Engraving steel with Trumpf Trulaser Tube

Hi!

We're using Trumpf Trulaser Tube 5000 fiber to cut and engrave tube details. We've run into a problem with engraving/marking texts and logos on our details. We're trying to engrave a tube with 3 mm walls but Trumpf's default values (3 mm O2) for marking only leave a slight shadow on the surface of the tube.

Default values:
Power 110 W
Gate frequency 600 Hz
Speed 20 m/min
Nozzle distance 6 mm
Gas pressure 2 bar.

We have tried modifying speed, power and gas pressure to find values in which case the marking would be engraved in to the detail but in a way that it doesn't totally melt the material. So far in about 40 different sets of values we haven't found that middle ground between a shadow and melting.

For example

1) These values only leave this shadow on the surface as the default settings
200 W
600 Hz
6 m/min
6 mm
2 bar

2) Only increasing the power by 20W and leaving everything else the same, half of the marking is already melting the material.
220 W
600 Hz
6 m/min
6 mm
2 bar

Has anyone else ran into a similar problem and found a solution or how would you solve this kind of a problem?