(10-08-2020, 11:08 AM)earthball Wrote: Kasimira, don't give up. I know it can be frustrating when starting out, but there are all reasons why the prints are failing. None of what you are describing will likely be fixed by getting another printer. These sound like the same issues I had on mine and found just a few tweeks got things running more smoothly. I haven't had a failed print since I stopped printing the rooks.
First, I am pretty sure the failure of the test rooks is due to the contact area with the build plate being too small. Mine always failed at the first layer that cures over the entire diameter (base of the stairs) and is nearly the same area as the build plate. This means that the suction forces on the FEP and the bond at the build plate are very similar and often result in the part being pulled off the plate. If you take the rook and add a raft or supports, I suspect you would have much more luck with the grey. I print everything with supports generated in Chitubox. If you aren't yet experience with generating supports, you can try just using a raft, which will add a lot of contact area to the plate as well. This made the biggest differnece in my case.
Second, You can try slightly sanding the build plate surface. You need to be careful not to change the shape of the plate, but just give enough "micro-scratches" to help with adhesion. I used a 600 grit Silicon-Carbide (grey color) wet/dry sand paper that you can get at hardware stores or autoparts stores. I used a granante surface plate to be sure I kept the surface flat, but if you don't have a very smooth surface (like a sheet of glass), then just be very gentile while sanding and ensure you evenly cover the surface. Also, I cut my finger once on the edge of the plate when I tried to dislodge a stuck print, so I recommend rounding over the outside edges slightly to "debur" the plate.
Third, I actually found when I replaced the factory FEP with a new sheet, I had better prints. Maybe it was form my initial failures and trouble shooting, but the quality did improve. This shouldn't be necessary to prevent the built plate issues, but something to consider after you get the hang of things.
Finally, I am using the Mars Pro with standard grey too, and the default 60sec/4 layer bottom and 8 sec exposures were enough for good prints. I actually think they may be over-kill and I think I can get better sharpness on my prints if I turn things down a bit. I have successfully printed with 55sec bottom and 7sec standard exposures for 50um layer height. Settings also change if you use different layer heights, so stick with the .050mm until things start working. I also added 1s "Light Off Delay" and "Bottom Light Off Delay" to my Chitubox settings. Not certain how much impact this has, but was attempting to again get sharper prints. Also, be sure the resin is mixed well each time you print. This resin has a rather low viscocity and letting it sit even for a day or two can cause the pigments to settle out and cause exposure isses, especially on the first layer. Use either the plastic scraper (I like to use an old hotel key card) to lightly stir the tank and scrape pigment off the FEP.
Hope this gives you some ideas. I recommend only changing one thing at a time so you know what did the trick. Let us know how future attempts go.
Also, don't be discouraged if you have more failures. This is part of the "hobby" and the more mistakes you make and fix along the way, the easier it gets to trouble shoot and prevent future issues. I know it seems like a lot now, but you will get the hang of things with practice.
I will definitely give some of those suggestions a try. I'm going to stick with it, especially since we seem to be getting somewhere in this thread. I do enjoy the little printer and I'm sure I will enjoy it far more once I work out the bugs.
Yes Cliff, that is exactly what my build plate looks like as well. Much thanks for going out and ordering a plate just to try to solve people's problems here. I'll keep an open eye on this thread to see what the results are from you scuffing up or sandblasting it.