I have been cutting 3/8" thick hardwoods like cherry, walnut and hard maple for quite sometime very easily in single pass. I recently had an application where I wanted to use mahogany for contrast. I specified Mahogany from Central America instead of Africa since its density is similar to the wood I typically work with. I was surprised it took 4 passes to completely cut through, which of course results in a fairly think layer of charring. My only guess with mahogany like many of the other tropical wood species possess unique characteristics. In this case I'm thinking its preventing the energy from the laser from being absorbed adequately. Has anyone else experienced this and if so did you find away to cut the through in fewer passes.....preferably one. Like all the woods I work with, they are kiln dried to approximately 7%. I have a 50 watt Helix from Epilog.
I've attached a picture of the completed piece, luckily the raised maple contrast covers the seam between the walnut and mahogany so the "char" is hidden in this instance. If I did the attachment procedure correctly it should appear.
John
Iron Horse Engraving