FEP ontop of PDMS

I like to hear your thoughts and comments on adding FEP on a very thin layer of PDMS. This on the new FEP Vat & new adjustable build plate.
Before building the Vat, you add a 2mm layer of PDMS and not over the holes which are on the edge. Then you build the Vat as normal.

I like to see what your thoughts are.

Very good question!Because for my side i revert FEPvat to regular vat ,fails was avoid.

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@Vaughanza Are you talking about making the Advanced Vat that is on the 200 for the Moai 130?

Not to sure how the Vat for 200 is but been thinking of it for a long time. Thinking of laying down a very thin layer of PDMS up to the edge of the holes. Then build the vat like you normally do with the Moai 130 vat. Thereby it might create a thin cushion for the build plate. Also maybe it will protect the PDMS from fogging etc. Any suggestions will be appreciate it.

The advance plate for Moai 130 is
Laser > Glass > FEP > FEP
This helps to reduce suction between FEP and glass.

The Moai 200 Advance plate is
Laser > Glass >PDMS > FEP > FEP

The PDMS does help with getting more reliable prints.

You could do this yourself, the trick is will you replace the entire glass + PDMS layer or is there a way to remove the PDMS without damaging the glass?

You risk the chance of ruining your vat and resin leaking, but if you are willing to take the risk it may help.

Simply adding a 2nd layer of fep ontop of glass then your resin FEP helps.

There are two forces to overcome during each peel.

A - Peeling the cured resin off the FEP / PDMS
B - Releasing the FEP over the glass

PDMS is great because it is directly stuck onto the glass in all surface area, not just on the edge of the vat and rejects resin very well. the downside is that it degrages a lot faster.

With your idea, one must make sure the PDMS is stuck well onto the glass and does not get pulled away with the fep.

Thanks for your reply, my vat has acrylic for a base. So what you saying is that I can add a second layer of FEP and that it would work better than one layer of FEP?

It might, but you need to becareful about how you secure it ontop of the acrylic glass.
The glue you use should just be around the edges and wont fog the glass.
you can also use a thicker FEP with less flex on the first layer, the resin fep should be flexible.

Before you do ANY mods, make sure you have a backup vat ready and keep an eye on resin leaks.

I am not recommending you to do this BTW, dont hold me responsible if you break your Moai :slight_smile:

Heres some light reading on your journey.

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there are a lot easier ways to improve prints, lowering the PM motor speed and increase PMreset is the first. at the expense of slower print times.

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I lowered PM motor speed but not the PMreset, not sure what the PMReset does? .
The new FEP vat I have now has screws so there is no glue involed. It’s Peopoly new vat.

PM Reset Position
This value defines how much the vat tilts. The higher the value, the longer distance the vat will move to separate the layers. Default is 40

There is more info on the different settings and what they mean.

Hi , being new in the Moai 200 universe, I come from other 3D printer dimensions, but I have doubts about the correct setting of the PDMS-FEP Vat. The Fep, is right to be used only if it does not adhere to the floor below, as indicated by the Youtube video, it makes no sense to use the Fep in this way, it must remain free to flex while lowering the Vat! Another question : the parameter “Z follows” is used to be able to bring down the plate to soften the gap ??? Ok , but if I wanted to make the plate go up during the peeling phase? Can’t use negative values? Thank you

on the advanced FEP vat, the PDMS layer does not cover the vent holes of the acrylic plate, so the mechanism of the FEP vat doesn’t change

First, there’s no negative values for the z-follows on Moai. SLA printers produce much higher peel force than DLP/MSLA printers, so having a similar peel motion from those is rather harder for the users to success
Z follows is the value which the build plate moves down following the tilt motion. This way, instead of having the whole layer being peeled at once, the layer will be peeled slowly from right to left, like peeling a piece of tape
If you want to have strait up peeling, just set the z follows and PM reset position to 0

For the parameter “Z Follows” you should know:

  1. Z Follows is switched off by the firmware in the first approx. 20 layers (like Z Follows = 0)

  2. Z Follows = 40 means that the build plate moves immediately towards the start of the PM (Peel Motor) in the direction of VAT by 0.4 mm

The larger the value of Z Follows, the greater the risk that the print object will be compressed by Z Follows. This can lead to broken support, layer shifts or other errors.

I could not find any positive benefit from the Z Follows procedure.

I recommend everyone to turn off Z Follows (Z Follows = 0).

@peopolysupport: These values I have determined on my Moai 200 (firmware V1.0). Maybe the Moai 130 behaves differently ?

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each value is = 0.1mm, so 40= 4mm

this is true, if the z follow is set too high to the PM reset position

as i stated above, the z follow and tilt motion is to try to have tape peeling motion, rather than having the whole layer at once
this is great for high laser power resin, but if you are using DLP resins, which have less peel force, then strait up would work but the chances of failing is higher

the 2 Moai operates the same way, although having a bigger print size makes it a lot harder during pre-print set up

Thanks anonymous @peopolysupport for the quick answer!

Please excuse me for disagreeing:

I have measured the way of the building plate (Z Follows=50 corresponds to 0.5mm):


What do you think is “too high”?

What sense should it have if the freshly printed layer is completely squeezed against the FEP/PDMS film?

If so, please check the peeling process and correct the instructions and descriptions in the wiki accordingly.

The parameter Z Follows has already done far too much damage and wasted resin.

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your measurement is correct. The z follow moves the plate toward to the vat based on the parameters. we found that help wil peeling when used very sparingly. it is also dependent on resin type and if there is any custom set up. It also does not move right the way as it would smash again the vat bottom. That is why it is only at 2 and moves slowly for recommended value.

Thanks Mark!? aka @peopoly for your quick reply with confirmation.

If you recommend the value Z Follows = 2, then this corresponds to 20μm = 0.02mm: this is in the range of the ball screw’s backlash … this value can not have any significant reaction beyond the placebo effect.

At least Z Follows = 2 can not do any damage. :hugs:

PS: An additional good technician / programmer, replacing two support staff

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thanks for the technical and human resource feedback, @ad_fontec

You are free to make up your mind regarding how you want to use those settings. That is why we have open settings. And if you have issues, you can always reach me directly here or via email. Support staffs are people just like you. They can have good and bad days, but the responsibility is still on me, so take it up to me.

Dear Mark, I’m so sorry that you feel personally attacked (honest, no irony).

Thank you for the open words. I generally formulated and meant my Post Scriptum. If a product / manual is self-explanatory and low-error, then you need (almost) no support.

Maybe two different cultures come together here. I work solution-oriented and say what I think about this.

But how should I understand if, even after repeated inquiries, I do not receive an answer to questions?
Here again:
When can we expect to update the firmware for the Moai 200 at the earliest/latest (bug fix and extended G code instruction set)?

I appreciate your work very much and see that a little help can not hurt. I’m happy to help you and the users, and I’m very happy when something comes back. And I do not like to push myself when I’m not welcome. What do you think about that?

@Vaughanza: Please excuse the digression from the actual topic.

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Been Using the Moai 200. I’ve made about 4 or so medium sized prints and already the FEP film is getting holes in it forcing me to change it out. I find the film even when brand new to be far too fragile so far because if resin gets under the FEP then the PDMS starts to get damaged as well when trying to get the cured resin off of it. Not fun.