Method for welding processed article and welded processed product

A method for welding thermoplastic articles characterized by comprising the steps of:

• providing first and second thermoplastic articles having joining surfaces to be vibration-welded together, one of the first and second thermoplastic articles including a first convex column surrounding the joining surface thereof and a plurality of second convex columns formed in a region surrounded by the first convex column, wherein the first and second thermoplastic articles include a supply port and a discharge port for a cooling fluid for effecting cooling in the region;
• placing the first and second thermoplastic articles on a vibration welding machine in such a manner that the first and second convex columns are superposed under pressure on the joining surface of the other of the first and second thermoplastic articles;
• activating the vibration welding machine so as to vibrate the first and second thermoplastic articles to thereby weld the first and second convex columns to the joining surface of the other of the first and second thermoplastic articles;
• and
• supplying the cooling fluid from a cooling fluid source to the region surrounded by the first convex column via the supply port and discharging the cooling fluid via the discharge port so as to effect cooling in the region during the vibration welding.