Support structure adhesion issues
So I have noticed an issue recently where the support structures (generated with Prusa Slicer 2.1, and support modifiers) are not adhering at the point where they change direction when printing with PLA. This causes a raised blob that then gets caught on the pinda sensor or the nozzle and causes a failed print. I have adjusted temps, cleaned the PEI sheet with alcohol, and I even tried using a glue stick to help but nothing seems to work except removing the blobs after the printer has laid down the first few layers, then the print will complete successfully. Does anyone have an idea how to keep this from happening?
RE: Support structure adhesion issues
If your bed is absolutely clean of all oils using the much described dawn or similar dish soar and paper towel method and your live z is set correctly that does not happen.
Its hard to tell from your pics but your live z could be too close and its scraping up the edges.
RE: Support structure adhesion issues
Using glustik to help adhesion is proof your bed is very very dirty.
Soap and water is your friend here : alcohol your enemy. And touching the bed with fingers is sending reinforcements for the alcohol.
Hot Water wash: often, as needed, and after any of the following
(not recommended for daily use on Powder Coated sheets)
- Handle the bed only by the edges.
- Wash the bed in hot water, use a fresh paper towel as a wash cloth, with a few drops of plain dish soap (Dawn, unscented, no anti-bacterial, etc.).
- Rinse well in hot water - if you have very soft water, rinse a bit longer.
- Dry the bed with a fresh paper towel.
- Handle the bed only by the edges.
- Place bed on printer.
Alcohol wash: every few prints as needed
- Gloves recommended.
- Once in a while, an alcohol rinse is helpful to remove PLA residue. It does not remove finger oils well.
- Pour a 5 cm puddle of 91%+ alcohol in the middle of the bed, with clean hands use a fresh paper towel to scrub the bed. Wipe up all the alcohol.
Acetone wash: infrequent as needed
(Not recommended for USE on Powder Coated sheets, but some find it necessary)
- Pour a 2 cm puddle of acetone on the bed, scrub it around with a fresh paper towel. It will evaporate fast as you clean. This step removes PEI oxides that form over time and with heat, and improves PLA adhesion to a like new state.
Streak test: when contamination is suspected
- With a fresh piece of paper towel, and very clean fingers, dampen the towel with 91%+ alcohol, and wipe the bed side to side moving back to front, like you're painting it with alcohol. The alcohol should be thin enough on the towel it quickly evaporates from the bed. If you see any streaks, the bed is dirty and needs a wash.
RE: Support structure adhesion issues
I washed the build plate again, and adjusted the live z, but the issue remains. I normally don’t have any issues and I only used the glue stick as a last resort. I think it might be the filament as I haven’t changed anything since my last successful print except that.
RE: Support structure adhesion issues
I have this problem with Sunlu PLA+ - small features don't adhere well and support peel up at the edges on first layer. Even gluestick doesn't help. I don't have this problem with Hatchbox PLA. So, if you already washed the PEI sheet and are using IPA, it very well may be related to your filament. One other thing to try is to increase the bed temperature by 10 deg and see if that helps.
RE: Support structure adhesion issues
In 99.9% of the cases, lack of adhesion is contamination. The other 0.1% is Live-Z is too high. Unless you are wearing gloves, IPA simply removes oils from your fingers and transfers it to the bed. Soap and water is always the last step.
On rare occasions, acetone is useful to remove oxides that build up over time. But I do the soap and water after acetone, too. Nothing beats gallons of water to rinse off residuals. And you probably aren't using gallons of alcohol.
This image is a print after a substantial cleaning effort using only alcohol: you can't see the oil film, but it is there.
