The present invention relates to an arrangement (1 ) for processing of a material (7, 8) comprising at least one layer of material by means of an ultrasonic device (2) consisting of an ultrasound horn (3) arranged adjacent to an abutment (5; 5'), in conjunction with which a gap is defined between the aforementioned ultrasound horn (3) and the aforementioned abutment (5; 51), in conjunction with which the aforementioned ultrasonic device (2) is arranged for the purpose of feeding the aforementioned material (7, 8) through the aforementioned gap (6). In accordance with the invention, the arrangement (1 ) includes a pre-compression unit (9; 9') for the mechanical compression of the aforementioned material (7, 8) before it is fed through the aforementioned gap (6). The invention also relates to a method for processing of the aforementioned kind.