Raft Sticking to Parts

Good Morning, all!

I'm very much a beginner, but my first couple of prints went off flawlessly, so I was a bit stuck last night when my new spool holder finished up.

The print looked great, considering I used a .2 layer height and 200% speed on the printer. I'll admit I wasn't being very scientific... I used both a new filament and different settings than I've used in the past.

When I went to pop the raft off the part, however, it was stuck TIGHT. Every other print that I've done was printed on a raft and done with Monoprice PLA and the raft popped off SUPER easily, leaving no trace. I've never changed any raft settings in Cura, so I don't think that's the issue, but I could be wrong.

The Microcenter PLA that I used recommended a higher temp range than the Monoprice PLA. Where the Monoprice PLA indicated a preferred temp of 185 - 195 C (which is what the printer assumes for PLA) the Microcenter stuff indicated 205 - 220 C. I picked 210, and it seemed to work really well for everything but raft separation. I also set the bed to 60 C, instead of the 50 C that I had been using, assuming that higher temps all around were appropriate. Maybe that was a bad assumption.

When I say the raft was stuck, I mean REALLY stuck... after 45 minutes with an exacto and some jewelry pliers, I managed to peel off most of it, but still had about a thumbnail-sized chunk that was not coming off. I gave up peeling and sanded it down.

These are the basic settings that I used, I'm not sure what else might be relevant to put here, but I'm happy to fill in more info if it's helpful.
I probably could have printed this particular part without the raft, but I'm sure I'll want to print with rafts many times in the future, and I figure it's a learning opportunity. Any thoughts as to what I can do to promote easier raft separation in future?

Printer: Monoprice Maker Select Plus
Filament: Inland PLA from MicroCenter
Layer Height: .2mm
Infill: 20%
Extruder Temp: 210 C
Bed Temp: 60 C
Raft: Yes
Supports: No (No Overhangs)
Slicer: IIIP Version Cura

Thank you so very much for any help given,

Mika

Try adjusting the Raft Air Gap and the Initial Layer Z Overlap settings. They are in the Build Plate Adhesion section. If they are not visible when Raft is selected, press the settings icon ( gear) next to the drop down arrow and check those two settings.

Thank you! I'll try those. Looking into the raft settings, I see a lot of terms I'm not familiar with, and Google's been surprisingly unhelpful... I've read the tool tips, but they're a bit self referential.

Do you happen to know of any good place to find definitions for exactly what each of these settings does?

Specifically, what is the Interface Layer? Also, Cura defines 'Airgap' as the gap between the last layer of the raft and the whole print. This leaves me imagining the print floating a layer or so above the raft, which is obviously not happening... How is that gap created? Are there tiny supports or something happening there?

Thank you again, I really appreciate all help. Don't mean to get too wordy, I just like to understand what's going on behind the scenes :)

So, first, I do not know of a definitive dictionary of phrases. Also, each slicer uses different terms. Yuck. Now , the air gap is exactly what it sounds like. It does try to print a little higher off the raft. So, in theory, it does float. In reality, it does attach to the raft ( gravity and extruding and all that ) but creates a weaker bond than if it did not create that gap. Give it a shot. It's not perfect, but does help

Ahh, lol, I guess I didn't think about just printing in mid-air, lol. Thank you so much! I'll give that a try with tonight's prints, and see what kind of results I get. I'm hoping that I can get some fan guards and a little tool caddy done this weekend, providing good long naps from the kiddo ;)

Thanks again!

Quote:

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Originally Posted by mjf55

So, first, I do not know of a definitive dictionary of phrases. Also, each slicer uses different terms. Yuck. Now , the air gap is exactly what it sounds like. It does try to print a little higher off the raft. So, in theory, it does float. In reality, it does attach to the raft ( gravity and extruding and all that ) but creates a weaker bond than if it did not create that gap. Give it a shot. It's not perfect, but does help

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After a bit of experimenting, this has made a HUGE difference.

Thank you again!

Mika

BTW, I also use the Inland microcenter PLA and after printing a temp tower it seems to actually like 196 deg. the best. I run my bed at 50C but honestly you could probably go down on that too. If I have a big footprint print then sometimes w/ blue painters tape it's hard to get off but if I let it cool it's fairly easy after I break the bond at one corner. I found even going to 30C helped w/ the super adhesion of prints.

Dave

Interesting! I'd gone with the higher temps becuase that's what was indicated on the ackaging, but I'll give some lower temps a try too.

Thank you!

I am using 0.3mm gap between raft and part
S3D 4.1.1 -> edit process -> Additions -> use raft -> Seperation Distance 0.30 mm