Build Your Own SLA/SLS

I am getting close to good prints, but could use some help on the fine tuning.
I have the following setup:
ACER H6510BD projector (set to defaults)
drumhead flexVat
Madesolid V2 red

I have been trying to tweak the exposure times and I can't tell if I am underexposing or over exposing. I have been using the calibration block as a test. I am consistently getting resin globs under the posts, and the holes are filled most of the way, regardless of exposure times. Also, the prints are somewhat sticky. I have gotten up to 4000/4500 exposure time, but I am starting to see other imperfections popping up like bumps on the side surface that should be flat. I have attached some pictures to illustrate my results. The pictures include the layer/base layer exposure times.
Any advice would be greatly appreciated.
Mike

The problem unfortunately is that the V2 resin isn't ideal for high powered DLP printers. While the V1 resin was great in red (and black without pdms) the V2 resins just have too much bleed, similarly the tacky surface feel leaves a bit to be desired.

Of the madesolid resins, I currently recommend the Vorex in Orange, it prints well and holds detail.

The calibration piece does a couple of things
- Tests the resin for adequate uv blocking (ie. is there material under the posts like you are seeing) There isn't much you can do without adding extra blocker.
- Test the cure time of your profile (I generally increase the cure until each of the posts has fully formed, the smallest one being floppy is ok) This you do have control over.

Unfortunately for us the Formlabs printers are Madesolids main focus, so when they reformulated the V1->V2 resin, we lost out. That said the Vorex Orange works really well, and with the LittleRP flexvats available you can use a larger number of resins that would have previously damaged a PDMS surface.

Let me know if you have any other questions!
Brad

Brad,
Thank you for the response, and for all your work on these printers. The LittleRP seems to be an awesome little machine once dialed in.
That is unfortunate about the V2! I just bought the big bottle. Do you have any thoughts on the MakerJuice resin? I like that price point a lot better!
Thanks!

I also had severe light bleed when using the same V2 resin and projector. As Brad suggests it needs extra blocker. Adding black pigment worked well. For 30um slicing I added 2% volume of black pigment from makerjuice and increased the exposure to 5.5s

Nb This pigment settles and needs stirring before each print. For thicker 100um slicing a lower dose of 1% black pigment helped. To remove the tackiness rinse for ~ 1 minute in isopropyl alcohol followed by ~ 10 minute post cure under water in sunlight.

Regards

Cew, thank you for the suggestion! I will give that a try.