I bought a Neje A40640 laser diode module to use with the MPCNC. I did some calculations about the OD and it came out to 4.2. I already have a Jphotonics window OD 3+. My question is what does the “+” mean…as in does OD3+ mean all above OD3? In other words could an OD3+ window be safely used with OD4.2 or would I need a window rated at OD4+? I can’t seem to find such a windows for less than $1.45 per square inch…or $208.00 per square foot.
I understand that any answers are to be used at my discretion and that no one but me is responsible for my actions. Thanks in advance.