Method for welding seams in disposable garments

A method for welding together with a movable ultrasonic welder opposing moving panels which are to be joined together to form a disposable garment in a direction of manufacture, at least one of which panels contains a plastic material capable of being rendered amorphous with heat, the welding method comprising the steps of:

• providing an ultrasonic welder movable along a portion of the direction of manufacture;
• bringing the two panels together and pressurizing at least a portion of each panel into contact with the other panel using the ultrasonic welder during a predetermined period of time;
• carrying out the pressurizing step during the predetermined period of time while the panels and the ultrasonic welder are moving continuously together along the direction of manufacture;
• heating the two panel portions using the moving ultrasonic welder to heat the plastic material with ultrasonic energy during a first segment of the predetermined period of time with sufficient heat and for a sufficient duration to render the plastic amorphous;
• maintaining pressurization using the ultrasonic welder while the ultrasonic welder continues to move together with the panels during a second segment of the predetermined period of time without heat sufficient to permit the plastic material to solidify;
• then
• withdrawing the pressurization of the ultrasonic welder from the welded panels;
• and wherein
• the second segment of the predetermined period of time is substantially greater than the first segment.