Ultrasonic welding of fabrics for sleep apnea treatment

A method of making headgear for use in holding a respiratory mask in position on a patient's face, comprising:

• forming at least a first headgear component having a first thickness, and a second headgear components having a second thickness, the first and second headgear components including at least a fabric material;
• overlapping the at least first and second headgear components in an ultrasonic welding tool to form an overlapping portion having a third thickness that is equal to the sum of the first thickness and the second thickness;
• ultrasonically welding together the at least first and second headgear components to form an ultrasonic welding joint;
• shaping one of the at least first and second headgear components, thereby forming at least one headgear section;
• and
• removing part of the overlapping portion of the first or second headgear components, so that a remaining portion of each of the first and second headgear components abut each other to form a flush joint and the overlapping portion has a fourth thickness that is equal to or less than the first thickness.