I posted my project over here: 2 sided engraved penguin sign
but had some questions about it so I thought I post what I learned here instead of cluttering up the project post with individual answers.
I’m an AutoCAD user, so most of what I describe below will use AutoCAD terms/commands, but I’m sure most of them are used in other CAD software as well.
I’m sure if you’re experienced with CNC/milling crating G code, some of this stuff will come naturally to you, but I’ve only used AutoCAD to design buildings, never anything this detailed before, so it was a learning process for me.
- To start off I downloaded a reference image & imported it into AutoCAD. I traced all of the major outlines with a Pline (Polyline), as you can see on the right side. I then faded the image with transparency and started to fill in the interior areas (left side). As you can see I had to deviate from the original image to create the arrow & scale down the logo. My role of thumb was everything that’s black would be engraved/pocketed, with the exception of the logo.
- I offset each Pline 3/16" so the bit would overlap a little bit. Here was my first big lesson learned. I didn’t connect all the Plines. So the Maslow would engrave 1 path/Pline, lift the bit, go back to the other end, drop the bit, over & over again… It took over 4 hr. to engraving the first side of 1 sign.
- I then learned to connect all of the small single Plines into 1 long Pline.
- Then changed the width of my Pline to 1/4" (the size of the bit) to see what areas are being missed by the bit. This worked pretty good, but because of the way Plines work with sharp corners, it looked like it was cutting areas it really wasn’t. So if I made the width a little smaller, I could see the areas I needed to fine tune.
5, Lastly, getting the 2 sides to register & match up. This actually worked out better then I expected. I posted earlier on how to do this: Engraving on both sides of plywood
There were a lot of good ideas, like using 2 pins to register the part, but I went the simple & easy direction. In AutoCAD I laid out 1 side of the sheet & then mirrored it left/right. Remember to un-mirror your text/logos, so they’re readable. Since Maslow is a 4’x8’ sheet I could just use the edges of it to line up my 4’x8’ MDF sheet. The important part is where the router starts it’s home point. On side 1, I had it drill a hole all the way through. This hole was at the center of the sheet horizontally, so 4’ in from either side & then it did all the engraving for side one. I then flip the sheet left/right to side 2. I then use the Maslow controls to set my home point of the router over the hole that was drilled on side 1 & then start engraving from there. For the most part everything lined up perfectly. I did have a chain skip on one side & that made things around 1/4" off, but it was still good enough… 
- Painting tip. Using this engraving method to “color inside the lines” is helpful, but it also had a down side. As you have to also make sure to paint the edge of the lip of the pocket or else you have exposed MDF between your 2 colors, so it can be a little tedious. I painted all the colors first & over painted the edges/lips & then filled in the black & cleaned the edges last.
I think that’s it for now. Let me know if you have nay other questions.
