Adhesion Problems - Help with my Theories
Posted: Wed Jul 27, 2016 2:52 pm
I recently upgraded my old 19v/12v v3 to a shiny new 24v v4. From an assembly/mechanical standpoint, everything looks good. I was having some issues with the extruder temp that were resolved with a firmware update. The physical unit worked; the firmware just wasn't tuned properly.
Since finishing all of that though, I've been having a hell of a time getting things to stick. On my old hotend, I usually printed PLA at around 190-195 with a 60-70 bed temp. I've tried a whole range of temps and the corners keep lifting on some prints. Small test prints like a 20mm cube or the stepped 5mm cubes on Thingiverse print fine. I don't see corner warping. Adhesion is good. Layer alignment is perfect; even better than before.
The specific prints I've been having trouble with are the Open Forge Dungeon Tiles on Thingiverse. The corners just insist on curling up. I even bought some Buildtak after reading all the positive comments about it. Early tests were promising. The small calibration items printed awesomely well on a cold bed. I couldn't pop them off without a little assistance from a print removal tool (long, rounded spatula with a very thin front edge - it's on Amazon. I love it) - which is how I think it should be. I then printed a single 2x2 wall tile and it looked really good. I didn't see corner warping.
Then last night I filled up the build plate with six 2x2 tiles. Extruder @ 197. Bed @ 0. 60mm/sec with a 50% underspeed for the first layer which was at 90% height. I checked on it this morning. The print was done, and half of them had rounded to the point of being rocking chairs.
I've got another batch printing now while I'm at work. This time I've decided to try a heated bed temp of 50 (last night was a cold bed), and I tweaked a Z offset of -0.03 to get the nozzle slightly closer to the bed. I'll see how it turns out when I get home from work.
Anyway (sorry this is so long) I was thinking... a single tile worked fine, but a plate full of tiles warped like crazy. Is it possible that with that much area to cover, by the time the nozzle makes it back to any given piece, the previous layers have cooled too much? My experience with PLA has always been about cooling it as much as possible due to the low glass transition temp, but with a print this large, is it in my better interest to keep it warm?
I've dealt with my share of tweaking this thing in the past, but it's getting really discouraging right now. I'm beating my head against a wall trying to figure out what the problem is. There are just so many variables...
Since finishing all of that though, I've been having a hell of a time getting things to stick. On my old hotend, I usually printed PLA at around 190-195 with a 60-70 bed temp. I've tried a whole range of temps and the corners keep lifting on some prints. Small test prints like a 20mm cube or the stepped 5mm cubes on Thingiverse print fine. I don't see corner warping. Adhesion is good. Layer alignment is perfect; even better than before.
The specific prints I've been having trouble with are the Open Forge Dungeon Tiles on Thingiverse. The corners just insist on curling up. I even bought some Buildtak after reading all the positive comments about it. Early tests were promising. The small calibration items printed awesomely well on a cold bed. I couldn't pop them off without a little assistance from a print removal tool (long, rounded spatula with a very thin front edge - it's on Amazon. I love it) - which is how I think it should be. I then printed a single 2x2 wall tile and it looked really good. I didn't see corner warping.
Then last night I filled up the build plate with six 2x2 tiles. Extruder @ 197. Bed @ 0. 60mm/sec with a 50% underspeed for the first layer which was at 90% height. I checked on it this morning. The print was done, and half of them had rounded to the point of being rocking chairs.
I've got another batch printing now while I'm at work. This time I've decided to try a heated bed temp of 50 (last night was a cold bed), and I tweaked a Z offset of -0.03 to get the nozzle slightly closer to the bed. I'll see how it turns out when I get home from work.Anyway (sorry this is so long) I was thinking... a single tile worked fine, but a plate full of tiles warped like crazy. Is it possible that with that much area to cover, by the time the nozzle makes it back to any given piece, the previous layers have cooled too much? My experience with PLA has always been about cooling it as much as possible due to the low glass transition temp, but with a print this large, is it in my better interest to keep it warm?
I've dealt with my share of tweaking this thing in the past, but it's getting really discouraging right now. I'm beating my head against a wall trying to figure out what the problem is. There are just so many variables...
