Rumbling sound over previous layer?

[LePaul 321]

Well let me show you how the print is progressing...bed leveling looks fine to me?

[LePaul 321]

12 hours later...printer reports 2 hours left to go. (Wish I knew why the printer gives such crazy numbers this time around)

Brim seems to be holding it down well. I know some like brim, some do not. But for a print this sized and at this orientation, it might be what works.

[gr5 2,172]

Why the gaps on the bottom layer? Is that the support structure? Hmm. Cura needs an option where the bottom layer is solid below the support structure. maybe that's what brim does to support?

[LePaul 321]

Maybe @tinkergnome or @nallath can chime in

[neotko 1,417]

Afaik cura has bottom rooftops right? Ummm

[neotko 1,417]

Nope. Rooftop doesn't apply to the layer touching the plate, that's the problem. But it does it when is printing supports over the print part... Well.

Well a Brim does grip the supports and should be enough to keep them in place without a Raft that is much slower.

[LePaul 321]

Good illustrations

I was beginning to think I should try a different support type

I think others that print this part up use S3D and "Helper Disks"

Edited November 7, 2016 by Guest

[tinkergnome 927]

Why the gaps on the bottom layer?  Is that the support structure?  Hmm.  Cura needs an option where the bottom layer is solid below the support structure.  maybe that's what brim does to support?

 

@gr5: it's not brim, the previous pictures are showing the first two layers of the raft. It always looks like this. I know, a raft is a bit antiquated these days... but it builds a nice solid base for the supports, doesn't it?

Edit:

 

I was beginning to think I should try a different support type

 

Which support pattern have you used so far? "Grid" should produce the most stable structure.

Edited November 7, 2016 by Guest

[LePaul 321]

I think it is using ZigZag, which seems to be the default in Cura

[gr5 2,172]

Better to use raft than to have supports that fall over.

Instead of Zig zag maybe pick some of the stronger structures such as grid?

[LePaul 321]

@gr5 is grid stronger?

When I searched here for information on which support type is stronger...or any benefits between them, I found no information.

[gr5 2,172]

I don't know. I recommend you try all of them and look at it in layer view and decide for yourself. I think it's kind of obvious when you see them in layer view if the structure makes sense for your particular print. There is an infill called I think "lines" that makes unconnected parallel walls - that one I think is the weakest - the walls can easily fall over. Grid I think is like graph paper lined up with X and Y axes. There is one called triangles maybe? That one should be even stronger but your problem was at the bed - not up in the air. I'm thinking "raft" will help your support stick to the bed but I really don't know. I've never tried raft and rarely use support but for your BB8 print I think support is mostly required. You can have it abandon the raft when the angle of support is maybe 60 degrees from vertical. Certainly by 45 degrees you no longer should need support. Increasing this angle can save a lot of print time. Especially if you will be sanding and painting this anyway - in that case I would go with at least 60 degrees support angle to save tons of print time.

[LePaul 321]

Hi @gr5

I've adjusted the part to be as vertical as possible, eliminating addition support and saving on some print time.

The last three prints have gone OK. Some "hair" and minor stringing, but that is from the nGen settings I need to tweak.

The z-hop has helped a lot

Of course with so much support is the hassle of removal. (Dear Santa, Paul needs an Ultimaker 3. @sandervg knows I've been good this year) :-)

The raft is working very well and I certainly didn't expect that to be the fix to this problem. These prints take 15.5 hours each, and I need 21 more! That said, I am tempted to stick (see what I did there?) with what seems to work for now.