I’ve just swapped my K40 to run from a mini gerbil 3. I’d previously been using K40whisperer, but was getting USB errors so made the jump.
Some of my items which were engraving absolutely fine in K40whisperer are now missing the finer details. You can see it particularly well on the ball here. The preview looks fine, and it looks fine when seen with the wire frame filled, but it isn’t appearing when engraved. Settings are actually higher than I used to use, hense the darker engraving, but it’s as if it’s tickling it but not achieving anything.
Ramp’s turned off, I’ve tried reducing intervals, increasing power, decreasing speed… Nothing seems to be helping. It’s a G code controller so no min power settings.
Niamh was done on K40Whisperer, Alexander is with lightburn.
Any help much appreciated before i tear my hair out!
The red on your photo is the where the head is moving… the right side shows the overscan where the head slows, turns around and speeds back up. So no need for a minimum power setting.
This is only applicable to line or vector cuts where, needing to turn or change direction, the head can’t maintain speed through the process.
In theory, changing out a controller shouldn’t matter. It should generate that same pwm for the same area. I can see the difference in power applied.
Need someone to show up that knows mini grbl with a more though knowledge…
Thank you, I’m having to use a significantly higher % setting in lightburn vs the old controler that was built into the lid to achieve the same mA, and even on slower speeds and higher power its missing those bits. I’ve managed a work around by significantly thickening the lines up, but it’s not really a permanent solution as means I wouldn’t be able to work with many fonts… Even at sizes I could easily cut and weed from vinyl, text is largely coming out the same as the football, needs to be really chunky to be clearly engraved properly!
I suspect there’s something not quite right somewhere, I just don’t know what I’m doing well enough to work out what or fix it. Not sure if it’s lightburn, or the GRBL causing the issue. Or my own stupidity for that matter!
I don’t know much about K40 Whisperer and very little about MG3.
Ed’s suggestion to review the S Value Max and $30 are sound basics.
What strikes me is that characteristics of the two burns are so different. To me this looks like something more fundamental than just basic settings but not sure.
A checklist of some other things to check:
Can you confirm that focus was exactly the same in both cases?
Are you able to confirm DPI setting in K40 Whisperer?
Please confirm original speed setting in K40 Whisperer.
How did you control power with K40? Was this with a potentiometer dial? If so, do you know the current while burning?
Are you able to determine current while burning in LightBurn?
Do you know the frequency that you were using to drive the laser in K40 Whisperer?
Didn’t think of this… If he’s driving the IN of the lps, that will be whatever it’s response time is. Usually 1mS is the period (1hHz). This is 1.5kHz…
I’m only considering it because the character of the burn seems so different and since K40 users purport to be able to affect burn quality with different frequency.
I can’t work out how to reply properly to mulitple people without spamming with multiple posts, sorry, it’s saying I can’t reply with too many tags so I’ve had to remove them. Thank you for the suggestions! I’m glad it doesn’t seem to be me expecting too much from it at least. I’ve been close to binning it and going back to the old system, but needed the USB timeout error I was getting to stop so it isn’t really an option.
ednisley I’ve not heard of this so looking into it now, thank you!
jkwilborn the pot? I’m having to use more of a % setting to reach the same mA output if that’s what you mean? I was told the mini grbl was plug and go, expected a degree of finding my feet again, but not to this extent ha!
berainlb I’ve tried to follow in order of the questions, you’re right that they’re very different burns. They’re the same batch of wood too so not a difference there - I’ve tried using something I’ve engraved on previously to make sure it wasn’t a difference in material, but it looks different and the detail’s not working. I’m struggling with smaller/fine text and smaller details which didn’t used to be a problem.
Exactly the same focus
500dpi (I think! I’ve just gone back in to check)
200mm/s for this material, at 20%
It had electronic controls for % in the lid, I have an mA monitor too though so could see both. The laser looks like this for context if it helps!
I can with the mA monitor. It seems to need a higher % setting to reach the same power since the switch over if this means anything?
I’ll be honest, I don’t understand this question what do you mean by frequency? Apologies, it’s been a long day! I’m googling and not understanding what I’m reading, nor understanding what the table shared means. Still learning the ropes, getting there slowly but bits like this can be a bit of a slog until I’ve gotten my head around it!
Purely lightburn, the display panel no longer works at all due to the controller switch. Being honest, I wasn’t aware there was separate GRBL software either though - I’m trying to get my head around that to set the $30 value atm.
S Value Max is set at 1000
Do you want the original file, or the “I’ve bodged it to work in a roundabout manner” one? It’s an etsy purchase so I might need to run a generic test through in the morning with the new settings to give a file that I’ve got a licence to share, but can replicate things like line thickness easily to reflect whichever. I’ve this evening managed to get smaller text legible, at a speed of 120 and power of 30.
Interestingly my cuts are also running at a significantly higher power %, with this material now on 8mm/s and 25%, where it was 8mm/s and 15% on the old board/whisperer. Which suggests to my (very very basic) logic that perhaps the power’s got a cap on it that’s lower now? Though this doesn’t really explain the lack of detail in engraving as far as I can see. Thank you for being so patient/the help and ideas so far!
Your machine knows what the power it set to by an S code sent to it by Lightburn. If the machine has $30 set to 1000 and I send an S1000 that will be full power. Lightburn has to know what this value to generate the proper code. If the S Value Max is set to 500, Lightburn will send an S500 code for full power, the laser controller will interpret it as 50% power or half power, based on it’s own reference of 1000.
I don’t use grbl much, someone can correct me if I’m mistaken…
There are only two lines that need to be wired up…
MG2/3
LPS
LO
L
PWM
IN
Somewhere I seem to remember that the maximum power on these are set to 80% and can be changed… how… I don’t remember…
The tubes actual operation in a standard K40 is different from how your MG3 controller drives the tube. This is why you have no current knob… I wouldn’t think you would see much difference, but it appears that you are. Don’t know if this is responsible.
If you highlight a phrase you wish to reply, click on Quote and it will place it with the username so you can direct your answers…
This produces the block above… although it looks like this in your edit window
[quote=“purplerhino, post:9, topic:118348”]
reply properly to mulitple people
[/quote]
what do you mean by frequency? Apologies, it’s been a long day! I’m googling and not understanding what I’m reading, nor understanding what the table shared means. Still learning the ropes, getting there slowly but bits like this can be a bit of a slog until I’ve gotten my head around it!
