I get noise when engraving with lower power, is this normal?

I get noise when engraving with lower power, is this normal? Higher power at 10mw is fine, just gets noisy when it’s lower. I made sure my grounding is good and used distilled water

How long has the water been in there? Is it a sort of squealing noise?

Just as a comparison mine makes no noises different at lower powers vs high… I’d change the water also as it’s a cheap check. Have you had the laser long?

Could also be the material you are engraving. I have had certain plywoods make a funny high pitch noise when engraving or cutting it at 4mA.

It’s like a squeaky noise, high pitched. I just did a flushing of my water lines with mild bleach, tap water, distilled, and then refill with fresh distilled water.

If I’m doing continuous cutting it also makes that noise at low power. I’ve always had this sound a low power but now am trying to make sure everything is right since I’ve already gone through 2 power supplies over several months.

@Jonathan_Tzeng if you are in the US. I (the LPS ambulance chaser) wouldn’t mind if you donated one to the LPS research activity :).