Vat being filled very slowly

Is anyone else experiencing very slow filling of the vat on their Form 3? We just got ours and it seems incredibly slow. I don’t remember our Form 2 filling this slow. It took around 3-4 hours for the initial filling of the vat and every new print drags on and on whenever the vat needs more resin. It appears to be a very thin trickle when dispensing. Doing a print right now and it’s been filling for the last 45 minutes.

Is this normal? Anyone else having this issue?

I’ve inspected the bite valve and it doesn’t appear to be any different from any other cartridge we’ve used.

Also, our last print finished a bit after closing time so it stayed dripping excess resin all night. However, the next morning, there was still a significant amount of excess resin pooled around the rafts and more than usual still on the platform. We’ve had our Form 2 for 2 years and never had so much wasted resin after a print.

We’ve only done a few prints on this machine but so far I’m not impressed. The Form 2 seems to perform better (until it failed badly a couple of weeks ago, thus the need for the Form 3). Really hoping there’s something that can be done to improve this machine because it’s been very disappointing thus far.

I have a few things that help.

  1. Make sure the rubber valve on the bottom of the cartridge is fully split.
  2. For a new tank, pore resin directly into the tank to get it a good start.
  3. make sure your resin is at least room temperature before you use it.

hope this helps.


Thanks for the reply StevePeters.

  1. Checked the bite valve. Appears to be normal.

  2. It has printed about 3 times now so this morning’s print had a mostly filled vat. All it needed was the typical topping off once it reaches the correct temperature. But even that took over 1.5 hours just to add that last bit of resin. At one point, it kicked a “dispense error” after which, I checked the bite valve again. Then it continued to fill and still took much time to complete the task.

  3. Resin was at room temperature at start of the print.

Definitely worth getting in touch with Support. Shouldn’t take 1.5 hours just to “top off” a tank in between prints.

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Remove the screw cap on the resin tank and make sure the vent isn’t blocked.

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Depends on the resin(and whether it’s first fill) but agreed! That’s longer than we’d like to see!

Thanks for the replies. I’ve been off since last week but I’m starting the fourth print on this machine now. I’ll update later today.

And yes, I’ve checked the screw cap to make sure the vent isn’t blocked. Both bite valve and vent cap appear completely normal.

Ok, so printing finally started.

Heating took 6 minutes. Filling tank (topping off from previous print) took 1 hour, 4 minutes.

It filled faster than last time but still seems a bit slow, right?

Also, noticing a discrepancy in print time. In PreForm it says 5 h 20 min but on the Form 3 screen it says 4 h 16 min. Anyone else experiencing this?

Preform’s print time estimates aren’t very good. I use them as “rough estimates” only like, will this job be likely to finish before I decide to go to bed?

You say your resin is at “room temperature” but that’s kind of a subjective measure nowadays. Could be mid 60ºF up to mid 70ºF. The resin flows much, much slower at colder temps.

Try taking the cartridge out of the machine and putting it someplace warm(er) for 10 minutes, and then put it back and see if the behavior is different. If there’s a big difference, I’d lean in the direction of temperature being the issue. If there’s a small difference, I’d lean in the direction of an issue with the bite valve opening mechanism.

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We’re 2 weeks into using our Form 3, and noticing very slow filling as well. Trying to print a part in 10k right now. We pre-filled the tank some, but it’s been almost 5 hours and printing hasn’t kicked off yet. You can see the smallest stream of resin coming out of the cartridge. Our form 2 is way faster. Is it possible some of the new machines don’t press the bite valve as hard as they should? The actual bite valve seems fine…
It hasn’t been a problem for us after the first print, but the first print for any new tank is ridiculously slow…

Something’s wrong. I did a print last night with an empty cartridge, just what was left in the tank. I think the fill timed out after 90 minutes. When it times out, you have an option to ignore and continue, abort, or continue to try and fill. The dashboard should say something like “fill error” when the printer is in this state. You have to physically touch the desired button on the printer’s front panel to continue the print.

The fill cycle has been changed in recent firmware updates. Make sure you are using the latest.

Brand new Form 3, having the same issue on my first print with Clear resin. The resin was dripping about once per second into the resin tank which will take a VERY long time to fill. No obstruction on the vent cap and the bite valve appears cut fine. If I stretch the bite valve towards the center of the resin cartridge, when reinserted it will actually run into the tank at a slow rate. Eventually it returns to a drip (10 minutes?) There’s not a lot of play between the cartridge and the tank, but if I attempt to shift the cartridge in its pocket away from the bite valve the resin comes out a little better. This suggests to me the mechanism in the printer is not squeezing the bite valve adequately or the cut isn’t as big as it’s supposed to be. I tried putting a small shim behind the bite valve which seemed to help but the printer has displayed an error 5x now of an empty or not fully inserted cartridge (it’s new and all the way in) and I’m coming up on 2 hours without it actually starting to print the part. Suggestions?

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I slip a #11 Xacto Knife blade in to the bite valve’s slot and slice to make sure the slot is slit for the full length.

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Yeah I ran a utility knife blade in there to make sure it was at least pierced all the way through but have no reference for how long the slice should be. When you say “full length” are you meaning outer edge to outer edge or matching the inside diameter of the bite valve? Though my printer says I still have over 900mL of resin the cartridge is quite low so I’m about to order another. Will be interesting to see how long the slice is in the new one and if it behaves any differently.

I jabbed the Xacto in to the full length of the #11 blade and then pushed the cutting edge until I’d reached the width of the existing slot (as seen on the outer surface of the valve). Then I turned the blade around and did the same thing going in the other direction. So I didn’t make the slot any wider, but I did ensure that the slot’s “depth” was uniform across the entire width of the slot.

Definitely sped up the flow. Was worried it might leak, though, so I kept an eye on it for a day or so to make sure it wasn’t leaking, which it wasn’t, and then I forgot about it. That cartridge is almost completely empty now, worked great for the last 15 prints…


for resin with big viscosity like E50A for filling even with inspected bottom valve not enough time (RT = 27C), printer show message about can`t load resin.
I remove top cork from cartridge and by compressor apply pressure below 2ATM :slight_smile: Maybe will be useful preheat a little cartridge before print.


Same symptoms. Xacto knife (or similar) for the win. Thank you. I didnt have to be to precise either. Just a careful slice to make sure the slit exists. Done!