Printing in ABS WITHOUT a HBP?

[anon4321 16]

Can you use ABS without a heated platform? I have a UM1 with the acrylic platform.

If it is possible, how would I do it?

I'm willing to use rafts and such if that is the answer.

I'd like to print this replacement minimum print head: http://www.thingiverse.com/thing:154845

 

[anon4321 16]

PS: why doesn't the forum search for ABS return anything?

 

[gr5 2,265]

because the forum search sucks. It ignores things 3 chars or less. I hate that feature.

Try google:

in google use:

site:umforum.ultimaker.com

And then add to that whatever you want to search for such as "abs without heated bed"

 

[gr5 2,265]

Yes you can do it. It's not as easy. Clean the blue tape with alcohol first so it sticks better. The main problem is that ABS warps twice as much as PLA. So if you print something small like a UM Robot it's not too hard - just add some brim. But if you print something say 100mm across now it will tend to lift at the corners.

A raft can help quite a bit - the raft flexes a bit and stretches so that the lifting energy is spread out over a large area.

Enclosing the whole UM1 and warming with a light bulb to say 35C can help a little also. Most of the shrinking issues are from glass temp to air temp. So for PLA glass temp is around 50-60C. For ABS around 100C. It's not that it doesn't shrink above glass temp, it's just that above glass temp when it shrinks, it shrinks "in place". It doesn't pull the sides inward as it is too liquidy to pull so instead each string gets narrower. basically. It's hard to put into words.

But really if you will be printing things wider than 100mm at the base you should get a heated bed. UM plans to offer a heated bed upgrade kit for the UM Original. Soon. Soonish. Not sure when. Hopefully this summer?

 

[nick-foley 5]

Hahah, was cursing the forum yesterday for the same reason - abs is too short (or too common?) of a string for the forum search to use it. So searching for ABS related pages is a real pain. Pretty dumb/unfortunate.

Anyway, yes, you can do it. Brim and Raft both work fairly well, the crux of the operation is getting the first layer smeared aggressively right on to the acrylic. It should also be very very hot... 260+? I've done it with a dozen or so medium-to-small parts and the results are ok.

Honestly though, ABS is sort of a pain to get right, and even though I now have a HBP it is proving difficult to get the right balance of low fan for good layer adhesion vs. some cooling for good overhangs. If you need the thermal performance, ABS may be worthwhile, but my feeling now is that if you want ABS parts that are actually stronger than PLA, you probably need some sort of heated chamber.

 

[anon4321 16]

One other question, during printing ABS do you need ventilation? I mean more than printing in a large room? Like fresh air from an open window of exhausting through an open window?

 

[gr5 2,265]

I haven't printed ABS but many printers were printing ABS at the last 3dprintshow in NYC and the smell is really not that bad. If you print in a small 8x8 foot room (what country do you live in anon - please add it to your description in settings) with closed doors and windows - then yes. But if you are in a large house or building with open doors then probably not.

They have ABS printers at schools and such - I've seen them at two local high schools and the people using them didn't seem to think it was a problem. But the buildings are of course huge. Even the classrooms alone have as much air volume as a small house.