My 20w Phecda and Polystyrene

Community Laser Talk
, ,
1

Hi all,

I’m a true newbie to laser engravers/cutters and the respective software. I decided to start with an Elegoo Phecda 20w machine and also purchased Lightburn. I’m the sort of person that will beat my head against the wall until I figure something out but I also recognize when I need some help. So here goes.

As mentioned, I have the Elgoo 20w Phecda and I’m attempting to cut 1/4" Polystyrene foam. I did some research before attempting this and found many recommendations before trying it because I wanted to make sure it was even possible. So I ordered the 1/4" Polystyrene sheets (11x17) and have tried many different settings. The recommendations I kept finding were in the neighborhood of 6mm/s and 20% power. Well, that doesn’t even make a mark on this stuff. After attempting a wide range of settings, I thought maybe it was something with the focal length. This laser has a positioning bar that flips down to help adjust it to the proper distance and set the focal length. I’ve done that as I understand it to work but the best I can get between trying that and various settings is a couple of melted holes (from repeated attempts) and some very light surface etching.

So I thought I’d reach out and see if anyone had any recommendations?

Thanks in advance!

2

If it’s white polystyrene foam, a blue-light diode laser can’t cut it: the foam reflects essentially all of the light.

With the reflectivity in mind, the speed is exceedingly fast and the power very low.

Most likely, you are using the wrong speed units. Diode lasers travel relatively slowly, so use Edit → Settings to select mm/min rather than mm/s; that will slow the laser down by a factor of 60.

Then run a Material Test for speeds from about 10 mm/min up through 1000 mm/min and powers from 25% through 99%. Then you can pick the settings that produce the right results for your laser and your material.

1 Like
3

Aha, that explains a lot, primarily the mm/min rather than mm/sec. When I read those settings in the recommended settings spreadsheet they provided for the machine, I thoughtit was a typo or I needed to make a conversion. What you just explained makes a LOT more sense! Thanks so much! That’s (hopefully) going to resolve the issue. I wanted to do a material test initially but given the fact it wasn’t cutting at all I had no basis for beginning and ending settings.