So you’ve got a new resin for your 3D printer, but what Exposure times do you use?
Hey guys, this is a common enough problem. Getting the Exposure times wrong can lead to poor quality
prints or even worse, print failures. If there’s no helpful information or a RERF,
you feel lost. And even if there’s numbers out there, there’s no guarantee someone
else’s settings will work perfectly for you. So it’s generally best to figure it out yourself,
and personally I’ve been using the XP2 validation print by Photonsters for ages.
However, Phrozen have a very useful resource to dial in exposure times and you can use this
on any make or model of printer or resin. So here I’ll talk you through using it.
It begins with their help centre and I’ll provide a link to that in the description.
There you can download the Phrozen XP Finder print and open this in the slicer of your choice.
Starting with the Normal Layer, you need to enter a number will get you started
and personally, when dialling in, I prefer to overexpose than underexpose.
If you use too low a number and underexpose, you might end up with no print at all and a soggy mess
stuck to your FEP. If you overexpose, you will get a print, but the detail might be blurred.
Personally, I know which problem I prefer to work with, so it’s over-exposed all the way for me.
With MonoChrome printers, if I have no other information available and it’s a standard resin,
I tend to begin with a Normal Layer time of 3 seconds. If it’s a castable or speciality resin,
I’d probably double that as my first guess.
If you’ve got a pre-MonoChrome resin printer, like the original Elegoo Mars, exposure times
are typically between 7 and 15 seconds, but a guess of 12 seconds has always worked well for me.
We’ll be sticking with a layer height of 0.05mm here, which should get you great detailed prints.
You’ll also need to think about the Number of Burn In Layers and Bottom Exposure times.
These settings are to ensure that the first few layers stick well to the build plate and again,
if there’s no other information available, I’d go with 6 or 8 bottom layers, which is fairly
typical, and a burn in exposure time that’s around ten times longer than the normal exposure. Now for
this printer, which is the Phrozen Sonic Mini 8K and this ZMud resin, I’m ignoring my own advice
and sticking with 20 seconds and if you’ve watched my recent videos you’ll understand
why. But ten times Normal Layer is generally a nice starting point for Bottom Layers.
And with that you can slice and print the Phrozen XP Finder. Once you’ve cleaned
and cured it properly, you can inspect it carefully looking at the Phrozen help page.
It’s easy enough… just compare your print against the images shown.
This will help your figure out whether your print is under or over exposed, so that you
can increase or decrease your exposure times. Now I’ve been fairly lucky here. Three seconds
looks pretty good, though as expected I think it’s a little over-exposed.
I don’t think I need to increase the exposure any further, but maybe I’m wrong. And right now we’re
just trying to narrow down our search range. So I’m going to over-expose even more and
see if I’m right. As the Mini 8K is a monochrome screen, I’ll make a leap of another half a second,
but with a pre-monochrome I’d increase the Normal Layer by a full second.
Here’s the resulting print… and a good tip is to label these on the back so you don’t get confused.
These changes are on the subtle side, but it’s fairly clear that this print is more
over-exposed than the previous print. The text is slightly blurred and the Lines are a little wider
than ideal. Unfortunately, at the moment, Phrozen doesn’t tell us anything about these corner areas,
but it seems obvious that the 3.5 exposure is starting to bleed detail together here.
Another common sign of over-exposure is unexpected holes forming in the print, like these.
From this I’m confident that my exposure time should be less than 3 seconds.
So now I’m going to do another half a second jump in the opposite direction, reducing from 3 seconds
to 2.5 seconds. My guess is that my ideal exposure time lies between 2.5 and 3 seconds,
but let’s see what happens. Here’s a printed Phrozen XP Finder
with an exposure of 2.5 seconds, and at a glance it’s pretty much the same. But look more closely.
Some of the text is missing. The boards and lines have certainly thinned out,
and the layering of these pillars is much fainter – or at least that’s how
it looks to me. On camera this may seem a little different, so you’ll just have to trust me. But
certainly for me this print is slightly under-exposed, but not by much in fairness.
Now these prints don’t take long to do, only about 20 minutes in my case,
and dialling in the exposure times helps guarantee better quality prints.
As I’m thinking my guess was right and that my ideal exposure is somewhere between 2.5 and 3
seconds, I’m going to perform print tests at 2.6, 2.7, 2.8 and 2.9 second exposures.
Again, if this was a pre-monochrome, you could perform similar print tests
at half second intervals. Any less than that, you’d really wouldn’t see any changes at all.
And here they are, from 2.5 to 3.0. From your perspective they probably all look pretty similar,
but with a very close inspection, you can see the subtleties.
From this, I’ve decided that 2.6 seconds was my best test print. But before you get
cracking printing your favourite model, take a look at what Phrozen say here.
After finding the perfect settings on the Phrozen XP Print, we recommend increasing the normal layer
exposure time by at least +10% on an actual print and by +20% on large models above 12cm.
Well, we’ve followed their guidance so far, so let’s carry on.
10% of 2.6 is point-2-6, which means our ideal printing exposure is either
2.8 or 2.9 depending on whether you want to round up your decimal places or not.
After looking at the 2.8 and the 2.9 prints, and I think I prefer the look of the 2.8,
so that will be my Normal Exposure time for this particular resin.
This mean I can feed this figure into my Slicer with confidence.
If we’re sticking to the ten times rule for the Bottom Layer, we would adjust our time to
28 seconds. As I said, I’m happy with the 20 I’d decided on earlier, and that’s something
else you can adjust if you like. If you feel the prints are sticking too well to the plate,
trying lowering this figure by a few seconds and test again. If it’s not sticking well enough,
try increasing by a few seconds. You’ll quickly find a level where it prints well,
but slices away cleanly from the plate. I’ll test my settings on this excellent
miniature by Mammoth Factory. I love this little guy. I’ll include a link in the description to
these excellent miniature designers. So what do you think? I’m happy with
that print. There’s plenty of detail and no failures, so that’s a good printing result.
You can see how by increasing or decreasing your exposure times in small controlled tests,
the Phrozen XP Finder and similar printing aids can help you dial in your perfect exposure time,
helping you to achieve the best possible prints. Whether you own an a Phrozen,
an Elegoo, an Anycubic, a Creality or whatever, this test will still work for you
and it has been made freely available to the printing community by Phrozen – so well done them.
And before finishing, I have a few more quick printing tips that you may find helpful.
Prints usually fail because of poor supports.
Getting this right isn’t difficult and I’ve useful video you may wish to watch
If you’re dialled in nicely with perfect supports, but your prints fail to form properly,
try reducing the Lift speed. Lift is the speed at which the plate withdraws from the FEP.
If it lifts too fast, brittle resins can often snap free and prints will fail. Slowing
the process down does mean that the print will take longer, but a successful print
is better than a failure. So reduce it by 5 seconds or so and do another test print.
One last consideration is consistent temperature. Most resins are happiest around 25C,
so if your room temperature is less than this, consider fitting an enclosure heater.
And that’s it for this video guys. If you have any question, as always feel free to drop me a line.
So take care guys and thanks for watching.