FEP vat for the LittleRP?

[sgraber]

Could you post a schematic of how you have the parts stacked? I might just download the git repo and do some work on it myself as I'd really like to get away from PDMS dishes.

One "gotcha" I see in this design, though, is how do you empty the vat once it has resin in it? With the petri's, you can pour them back into the container...

EDIT #1: When working with the SCAD files, I am getting an unknown module called "offset". Any idea what that's about?

EDIT #2: Ah, I had to update my OpenSCAD to the latest version to get the offset module.

EDIT #3: Would you mind posting a pic of your flex vat print?

[maurice]

I planned to update with instructions after the next design iteration, but I see you can't wait for it

So put the tensioner directly on the littlerp, the fep film is put on the lasercutted middle, the gasket on top of the film, and finally the pla_vat is on top of it all.
For assembly it's easier to put the pla_vat upside down, then put the gasket, film and middle on it, and then screw it together.

To make the gasket you can eiter use mold_bottom and mold_top, put them together, or the gasket_mold, then simply fill it up with silicone, and wait for to cure.
I never tested the gasket_mold way, and I assume the lasercut mold is more precise, and will lead to better surface of the gasket.

The VAT can be taken off the printer with the resin inside, I defined that as a requirement for the design, but maybe it would help pouring the resin back if I add a spout.

[maurice]

Heres a picture of the first two prints.

[HTL]

I have been checking in on this thread for a while and decided to put together a vat sized for the littleRP based on my tensioned vat.

Here is a video showing what the tensioned FEP sounds like when struck.:

Parts: bottom clamp, top clamp, vat wall extension, gasket, baseplate, tensioning riser, FEP


Assembled Top:


Assembled Bottom:

[PacManFan]

[sgraber]

HTL: Have you posted your files for this anywhere?

[maurice]

I think the your vat looks very well engineered, and I wondered as well if you can share the files with us?
And how did you make the holes in the gasket? Did you cut them out after curing, or is the gasket molded like that, and if, how did you make the mold?
And how did you cut the FEP film?

[maurice]

Another question: Is the tension of the FEP Film a sing of quality? Of course it has to be tensed enough to have an even surface, but doesn't tensing the film too much cause losses in it's layer releasing flexibility? I mean, the features of the FEP are its non sticking surface and the flexibility. Or rather, is there maybe a optimal tension?

[HTL]

Everything is laser cut. The clamps, base plate and vat wall extension are 1/4" (6.35mm) CAST ACRYLIC. The tensioning riser is cut from 1/2" cast acrylic (a very wasteful cut btw). The gasket (ok, stay with me on this) is laser cut craft foam from hobby lobby (my testing so far shows that the craft foam is unaffected by printing resin and makes a very effective gasket). For the craft foam to act as an effective gasket and grip for the FEP you need as much surface area as possible under even compression so I also designed an inexpensive torque wrench (also laser cut) that is used to torque the clamp bolts and adjust the FEP tension. I will post information on the torque wrench once I have tuned it a bit more. The FEP is also laser cut.

My intention is to provide this vat in kit form and also make individual parts available (gaskets, laser cut FEP, tensioning riser, torque wrench etc.). I will release the drawings after I have completed the kit design and made molds for the tensioning riser and vat wall extension which will be available as pre molded parts (as opposed to having to throw away 90% of a block of acrylic). The kit design should be complete within a week or two.

[HTL]

The purpose of tensioning the FEP is twofold first to make it perfectly flat and second to prevent it from sagging in the middle from the weight of the resin and from bowing in the middle from resin "squeeze out" (when the build plate drops in preparation for a new layer exposure and squeezes out the resin between the FEP and the build plate). My experience has been that you probably cannot over tension the FEP so much that it loses its release characteristics but you must tension it enough to make it flat and resistant to squeeze out .