| abstract |
An energy director structure with an auxiliary weld depth limitation feature is provided. The energy director (14) is located on a first contact shelf (12). A second contact shelf (16) that is shorter, broader, forming a mesa is positioned laterally adjacent to, and below, the first contact shelf (12). The second contact shelf (16) forms a mesa that limits the depth of the ultrasonic welding. Limiting the time, pressure, or temperature of the welding process additionally ensures the weld depth is limited to the height of the second contact shelf (16) or mesa. Two plastic pieces (10, 30), one of which includes an energy director (14) and mesa structure, may be welded together to form a capillary having precise volumetric accuracy. |