Hi there. We’ve just this morning started a print for the first time with our new Form 3B.
It’s been printing for an hour and so far the build platform hasn’t raised once. Is this normal? With the Form2 the platform would raise after curing every layer. It does kind of move slightly, but not enough to actually see what’s already formed.
Sorry if this is a totally dumb question!
Every few layers, not sure of the actual count, the platform should lift up high enough for the mixer arm to make a sweep. There’d be no way to miss seeing that. But between those, it does not move very much. But it does move enough you can see it if you’re watching. What layer does it say it’s on? Has that changed? You can go in to PreForm and move the slider thing on the right of the window to see what the print should look like at any layer. Go there, do that, see what it should look like for the layer reported by the printer. If it shows a 50cm high partial print on the platform, and your printer’s platform is still below the top of the tank, something is wrong…
Thank you so much for replying! It was a two hour test print and for the whole two hours we never once saw how the model was developing as it never seemed to raise.
Thank you for the tip of looking at the slider on Preform, that’s good advice. Confusingly, it was only as it was approaching the end of the print that we saw any of it and even then we could only see the supports. The resulting models were really brittle and overly stuck to the platform.
I’m starting to think there’s something not quite right with our Form 3B!
Post a picture of what you were trying to print. Screengrab the PreForm window so we can see how the parts are oriented and supported…
Hi Randy. Thanks for replying again.
So the print was actually the official Formlabs test butterflies. So in retrospect, it was so few layers that I guess one wouldn’t expect the platform to come very high anyway?
Sorry if I come across like such a newbie! We’ve had a couple of successful prints since then and even if I don’t see very much movement of the platform, I’m not questioning it as it’s working (though I have genuinely yet to see the wiper blade pass below while printing!).
If you’re interested: with our first print being brittle and overly-glued to the platform, we decided to fiddle with the Z-compression feature and have basically made the rafts thinner. That seems to have helped when getting the models off the platform.
Thanks again for your support. I’m positive I’ll be back soon to ask more silly questions.
Yeah. The butterflies don’t have a lot of z-height. Whether you see the platform move or not, if the print comes out as expected the printer is clearly working as designed. 
How hard rafts adhere seems to be highly variable. Even from one print to the next, I have some that come off easy and some that are a real fight. But I’m a long-term FormLabs user, started with a Form1+ when they first released it, then a Form2 and now a Form3. I long ago tried an assortment of different tools to help get prints off the build plate. I settled on a 12" “insulation knife” which is a thin steel blade that easily gets under the edge of a raft so that a little twisting pries it off. But it’s dangerous as hell. I have yet to hurt myself, but I worry about it every time I go through the process (which is probably why I have not hurt myself, I’m always being extra careful).