Would like to create an inlay grid in MDF for my mini mosaic tiles (How to?)

Hello, I have a mini mosaic I've been working on using 3/8 (10mm) square tiles. The 'picture' (my interpretation of the Fibonacci spiral) comprises 5,487 tiles (59x93) which is ~ 24" x 36". The tiles are ~ 1/8" deep.

I thought it would be great if I could use the CNC to machine in the little pockets in 1/2" thick MDF, in effect making a custom 'backer board' I would 'seal' the MDF with a diluted Weldbond wash, and then glue in the tiles with Weldbond as time permits. This is for indoors only.

Is there an efficient way to design a grid like this in Aspire, rather than drawing in all the individual lines or squares? I'm thinking a 1st round of roughing in the squares (1/8" bit) and then using a V-carve bit to finish the square outlines, since the tiles have a nice (45 degrees?) slanted angle. Or could I just use the V-carve bit for the whole operation since the squares are so small? The pockets would likely be just 1/32" deep, enough to hold the tiles in place.

I may have to do two boards, like two of 13" x 37", depending on the spacing between tiles (I may or may not grout afterwards).

Thank you for any comments on how to design the file.

Yes… you can do an “Array Copy” (under offset and Layout). You can specify number of rows and columns and gap or offset. Start with your desired pocket size and then fill in the blanks!
A little playing around will have you an expert in no time!
SG

One thing to remember Carolina, is to make ONE tile on a separate layer, and toolpath it all the way, THEN array and copy with the toolpath "Vector Selection Order" set to automatic with that layer checked and visible. Then no matter how much you fuss with dimensions/bits/and different toolpaths, you can just hit recalculate all toolpaths:)
It might be a good idea to buy some of Drillman1's Kyocera .125" 45 degree engraving bits. They have a .012" flat(unless he specifies it as a "Sharp"(.006"flat). You'll be using such a small bit of the tip, and on MDF which is dulling, that you can swap out bits with your pocket book crying;
http://www.ebay.com/itm/5-45-degree-...AAAOxyVLNTAD1B
A 20% stepover with it entered into tool database as an Engraving bit(note that engraving bits are entered as side angle) will give a smoother surface than a VBit and faster.
His .125" and .0625" downcuts give excellent surfaces as well.
Looks like a very interesting and time consuming project:)
scott

Thanks very much Steve and Scott for the help and encouragement. I've ordered the 45 degree engraving bits from the link and look forward to learning the Array Copy. I'll start with a simple 4x4 grid for practice.

Attachment 30189

OK, I did it. It took about 24 hours, so this was the first time I went to bed on a CNC job!

Looking good Carolina! :)
Shame they were so small you could never get up a decent speed.
Bet it's not the first time the first time you call it a night on that job.
Might have been better to split the job up so vac and Max weren't both running unmonitored?
I hate to have both running without me close by because of fire.
My longest run was 19 hours, but it was a 3D Finish toolpath and I shut the DC off...put 3 smoke detectors around...and STILL woke up everytime it stopped cutting to load another batch of the 2.6 million lines of code:)
Congrats on getting that part done!
Make sure and post pics of the finished mosaic please.
I think when I saw that time...I would have seen what a 50% stepover looked like on a small test, and kept my Z1 and Z2 WAY down in the grass:)
scott

Scott, I did not have the vacuum going. I have the plexiglass side rails which catch most of the chips, and in general still hand vac intermittently on a job. My Desktop Max is still on the floor, since the original crate was damaged and it took awhile to get a new one to me. And now, with limited time on the CNC, I seem to always want to get a project going rather than take that time to put the crate together... some day... but that is one reason I haven't set up a vac yet...

If I ever do another mosaic board, I will test out changing the stepover, %, thanks for the suggestion, since the grid will be covered up by tile and glue, smoothness prolly would not be much of a factor. I do love how this grid affords alignment for OCD tendencies!