Build plate adhesion issues?

[Kasimira]

I just received the Elegoo Mars Pro and got it setup.  I followed the instructions to the T, including watching a video on Youtube.  So far I have not had any success printing.  Steps I have followed;

Leveled build plate via instructions
Leveled machine with legs
Set UV light to 3 second test, fully lit rectangle verified it is working
Ensured no protective film remaining anywhere on vat
Used rubber seal around housing

Currently using Elegoo Standard Photopolymer Resin (Grey)

My first print resulted in the base of the test rook's being still stuck to the film and not the build plate.  I came back about 3 hours later to find nothing but uncured resin on the build plate.  Using the plastic scraper I got the failed prints off the film.  They were perhaps 5mm high and solid.  So clearly the UV light is working properly.

My second print resulted in even less of a print, 2.5 hours later the build plate was hovering with uncured resin on it.  This time I emptied the vat back into the bottle and seen only the very beginning of the models were stuck to the film.  Maybe at best 1-2mm thick.  So I'm curious why things are not sticking to the build plate.  I've thoroughly cleaned the vat and the build plate with 99% iso and dried them, re-leveled the plate with the a sheet of copy paper and ensured it was tightened.  I'm going to try another test tomorrow where I can keep an eye on it.  I've read reviews on other models of resin printers that sometimes the build plate needs scuffing up because of adhesion problems.  Before I do anything does anyone here have any experience with this issue?

Thanks

[cliffyk]

How many bottom layers at what exposure are you using?

I had been led to believe from marketing photos that the "Pro" platen's "business surface" was what appeared to me to be fly-cutter machined bare metal resulting in subtle circular striations, and prompting claims of improved adhesion. Can you post some photos of yours?

[Kasimira]

I'm not sure how many layers or what the exposure is. I just left the settings however they came in default as the instructions didn't say anything about setting exposure outside of doing the quick exposure test. Both times it ran through the majority of the print. I believe the test rook says 1000 layers. I observed it the second time going through layers 1-200 then again at 450 or so, then lastly around 700 I seen the plate was no longer submerged and about an inch above the resin and nothing was attached to it so I stopped the print. The printer itself was just moving along as if nothing was wrong. When I drained the resin from the vat there were two very thin pucks less than 2mm thick attached to the film.

I can take some photos of the unit, build plate etc and attach them when I get home.

[earthball]

I had the same issue. I read on other forums that the test print fails most of the time...kind of defeats the purpose, I know. I eventually just gave up on the rook test print and just started printing my own parts. Didn't have the same issues with sticking to FEP.

I would recommend trying something you are confident should print okay. Make sure there is more contact area on the build plate than with the FEP in later layers.

[cliffyk]

The "Pro" is marketed as being significantly faster (I.e> shorter exposure times) than the original Mars, however many of the "recommended" exposures I* have seen (2 s/layer ans 20 s bottom layers) have struck me as just wishful thinking. With the plain ol' Mars poor platen adhesion is almost always either the glossy powder coat finish, or too short exposures for the bottom layers.

I agree 110% with "earthball' re; making certain your model ALWAYS, at any point in the print cycle, has more contact area at the build plate than at the FEP--also keep in mind that with SLA printers things are printed upside-down--be sure to envision it that way when evaluating in-process contact areas and the like...

[Kasimira]

I'm giving it another go after thoroughly cleaning everything down and re-leveling. The bottom exposure is set at 50, the basic exposure is set at 6. I did a little reading and it seems the Pro 2 exposure time is divided by 4 making them really short times. Mine is just a basic pro. I did take pictures of the build plate but forgot to send them to my PC to upload. I will get them up in a bit. I also read some people mentioning using lubricant on the film?

If this test rook fails again I will see about finding something different I can print. I'm guessing you're talking about something with less of a simple round base that could get stuck to the film? I don't have any experience really designing in things like blender or splicing in cura. This was supposed to be a learning experience for me but I also don't want to chalk everything up to user error if the printer itself simply isn't working properly.

[Kasimira]

---

When taking photos I noticed there are some minor scratches on the film. I'm not sure if that could be causing the issue. The thin little pucks there are the result of the last print I tried a couple hours ago.

I've again taken everything out and cleaned it thoroughly as well as ran the 45 second exposure tray cleaning option on the machine. I just switched the standard grey resin out for an abs like clear blue resin. Going to try again and see if a different resin makes a difference.

[Kasimira]

So upon switching resins I had a successful print.  I'm not sure why the difference but it worked. 

Failed 4 times using the Elegoo Standard Photopolymer Resin (Grey)

Success 1st time using Elegoo ABS-Like Photopolymer Resin (Clear Blue)


I'm going to try again with the grey and see if it is just the resin or if maybe it just decided to stick for a change.

I do have another question though... upon trying to remove the rooks from the build plate.  I tried being as delicate as possible but they were really stuck on there.  Using the metal scraper definitely left some scratches on the plate trying to peel them off.  Is this normal and are the scratches a cause for concern?  I tried my best to be gentle but they were really stuck to the plate this time.

[cliffyk]

Don't be concerned, it is normal. A way to minimise it is to polish the scraper's edge with some fine (220 to 400 grit) wet/dry sane paper. I ground the end of mine to at 30° or so single edged bevel and the polished it up with 320 grit paper leaving a very slight radius on the non-beveled edge. Round off the corners to a slight radius and polish them as well. Use the non-bevel edge against the platen and beveled edge to slip under the print.

What exposures did youi use with the semi-clear resin? Opaque resins require longer exposures, the darker the longer...

[Kasimira]

Don't be concerned, it is normal. A way to minimise it is to polish the scraper's edge with some fine (220 to 400 grit) wet/dry sane paper. I ground the end of mine to at 30° or so single edged bevel and the polished it up with 320 grit paper leaving a very slight radius on the non-beveled edge. Round off the corners to a slight radius and polish them as well. Use the non-bevel edge against the platen and beveled edge to slip under the print.

What exposures did youi use with the semi-clear resin? Opaque resins require longer exposures, the darker the longer...

I didn't adjust anything.  It was still the same exposure.  I believe it said the first x amount of layers were 50 and the rest were 6.  Same as what I used on the grey and it just worked for some reason.