I was using my laser to cut the thickest metal that I've cut before and encountered some problems. The attached pic shows the results where there are a number of pits that form because the laser just wasnt penetrating the metal.
I tried some other test cuts. The behavior of the system was really sporadic. Sometimes it would cut the complete part, other times it wouldnt. A lot of times it would look like the laser would splash out some metal, but just not make it all the way through.
I was musing over the situation and first wondered "hm, I wonder if the laser just isnt warmed up?" But that didnt make sense, at least I hadnt seen that happening ever before. And there were the cases where it would cut the thick stuff fine, but then it would fail again. Then I said to myself:
"hm, I wonder if the _part_ isnt warmed up?"
The laser has a tough job getting through the metal, its gotta a short period of time to heat up a little microspot, poke on through, and then participate in a continuous cut. If heat was getting transferred away from that cut point, then I could imagine the cut just wouldnt happen.
So I broke out the propane torch, warmed over the metal, and flopped it on the cutting table. It worked like a champ. No pitting, cut cleanly through at every point, and behaved flawlessly the way the laser works with thinner metal.
I think I was getting sporadic results before because in some cases the laser was warming the general area but didnt make a good cut, but when I'd cut another part nearby it was warmed enough to get a good cut.
I'll try some more tests but I think its the temperature of the metal. It doesnt have to get heated up much, but it makes me wonder if I could get even thicker with more heating.
owen