Raft options

[Deifox]

I've been printing in pc abs, and I've been getting a lot of warping. So to combat this, I've been using a raft. This way the raft corners curl, instead of my part. But the other day I noticed something, my round parts don't curl. (Or at least not as much) This makes sense to me because of the round shape. It has no corners, so there's nothing to curl. This this got me thinking... why not have the ability to print round rafts? I believe the current rafts seem to mimic the shape of the object. So if you print a round part, I think you'll get a round raft. (I haven't tried this yet) But what about round rafts on parts with edges? All I can do right now is make a bigger offset in the raft so that the curling never reaches my part during the print, but if I could print a round raft, I could use less material, and maybe it wouldn't curl at all? That would save me filament, and stop a problem. Maybe you can already do this? I'm not sure, I'm on the new 4.0 version. Anyone else think this would be a great addition?

[brian442]

The 4.0 raft already seems to put a nice angled edge at the corners which helps a bit. If you want it to be completely circular, that might waste a lot of extra plastic for some parts..

[Deifox]

I see it differently, I believe you'll use less material than a squared off raft. Because you can make the raft smaller without having to worry about curling, and I mean so small that the outer diameter of the raft isn't any bigger than the parts furthest outside edge. Right now I have to run a good 5mm of raft to make sure that the pc abs raft doesn't curl back to my part base, and even then, sometimes it's not enough and I have to put up with a bit of base warping. So now I gotta make the raft a bit larger to prevent this. I experimented with some round and square rafts to see how each would act with pc abs at max temp. And the round rafts never curled and performed excellent. It kinda makes sense to me, corners curl because the tips cool to fast, but circles don't have corners so the raft keeps a more consistent temp which aids in curl prevention. I don't know, I think it's a good idea, but maybe I'm as crazy as the professor.

[Deifox]

Ok, correct my math if it's off, but if I were to print a cube with 5mm sides, and use the standard 5mm offset for my raft setting. This would give me a raft area of 225mm squared. But if I were to print a circle that was no bigger than the furthest outside edges of the cube, it would only be (roughly) a 7mm diameter. So the area for that would be roughly 38.5mm squared. That's roughly 83% savings in material when the circular raft is kept at its smallest diameter compared to a 5mm offset square raft, and even if the circular raft is made bigger, you will still save material. I mean, you could always save material by making your raft offset smaller, but you risk curling the edges into your part, where a circular raft could prevent this. I guess all in all, if your not having a problem with curling, this is all kind of pointless. Lol, but if you are, I think it's a great idea.

[brian442]

That's not a fair comparison though. You're comparing a squire raft with an offset of 5mm with a circular raft with an offset of 0mm. You could just as easily set the square raft to an offset of 0mm, and it would only use 25mm squared. A circle around the entire part is never going to be as efficient as what they have right now. It would also have a lot of trouble with other shapes like a 100mm x 20mm rectangle. The square raft with no offset would use 2 thousand mm sq, but the circle with no offset would be close to 8 thousand mm sq!

[Deifox]

Your absolutely right about the longer rectangular parts... a circle raft would just be a dumb idea. I forgot to point out that I was referring to smaller more equally dimensional parts, and as for the poor comparison, your kind of missing the point... I wouldn't run a raft at a 0 offset, because that's just assuring a doomed curled print. The whole reason I use the offset is to get the curling edges as far away from my print as possible. So a zero offset would just make for a poor choice of raft. However a circular raft I wouldn't mind having at a 0 offset because it is less likely to curl. (Hence my comparison of the default 5mm raft vs the 0mm round raft) This would mean that in my example stated above, a round raft is a better choice (In that particular situation). I guess the point I'm trying to compare here is (assuming your expecting curling) would you rather use a larger offset raft to prevent the curling from ever reaching your part? Or would you rather use a smaller circular raft that's gonna have a better bond to the build plate and less chance of curling? I agree that in some instances, the circle raft seems stupid. But for most smaller objects that sometimes need rafts to stay stuck, a circle is just a better idea. Also, even if you have let's say a 100mm x 10mm rectangle, why not completely round the corners to a full radius, making a parallel sided oval-like raft? That would be better than having corners. I'm not begging for simplify 3d to change there raft style entirely...lol that would be stupid, the rafts work fairly well. I'm just saying why not add an option to print a round raft for those instances where it would be beneficial?

[Deifox]

Let me apologize in advance brian442. In no way did I mean for any of this to sound like I was arguing with you. What you have said has been 100% accurate and I agree with your remarks. I just feel that we got a little bit off topic with the material use. (Which is a logical debate), and again, we can both be right on the topic. Because it really comes down to the shape of the part. I'm sure we both can agree on that. But the main question I was trying to implement here is "are circular rafts better at preventing curling than the stock rafts?" Which I found in my testing that the answer is yes. Now, I'm just basing this off polycarbonate. I don't use rafts for anything else. I seemed to have mastered everything but polycarbonate when it comes to using rafts. So the question I want to know is, any ideas on how to implement a circular raft on some parts? I actually thought about creating two seperate stl's and have one be my part, and the other be a thin layer that resembles a 2nd raft that is the shape of my choosing, and trying to use that 2nd raft to make the initial raft mimic it's shape. (Which I'm aiming for more circular.) Then I can offset my z on my part stl to my desired spacing for removal, just like the normal raft settings. I would also make no space between my base stl and the raft, this way they are one strong solid base. I have no idea if this would work, I'd have to try it, unless you have a better suggestion? I've tried brims.... they warp as well. Rafts seem to work well, but I'm still getting corner peel over time, which sometimes screws me. I'm sure most of us can all relate to how much of a pain it is to have a 6 hour print warp off the bed after 4 hours. That's why I'm so addiment on using a circular raft. The results have been flawless, no warping, peeling, or seperating. Just flawless finished prints. Again, apologies if I by any means I offended you. I know these forums are for helping each other and not arguing.