A powder bed fusion apparatus comprising: a powder application device; and a powder delivery device for providing raw material powder to the powder application device, the powder delivery device comprising: a powder supply section configured to receive raw material powder, the powder supply section comprising an outlet for providing the raw material powder to the powder application device; a first physical parameter determining unit (62, 66, 70, 84, 86) arranged at a first location of the powder supply section and configured to determine a first physical parameter in the powder supply section; a second physical parameter determining unit (64, 68, 80, 82) arranged at a second position of the powder supply section and configured to determine a second physical parameter in the powder supply section; a control unit configured to determine whether the first physical parameter meets a first tolerance criterion and to determine whether the second physical parameter meets a second tolerance criterion; a powder treatment unit (72, 74, 76, 88), wherein the control unit is configured to instruct the powder treatment unit (72, 74, 76, 88) to perform a powder treatment in case it determines that the first physical parameter does not meet the first tolerance criterion; and wherein the control unit is configured to, in case it determines that the second physical parameter does not meet the second tolerance criterion, stop a powder application process of the powder application device, or wherein the powder bed fusion apparatus further comprises a valve located at the outlet of the powder supply section and the control unit is configured to, in case it determines that the second physical parameter does not meet the second tolerance criterion, close the valve. a powder application device; and a powder delivery device for providing raw material powder to the powder application device, the powder delivery device comprising: a powder supply section configured to receive raw material powder, the powder supply section comprising an outlet for providing the raw material powder to the powder application device; a first physical parameter determining unit (62, 66, 70, 84, 86) arranged at a first location of the powder supply section and configured to determine a first physical parameter in the powder supply section; a second physical parameter determining unit (64, 68, 80, 82) arranged at a second position of the powder supply section and configured to determine a second physical parameter in the powder supply section; a control unit configured to determine whether the first physical parameter meets a first tolerance criterion and to determine whether the second physical parameter meets a second tolerance criterion; a powder treatment unit (72, 74, 76, 88), wherein the control unit is configured to instruct the powder treatment unit (72, 74, 76, 88) to perform a powder treatment in case it determines that the first physical parameter does not meet the first tolerance criterion; and wherein the control unit is configured to, in case it determines that the second physical parameter does not meet the second tolerance criterion, stop a powder application process of the powder application device, or a powder supply section configured to receive raw material powder, the powder supply section comprising an outlet for providing the raw material powder to the powder application device; a first physical parameter determining unit (62, 66, 70, 84, 86) arranged at a first location of the powder supply section and configured to determine a first physical parameter in the powder supply section; a second physical parameter determining unit (64, 68, 80, 82) arranged at a second position of the powder supply section and configured to determine a second physical parameter in the powder supply section; a control unit configured to determine whether the first physical parameter meets a first tolerance criterion and to determine whether the second physical parameter meets a second tolerance criterion; a powder treatment unit (72, 74, 76, 88), wherein the control unit is configured to instruct the powder treatment unit (72, 74, 76, 88) to perform a powder treatment in case it determines that the first physical parameter does not meet the first tolerance criterion; and wherein the control unit is configured to, in case it determines that the second physical parameter does not meet the second tolerance criterion, stop a powder application process of the powder application device, or wherein the powder bed fusion apparatus further comprises a valve located at the outlet of the powder supply section and the control unit is configured to, in case it determines that the second physical parameter does not meet the second tolerance criterion, close the valve.