An apparatus for forming an absorbent pad for an absorbent sanitary article, the pad comprising a first layer, a second layer and an absorbent material interposed between the first and the second layer (101, 102) and arranged according to an absorbent material spreading pattern M1 having at least one channel (104, 105) which is free of absorbent material, the apparatus comprising a forming drum, a first feed system for feeding to the forming drum a first web, intended to form the first layer, a second feed system for feeding to the forming drum a second web, intended to form the second layer, at least one spreader for spreading the absorbent material on the forming drum, creating a gap between the spreader and the forming drum, the forming drum comprising a suction system to create on the first web disposed on the forming drum a spread of absorbent material according to the absorbent material spreading pattern, the forming drum comprising at least one insert in the suction system to inhibit suction at the channel (104, 105) so that the absorbent material is not retained at the channel (104, 105), the first web, the second web and the absorbent material together forming a composite web, the apparatus comprising a system for joining the first and second webs (NW1, NW2) and located downstream of the second feed system, the apparatus comprising a removal system for removing the absorbent material to remove any absorbent material that may be present on the first web at the channel (104, 105) wherein the removal system for removing the absorbent material is located downstream of the absorbent material spreader in the feed direction V1 of the first web and comprises a blowing system comprising at least one centrifugal impeller whose axis of rotation R19 is parallel to an axis of rotation R2 of the forming drum. a forming drum, a first feed system for feeding to the forming drum a first web, intended to form the first layer, a second feed system for feeding to the forming drum a second web, intended to form the second layer, at least one spreader for spreading the absorbent material on the forming drum, creating a gap between the spreader and the forming drum, the forming drum comprising a suction system to create on the first web disposed on the forming drum a spread of absorbent material according to the absorbent material spreading pattern, the forming drum comprising at least one insert in the suction system to inhibit suction at the channel (104, 105) so that the absorbent material is not retained at the channel (104, 105), the first web, the second web and the absorbent material together forming a composite web, the apparatus comprising a system for joining the first and second webs (NW1, NW2) and located downstream of the second feed system, the apparatus comprising a removal system for removing the absorbent material to remove any absorbent material that may be present on the first web at the channel (104, 105) wherein the removal system for removing the absorbent material is located downstream of the absorbent material spreader in the feed direction V1 of the first web and comprises a blowing system comprising at least one centrifugal impeller whose axis of rotation R19 is parallel to an axis of rotation R2 of the forming drum.