A waste removal and transfer assembly for a 3D printing system comprises a waste material remover and a waste material collector. The waste material remover comprises a movable waste removing element selectively movable into contact with a planerizer roller to remove 3D printing waste material from the planerizer roller. The waste material remover is coupled to translate with the planerizer roller and comprises an opening leading to a waste material receptacle configured to receive waste material and at least one port selectively operable to transfer waste material from the waste receptacle. The waste material collector has a receiving position that is stationary relative to the waste material remover. The waste material collector comprises an opening and a waste material storage recess to receive waste material transferred from the waste material remover via the at least one port and to store the received waste material for subsequent disposal.