way of lining things up.....CAN YOU HELP US PLEASE?!?!?!

Thanks so much,



UDC

[pkirby]

Yikes!!! That process sounds painfully slow. There are several options that will allow for easy and consistent alignment. Below is a sketch that I just drew to give you one idea. It involves a dedicated jig mounted to the table with a pocket in it to accept the board you will be cutting. If you could post some more pictures/details of the boards you're trying to cut, then we'll be happy to give you some more specific direction.
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[Keyco Wood]

Here is a jig i made for guitar neck. Found the idea on Thermwood video on utube. The trick in this one is to zero to center of the jig which was made from same layout as neck toolpaths. When i run the front side (lower part), I add the index holes for the upper part of jig. The the fretboard will cover them when installed. When neck is cut out, flip it over and put it on the dowels in the jig and it is perfectly lined up for the back side neck toolpath everytime. You can do a lot with jigs. They are a very powerful tool in your book of tricks.


17474

17475

[twelchPTM]

Using a jig is probly the cheapest way to go but I have seen Laser setups that project the cutpath prior to the file running. Typically found on larger CNC machines, it allows you to align your work piece and also make sure there is nothing that shouldn't be cut in the way. I have seen this on machines for wood, metal, and stone.

[Unckdecamp]

Hmmm,

These are great ideas, but our boards are 4'x8' so it pretty much takes up the entire table, and leaves no room for a jig. The print varies on application to the board as well, so I don't think it would work.

Is there are way to get the X and Y axis zeroed at the same spot every time? The way we do it now is just move the bot over to the corner of the table and zero it out. We then do our cutting and then return to zero and shut the bot off.

We were thinking about a possible laser solution, but never got around to it.


Thanks so much,


-UDC

[jim_vv]

Greetings, Mark

I do this all the time for the sign guys for whom I cut. They put corners in their vector files and printed on their masked material. (We started with cross hairs, but found that corners of rectangles work better because I can easily and quickly use my transform tool to find the corners rather than centers of cross hairs.) I move the machine with a 30V bit in the spindle to one of the corner points in x and Y in the vectors and then move the material so the corresponding mark lines up. I then move the machine to another point and verify that the material is lined up (I may go back and forth a couple of times to confirm) and then turn the vacuums on, put a cutter in, zero Z, and cut. Sometimes I have to move the material slightly to split the difference in the printed marks and the dimensions in vectors to make up for stretch in the vinyl. Here is a post that I started a while ago regarding this same question.
http://www.talkshopbot.com/forum/showthread.php?t=14484

Kind regards,

JIM

[donek]

Sounds to my like you really only have to locate off of one spot and then ensure your artwork is square. Right now you are doing this by positioning a cutter over multiple registration marks. All you really need to do is position two registration marks in your artwork along the x-axis with the same value in y. Position your tool over one of these registration marks and measure the distance from the side rail to that mark. Then move down to the other mark and move the material until it is the same distance from the rail as the original mark.

We actually use a similar technique all the time to center parts on our table. We have a stick that is the right length. We hold it against the rail and position the center line at the end of the stick. If you always give your registration marks the same y-value, you can very easily align in that axis. I'm sure that you can figure out a way to create a similar alignment tool for your primary registration mark with a little application of these same principles.

[twelchPTM]

if you need to ensure your xy zero is in the same spot everytime its time for a little upgrade! newer bots have a prox. sensor on the x and y axis for zeroing