When do you use Rafts while 3D printing?

[Yancy]

I've never used rafts when 3D printing. Do you guys commonly use them? Do they work well? What is the main purpose of the raft, and when is the best time to use them? I've never really had any issues printing without rafts, but my buddy said that it can help the bottoms of prints come out a lot better.

[Mjolinor]

It helps if your bed is not flat and level. By the time the raft has been laid then it is level and flat so your model will be more dimensionally accurate. Mind you if you have a flat level bed then I can't see an advantage other than types of plastic and sticking.

[Davo]

It can also be useful when you are printing a tall shape with not much bed contact, giving it more anchor to the bed.

[curious aardvark]

And if you've got a flashforge and haven't yet sorted out how to use slic3r. It's pretty much the only way I can get anything to stick to the bed.

That said - I can print anything - as long as it's on a raft. The printer's sound. Just need to get some layer control and I won't have to use a raft :-)

But yeah, if it's not compulsory (as mine currently is) then what the guys said. It's useful to anchor something that doesn't have much bed contact.

A brim would work just as well and give you a better finish on the bottom of your print. And probably use less plastic.

[3DPBuser]

I like to design parts that print as-is.

[curious aardvark]

so do I, and when i can - I will :-)

[Steven57]

I use rafts when a wide brim won't keep it stuck to the bed. Parts with minimal contact usually.

[curious aardvark]

Actually I use rafts when using abs as it just won't stick by itself. Also helps stop it warp.
Pla - never needed one.

[T-MAC]

I use rafts when using makerware generated supports or the object doesn't have a lot of surface area. Rafts take a long time to print in my opinion. Don't use them if you don't have to.

[Zhall]

I use raft in order to help fight warping, or if it is clear that the parts will have a hard time sticking to the plate due to little surface area touching.

Otherwise I avoid raft like a plague when I can, mainly in my production pieces that get made all the time, it's a total waste of time.

Custom raft is possible, but really only in conjunction with custom support for special pieces.