I am using a JPT 100w MOPA laser with a rotary. I have been doing some test engravings and the rotary is set to turn along the Y axis. As you can see in the photo the coating is removed fine along the y axis but the part of the T that runs along the X axis seems weaker and coating is not removed.
Can anyone recommend what to check on what would cause this to happen. I am new to lightburn and never experienced this with the previous software I used so i assume it is a setting somewhere that needs to be tweaked. To get the full T to engrave like the one below the circle it has to run several passes.
Hello, Bryan
Please post screenshots of your settings. My WAG with only looking at your photo is the heat remains high enough on the short passes of the top of the T, but as it scans the longer length of the stem of the T it cools just enough to make a difference. To confirm you could make a series of bars varying in length from the top of the T dimension to the stem of the T dimension. Could be a couple dozen other things as well. Removing colored coatings with a fiber can be a challenge.
Got to “File > Settings” and disable the Beginner Mode. This will give you access to the Scan Angle setting in the Cut settings.
Which is your rotary axis?
From the Rotary Docs:
When rotating on the X Axis, you’ll want to engrave along the Y Axis, with a Scan Angle of 90 or 270. When rotating on the Y Axis, you’ll want to engrave along the X Axis, with a Scan Angle of 0 or 180.
I believe I have the scan angle set up correctly based on y axis rotate. Here are some updated screens without beginner mode on.
If I misunderstood and I have something set wrong let me know.
I really appreciate everyones help on this. This software is awesome but it is way more advanced then the last one so I have learned most of the other stuff but struggling to get the rotary right.
Thank you for the screenshots.
The Rotary Axis and Scan Angle look fine!
You should disable Flood Fill on the Cleanup pass to minimize the rotary jumping between the splits. - To rule it out as the issue, best disable the cleanup pass alltogether for now.
I will check that flood fill setting and run a test triangle and see. Running them flat without rotary I did get a better result. That is why I am convinced its just a setting I am missing. I will give that flood fill and even disable cleanup pass altogether and see what happens.
I will also run @Albroswift’s suggestion too and see what I get.
Also, just curious, where did you get your parameters? They are not typical of what I would expect. Not saying they are not good settings, just unusual. Seem to be working for the most part.
I just had a minute to go back and test them again and I am not sure what did it but it is working better now. I did one thing at a time and it worked on the first thing. Just putting it into advanced mode seems to fix it. I did later turn off flood fill and there was no change so I will just leave that off.
I have advanced off because for my normal every day marking that does not use rotary in beginner mode it engraves in 4 minutes but when advanced is on it estimates it at 59 minutes. So I have not found what is in advanced mode that is causing such a difference. Might have to dive into that now and figure it out.
Found some that were very different online and weren’t working how I wanted so just kept changing numbers until I saw gradual improvements. Those are what I ended up with. Probably better ways to do it and probably faster but my first time doing drink tumblers so just trial and error at this point so I can get an order done for a customer. Got a bunch to do so faster would be better but current settings get a pretty good mark and don’t have to wipe with magic eraser sponge like I see a lot of online videos do.
The estimated job time should be the same in Beginner Mode. I made some tests and found that this is not always the case! Will report internally.
Thank you for bringing this to our attention. If possible, send one of your .lbrn2 project files to support@lightburnsoftware.com and mention this forum thread for us to investigate.
Absolutely! I recommend doing some Material Tests and most importantly, save the good values in a Material Library to use them in the next project.
So no disrespect, really trying to help. If this is for a paying customer you really need to get professional results, so follow me here.
There is a lot to learn about parameters and setup, and a lot to learn about rotary, AND coated tumblers are one of the harder items to get right with a fiber galvo ( UV galvos are more suited). Blue is one of the harder coatings to remove with a fiber galvo. So you are jumping into the deep end full of sharks without having learned to swim or any shark repellant.
I understand your trying to get an order out but if you are just substituting numbers until it looks OK I’m afraid you are going to be in for some frustration. There are a lot of numbers.
Go back to the start. Learn how to use material test and run some material tests. Start with more common parameters, 200 Q pulse, 0.0254 LI, frequency maybe 40KHz to 100 KHz range, Speed maybe 1000-2000 range. On Laser Master Academy there is an example of blue tumbler/ rotary/ fiber laser that came out really nice, but the parameters are behind a paywall so you would need to join/ pay a membership. (I’ve been a member for 3 years, worth the money in my opinion)
I see on your image a lot of artifacts that suggest your rotary setup is incorrect. So once you get your parameters looking good, you need to burn some shapes and get your rotary dialed in.
No disrespect taken. It is an order for someone I know. We are going to run and see what results we get. I fixed the artifacts already so the engraving looks much better already. We do have someone on backup though if we are not happy with the results. I am going to look into the Laser Master Academy you were talking about. Do you happen to have a link to the video of the blue tumbler that you were referencing?
Not a video, it is in the user database where we started posting parameters that work. It is using a 60W so you would have to convert the power, but we have one of those available also.
With my F163 (110mmx110mm) lens, I have a focal spot size of 0.03mm.
It seems best to avoid overlap by firing 1 to 1.5 pulses every FSS
At 750mm/s, I would use 750/0.03=25000=25KHz
But I’d be going MUCH faster to begin with, scaling up the KHz to maintain one pulse every 0.03mm.
More then 2x overlaps results in degraded quality in my testing.
You’re firing with 60 overlapping pulses. You’ve got the power turned down. So now it’s not marking on the first pulse, or making starting to mark in the center and just heating with a lot of pulses over each point on the paint.
When not overlapping, the mark comes from a single pulse and they don’t affect each other (much). So doing it at 750mm/s 25KHz or 1500mm/s 50KHz should give similar results, each pulse doesn’t care what happens with its neighbors. Each point on the paint only sees one pulse for however many ns the q-pulse is.
Shorter pulses lead to better effects in my experience. The quicker flash cleanly burns off the paint with no time for the heat to bleed over and scorch the paint adjacent to the part that blasts off.
I would suggest starting from freq=speed/FSS, then 100% power and find the shortest q-pulse that marks your paint at 100%. If that one is too much but the next shorter is too little, then reduce the power as desired.
