Stopped printing correctly

[GL550WL]

Hi
I have had my printer since March 2020 and have been using it regularly with few problems. However about 2 weeks ago it started playing up. It prints just part of an item, or it puts a split in an item.

Im not doing anything I havent done before and Im using the same stl files. there are three images in the links below.


printing

same item

This was the image of the Chitubox set up as you can see there was one that was supposed to be taller than the others

chitubox

The only thing I have done is to change some items I print to the water based resin, the rest are staying with ordinary resin, but I changed that over a month ago

Anybody got any ideas please Im tearing my hair out

Many thanks
Sandra

[cliffyk]

Given that you have been printing sinced March, I'd wager the LCD shutter has gone bad. They only last for 250 to 300 hours of printing--it is warrantied for 3 months. They are available on Amazon for $30, however Elegoo has been quite generous in sending a first replacement to users. Contact Elegoo support.



To test it remove the resin tank and platen, and "print" this file (LCDTest.stl. Unlike the built-in Exposure test--which is largely useless for testing the LCD-- it "prints" a 120 x 68 x 5  mm solid block:



Place a sheet of paper on the LCD, you will see fading and dark spots as shown below:



If you can, post a photo of what you see and we will be able to verify that is the problem.

[GL550WL]

Wow Cliff thank you so much
Yes I have probably done enough hours for it to have gone
I will do as you suggest tomorrow morning
Thank you again
Sandra

[GL550WL]

Hmm mine didnt look anything like that. How far into the print do you want me to take it as it would seem that at the beginning of each print everything actually starts by sticking to the platten, its only after half an hour that the thing goes daft and i get split prints.

paper

This is the resin tank after the last print

resin tank

Sorry to be a pain

Many thanks
Sandra

[cliffyk]

In order to judge the LCD's condition it is only necessary to observe one or two frames. Looking at your photo I'd judge the LCD is in the early stages of death (it appears dim overall), where a number of individual liquid crystal cells ixels have hardened and lost their ability to shift the phase of the polarized (by a bottom layer in the LCD assembly) curing light.

This  causes the overall light transmission level to be lows and occurs before the clustering of bad cells in the later stages causing the spots shown on my bad LCD.

You can try buying some time by increasing your exposure tines by 150 to 175%, but be aware this is a temporary fix as it is the UV light that damages the liquid crystals--longer exposures will exacerbate their demise.

You can read more about how the LCD screen works in my post here.

'Twas I you I'd get a new LCD on order--you will need it. I now keep a spare "on the shelf" as it is a consumable component.

[GL550WL]

Thank you so much, yes with my printing schedule I will definitely keep one in stock. but i will put the curing times up by 150 as i have a print that has to be finished.

Is this the one I need:

"ELEGOO 5.5 Inch 2K LCD for MARS Pro 3D Printer with 2560x1440 Resolution and Tempered Glass Protection, SHARP LS055R1SX04 Light Curing Display

"

Thank you so much for your help

Sandra

[cliffyk]

That's it...

---

You are I take it from the U.K. My mum was a "war bride", she was from Sweffling, Suffolk but was in London visiting her Aunt in February of '44. She and my father (a young "yank" GI) met in a USO club I believe, and must have "hit it off" as when he returned from Germany in late summer of '47 he looked her up and they wed. They moved to the Colonies in early 1948 and I came along in April of '48...