Polycarbonate and ABS have the same shrinkage factor (between 5 and 7 %) in molding resins and I would guess the results from printed parts might be pretty similar however the molding temperature used for PC is always higher than straight ABS. If you can adjust (raise) the temperature of the filament slightly it may help - or another option is to slow down the print speed as that will effectively raise the temperature as well but it may be hard to actually identify just how much.
I'm not speaking from experience in printing with PC/ABS but would also be on guard for more warpage (more heat, takes longer to give up that heat) and especially if you printing sections with higher percentages of fill. A part printed with 100% fill would likely retain far more heat for a longer period of time than one printed at 30%.
I would agree that the aluminum bed needs a higher temperature than your 70 deg/C but would defer to "elmoret" to the actual temp that works. As long as your bed temp is so low, it just becomes a heat sink - pulling the temperature out of the filament causing it to solidify again and that probably decreases the ability to stick to the aluminum at all. I see this thread is a bit older but would be interested to learn what others might have found that works for the PC/ABS filament and the temp settings that work well. Thanks.
