DIY DLP printer + FEP foil / Utrecht

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Kvirre
Posts: 140
Joined: Tue Jun 24, 2014 8:14 am

Re: DIY DLP printer + FEP foil / Utrecht

Postby Kvirre » Sun Nov 09, 2014 3:08 pm

EdgE wrote:Well, I tried adhesive FEP already in 2013:
http://khwelling.nl/3d.dlp_printer.testing.php#tripple_vat

Here I created one PolyStyreen resin container, with 3 different sections:
* No coating
* Adhesive FEP foil
* PDMS

So the results I found so far, working with this 'adhesive FEP':
* It works better then no coating (on a PolyStyreen floor).
* It's more durable then PDMS (because of the fogging issue of PDMS).
* Transparency is worse, in comparison with the PDMS layer or without anything.
* It's still very easy to damage when having a wrong build.
(flat part, cured on this FEP, trying to get this off with a knife, will very easily scratch the FEP)
* Do to the fact, it's "adhesive", your intention is to attach this foil to something (glass/plastic/..)
So when releasing the part from the floor, you still have this 'stupid' strong layer below.
This will cause the high tensile force, you need to release the part (and brake it).
So actually you want to stick this FEP to something more elastic (an other transparent foil :!: ).
But when you want something elastic, why not using FEP without this adhesiveness?

So from my point of view, it doesn't make sense to use 'adhesive FEP' at all.
Most important is still the building speed.
So everything which makes the vat floor less transparent (like adhesive FEP, which you can see in the link above), will make your printer slower.

I'm trying to make a full list of FEP foil suppliers here: http://khwelling.nl/3d.dlp_printer.php#pillow.
(So if there are more suppliers, let me know.)



I read your writeup, very nice work!

When you say :
Learnings:

Lowering the retraction speed towards 50 [mm/min] gave much better results.


Is this the "lift speed, OR the retraction speed back down INTO the resin"

EdgE
Posts: 32
Joined: Sun Jan 26, 2014 1:28 pm
Location: Utrecht - NL
Contact:

Re: DIY DLP printer + FEP foil / Utrecht

Postby EdgE » Sun Nov 09, 2014 3:53 pm

"Retraction speed" is used within the PronterFace program and works in both ways.
(It's used like: "g1 z2 f50")
My guess: the lift speed is the most important. (But I'm not able to test this.)

Even better would be a ramp-up, actually in both directions, I'm not sure if this is possible with CW?

Kvirre
Posts: 140
Joined: Tue Jun 24, 2014 8:14 am

Re: DIY DLP printer + FEP foil / Utrecht

Postby Kvirre » Sun Nov 09, 2014 7:32 pm

EdgE wrote:"Retraction speed" is used within the PronterFace program and works in both ways.
(It's used like: "g1 z2 f50")
My guess: the lift speed is the most important. (But I'm not able to test this.)

Even better would be a ramp-up, actually in both directions, I'm not sure if this is possible with CW?


Have not seen this in CW, but I have a suggested workaround.
Lower the Acceleration (a lot) in Marlin FW (or what you are using).
- Then you will get the ramp-up you are looking for (I did this)

I am using CW, and I am basically curious if the first part of the lift movement is most crucial?
In other words, the movement that separates the part from the VAT, or if it's the reverse movement - coming down to the VAT.

Since I am using a flex-vat (FEP-film), this could influence the detail-level.
But then again, I still need to trim down the exposure-time to optimal first (to get rid of bleeding through layers).

However, I hav no clue if semi-cured layers could bend and distort, and therefore not optimal at all.
=)

Loads of problems to handle and figure out, hope people will continue sharing.

Thanks for the writeup once again, love it.

PS.
How do you use pronterface?
Or rather how do you sync the movement with the projector exposures and how do you slice?
=)

EdgE
Posts: 32
Joined: Sun Jan 26, 2014 1:28 pm
Location: Utrecht - NL
Contact:

Re: DIY DLP printer + FEP foil / Utrecht

Postby EdgE » Tue Nov 11, 2014 2:46 pm

Here I'm explaining how to use pronterface/projectlayer.

Pronterface handles the USB-connection. Within pronterface, there is a program called 'project layer'.
That's the one which is projecting an image to a second screen, by dragging the window there. Then this program also send NC-code to you hardware and updating a new picture after that. The trouble, is making a SVG file first, so that's all handled in one package within CW.
Right now I like the simplicity of pronterface/projectlayer, but on long term...

Image

EdgE
Posts: 32
Joined: Sun Jan 26, 2014 1:28 pm
Location: Utrecht - NL
Contact:

Re: DIY DLP printer + FEP foil / Utrecht

Postby EdgE » Mon Dec 01, 2014 3:13 pm

Got some questions from Jeff by mail, maybe better to post it here instead:

Nice work on the DIY 3d printer! I found your blog really informative and helpful. Thanks for sharing the build.

Anyway, I saw that you have changed to a pillowed flex-vat design utilizing an off-the-shelf plastic container. I have a few questions about the setup:

1) What material is the container made of? (i.e. PP / PS / PETE etc) Should I be picky about the plastic material reacting with the resin?
The transparent part of the container seems to be "PPRA". I have never seen this material before. Any way, the resin is not (yet) reacting with the container.

2) The container looks foggy. Wouldn't it degrade the resolution of the projected image? Also the UV transparency?
Well, the beamer is not shining through the container. There is has a hole in both the container & lid. So it's only the FEP foil between the lid & container.

3) What is the purpose of the pillow? Can't you just fix the container directly to the wooded frame?
I guess, the pillow is called, the way the FEP is temporary able to be changed like a pillow.
The container is fixed directly to the wood, so there is not real pillow..

4) How does a flexible tank with so much play in it (especially with the pillow) could maintain a totally flat and uniform surface for printing layers as thin as 25 microns? Am I missing something here?
Well, there is no pillow in-between. But still you have a point. The FEP foil could stretch a little, and so it could buckle (?) under litres of resin.
So how to solve this: 1) don't use to much resin on top. 2) try to stretch the foil, so it will remain more flat. 3) Maybe this is less useful for a very large build area.

5) Is tilting required for this setup?
No. This is one of the biggest benefits using a 'pillow approach'. When releasing, the foil will bend of the model by the edge of the printed part. This way it will act/form like a pillow shape.

6) How does it perform compared to PDMS? In terms of sticking force and longevity.
Please have a look in the posts before.

Hope everything is clear.

hp_
Posts: 300
Joined: Tue Dec 24, 2013 10:25 am

Re: DIY DLP printer + FEP foil / Utrecht

Postby hp_ » Mon Dec 01, 2014 5:32 pm

Hoi Koos,

i got the exact same email from the guy..

could he be a spammer or something?

cheers,
hp

karthik
Posts: 4
Joined: Wed Aug 10, 2016 11:40 am

Re: DIY DLP printer + FEP foil / Utrecht

Postby karthik » Thu Dec 29, 2016 7:37 am

hi, anyone try hydrophobic (water repelling) & oleophobic (oil repelling) sprays in Vat film ?


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