The first thing that people new to 3D printing are told is that ABS is too hard, and PLA is easier. That statement is absolutely true, but ABS shouldn't be feared and is actually pretty easy to handle, as long as you follow the rules:
- ABS requires a heated bed.
- ABS requires adhesion solutions
- ABS fears drafts
- ABS requires high ambient temperature.
- ABS doesn't like too much heat.
Rule 1 and 2
ABS requires a considerably higher bed temperature than PLA, not only to stick to the bed at the first layer, but also to stay on throughout the print. Depending on the size of the print, the required bed temperature can range from 100C to 130C.
While it is certainly possible to have smaller prints to stay on the bed with no adhesion solution, by setting the bed to 120-130C, there are a number of drawbacks that I will expand on later, large prints will still require a solution.
There are a number of adhesive solutions that can be applied to the bed, but they will require a whole dedicated post, so for now just a short list:
- Low first layer
- ABS Juice - ABS diluted in Acetone
- Hairspray - Aquanet brand, hairspray
- Glue stick
- Kapton Tape
- Window tint film
ABS fears drafts. Drafts cause fluctuations, in the layer temperature, and will cause random delaminations, especially on the sharp corners of the print, and the larger the print the more visible it will be. ABS fears drafts so much, that if you run an E3D hotend, whose cooling fan “leaks” and creates drafts on both intake and outtake, you will get delaminations. I've found the problem to be so severe, that i ducted it upward on the outtake, and enclosed on the intake to prevent air movement anywhere close to the print.
Never run the print cooling fans when printing ABS. Close all windows, doors, or enclose the printer, or print a thin wall around your print.
This rule is an extension of Rule 3, as it requires you the possibly enclose the printer.
Now enclosing the printer is beneficial not only for protecting the print from the drafts, but it also allows you increase the ambient temperature everywhere around the print. High ambient temperature, is tremendously important when you print large prints, as the larger the print the more sensitive it is to temperature fluctuations. Back when I didn't have my enclosure, in fall, when the room ambient temperature dropped to 18C or so, i kept severe getting delaminations, on large prints that just a week ago printed just fine. The difference was that the week earlier the room ambient temperature was close to 27C. An enclosure can be a temporary cheap solution like a large cardboard box, or a fairly pricey custom cut Lexan.
ABS doesn't like too much heat. Contradictory isn't? But nevertheless a fact.
And I don't mean the hotend temperature specifically, I mean the bed and the ambience.
See, ABS shrinks and warps when the temp. drops, but it also warps when the temp. is too high. The simplest solution, is to print the first 5 or so millimetres worth of layers, at a lower temperature, say 90-110, and then increase to 110-130. It will require a bit of experimentation, to find the right layer for the increase, but 5mm is a good starting point.
Armed with those rules, printing with ABS should prove as non challenging as printing in PLA.
In the coming up posts I will expand on the adhesion solutions as well as simple enclosure solutions, for those with unenclosed printers.