Laser power change?

#1

Good evening-

Having an issue and not quite sure how to proceed. After printing a test print (checking for electrical interference on this thread: Striping on prints) which showed that the heater was causing stripes, I printed the same test piece again, but with the heater on at half strength the entire time. That print was the first print I have had fail in months prior to this, and even though they were quite solid, they didn’t hold together. The prints were with Grey NEX resin at power level 52. With this resin I never had any problems with burning the PDMS. I had run liters through it, and I scrape it clean every time to make sure it is clean, unscratched, and nothing is sticking on it. It was very close to pristine. The next print I did was a few miniature figurines. This was also a failed print (much of the print peeling off of the build plate), and it was surprisingly delicate… easily breakable. Seemed to be underexposed. When I looked at the build plate afterwards, after this one print, there were big areas where there were very opaque burns in the PDMS where the figurines use to be. This is from a single print…

I am trying to figure out what happened, and if anyone has a clue as to why prints are now failing. I am able to print the ring pattern at 52 power, but it seems a bit weak, as well, and the supports fall apart to the touch. I printed the four pillars to make sure it was level, and they were all within parameters, but tended to break off at the shoulder between the base that connects to the build plate and the pillar portion.

I am wondering if it impossible for the laser to go bad? It clearly still does fire, but I suspect it may be underpowered compared to how it used to be. How do I test this? I switched build plates to a new one (shipped directly from Peopoly) and tried moving power to 59 and using black Peo resin, but I got only a small amount of polymerized resin on the build plate and some in the resin tank.

Should I just up the power to 65 and see? Is there a way to check the laser? The Machine has been well used and has probably over 500-1000 hours of printing. Could it be the laser power module? Do those go bad?

I checked the mirrors, as well, to see if the clouding issue occurred again-- it has not, as far as I can tell.

0 Likes

#2

can you upload pictures? videos would be better
take pictures of the pre-sliced gcode prints, it would be better to imagine the problem

0 Likes

#3

I’ll try. I just redid the 4 peg test to take pictures and suddenly it worked normally. Maybe slightly more brittle than usual, but all 4 printed. I can certainly take a picture of the plate with the very opaque areas on it. I’ll try to take care of it tomorrow.

0 Likes

#4

Well, never mind I guess… I switched to using black resin and after the first failure I have had 2 successful prints. That being said, here are the pics of the failures.

Here is the plate with the spots that are very burned in… note how focal they are. They appeared after a single print, and there were no spots or cloudy areas beforehand. That, to me, is the major advantage of the NEX resin… lower resolution, bu the surface finish is great and the low power seems to make the PDMS layer last forever. Multiple liters of resin went through this plate.

Here is the most recent failed minotaur test. The plate already had the burnt areas, but I positioned the model so it was out of these areas when printing. Even with VERY robust supports it still failed.


0 Likes

#5

it seem over cured, the nex resin is recommend at 51 and some even uses at 50, the main issue for the brittle is most likely was cause by it

0 Likes

#6

hmmmm… interesting. I was thinking under cured. It is true that the ring file prints best at about 49 for me, but at that level all of my bigger prints failed ALWAYS, so I upped the power until’ things stopped failing. I looked at this thread where people recommended over exposing a bit for better surface texture, and that ids what I was trying to do.

When I switch back to NEX (I have Peopoly Black now) I’ll try to lower the power a bit and try again.

0 Likes