Hi folks,
just wanted to report a problem I had - for you to learn from it 
I did not use my Snapmaker for ~ 2 month and had it standing around (in the enclosure) with the printing configuration mounted, i.e. the heated bed plus sheet in place. I could see that some dust had settled on it, and I wiped it (as usual) clean with a cloth and then with some alcohol. But for my life, the print did not want to stick! After I guess 6 or 7 tries I took the print sheet to the kitchen and rinsed it with a mild dish washing detergent and a lot of water, immediatly dried it off with a paper towel, and - lo and behold! - Next print immediate success.
So, keep your sheet clean, and do not underestimate the stickiness of the smallest dust grainsā¦ It must be the grainy texture of the sheet - with my old printer and its glas bed I never had this problem.
If your print wonāt stick, try cleaning the sheet.
Cheers
Hauke
Excellent Advice!
Many people do not know that alcohol doesnāt do a very good job at removing water based contaminants, it really works best with oil based contaminants like your finger oils. The best way to remove the water based contaminants is with a light dishwashing soap and water solution, which you can put in a spray bottle. Just be careful with over spray.
BTW, this works extremely well on windows too.
I use IPA most of the time. But every so often I will wash off the print sheet using dish soap under the sink, and then wipe down with IPA. That way I make sure Iām covered. No soap residue.
-S
Iāve had much better luck with sticking since I printed a build plate cover. I havenāt wiped down the build plate in at least 6 months, probably longer.
Itās sized for the v1ās small 125mm x 125mm build plate though. It should scale up for the A150, but it would need to be redesigned for the rectangular A250 and A350. There is a link to the TinkerCAD project if you want to give it a try.
Interesting as Iāve had nearly the opposite experience, at least superficially. I was also away for a little over 2 months and left the Snapmaker sitting as set up in the 3D printing configuration in the enclosure. Upon my return, I did not do any intensive cleaning, but have had far fewer problems with adhering than I was having prior to my trip. Since there were new versions of both the Snapmaker firmware and the Luban software during my absence, which I installed before my first print after my return, I was musing that perhaps the improved adherence was due to software or firmware upgrades.
Thanks for sharing your experience. I may need to add that the printer in my case was in a particularly dusty environment, my workshop, where I also do woodworking etc., all creating dust.
Iām sure that you nailed it - the dust was the problem. And, my environment is fairly clean. What surprised me is that Iāve done about 6-8 prints since my return with several different filaments, and have not had one adhesion issue. Prior to my 2 month absence, I probably had adhesion issues half the time.
For a while using blue paintersā tape worked pretty well, but about a month before I left, the tape had deteriorated to the point where I had to remove it. I did a few prints after that before my departure, but again had adhesion problems especially with skirts.
After my return, even the skirts are adhering nicely.
I have never found the need to use a stick or painters tape (but i only do PLA) i have used glass, stock PEI and engergetic smooth PEI surfaces.
I have found washing the plate with warm soapy water to be the most effective way to clean my plates.
this, IPA only breaks down the oils, it doesnāt actually remove them - so you just move the oils around the bed, i have only ever used soapy water, it works really well. i am not convinced that IPA is anything but a fools errand - i see loads of posts across multiple manufacturers forums where people start to use IPA and eventually seem to have issuesā¦ guess i need to use some IPA myself to know what i am actually talking about. I found the soapy dishwasher tip on the prusa forums where a select few were saying ignore prusas advice on IPAā¦ so i donāt know what to think, lol 
(my IPA arrive a week or two ago, the acetone got cancelled 
)
With glass beds I had all sorts of problems (on my old printer). It could be that one day every print just worked perfectly, and the next I could not get anything to stick at all. Glue stick, hair spray, painterās tape and Kapton tape then helped. The SM2 print bed works nearly perfect for me, rarely a print does not stick, and if, then it usually was an error on my side.
Thank you! This solid advice restored the āstickā. Iāve also messed with alcohol solutions and not getting a good first layer. Now it prints beautifully and with a perfect stick. 
what did you do that worked for you?
@scyto Superglue!! Works every time! One way street though, need some elbow grease to get the prints off!
Disclaimer: Iām being extremely sarcastic, for the love of all that is holy, DO NOT put superglue on your bed lol.
2nd awesome joke of the day on this forum that made me lol (for reals)
I mean, sounds potent, but ok
I cleaned the build plate with dish washing detergent as suggested.