Lightburn not burning all the way through

Hello Lightburn Community. After searching I could not find an answer to this solution. I have a 50W Laser running a Ruida board. I started by using RD works and was able to make several full depth cuts on 5mm plywood, using settings such as 5mm/sec and 65% power, and some only a .5mm or less from going fully through. I tried to repeat this with Lightburn using the same setting for speed and power only got about 1.5mm deep. I did change the file by duplicating the area to be cut, and changing the duplication to a separate color, so I could make a second run around the same line at a faster rate. So basically first evolution was 5mm/sec at 65% power, and second evolution (follow up cut) 10mm/sec 65% power. This only yielded me a 1.5mm deep cut. Do changes to focus, depth of table, and there’s no way it could have fell out of alignment. Any suggestions would be appreciated. Thank you.

Part of the issue might be that plywood is notoriously inconsistent. Enough power for cutting through one area of a sheet of plywood is not enough for another area in the same sheet (totally different sheets can vary even more). This can be due to differences in glue thickness, unseen knots in middle layers, unseen voids and voids filled with glue.

chek to have activated bi-directional scanning and the dpi’s or line interval are the same than rdworks

Doug, you are right that there are inconsistencies in the plywood, and in think case these pieces are fairly straight. However I think I found the solution. I turned the “burn through” mode on in the line settings and it is cutting deeper. Not all the way through but deeper. I also think in the areas where it didnt cut all the way through my adjustable bed is not level. It’s always cutting the least through in the bottom right.

Eduard can you tell me where in the RDWorks setting it would tell me those settings? I should be able to check when I get home in a few days. Thank you everyone for your help with this

It’s nothing to do with your alignment or the wood.

You are cutting at 10mm/sec, which is the default “start speed” in a Ruida controller. That speed means that it’s only using the Min Power setting, not the Max Power. If you’re cutting at or below that speed, set Min and Max power to the same value.

Ahhh thank you Oz that makes sense. I will give it a try. I keep reading for my 50w laser (likely really 40w) that 65% power is the max I should run it to prevent premature wear on the CO2 laser tube. Just to clarify basically it would be a good idea to do 65% min and 65% max to get that effect? Thanks again for the information and look forward to trying it out when I get home in a few days.

That’s not really true - there’s a maximum current that you can safely put through the tube, but if you’ve never measured that, your “65%” is 65% of some unknown value.

For a typical 50w tube it’s 18ma - if you stay below that, you should be fine. If you dialed your power supply to produce a maximum of 16ma, you could run 100% of that all the time with no issues. If your PSU is putting out 20ma, exceeding 90% would shorten the life of the tube.

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