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It depends of what 3D-printer, plastic and settings you use. If you are unsure you should use raft and support. All parts are designed to be possible to print with PLA plastic directly onto a suitable print bed surface, without the need of raft or support.

To be on the safe side, use PLA with slow print speeds such as 30 mm/s and make sure that you have a good and effective cooling fan aiming at the 3D-printed object.