Ultrasonic Welding for Packaging industry
Packaging is an application where ultrasonic welding is often used. Many common items are either created or packaged using ultrasonic welding. Sealing containers, tubes and blister packs are common applications.
Ultrasonic welding is also applied in the packaging of dangerous materials, such as explosives, fireworks and other reactive chemicals. These items tend to require hermetic sealing, but cannot be subjected to high temperatures. One example is a butane lighter. This container weld must be able to withstand high pressure and stress and must be airtight to contain the butane. Another example is the packaging of ammunition and propellants. These packages must be able to withstand high pressure and stress to protect the consumer from the contents. When sealing hazardous materials, safety is a primary concern.
The food industry finds ultrasonic welding preferable to traditional joining techniques, because it is fast, sanitary and can produce hermetic seals. Milk and juice containers are examples of products often sealed using ultrasonic welding. The paper parts to be sealed are coated with plastic, generally polypropylene or polyethylene, and then welded together to create an airtight seal.The main obstacle to overcome in this process is the setting of the parameters. For example, if over-welding occurs, then the concentration of plastic in the weld zone may be too low and cause the seal to break. If it is under-welded, the seal is incomplete. Variations in the thicknesses of materials can cause variations in weld quality. Some other food items sealed using ultrasonic welding include candy bar wrappers, frozen food packages and beverage containers.