I recently took delivery of a 700W fiber laser and had decent success overall cutting stainless and cold rolled steel. I've been able to cut intricate patterns on 1.3mm stainless steel with relative ease using nitrogen. However, when I try to cut 3mm cold rolled steel with oxygen, I'm not able to replicate the same intricate cuts. It's as if the metal is heating up and vaporized when the cuts are close together trying to leave a thin strip of metal behind (I'm sure my terminology is wrong). Any thoughts or ideas? Perhaps I simply can't cut intricate stuff using thicker material?