An additive manufacturing machine (910) includes a build unit (920) including a powder dispenser (906) having a hopper (904) for receiving a volume of additive powder (902). A powder supply system (1000) includes a powder supply source (940) and a conveyor (1024) for transporting dispensed additive powder (902) to the hopper (904). A supply sensing system (1060) monitors the additive powder (902) that is dispensed from the powder supply source (940) and transported to the hopper (904) and a hopper sensing system (1040) monitors the additive powder (902) within the hopper (904). Each of these systems includes one or more powder level sensors (1042, 1044, 1062), weight sensors (1050, 1064), and/or vision systems (1054, 1070) for monitoring the additive powder (902).