Adhesion and general bed problems-Max V3

[cruzinbill]

Overall this printer has been pretty great. I seem to be having issues with what seems like a warped bed. One side will print so close it blocks the nozzle and causes the extruder to click. The other side will print fine at this level. If I increase the z then the low side is fine and the high side will not adhere at all and is essentially laying down a string.

The second issue is I cant seem to get a print to stick 8/10 times regardless. With a cold bed the pla will not stick at all anywhere on the bed, this is with and without the use of hairspray. With a bed at 55-60 and use of hairspray I can sometimes get the print to stick but that's still a gamble.

When it does stick the prints turn out generally really really well. I still have a tiny bit of tuning for them but can't really focus on that until I can get it sticking every time.

I've seen a few things on here about radius adjustments or something like that but nothing I have seen seemed to lead anywhere notable.

Also I've noticed if I adjust the z for printing on the cold bed then later print on a hot bed it is a huge difference and will always be around .03 too low when hot. Not sure if this is normal as I've never used a glass bed before.

[RichWP]

Try holding down the glass bed using only 3 of the six blue plastic retainers (use every other one) - make sure ALL of the retainer screws are tightened fairly tight, as the same screws are holding the plastic pieces that your bed sits on (and it sounds like you might have bed level issues). Your bed level should be at the same level relative height to the wood frame it sits in all the way around. If it's not, then you might have picked up some debris under the glass, heater and/or mounts, or it's not mounted correctly (at first glance, the bed mounts look like they can face either direction, but one side is actually higher than the other). Otherwise, it could be that your towers are not squared 90 degrees to the bed.

For bed adhesion - I've heard great things about printing on a PEI surface, but I've been mostly printing PLA on a cold bed with a very thin layer of glue applied from a glue stick for adhesion... This works really, really well for me. Just be aware that your first layer will only be as flat as your glue application. Not sure if it matters, but I use the Scotch glue sticks - I get them in bulk from Costco pretty cheap.

[cruzinbill]

I gave that a shot, first print seemed to stick right away now on a cold bed and looks pretty level... going to try a couple more to see how it looks. Think that may have been the issue tho.

[Xenocrates]

First problem: You have unmatched endstop offsets. These can be tuned in software, or the screws can be adjusted (I think). You should also be able to use the bed compensation wizard on Seeme's website, or in Octoprint.

Second issue: If you want to use a cold bed, I suggest something more like PEI or Lokbuild, or one of the other engineered coatings instead of hairspray (Why you want a cold bed is beyond me, your machine has a heated bed, and it doesn't take that long to heat up to PLA temps)

Third thing: Behold, the magic of thermal expansion. Glass, and many of the other parts used have a positive co-efficient thereof (Boro glass has a co-efficient of ~3x10^-6, but the PCB has a co-efficient of ~7x10^-5, as compared to Steel's 1.2X10^-5, when thermal expansion in steel is used to fit rivets by heating them to force them to elongate and reduce in diameter). Thermal expansion is kinda annoying, but at least it's semi-predictable.