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Choosing resin profiles  

Active Member
Choosing resin profiles

Dear all

I am new to resin printing and unfortunately could not find a 100% clear answer to the question in the forum. Together with my SL1S I ordered Prusa 939-transparent-red-tough-resin. Unfortunately this is no longer listed in the shop and on the bottle I can not find any information on the recommended exposure times. Also there is no profile in PrusaSlicer for this resin. My questions are:

1) Does anyone have the exposure times and first layer height for said resin?

2) How do I choose parameters if this information is not available (in general, for the future)

3) I see that the SL1 printer profile in PrusaSlicer has much more resin profiles available (also not the one I look for, but many more). Is there printer specific peculiarities to the resin profiles and this is why those are not selectable when using the SL1S? So far I thought exposure times are independent of the used printer?

Thanks for taking the time to answer.

Posted : 05/09/2021 9:39 am
Noble Member
exposure times

The exposure times do depend on the printer used.

Even if there would be a profile in PrusaSlicer, you should always do a resin calibration.

For the SL1 you could use this. But for the SL1S, they are still working on the files.

So, at the moment, you need to print the exposure tests one after the other. Popular test models are the Ameralabs Town and the XP2 validation matrix. (There are videos on YouTube on how to interpret the results.)

Being new to the SL1S as well, I start my calibrations (using the XP2 validation matrix direct on the build plate) with 1.7s/25s.

The first layer should stick well to the plate, but should also still be flexible enough to remove the print easily.

For the other exposure time, you can compare the pins and holes of the XP2 test. There should be the same number of pins as holes printed. If you miss some pins, your exposure is too low. If too many holes are filled, your exposure is too high. Be aware that the first layer exposure might have filled some of the small holes and that is OK. Just do the comparison on what you can see on the top side.

Posted : 06/09/2021 6:17 am
Trusted Member
resin calibration

Someone on the Prusa SL1 Facebook group seems to be reporting that an SL1S resin calibration tool is working.

He references this calibration object and shows pictures of prints from 6 profile variations, all apparently done in the same job.


Posted : 06/09/2021 6:57 pm
Estimable Member
Resin cal is working


Posted by: @mikeh-2

Someone on the Prusa SL1 Facebook group seems to be reporting that an SL1S resin calibration tool is working.

I can confirm that SL1S indeed can make a resin calibration, given a proper file. Yesterday I made my own 25, 50 and 100 µm calibration objects, before I saw this discussion. I tested one of them without vat and resin, so I could see the timing difference on each of the 8 duplicated objects. And it works perfectly. I get to choose the timing parameters in the SL1S menu, and then it does light up the 8 objects with different timing.

I haven't tried with resin yet though.


Posted : 08/09/2021 5:41 am
Eminent Member

That's GREAT to hear!  I really need it too, since the Prusa store appears to be completely out of *everything* that there's a preset for!

Posted : 11/09/2021 3:48 am
Estimable Member
My version of cal files

If you can use them, you can grab my three calibration prints here:

There are 25, 50 and 100 µm layer heights (25 µm doesn't seem to be included in the other link from Facebook). I have tested 50 µm on firmware 1.6.2. I haven't tested the other two, nor have I tried any of them on the new version 1.6.3 yet.


Posted : 11/09/2021 10:28 am
Estimable Member
Tested on 1.6.3

It seems to work on 1.6.3 too.

Calibration settings are available:


After printing, there are 8 calibration objects:


But unfortunately they are stuck TOO well to the build plate. The 15 second initial layer time apparently cure the resin so much, that it is already crisp and brittle. I couldn't get a single one off the plate without it shattering into many pieces, no matter how gentle I tried to be.

Posted : 11/09/2021 2:43 pm
Estimable Member
Much lower first layer time needed

Finally, a good calibration and the printed objects could be removed from the print bed.
The SL1S won't let me set the initial layer time lower than 10 seconds, but in PrusaSlicer it can be set as low as 3 seconds. I tried to make a print with 3 seconds initial, and the printer accepts it, as long as I don't try to adjust it in the printer.

After the print, I now have other problems, but I'll make a separate thread about that.


Posted : 12/09/2021 1:36 pm