New Form 3 fails to load resin -- Bite not working

Just got a new Form 3 to replace our Form 2. Loaded new resin cartridge and tried our first print and the printer fails to load any resin. Tried another new bottle and same result. Don’t think actuator on bite is working - anyone else have/had this problem? Thanks

Hey there @Mr_Mechanical!

I’m so sorry to hear you’re running into a few issues. Let’s see what we can do to get that sorted out for you as efficiently as possible.

You’ve probably already checked this, but just in case, can you confirm that the slit in the bite valve is present? You can do this by turning the cartridge over and gently pressing on the bite valve with your finger.

If you’ve confirmed that both cartridges’ bite valves are opening as expected, please get in touch with our support team here, and they’d be more than happy to lend a hand to get you back up and running.

1 Like

Bite valves working good - reached out to tech support - was able to observe bite depressor not actuating - thanks

Wow – it was a simple fix – unplug and replug in printer and now it works!

Fwiw, sometimes I get bite valves that need to be manually pried open with a knife before the bite valve will open the valve itself.

Learned that lesson the hard way with my very first print.


I have been finding this is the case with a lot of them, so I am in the habit of checking every single one before using them the first time.

Same, very frustrating, been happening forever.

my new form 3 bite depressor was sticking into the bite valve. After I put the cartridge in, it instantly started to drip resin. I took out the cartridge and pushed the depressor arm back. I have cycled power on it several times.

Under job setup, PreForm can see that the Gray-Pro resin cartridge is installed in the printer but it does not give me the option to select it in the material resin pull down. I wonder if Gray-Pro is not supported for the Form 3?

There have been various posts on here by Formlabs, in which they gave roll out schedules for different types of resin profiles with the Form 3. The last one I saw said that Grey Pro Ver 1 profile would not be released until Sept 2019 for 100um layers and October 2019 for 50um layers

I guess that is why its not in your list - its simply not yet configured by Formlabs to work with the Form3

1 Like

This is the list:

1 Like

Trying to understand this post. Where do I find the bite depressor and where do I find the bite valve. And how do they look like?

Small tip when doing this that i’ve learned the hard way:


I would also add that it’s a good idea to use something very thin but dull, such as a butter knife or credit card, rather than a sharp knife or razor blade.

1 Like

Sometimes a sharp blade is necessary, as the cut is almost completely missing. It seems the slit is done from the inside. On some of the bite valves i got, the cut wasn’t even reaching half of the thickness of the material, so there was literally nothing to do but take a razor blade to it and cut it (very carefully) open.

Usually, once punctured all the way through, you can just squeeze the valve and the cut will “spread” all the way to where the “pre”-cut lets it.