How do you re-align your sign blanks in shopbot?

[Call-Tech]

I am new to shopbot, just got mine a couple of months ago and I am just beginning to learn how to use it.

I have read much in these forums about methods of painting and masking signs before engraving text and flourishes. (thanks everyone for all the great info)

So now that I have cut out some blanks in various sizes and shapes and painted them, and applied mask. How do you get the blanks lined up right to cut your text and maybe a boarder just inside the edge of the blank?

PS. this is just practice, I have not attempted to sell any jobs for bot yet.

[rookie432]

Fred,

Try cutting out your blanks. Then find the direct center of the blank. Then when you design your signs in your software design from the center of the shape. XY Zero at the center of your blank and cut your file.
I do this for most of my files instead of XYzero at the lower left corner beacuse it is easier to find the center of the material than to get an exact coordinate on the lower left corner.

Bill

[gerald_d]

Wouldn't it be better to "cut the blank" at the end, out of the same program, with the x,y not having moved? Until then you can have screws going through the waste edge.

[Call-Tech]

Maybe I am confusing myself here, I am used to large format printing and then cutting out prints on vinyl cutter. I have alignment marks that print on prints and are then used to realign x,y in cutter.

Now I have never done any routered signs in my shop. but the problem as I see it is that everyone recommends priming and painting base coat on the sign blank. Lets say for example that the sign blank is shaped like a shield. So we cut the sign with the shopbot, it is going to cut out this irregular shaped sign, maybe round or bevel the edge of the blank. Now we remove it from the shopbot to prime and paint it. After couple days of drying we then put a mask over blank and spray either clear or base coat to seal mask. let dry. now I want to cut a 1/4" v groove 1/4" inside edge bevel all the way around. Similar to Bud's "god bless our home" under painting techniques. And then cut text and anything else. Now to accomplish this we must place our shield shaped blank back onto the shopbot and not only get an x,y point lined up, but also make sure that it is rotated into correct position.

Now I can only assume that there is something in my scenario above that is not correct, because it would be very difficult to realign blank and cut all the way around just inside edge while keeping everything perfect.

My next assumption would be that everyone is only painting surface of sign blank in advance and not cutting sign out until after text and graphics have been cut. Thereby needing to paint cut edge of sign with base color later.

We all know what it is to "assume" something. So please feel free to correct the new guy on his thinking process. (-:

[WCSC (Unregistered Guest)]

I just cut a profile or outline of the blank. at a 1/64" depth and double tapes stick the blank back on

[gerald_d]

Fred, don't let me confuse you, I don't make finished signs.

[richards]

I often use a 'pin register board' when I'm cutting plaques. The 'board' is just a 2-foot x 4-foot piece of MDF with 8mm dowel holes drilled every inch - like a peg board. Then, when I layout the plaques, I mirror image one drawing, which becomes the plaque's backside. To that mirror image, I add the necessary holes to match at least three of the pin register board's holes. Then, when I cut the plaque's profile, I place the material face side down on the shopbot's table and use the mirror image tool path. After I've painted the plaques and applied the Gerber masking material, I use some shortened 8mm dowels to align the plaque with the 'pin register board'.

For the two sizes of plaques that have become almost standard sizes, I have a piece of MDF with cutouts that match those two sizes. That piece of MDF is also plumbed for my GAST vacuum to quickly and easily hold the plaques in place.

[Chippee Marshall (Unregistered Guest)]

Fred, Home depot makes some pink insulation foam that can be used to experiment with. The cut comes out kinda fuzzy but you can't beat it for trial and error. The stuff costs $8 or $9 per 8" X 3" sheet(approx).

Bill jarvis has the right of it, though... Design the sign with zero in the center. I do this almost exclusivly with signs. The only exception is if I am making a row of signs from one board.

I usually program in some waste on the edges too. This way I can be sure to cut a whole product.

On large signs, my brother programs screw holes in places outside of the cut. You can make a separate toolpath to drill for the holes while you hold the piece to the table. This works best with large signs since the foam is too heavy to move with the bit.

Cheers!, Chip

[btk]

I have used the following method for re-registering 3D objects and it should also
work for signs.

Screw down the sign material (i.e. 24 x 48) to
a slightly larger second piece of wood (i.e. 26 x 50 mdf).

Screw pieces together from the bottom of the MDF so that you do not ruin the surface of the sign.
Make sure to put the screws in a central area
that will not be routed.

This bottom mini spoil board will always keep its original corner even when the top piece is routed.

Added benefits:
(1) Easily use border area to screw entire assembly down to the table.
(2) Do not have to worry about ruining your
real spoil board (particularly helpful when using
ball end mill on 3D objects).
(2) The bottom board serves as a "tray" when doing painting for easy handling.


Brian

[mikejohn]

I am cutting out signs all the time now. Didn't get the ShopBot for this, but the business has gone in that direction.
I place a sheet of material onto alignment blocks, and V-carve everything, including pilot countersinks for fixing, then an angled edge
Replace the v-bit with a straight bit, then cut out the blanks,
Light sand and prime/topcoat the edges.
Treat the letters as has been discussed many times.
Cutting blanks first seems the difficult way to go.
It also minimises waste.
..................Mike