I have two parts which i need to ultrasonic them together. This is the first time i created this kind of assembly method for two plastic parts. The part thickness is 2 mm. I created a lip around the matching surface to ease the alignment for ultrasonic. Then created triangular energy concentration feature along the lip, after google around for ultrasonic welding design. Is this the common practice? For a 2 mm thickness part, i have to create the triangular sweep all around the lips or just few points around the lips? Any rule of thumb or sure do guideline for the ultrasonic feature dimensions? Is the triangular feature feasible when making mold-the height is 0.4 mm, angle between the equal length sides is 60 deg. Any help , suggestions would be much appreciated.