Need guidance

I am relative new to CNC Laser Cutting Machines and I am having a problem that I have not been able to figure out. I am using a Mitsubishi ML4020-F60 Fiber Optic laser machine. I don't seem to have any issues until I start cutting .375" Mild Steel. According to the chart I should use a 1.2 tip which is the same for .50" steel. It will cut the .50" all day with no issues but if I switch to .375" all of the sudden I have dross issues. I have done and re-done centering until I am blue in the face but I still cannot get rid of the dross and bad edge. What am I doing/not doing wrong? I am attaching some pics of what a part ends up looking like after it has been cut. There is a pic for each side (as the dross issue seems to only happen on one side) so that you will have a reference for what I am talking about.

Edited 1 time(s). Last edit at 09/20/2019 10:57AM by gregcunninghamokc.

... could be, your beam is not symmetrically -- or your air-assist "deforms" the cut while melting the material?

---

Viktor
--------
Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

Any tips or tricks on how to figure out which it may be?