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So most of the slicer settings are things that are built upon theory and thus you can fairly easily lock them down to pretty much either fixed values or easy theory that you can adapt as required.


Burn/bottom/base layers - you want to cover 0.2mm of depth at your chosen layer height.

For example if you've a layer height of 0.05mm then you'd need 4 layers to cover 0.2mm of depth.


Transitional layers - you want to cover the rest of the depth of your raft with these, plus a little more for the start of the support columns.

Most standard rafts are 0.5mm deep and you've already 0.2mm from your bottom/burn layers.

So you'd need a further 0.3mm depth with your chosen layer height. Then you want to add a few more layers just so that the start of the columns gets a little more exposure.



Note on raft thickness. Most presupports use a 0.5mm thick raft for the standard layer height of 0.05mm. If you use a lower layer height you can use a thinner raft (if you've a lychee lys file or chitubox project file where supports and model are separate entities and thus you can edit the supports and raft values).

Rough values
0.05 layer height = 0.5mm raft
0.04 layer height = 0.4mm raft
0.03 layer height = 0.3mm raft
0.02 layer height = 0.3mm raft


Lift speeds are basically built on plaster theory. Either you peel slowly or you rip fast; both work, but you don't want to be in the middle.
So its 60 or slower; 180 or faster. With no lower nor upper limits on those speeds.

Typically I have a slow speed for the burn/base layers then shift to faster for regular.

Two Step lift speeds are a thing now which make it a little more complicated. Two step just means that it uses 2 speeds; first one then the other; for different parts of the total lifting distance.




For lift heights that's fairly standard, I tend to err toward 7mm and that would be more than enough for a Mars 3 Pro.


Burn/base exposure time is typically 10X your regular exposure time; sometimes plus a little.


Exposure time - this is the one that varies the most. This is the one you use test prints for and which varies the most based on temperature, humidity, specific components in your printer; the mix of the resin you are using (yes different batches of the same resin can vary in performance).

One you get dialled in most variation is slight and often, eg using a new resin bottle, you'd just do a test to make sure and then carry on. If you buy resin in bulk then its normally the same batch so you can even skip testing entirely till you get a new batch.



Wait time before print. This lets the resin settle out under the build plate before exposing to UV light. Its generally set to 1 second.
Note sometimes you have to toggle a value to get this or you have to use light-off-delay which gets a bit more fiddle; so I'd wait to see what your settings page in chitu/lychee looks like before going any further on this.




So in general those are the theories I work with for exposure. I do tests with the Ameralabs Town print which gives you a range of properties of your resin to read from the results.
It's popular because it has an upright profile and thus captures actual exposures; whilst many of the super fast flat test prints can be influenced by the burn/bottom layer exposures.

For the Town Print simply open it, slice it and print it. No presupports.
Once printed, wash it, let it dry and then take photos of all 4 sides and the top for review. Then cure it.

NOTE because uncured resin is a skin hazard you have to keep your nitrile gloves on when handling even when part cured and dried, but not fully cured.

For more health and safety tips and also some tips on heating check out:
https://printhunter.org/3d-printing-articles/

So you can leave resin in the VAT for as long as you want so long as no light gets on it; as that will cause it to cure. If its in an enclosure or other dark spot that's fine; some people also print lids for their vats (typically using an FDM printer).

The build plate does not have to be cleaned extensively after every print. After getting the print off I give mine a wipe down with a paper towel (which is then put in a container for curing later before disposal) and that's it.

Cutting down on time kind of happens with practice at the process; after that there's a few things you can do to help.

Using fast lift speeds (the 180 or faster) on your regular layers
Using a thicker layer thickness - 0.05 is the standard top limit most use and gives great results. Going to thinner layer heights can improve some smoothness of curves and such; but comes with an increased printing time.

Also link for the town print
atlas3dss.com/learn

 lord_blackfang wrote:
Don't overthink things. Put some presupported gak on the plate and yolo it, start on the high end of exposure for your layer height (like 2.5 seconds for 30 microns) and drop it by 0.1 for every print until you start getting failures (usually models ripped from supports).

I mean that can work, but presupports come in all different kinds and that's before you consider that different resins perform differently. Presupports designed for a very flexible (when printing) resin can be different to those designed with a very firm (when printing) resin.
So you could get fails and keep upping your exposure, without realising that the issue isn't your exposure, but that the resin just needs a few more presupports to stabilize things because the presupports were originally designed with a different resin.



So the best thing is to use the calibration prints. These give you a a known level of standard performance that you can measure and work with. Then (assuming all else is good) if you start getting fails you can address it as a support failure issue and fix things.

The best thing with 3D printing and settings is to get as many variables locked down with theory/standard practice so that when you do get fails you can work out what's the likely cause by elimination of variables and thus apply fixes in a more specific way. Otherwise you can be increasing exposures and changing supports and varying this and that all over the place.

Garfield666 wrote:Thanks all for all the great advice!
Printer arrived and the first test was... complete failure
I actually enjoy doing the supports, at least in Lychee, but I went for light supports initially. So I got some supports with nothing else...
Yeah, the tank cleaning function directly came handy.
After that I just printed the default test pieces, the Elegoo Rooks, which came out perfect.
Now I am trying some presupported models, to see if the "pro" version is working better. Of course I erased all islands and added some extra support first.
If my next tries with big rafts and thick supports don't yield good results, I will have to look at the settings and the fiddly and confusing stuff begins...

I still recommend reading my earlier post and going here: Atlas Learn
To get the Town print and using that to help calibrate your printer.
It's much more reliable than doing your own presupports and messing with exposure at the same time as you won't know when the fail is because of exposure values; other values or the supports not being good enough.

That said if you're after good models what kind do you like? There's loads of great creators out there now with good models and presupports

ButtShani369 wrote:

Thanks alot for such a great and elaborative answer. Though I don't own the main thread but it helped me a lot.

Glad to help!