Printing without a raft?

[DrBoost]

So, I just got my Prusa together and am having an issue. Slic3r is printing a raft, or a skirt. I've read that this helps give s smooth surface for your prints. Well, I'm printing on glass, so that's way smoother than the raft, and the raft is impossible to remove. I've been sanding three small parts for an hour and am not all the way through the raft yet.
Is there any reason I can't print without a raft? I am printing a brim, the loop around the parts to clear the nozzle though.

[chris@radeuslabs]

I've not worked with a prusa nor rafting; but it seems redundant to use a raft and brim to me.

[BLKKROW]

In Slic3r you can disable the raft and brim under "Print Settings" > "Skirt and Brim" and "Support Material".

[Davo]

We very rarely use a raft.

We prefer (when needed) to manually place a print stamp (or brim) one layer high, at the same layer as the base of the object. Then it's only edge trim and finished.

[Marm]

We prefer (when needed) to manually place a print stamp (or brim) one layer high, at the same layer as the base of the object. Then it's only edge trim and finished.

This. I never use a raft, as it actually gave a worse surface than the glass, as you're finding out. And it's almost impossible to remove, although, that was before my new dremel. The sanding drums on the dremel are Very effective at removing support material, Although they tend to leave a smooth (flat? level?) rough surface (That makes no sense, but it's a smooth sanded surface). If you want a smooth finish, then acetone is required, but since the layers are sanded off, the finish is smoother and quicker. Sorry, went off on a tangent there. Nope, hate rafts.

[chris@radeuslabs]

Marm - when did you pick up yojur Dremel? How do you like it? I got mine about a month ago, its my 1st printer and have been very happy with it. We even picked up 1 for the shop.

Sorry all for going off topic

[Marm]

Ah, dremel micro rotary tool. Not a printer. LOL. Love my dremel though, got it for christmas, and was like meh, I have a corded rotary. This one is cordless, and I've found myself grabbing it a few times a day for stuff. Now my favorite tool in my ship. So much easier than having to run the cord every time.

[chris@radeuslabs]

ohhhhhhh ok now I am tracking lol I'll just go sit in the corner for a few lol

[Wolfie]

In my limited experience, rafts are really only useful if you don't have sufficient part surface area attached to the bed. With ABS and the way it shrinks, its very likely that a low surface area part could pull away from the bed during a print. In this case a raft could assist by providing more contact area of ABS onto the bed.

If you are, for example, printing a roll pin (no, nobody is printing roll pins but run with it ok?) standing up vertical on the bed, there would be very little surface area of the part to adhere to the bed. It could dislodge during printing. If you put a raft under it, the wide area of the raft would attach to the bed better. Obviously the wise choice would not to be adding a raft but to print the part horizontal in this case. But I suppose there may well be a good reason you don't want it printed that direction, say direction of layer orientation would be one example.

I haven't been doing this very long but I have only printed a raft once.

As for a brim, I usually go with 2 traces over 4 layers when .2mm layers or smaller. 2 layers if I am printing >.2mm layers. Anything less and its a pita to remove the brim from my PEI bed.

[DrBoost]

Good to know I'm not crazy. I printed some legos as test pieces and it took maybe an hour to remove the rafts. I also printed a light switch cover for my son's room, face-down. I'm scrapping that print because it would take a week to sand that raft off.