Layer delamination in resin prints

Question

I just recently purchased a Saturn 4 and had a few months of some pretty decent prints. Just recently though, my prints have started to fail due to delamination. I'll attach some photos of the failures.

I've tried increasing the exposure times for both bottom and subsequent layers. I've tried replacing my FEP. I've tried increasing the ambient temperature 24 °C (~75 °F) in the print area. I've tried reorienting the print itself to be more angled and have more supports. None of these yielded much success.

I'm noticing as I go through all the photos I've taken, that there's a lot of Z wobble as my prints are getting farther from the build plate. Not sure if the delamination I'm seeing is related to that but just wanted to throw it on here.

Any help anyone can provide would be greatly appreciated. I'll include all the data I can here regarding my prints. I'm just really disheartened and looking for anything anyone has tried in my situation that yielded results.

I really appreciate any advice.

Printer Settings:

  Layer Height: .05 mm
  Bottom Layer Count: 5
  Exposure Time: 3.5 s (I've tried up to 15 s here as well)
  Bottom Exposure Time: 35 s (I've tried 50 s here as well)
  Rest Time After Retract: .5 s
  Bottom Lift Distance: 3 + 4 mm
  Lifting Distance: 3 + 4 mm
  Bottom Retract Distance: 5.5 + 1.5 mm
  Retract Distance: 5.5 + 1.5 mm
  Bottom Life Speed: 65 + 180 mm/min
  Lifting Speed: 65 + 180 mm/min
  Bottom Retract Speed: 180 + 65 mm/min
  Retract Speed: 180 + 65 mm/min

For the head unit mount print, I was using Elegoo ABS-Like Black Resin. For the tulipa, I was using a mixture of Sunlu white resin and Elegoo ABS-Like Translucent Resin.

Pictures:

Answer 1

It's hard to tell with the pictures you've provided, but is there a way for resin to escape the enclosed area of these prints?

Most of them appear to be hollow vases or cups, which trap resin inside the volume of the print. As the print continues, the volume of resin trapped can cause warping, delamination, or what formlabs calls "Blowouts". You'll need to either add a drainage hole to the top (bottom?) of these cup-like prints, (obviously not desired if you need to hold liquid) or print in a different orientation.

Answer 2

As general rule, if you increase exposure the layers will cure more, so they might stick less to each other.

In this case, however, you said you had some months of fine printing, the issue pops up now.

First of all, go back to original, recommended settings. For example, I used an Elegoo Mars 3 and there's a table published on their website with exposure times for several third party resins too.

Now, the causes can be only three:

1. hardware failure, but not sure what
2. changes in resin brand, or resin degraded to various causes (left open too long, or similar)
3. change in printing conditions.

I would go for 3), since now the weather is colder for most people (northern hemisphere, not tropical) and resin prints should be done with resin at 25-30 °C. Maybe you print in the garage (which makes sense due to smell and toxic releases) and it's 10 °C colder than usual.

I don't see any other potential cause, surely not the print settings if you had success so far, so really be sure to go back to the original ones and look for a different cause.