Printing a brain... first test failed

One of my current print-jobs is a MR Scan of a brain.

What I’ve done is that I’ve made it hollow, and then divided it into two pieces, printed the first piece today, and just took it out from the printer and it have failed print the whole part. There are many light colored places in preform on the model because of the VERY organic structure. But I do get the printability verification.

  1. For the brain, how would you print it? Attaching my printfile for the first of the two halves.
    Internal supports isnt a big issue, the idea was to glue those two parts together.
    Would printing it as a solid model work better? Even though it will use shitloads of Resin…

  2. Also I checked my tank, and I have a pretty thick and very hard cured layer on the bottom, I cannot remove it with the spatula… I’ve printed 1 liter so far, so the tank should have a few more prints in it before ill replace it, but do you have any tips on how to remove the cured layer without damaging the bottom of the tank?

The PreForm file is here:

Thanks in advance!

best Regards Patrik

So I don’t have a lot of experience with formlabs printers but I had a look at your file to educate myself (and out of curiosity). I noticed a few points that would worry me if I were to print this model as-is :

Starting at layer 85 and all the way up to layer 155, you can clearly that there is an enclosed area without vent hole, which can I believe lead to print failure. The enclosed area will create a succion effect while the platform is going up to make space for the wiper to do its job.

Same thing in another area from layer ~170 to ~305 and 390 to 490. There are others but you get the point.

Also around layer 380 there is a very very thin wall that probably doesn’t print very well and can create detached bits of cured resin which can themselves obscure the laser and cause other issues.

Printing the model as a solid may work, I honestly can’t tell, but the surface area of each layer will be pretty big so that may also cause peeling issues.

I would get through the model layer by layer and check for thin features. Then I would add venting holes where needed and give it a try.

… and there are some - at least four or five - not supported areas.

Ahaaaa, just found the preview layer slider! (im using a REALLY wide screen so I’ve not noticed it before)
I can see what you mean now… that wont work… so increasing the density of the supports could probably work? Is it possible to add ventilation holes inside preForm?

Regarding my tray with a 7x8cm large, pretty thick cured surface on the bottom of the tank which I cant get off, should I continue trying or just filter the resin into a new tank and throw it away? (its printed 1000ml at this point…)

AFAIK, no.

It all depends on how valuable your time is. I use the Form 2 at work so if I have to launch a critical print I’d put the tank aside and setup a new one. Then I’d try for 30min max to clean the soiled tank, after that time it’s just more economical filter the rsin and to buy a new one especially is the tank at at >50% of its predicted lifetime.

If it was my own machine at home I’d scrape the shit out of that tank until there is no more resin and hope that I don’t destroy the PDMS.

I had another spatula that I use to remove FDM prints, which is really thin and that one did the job!
I will filter the resin in the tank now, and put it back!

Regarding the brain I’ll probably skip the print for now, he needs it tonight and I dont have time to fail again.
I’ll print it on my FDM printer instead although it wont look as good.

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