Engraving coming out "clear" rather than "Etched"? - Newbie to laser

Hi everyone, I am a newbie to laser cutting and I have been trying to etch 3mm Clear Acrylic.

I have been having this problem only recently, where the etching doesn’t seem to be engraving as it used too? Its hard to explain, but it almost goes clear rather than leaving the text white?

Please see photos below:
This is how the engraving is supposed to look:

And this is how its been coming out recently:

This is a photo of the side by side comparison:

For what I am making it needs to show up white rather than clear as it will go against a black background.

The current settings I have it on is “Fill” and 10Power. I have downloaded the Lightburn software at home to check my settings and it says 6000Speed, however at University its alot lower, so not sure if the machine is set to something different, in the hundreds.

However unfortunately I cant tell you the model of the laser cutter as its something I only use at University and don’t have access too right now but I know its a Ruida control.

Apologies I cant be of more help, when I can get access tomorrow I will update with better information, however Does anyone have any immediate ideas?

Any help is appreciated :slight_smile:

1st thing I would check is your settings haven’t changed to mm or inches/min instead of /sec.

Hi Chris, ah yes it was in mm/min, not mm/sec so I have changed that now. It might have loaded this way because I don’t have the laser connected to my laptop. So it is now 100speed/10power, on fill. I will see if this changes anything tomorrow :slight_smile:

Is there anything else I should check?

Check to see if you are using two different acrylic types. Cast acrylic will engrave clear, while extruded acrylic will frost over. I could have this reversed, but the idea remains.

Hi Fred, ah thank you! This might be the issue, I have been using extruded recently, whereas my first few test where some scraps that I had which could have been cast. I shall test tomorrow :slight_smile:

Yep next would be what Fred suggested. Then Focus and clean lens and beam path. It only takes a tiny spot of dirt to change results. Also check check your S-Value hasn’t changed.