[Jonhurst]

Hi guys, only been operating our laser for just over a year with very little training but we have a massive problem and running out of things to change, we have a bystronic byspeed 4020 and when we cut with nitrogen it will cut for maybe a 1/3 of a sheet and then just suddenly not cut through the material...when I check the lense it has what I can only describe as oil on the bottom off the lense.we are unable to use nitrogen now because of this, gone through a load of lenses, material is zintec,galv stainless and ali, what we use nitrogen for everything else is o2 and we dont get the problem when cutting o2, any help will be massively appreciated thanks jon

[Workingmetal1]

Where are you located? I know a great bystronic laser technician.

[RCaffin]

Thin coating of zinc or zink oxide maybe?
Finding out what the stuff is should be your first job.

Cheers