A composite material is a combination of two materials with different physical and chemical properties. When they are combined they create a material which is specialised to do a certain job, for instance to become stronger, lighter or resistant to electricity. They can also improve strength and stiffness. If these materials are needed to be welded by ultrasonic technology, an ultrasonic welding machine is used. Sonikel Ultrasonics, has designed and manufactured special sonotrode and bottom fixture to create a very tight sealing between 2 composite materials.