Laser cutting really illustrated a point I ignored in a graphic design class I took in high school: if you’re designing a logo, it better work in just 2 colors. Working with the laser cutter was a ton of fun, but this project really exposed some of the difficulties with calibrating it for engraving, which is, in my opinion, not the most impressive thing the tool can do. We also found that choice of material is just as crucial choice as the settings.

We started by cutting a series of test squares on 1/4 in, 3-ply that looked to be oak. Once we got an idea of our settings we started cutting small test pieces

We found, however, that when we wanted the laser to engrave this material it either came out looking patchy (likely due to the strongly differentiated grain on the face of the panel) or entirely scorched. We simply could not get more than 2 distinct colors (engraved or entirely untouched) from the oak panel, so we decided to try something else.

There was a scrap of 3 ply birch, so we decided to try to cut it using our existing settings as they were, just to see where things stood. It came out alright, and after a couple more iterations we ended up with this:

It is worth mentioning here that we tried to keep our color scheme as close to the original as possible, with the dark blue parts darkest, then the grey in the middle, yellow lighter, and white untouched. After this test piece, however, we decided to change that plan. The large swaths of dark engraving made it difficult to pick out the small details in other colors. We switched our scheme so the grey was darkest, followed by yellow, and left the blue as the lightest of the engraved color. This left us with this final result at a larger size:

• Grey:
  • Speed – 650
  • Power – 30
  • Scan Gap – .003
• Yellow
  • Speed – 750
  • Power – 20
  • Scan Gap – .004
• Blue
  • Speed – 750
  • Power – 25
  • Scan Gap – .003

By limiting the darkest colors to smaller areas, the detail in the piece was not obscured nearly as much by the deeper cuts the laser has to make to create the darker shades.

 

Some take-aways from this project:

• The scan gap was a very useful setting in creating different shades. By changing the distance between the sweeps of the laser as it engraves, we could dictate how much of the material was affected, while leaving some material in the middle less effected by the heat. This allowed us to find a range of power and speed settings that didn’t completely char the wood and stay firmly within those bounds, wile still being able to achieve a wide range of colors.
• Changing the material has a huge effect on the outcome of the piece. By switching to birch, we were able to create a much wider range of shades than on the oak, where the results were fairly binary.
• In the future, when designing something for the laser cutter, I will try to limit the number of separate shades that need to be engraved, and maybe even try to recreate line art by sending it to the cutter as a cut with reduced power. I believe this is what was done to produce the pattern on this little promotional card I got in the mail and it really highlights the smoothness that makes vector drawing so cool to begin with.

Overall, this was an awesome project working with a very cool machine. I’m looking forward to taking things up a notch at the plasma cutter…