Resin Printer - Resin Changes Color

[Delvan_Vellar]

So, let me start off by saying that I'm very new to this. Wife and I recently bought a Saturn 4 Ultra and went through a pretty hefty round of test prints. We were very impressed with the quality of the prints we were getting out of it. We intended to use it mostly for a bunch of gaming accessories for ourselves, and some other things around the house.

Mostly we were using the Elegoo Grey ABS-Like resin to start off with. Like I mentioned, we had a few issues but nothing significant that we weren't able to work through.

Anyways, wife wanted some christmas ornaments made, and we decided to change colors (but stuck with the same type of resin). I ordered a thing of the Elegoo Black ABS-Like resin, cleaned out the vat, and went to town. Almost as soon as I started, I noticed a pretty annoying problem. The faces that were parallel to the build plate were fine, came out a pretty decent black that I had no real problem with. But the "sides" of the object were coming out this really ugly white-ish grey color. I've not changed any settings on the printer going from the grey to the black, but I wouldn't have expected to need to?

I tried to look up how-to's but nothing seemed to match what i was seeing exactly. I did attach a photo to the post so you can see what I'm running into.

[Roberts_Clif]

Layer separation on a resin printer, also called delamination, is typically caused by incorrect print settings like improper exposure times, too rapid lifting speeds, poor bed leveling, contaminated optical surfaces, incorrect model orientation, or using a resin that is not well-suited for the print design, leading to insufficient adhesion between layers.
Key factors contributing to layer separation on a resin printer:

Incorrect exposure settings:
Too short exposure time: Layers won't properly cure and adhere to each other.

Too long exposure time: Can cause excessive heat build-up, leading to warping and separation.

Poor bed leveling:
Uneven surface on the build plate results in inconsistent adhesion between layers.
Rapid lifting speeds:
Pulling the print platform up too quickly can disrupt the curing process and cause layers to detach.
Contaminated optical surfaces:
Dust or debris on the resin tank window can interfere with the UV light, leading to uneven curing.
Model orientation:
Placing complex overhangs or thin features without proper support structures can lead to layer separation.
Resin quality or compatibility:
Using old or incompatible resin with your printer can affect curing and adhesion.
Temperature fluctuations:
Extreme temperature changes during printing can impact resin viscosity and adhesion.
Insufficient post-curing:
Not curing the print adequately after printing can leave layers partially uncured, leading to weakness and separation.

How to troubleshoot layer separation:

Calibrate your printer: Ensure proper bed leveling, Z-axis offset, and exposure settings.

Optimize print settings: Adjust exposure time, lifting speed, and layer thickness according to the resin and print design.
Clean the resin tank: Regularly clean the tank windows to remove any debris.
Support structures: Add appropriate support structures to complex geometries.
Check resin quality: Use fresh, compatible resin.
Post-curing: Follow the manufacturer's post-curing guidelines.

[Lez0]

I had the same problem trying to print black, the machine was not an Elegoo, but I do have an Ultra 4 as well I couldn't get it to work. I think the problem is the resin is not black, but smokey black.
White comes out perfect, so I think it's a colour thing. I just paint the parts black now, less trouble.
Lez

[Delvan_Vellar]

The resin color actually was black. However, today I actually cleaned everything out pretty heavily and switched to their "smokey white" to see if the problem continued. It was much less noticeable but was still there. I think it was less noticeable mostly because the color was more similar to the "off color". It also allowed me to see if I had a bad batch of black, so either it wasn't bad, or i had two bad colors.

I'm cleaning everything pretty heavily between color swaps, and the print is actually a pretty simple STL (was just some very basic christmas ornament silhouettes for the wife).

Going to dig further into the settings tomorrow to see if its a leveling or exposure problem, though the printer hasn't moved and I wouldn't think changing would require different exposure settings?

[Lez0]

One thing I remember, shake the resin to mix it thoroughly before use.