Laser cut single piece hatch grating - pattern and method

[Tim Holt]

I took my first stab a while back at making a single piece laser cut hatch grating.  This is a style used on Vanguard's grating set.  Here's a picture of one I cut out using some Maple, about 1.6mm thick.

 

 

It's not as clean looking as a machined or cut wooden grate, and there is a bit of risk that excessive visible grain in the wood will not look right.   But it's guaranteed to be at right angles, and it makes framing a "perfect" hatch a bit simpler.

 

To some extent the char is a drawback, but I like the "dirty" look of the grate, as this is more the style I like.  Also, a benefit of the laser char in the square holes is that it darkens the grating, creating more of that "and below is a dark area" illusion.  I actually applied flat varnish down in the cut holes to help fix the char so it wouldn't smudge.

 

To create them, you end up making two passes on the wood with the laser cutter:  a cut pass to make the holes and cut around the outside, and an etch (partial cut) to create a visual separation with the sections.  I've annotated the picture below with some red lines showing where the etch lines are.  The etch lines create the illusion of the vertical pieces being separate.

 

 

To make the cuts and etches, I used Inkscape (a free vector editing program) to create two patterns.   First the cut lines...

To create the above layout, I started by making a 1.6mm square, then began duplicating it at an even spacing until I had an area big enough for my grating.  Then I put a bounding box around it for a final separation cut. 

 

Then the etch lines, which I just created using the above pattern to let me know where they should be

I actually created these on top of each other in editor layers so that they would line up.  Here is a picture of them together in the editor.

Then I exported the cut and etch layers into separate SVG files (one for cut, one for etch), which I then passed to the Glowforge laser cutter to create the cut and etch tasks.

 

Here are a few things I've though of doing beyond this first attempt...

 

• Just create an entire sheet of grating without any cut bounds.  Then I could just cut out any shape I wanted to any size (in grate grid square steps).
• If I want my grating to be a very specific size (width and height), it would be easy to just rescale the entire cut to match exactly the size I want.  Using individual grating strips, I can't resize the grate, as they are forced to be dimensional increments of the thickness of your wood.
• If putting a bounding cut around the outside of a sized grate, leave a few small gaps so that the cut doesn't go completely around the whole grate.  The main reason I'd do this is because when the outside cut completes, it will sometimes drop the piece of wood a small amount if it's not sitting flat on the cutting bed.  That means subsequent cuts and etches may not quite line up right.  Leaving the small gaps means the grate section won't fall down.

[Gabek]

Very nice work on the grating, Tim!  I was planning to do the same for my 1:96 Triton, but with a 5.5W Genmitsu Jinsoku.  I think you're right about the burn marks adding depth to model, so to speak.  
Thanks for sharing this with us.

Clear skies and sharp tools!

- Gabe