Hi,
I recently got myself a SH-G350 laser machine. It came with an airpump for the air assist and the standard lens, I assume 40 mm.
When trying to cut corrugated cardboard I find it very difficult to get through the material. The cardboard is 5 mm thick and of the dual layer type (basically a sheet of fine corrugated board on top of a course layer).
I have to set the head as low as possible (focus almost on the bottom layer, head almost touching the material), but because the cardboard pieces are always a little bended I have to give it a little more room so the head will not touch the cardboard.
When I do one slow pass I will go through, but the cut is very wide and the edges are very charred. Two or more faster passes result in less charring, but it never seems to go through the bottom layer completely.
When I do a slow pass I notice flames inside the cardboard that sometimes linger even after the head has passed the area. It seems that the air assist works as an oxygen source rather than a flame suppressor.
So I have two questions. Will a longer lens work better in cutting (after reading a lot on this forum I understand that shorter lenses are better for engraving)?
And second, will a better compressor for the air assist result in cleaner cuts? The pump that came with the machine is a rather weak affair. I've read some posts about people setting the air pressure to two bar, the air flow from this pump can easily be stopped by lightly putting your finger over the outlet. No way of telling how much pressure it produces, but it can't be a lot...