Help with engraving.

[Gdempsey95]

Hi I went in today for laser induction as I had hoped I could use them for a product I am working on.

To date I have been using a diode laser at home which has produced quality results albeit a bit slow.

Upon testing out some files today I encountered two issues:

1. Laser power under 10% appeared not to fire at all.

2. When selecting faster speeds (40-70 mm/sec) to compensate for problem 1 I was getting a lot of wobbly lines. This is a problem I have managed to fix on my home machine by lowering the acceleration of my machine in the machine settings section of lightburn but when I attempted this today said section was not there.

Am I simply using the wrong type of machine for my purpose is this machine better for cutting rather than engraving?

The focal point of my home diode laser can get down to about .06x.12mm I am not sure what is achievable with the CO2 laser but I noticed that the kerf is significant which is leading me to believe that fine vector engraving (as pictured) isn't what this machine was intended for.

Thanks for any help or advice. I will be along on Thursday evening to have a gander at Gerald. George.

[amcewen]

Hello! :wave: Thanks for reporting the issue.

I don't have any great wisdom to import, I'm afraid, but as a minor note I happened to be doing a fill engrave (on MDF) this afternoon at 8% and it was working.

Having spotted this issue I did a couple of quick tests afterwards at 6% and 7%. Neither made any noticeable marks on the MDF, but the 7% one did seem to be generating the tiniest bit of smoke, so I think the laser was still firing then, but not with enough power to do anything.

It was only the second time I've used Tony so I'm still getting to grips with Lightburn — there are plenty of others with far more experience around, like the @DoESLiverpool/laser-maintenance team

[Gdempsey95]

Thanks for your reply. I'll hopefully get to grips with it on Thursday and let you know of any progress!

[magman2112]

It’s also worth commenting that there is a known issue with Tony when engraving (fill in Lightburn). The x-axis has some mechanical creep currently, hence the recommendation to rotate the engraving 90 degrees. This is planned to be fixed when Gerald is back online (to limit the risk of taking another laser out of action).

I suspect though that you were actually doing vector line art rather than engraving. One of the limitations of the larger laser cutters is the mechanical inertia that limits how fast the head can change direction, which may be one of the limits you are hitting with your designs.

There are lots of parameters in the configuration file for the controller card that allow us to tune acceleration, maximum and minimum speeds, etc. I suspect that your laser controller is different, hence the accessibility to some of these tuning parameters from within Lightburn itself.

I should be in DoES for maker night next Thursday night if you want to discuss some of these options further.

[Gdempsey95]

Brilliant see you there!

[Gdempsey95]

How would I go about changing the acceleration? Is this fairly straightforward? I have changed $$values (grbl settings in lightburn and laser grbl) so have a little experience with it.

[magman2112]

We use smoothieware on the controller, so I’m not aware of any commands at present that let you change the acceleration from the console. We currently change settings by removing the SD card from the controller and update the config file in a text editor.

We also have to be aware that any changes we make have to be suitable for all users, so we don’t currently have a process for making configuration changes for specific users. In other words, we have to get the best balance for most users.

[arthurrowland]

Just for reference of a real life result, here are the settings for cut and line etch on 3mm plywood from two weeks ago. I also found under 10 power to not be of any use.