Plastic paint cans are made of PP material. After the plastic cans are injected, on the top of the cans, the pp ring should be assembled for the lids. This assembly should be airproof and waterproof. Sonikel Ultrasonics, has provided a good solution by welding the pp can to pp ring by Ultrasonic technology. Before Ultrasonic welding, plastic paint can is fixed by two pneumatic mechanism with the ring on it. This gives a rigid body during Ultrasonic welding. Sonikel has designed and manufactured this Ultrasonic welder for an export project.