Vat jamming


I now have been getting frequent jams with the vat rotation using the same file that I printed previously without jams. Ember will print a number of layers before a jam. The PDMS layer is cloudy in sections.

Does release from the PDMS get worse as it becomes cloudy?


The resin tray have a limited serviceable life, due to the reduced performance of the PDMS over many print cycles. When this happens, it's a good time to replace the tray with a new one.

There are ways to extend the life of your PDMS. Placing your models in different locations on the build plate (rather than always printing in the center) prevents the center of the window from becoming prematurely clouded.

Also, some users report that draining the resin trays when not in use (and wiping the PDMS clean with isopropyl alcohol and a microfiber cloth - not a scratchy paper towel!) helps. This prevents the UV-blocker in the resin from penetrating into the PDMS when not in use.

If anyone discovers and tips that help with this issue, please share them here.


Understand that the vat has a limited life. What is the failure mode?
Release? Resolution? Other?


@Edward - Generally, when the PDMS wears out, the result is decreased transmission of the light from the projector, which results in under-cured models that fail to stick to the build plate. This looks like either the entire model, or parts of it, failing to build, and sticking to the PDMS.


Hi Shalom,

I took the advice you've given to increase PDMS life, and unfortunately, while draining might be helpful, cleaning the PDMS with IPA certainly doesn't help, as a little IPA is almost certain to fall down the edge of the PDMS, soak into, and eventually melt the 3M bond, meaning the whole PDMS comes away, and all your resin spills into your ember (this just happened to me).

It seems like a good idea to remove this advice from your forum, as the 3M bonding failing seems to now be a known issue.

I've ruined 3 almost new trays because of the above advice, and lots a vat of resin, and spent an hour cleaning resin out of my machine as a result of it. :(



When I feel the need to clean PDMS I only use acetone, without ever letting my wet tissue come in contact with anything else. Although I had many tray glasses detach during shipment during the hot summer, I never had a leak.

Before I use a tray for the first time I wear gloves and gently press on the PDMS surface to ensure adhesion. Also, I always check the reflection of light onto PDMS to evaluate flatness, mixed results on that one, I wonder if this is related to always having gaps during the beginning of model layers.



Thanks for sharing your experience about this. I'm happy to say that we've released our improved resin trays, which resolves this issue. You can learn more about them here:


I printed this part (takes up most of the build platform, and it took ~20 hours) and towards the end I started to notice that the print is not aligning with the PDMS window any longer (see picture). I did not get any jamming errors throughout the print. However, I assume this is happening because of jamming, only that this jamming is not large enough to give me an error. So the logical step would be to reduce the exposure settings, right? I wanted to double check with the folks over here since these are very time-consuming prints.


Check and see if you have “Use rotation homing for approach” checked. It is under Material Setup / Advanced Settings / General


Interesting…I had never checked that one before. In the print settings file it’s described as “This may prevent drift in tray position in partial jams”, so this seems to be exactly what could solve my issue. I will try it in the next print. Thank you very much!