Question on Constant Power Mode

LightBurn Software Questions
1

I was trying to an etch an item the other day and laser was doing something rather strange. As the etch was progressing the laser would just stop it’s motion, keep the laser running burning through the item I was etching and then continue on. It did this multiple times.

So I went into the cut settings for the layer and I found that the “Constant Power Mode” was enabled. I’ve never enabled it before so it’s beyond me why it was. I disabled it and the etch ran just fine.

So my question is, why would the laser stop like that when using “Constant Power Mode”? I may be missing something but it really doesn’t seem have a real purpose. I all open to being enlightened.

2

You are right it doesn’t sound like much, only if you like LaserGRBL.

image
image827×322 35.1 KB

Edit: I’ve never used it.
:smiley:

3

Opposite here, Mine stays on unless I am doing images. Choose what works best for you. Trial and error is your friend.

3 Likes
4

I still don’t understand why the laser would just stop it’s motion, keep the laser running burning through the item I was etching and then continue on. Wouldn’t just run the same but with the laser running constantly?

5

“Stop” is a relative statement. Stop for how long?

Can you put your Lightburn (.lbrn2) file in your reply so we can determine if there is something strange in your design?

6

As the laser scanned back and forth on the X axis the laser would stop it’s motion for a second while still firing and then continue on scanning. I ran it this way a few times while trying to figure out what was going on and noticed it was always stopping at the same locations.

As I mentioned, I don’t use Constant Power Mode. For some reason it got enabled. When I disabled the Constant Power Mode it scanned normally.

My question is more out of sheer curiosity rather than to troubleshoot.

Hat Patch.lbrn2 (678.8 KB)

7

With your Atomstack M50? Confirm if your laser is set as GRBL or GRBL-M3.

8

GRBL. All of my machines use the same. GRBL 1.1h

9

Same place in the laser physical location, or same place in the part program?

Same physical place would be a mechanical issue,

Same place in the part program, not sure. I can only offer the controller is processing the GCode and trying to figure out what the next move should be. Maybe create a 1" square and see if it does the hesitation at the corners in Constant Power. If it does, save as GCode and upload it here (use .TXT extension)

10

Well now I can say I’ve tried using it.

Some of the observations I found with this short trial.

From the Hat Patch file here are the results, the only change is with or without constant power mode.

Constant Power Mode
Constant Power Mode1625×767 321 KB

There were spots (red arrow) where the laser slowed giving a darker burn, the movement wasn’t as fluid using the CPM. (I didn’t see it stop completely).

So I tried with a different file. Left side using CPM the right w/o.

  • Text converted to path
  • Image
  • Text

CPM Test
CPM Test1635×708 288 KB

I slowed the speed and power and the laser movement seemed to be a bit more fluid.

I did like the look of the text as is, or converted to path, using CPM.
I’m not sure what happened with the “e” that burned first. (red arrows)

Could have been a spot on the MDF or a booger of some type. :man_shrugging:

Images looked similar, maybe a bit more burn definition at the sides.

This test wasn’t to be right or wrong, or trouble shooting.

I’m just trying to understand and share the results, so we can all be able to use the software to it’s full potential.

:smiley:

3 Likes
11

This short video should better explain what is happening to my laser movements with CPM enabled. (Note: I have the laser itself turned off but the motions are still the same.)

https://youtu.be/W1mHwZrgzog

12

After watching the video, I can say that mine didn’t stop like yours did.

It did slow way down leaving the darker areas, as in the sample hat patch test (earlier pics) but that was it.

I’m good at sharing results and trying things out.

To have a good answer to why that stopping is happening your going to need a sharper stone than me.

But if there is anything I can do, I’ll be glad to help out.

:smiley:

13

Thanks for letting me know that your laser acted totally different than mine did.

A setting in LightBurn? A setting in GRBL? Beats me.

As mentioned, it was just an observation and not a big deal for me. Would have been nice to figure out though.

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14

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