Not sure if he posted settings anywhere. Engraving is generally pretty forgiving and how you want to do it might depend a bit on the level of detail in your image. It might be faster and get you better results if you can do a test, but if this is your only sample of acacia, I might see if @shop wants to share.
Bought some nice marble/Acacia half and half coaters from Target for a request for 2 sets for someones housewarming gifts. This was my first engrave on this wood and this companies coasters. Unmasked I used settings: 100 - 65 - 340lpi with auto focus: unmasked: GF Pro. I noticed at 70 power, I could see more resin around the engrave, at 65 I did not get this. They engraved just perfectly! Thank you for all your input, it greatly helped.
What exactly does “all I get are burns” mean? All engravings are burns. The first thing that came to mind, though, is that if you place a cutting board on the floor of the machine without raising it up into the focal range of the machine (~1.5-2" off the floor), your engravings won’t look very good because they’re entirely out of focus. Read through this post for how to engrave on thick objects correctly:
Ditto what @dan84 said, and also I might suggest posting a photo of your results, and a screenshot of what you’ve got in your machine (showing the commands on the left all the way to the name of your machine on the right) - it’ll give us a better idea of where it’s messing up
This applies to any material that is organic. Wood is inherently analog, you can get large variations. There is no substitute for testing, and end results are completely subjective.
Various vendors have different finishes that effect it and manufacturing processes.
Everything I do that’s Ironwood acacia is 800 speed and 70 power. But if I do mountain wood acacia it has more of a live edge to it and settings are 550 speed and 55 power.