never had that happen, but I’ve never used the black resin.
@JasonSpiller What dimensional tolerances are you getting on photocentric resin parts out of your F2? If their grey is anything like their black I’d expect the F2 standard settings to heavily overcure the photocentric resin - and “swell” parts… if so then perhaps overcuring is why you’re not seeing the cracking I am. As I mentioned earlier I suspect the solution would be to overcure during the print - but that of course comes with dimensional effects, and also issues with detaching supports…
Also - what do you mean by the “new formula”? this is my first try with Photocentric I haven’t been following them - but looking on their website I can’t find any mention of a new formula?
Hey there! I do realize I have been slacking on my spreadsheet, but my AdamantAnt isn’t feeling that well after feeding it so many different 3rd party resins 
I have a hot swap in motion, and on Wednesday next week I can resume testing.
As far as the Laser Power Data goes, that was me just kinda messing around. @FredB made a very good point that I did not factor into my calculations:
So that might be why they are so different from other sources. I will recalculate everything using an object that is tall with no supports, and that should be more accurate, as far as ordering the different resin profiles by laser power goes.
Cheers!
Hello,
I have had the same issues with my Photocentric Hard Beige. It comes off the printer nice, but after about 20 min of post cure it just cracked in half. I suspect shrinkage as well.
Just wanted to add my experience to the discussion.
To be honest I’ve never really measured for dimensional accuracy, the nature of my prints are quite forgiving, but I’ve never had any issues or complaints from clients. I help them with their internal testing, I think I was the first formlabs owner to mention them here which gave them a nice bump in sales so I have a working relationship whereby they send me samples and I give them feedback before they release it to the public.
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The grey photocentric resin overcures heavily. Up to 0.5mm when printing a 25mm cylinder. This also adds extra stress on the PDMS and requires very heavy supports when printing large cross sections. Clouding of the PDMS is much faster than FL resin.
You talk about a “new formula”. When was this introduced?
The resin shrinks a lot too. I have never had any cracking though. I rinse the parts in water, then in paint thinner and cure them in water. The day after, 25mm diameter parts shrink by ~0.1mm. But I did some tricks to lower exposure on the resin with the F2 so can’t compare that directly with your printer.
For the smell… I don’t really smell anything unless I’m very close to the printer. Just don’t heat the resin and only print in open mode. It’s viscosity is low enough.
Below is my last large print. About 15cm in height in 0.1mm layers.
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I don’t think there will be a song and dance about the resin release, it’s just an ongoing development process.
Well, if that’s the case then I’d stay away from photocentric and develop a working process for the F2 with another brand. I can’t believe it that they would change the resin formula without informing customers or making an announcement.
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That cracking is pretty bad! Honestly surprised they are selling it with so much development still to do.
Photocentric used to have a low-shrinkage epoxy-based resin for the Daylight series (sent me a sample and they were selling it, but can’t find it on the site anymore). Talking to them at the TCT I understood that they were planning to release something similar fro the UV too. I don’t really like cleaning with water and this epoxy-based one cleans in IPA.
I think also they are on the second iteration of resins for UV. In fact, at first they just called it UV resin, now they make a difference for DLP and Laser printers. On the US shop there is not this distinction as yet, but there is on the UK one.
Other brands? seems like anything available gives mixed feelings 
Well I’m very happy with the results I get from photocentric resin, I’ve been using it for over a year with no issues.
I can recall they indeed had a very low shrinkage resin, can’t find it on the webstore anymore. I received an order one week ago and the packaging seems to be changed recently.
Isn’t the firm resin also shrinking much less than the hard resin? I have not done statistical tests on it yet. Will try that soon. They had shrinkage numbers on the website. Somewhere close to 0.5% for the hard resin or the low shrinkage one but not sure.
Already sent them a message and asked about the possible formula change. Not expecting a response, but you never know! 
FunToDo is the other brand, similar pricing. Have not tested it yet.
I’ve run with the Fun 2 Do resins and they over cure a lot.
I even ran a couple of tests with filter material in the optical path to reduce the exposure. This got the exterior shapes in check but a;; interior shapes were still over cured (holes/slots small or completely closed).
The PDMS wears quickly with F2D resins.
Fun 2 Do resin is known to be very fast (read: a lot of catalyst). I suppose you are talking about the F1+ blend, not the usual DLP blends, right?
There is a post about it here
Don’t know if the review is genuine or biased, but within its limitations it seems alright.
I wonder how expensive it would be to buy 5 liter of methacrylated monomers that work with these resins to dilute the photoinitiators. So far I only found some nailstudios selling the stuff(why?!)
Did some experiment with F2 resin bare in the tank today on a large piece… It ripped the PDMS off the tank. And every layer resulted in a loud sound. So it’s not very optimal to use it without added measures.
I’ve been working a little in my spare time to figure out what the profiles should look like for Formlabs clear 2 resin. With a resin profile for each thickness we can start to dial things down and figure out the third party resins.
The good news is that I think I’m pretty close for Formlabs clear 2 at all three standard layer heights. Bad news is I don’t have a working Form 1 anymore to test on. Is anyone interested in verifying my 25 and 50 micron material files for Clear 02 ?
Once we prove out the first material I think I can generate curves for all of the standard resins along with some suggestions for third party resins. Hopefully we can get to the point where a single person can calculate the power required for any layer height based on the power required for 100 microns.
What I’ve started is a spreadsheet that will give you a starting point for all three (or custom) layer heights based on the power required at 100 microns. If my simple LOG curve fit works it could save a bunch of work on each layer height.
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PM sent.
Are you beta testing the new formula?
I am in contact with photocentric and they indeed told me it is being beta tested right now and they will make a decision in about two weeks.
Can you measure some parts printed with this new formula? Maybe share some pictures?
I am, I’ll try to print some measurement tests over the weekend.
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Thanks!
OK, so with photocentric hard resin, a part that should be 11.7mm by 52.23mm x 2mm actually measures 11.81mm x 52.55mm x 2.14mm. The object was printed at 50 micron along its longitudinal axis at a 20 degree angle from horizontal. Which is good enough for my purposes! Sorry no pic, it’s a piece for a client and I don’t have permission to share.