Had to start a new thread since the 14 days expired.
Continued from this thread.
Since I have 3 junk tanks now I decided to do the small experiment.
I ordered in a few sheets of FEP.
I removed the Silicone layer from the tank and right off the bat I already knew I was in trouble. (Should have done that first before ordering the FEP.) There is a step down from the orange case to the clear lens so as soon as saw that I knew this test was going to be in open mode.
One thing I noticed when removing the silicone, The layer is between 2-3 mm thick and was not constant, So whoever poured this tank did not have it level. Using my calipers there was a .5mm Difference from the front to rear of the tank. This could explain the rash of failures I had on this tank. Unless the Z is also cantered to the rear.
My Initial thought was to try and cut the FEP to just fit on the clear. After 2 tries this was an exercise in futility. Trying to get the FEP off it’s liner is a small feat in itself, It has very Aggressive adhesive and deformed way to easily. Grabbed the second sheet and cut it larger and started on the side of the tank and worked my way down. Success. Smooth, no stretch marks or bubbles. (Guess 30 years of applying vinyl to cars and Signs has paid off)
I knew this wasn’t going to be a long test as on the stock tank the silicone is poured over a dimple where the Chip goes and that plug came out also and looking at the joint where the clear was glued to the orange I did not trust that joint as it was very spotty. Not a constant joint.(Once again from doing signs I know what a good acrylic seal should look like and this wasn’t it.)
So I went ahead and poured in some grey resin I had left over from the previous Bite Valve incident and let it sit in the tank covered for 20 or so minutes to make sure there were no leaks. (Didn’t want another resin disaster in the printer)
I installed the tank in the printer. Since There is no silicone in the tank you can not adjust the Z deep enough to compensate for that difference… You can only go -2mm. So I know I was not going to able to test adhesion to the build plate but wanted to see if the cured resin would stick to the FEP so I ran a file with the first 2 build layers at 50mic…
Nothing stuck and when I poured the resin from the tank I noticed that the remain resin acted like water and oil trying to repel each other.
So in Short… If Zvat industries starts making tanks and creates a Slightly raised clear section where one could install the FEP I thing it will work bette rthen the silicone. Will still need some more testing to see the long term results of the laser and resin effect on the FEP.
FEP doesnt cloud at all, it can hold up for a LONG LONG time without issues. IF you take care of it… The problem is if the build platform isnt perfectly flush with it, prints dont adhere. If something comes along that is as soft as the PDMS layer, with the properties of FEP thats a winner.
THe Flex vat of the muve3d is actually perfect. Once a layer is cured the platform is raised and the FEP can flex up , slowly releasing the part. It works very very well.
You Just nailed it… I took a scrap piece of FEP and applied it directly to the PDMS… It stuck like no tomorrow. So now there is a protective layer between the resin and silicone. So now the FEP will conform when the build platform comes down for the initial squish. I am comfortable testing that on a full print
but its pointless to put FEP on top of silicone because the silicone will still fog up. Thats the ONLY drawback to silicone if you ask me… It fogs and needs replacing… So having FEP on top wont change anything, but im sure it will work
But does the laser cause fog it or is from the resin curing against the silicone. If it is Resin curing against the silicone the FEP will stop that as the resin will never be in direct contact with the silicone.
Thats a good question… I think it must be the resin curing against the silicone because it happens more and worse on failed prints where the laser cures and cures and cures the same spot because the part hasnt moved.
Hmmmm interested to say the least.i have a TON of FEP. i may have to try it
And the best time to add the FEP is probably when you pour the silicone… once the bubbles subside… then it actually adheres even better.
Cut a piece of 3mm clear Acrylic sheet to fit in the bottom of the tank first.
That will take care of the height difference caused by taking out the silicone layer.
The FEP can also be applied to the Acrylic before sticking it into the tank which makes it easier to eliminate bubbles.
I’ve used this method in a Form 1 and have had tray lives in excess of 6 months of heavy use.
we arent talking about removing the silicone… The silicone is a HUGELY beneficial piece because it helps in the case of slightly off level build platforms etc… We are thinking about FEP on Top of Silicone as perhaps the be all end all
I had a muve3d as well as I have a form2. I’ve also moved from a littlerp using PDMS to one using FEP. The challenge with FEP is that it isn’t quite as transparent. And because it requires more power to get the same UV through, cure times are often lengthened. What clouds the PDMS isn’t the contact with the platform, but the UV going through it. There are other PDMS failures, but the most common is clouding. I would not consider the flex vat on the muve3d perfect. It leaks and has other issues. The newer versions are better, but not without fault. And using it would mean longer print times.
That said, using FEP allows you to use more caustic resins which have a reduced curing time. FTD resin for instance takes about half the time that MJ does. But if you use it on PDMS you will tear chunks out rather quickly.
While I agree the flexvat is not perfect it is the best vat on the market. I really do think that… one FEP lasted me 9 months without any issue… If you print a PLA square instead of using the acrylic. I never had a leak the entire time I owned it… I loved that printer…
There has to be a better solution than FEP alone, or PDMS alone… has to be something out there that wont fog, yet is soft…
Cleaned my tank and added a layer of FEP on top of the PDMS and doing so test prints now… One thing I noticed right off the bat is I no longer hear the popping sound when the build plate lifts.
Will post more later after a few prints finish.
The FEP I have seen available only has UV transmittance at around 82%, how does this effect the resin curing rate, did you have to set up a new profile and use open mode?
It sounds like Formlabs could probably design a new resin tray that uses FEP and then adjust the material settings to compensate for the exposure. I’d be OK with longer print times if it means the tray doesn’t need to be replaced all that much if ever.
After running a few prints i have to say, It works, but I did have a few failures in the part on the real thin sections. so I am not sure if it was due to under exposure or if it was where I might have has a small wrinkle. The part on the left was with FEP the right without… The whole part is 1" (25mm) wide with .02" (.5mm) walls on average
I only had a 6x6" section left so I couldn’t get the whole build area covered perfectly as this stuff is a real pain to get off its carrier and did not want to run it unattended just in case the wiper might start to peal a edge… I think it might be viable option with a longer sheet that runs the full length of the the tray so there is no edge for the wiper to hit.
But if the laser is what causes the clouding of pdms then this a mute point as I just bought a pound kit of sylgard 184 for $42 ($63 with shipping and tax) and that should coat 6-8 trays so I think that is a more cost effective option unless we are wrong on the laser clouding the pdms.
As for the build falling off the build platform that problem has been solved with 120 grit sandpaper.
The one thing I did notice though, the prints seem to be a little smoother with the FEP as there is not so much force being applied to the part during the peel process so if the laser power can be adjusted then this may be a very viable option just for the print quality. But I have heard people have had fantastic results with the 184 so I will be pouring 3 trays once it shows up and coat one of those with the FEP also as a test.
Good results, keep us posted!
Could you please do a stress test on the tray that has the FEP layer to see if it does indeed still fog just as fast? I’d be really interested to know for a fact.
I will be doing that pretty soon. I want to see if there is a way to bump the laser power but that would have to be a software or firmware thing so I don’t see FL allowing me access to their code
I wish formlabs would undertake some of this testing themselves… I know it would hurt their tray/vat sales if it worked, but think of the goodwill to the community if they could develop a tray that lasted 10x or 20x longer? Me personally id buy 1 for every resin type, vs now cleaning a couple out…
Formlabs could really earn some points here.
Heads up that the old thread was reopened 19 hours ago by Frew