Corners Not Cut, Some Lines Missing

The corners aren’t cutting and some lines are missing. It seems to be the lines that are at lower speeds. From what I have read on the forums I need to increase my min power % however it is greyed out and unavailable. I am running an Acro 1510 GRBL with a Jtech 7W laser.

Thank you for your help.

GCode controllers do not have the ability to specify min power like DSP controllers do.

When you say “aren’t cutting” are you trying to cut through something? What kind of material? Is the laser focused correctly?

Yes, it is just paper. The laser doesn’t turn on at the corners at all, so it isn’t an issue of power.

That is likely the problem. Paper is white, and white reflects the majority of the light from a visible light diode. Try cardboard or something off-white. Though, when you say the laser isn’t turning on at the corners at all, that’s strange - Is it moving really slowly on those corners? Your acceleration might be incorrectly set.

I have the same problem even if I run it with plywood underneath.

In the console, type $$ and press enter. Copy and paste the output here.

Acceleration is also set to 10 as factory settings

That is remarkably low - factory settings for GRBL, which is normally used for CNC applications, so it’s really conservative. You can increase that to 100 without any issue at all, and could likely go to 500 or higher safely.

I made the changes to 100 in both x and y but still seeing the same problem.

I still think that I need to change the min power setting to above 10% but I do not know how to access this greyed out parameter

When I test fire the laser at 10% nothing happens. It isn’t until I get it closer to 11% that it fires

I suspect you have something wrong with your laser or your settings. What is the value of $30 in your controller, and what is the ‘S-value max’ setting in LightBurn in Edit > Device Settings (it’ll be in the lower right of the window).

They are both set to 1000

Is there a way to change the minimum power setting?

From the 2nd post in this thread:

You could switch to using GRBL-M3 mode, which is constant power output, but it’s going to burn start / end points of anything that is vector marked, and any corners in your design. If you have a diode laser that doesn’t fire until 11% power, something is wrong.

Okay I will inquire with the laser supplier and use M3 in the meantime. Thanks

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