FEP Vat failure


Ok so I need Peopoly to weigh in here because I am at the end of my ability to debug this issue. The FEP vat simply refused to print larger/taller prints. I am using the same or heavier support numbers as I have before with PDMS and its a fail with broken supports every time. I have tweaked the model orientation, the FEP vat itself, I have leveled and re-leveled repeatedly and each time - FAIL. I have gone back to PDMS but must say I am very disappointed with my $80 vat. It can look as pretty as it wants - if I cant get a print out of it then whats the use? Do I need to print in the middle of the vat? Do I need supports like tree trunks?

Please help😕


i was afraid of this issue as well as ive been reading that FEP can cause problems with large scale prints which i do all the time. hope there is an easy fix for this or i’ll be selling my unused FEP vat soon.


please post your moai settings. generally speaking the FEP vat needs a slower tilt action and z motor speed. Also you may need stronger/bigger/denser supports compared to PDMS especially for big prints.


My settings are straight from the wiki. Last suggestion was lower PM motor speed to 10 - I did that.


show us the model that is failing (orientation and supports on cura)


Just one of the prints that has failed


the base of the supports is a bit small, I would start by making it way wider


The supports dont fail at the base - they snap off at around 5 - 10 mm above the plate. I have a feeling that to get this to work I am going to need supports like freaking girders


in my experience a wider base always helps. also the body of the support could be bigger (the tip can still be small). both of those two factors help with stability of the supports that move less and hold your model better. if the model still snaps off the supports, you either need bigger tips or more dense support structure.


In my opinion you need way more supports.


I suspect you are right - I am currently trying to weigh if having a lot more supports = more cleanup = more lost resin is worth the FEP benefits


Try expanding the support attachments at the build plate first and, perhaps, more cross-links between supports. Remember that the supports are not completely rigid due to being not fully cured yet. In general, my approach has been to increase the seemingly adequate number of supports by 1.5. It also helps to think of the model as a topographic map while looking for regions of potential flexibility or motion, which are as deadly to a successful print as suction .


hey guys,

@Framingr can you share where the supports fail. I noticed you are printing on the left side of the printer so is it the left most extreme ones that go?

If so, can you increase pm reset position to like 70 (default is 40 at the moment) and check the print half way in?


I will do this when I am able - mid large prints. It did seem to me as though the supports broke pretty much evenly


fep have many advantages over pdms but it’s more sticky and hard to master especially on vats the size of moai’s


I don’t know where you got that impression; I think Peopoly made the FEP vat because so many people were clamoring to use cheap resins and were complaining about the PDMS lifespan. The FEP vat addresses both those issues. FEP isn’t a miracle material; it has strengths and weaknesses just like PDMS.


Maybe using rain-X would help the part detach better from the fep.

Anyone tried it yet?


No but i like your thinking. Im guessing it would mess with each layers bond though. Or screw the vat.


I cant speak from experience since i have not tried it yet but rain-x is made of PDMS.

Many people use it on D7s and Photon printers that use a FEP vat. From what they say, it wont ruin your fep, it wont cloud the fep and doesnt seem to have any negative effects on printed parts.

The idea behind it is to reduce the the fep stickiness… many people that started using it have never gone back xD.

But as i said… i havent tried it myself and if you, or anyone else decides to try it, it will be at your own risk.

If i can get my hands on some rain-x i will try it for sure.


Thanks for the info. Anything to get that suction down