Ultrasonic welding is certified as an economical joining process in the automotive industry for joining and installing plastic materials and metal parts.
Rapid cooling shortens the cycle time in the production process
Ultrasonic welding is certified as an economical joining process in the automotive industry for joining and installing plastic and metal parts.
Its significant advantage is that there is no need to use adhesives, connecting elements and solvents; therefore, this method is very environmentally friendly and effective. This is suitable for applications that require shorter cycle times, such as when using robots. Now, the innovative cooling concept has achieved a cycle time of less than two seconds on a fast production line.
Ultrasonic welding is certified as an economical joining process in the automotive industry for joining and installing plastic and metal parts. Its significant advantage is that there is no need to use adhesives, connecting elements and solvents; therefore, this method is very environmentally friendly and effective. This is suitable for applications that require shorter cycle times, such as when using robots. Now, the innovative cooling concept has achieved a cycle time of less than two seconds on a fast production line. In the automotive industry, when individual components need to be assembled into larger modules, ultrasonic riveting is usually selected. The plastic at the contact point is plasticized by effectively converting ultrasonic energy into heat, which is shaped and pressed under pressure. Therefore, when the thermal load of the product and the environment is low, a very strong joint is formed after the weld is cooled. In order to speed up this process and shorten the cycle time, riveting tools are usually used, that is, to cool the welding head. There are different possibilities for this, but there is a significant difference in efficiency between them.
It is more efficient when the welding head is cooled. It is a possibility to use only compressed air to blow the welding head. But the cooling process will last a long time, and the large amount of compressed air consumption is not efficient. Therefore, welding heads with an integrated cavity (ie, cavity) are more common, which can guide the compressed air to the tip in a targeted manner. The cooling air can also be accurately directed to the place where it is needed. This will speed up the cooling process and reduce compressed air consumption. However, the solution is more complicated in structure, especially when the welding head is installed on the robot. The compressed air must be fixed directly on the welding head. Therefore, this solution lacks flexibility, because the welding head can no longer be easily replaced. For example, when changing products, the compressed air pipeline must be loosened and then re-fixed. In addition, even if the welding head has a long service life, it is a worn-out part and will always need to be replaced.
Vortex booster
Therefore, ultrasonic expert Telsonic AG has developed other solutions for welding head cooling. In this patented solution, the compressed air connection is no longer placed on the welding head, but on the booster. In principle, the ultrasonic system consists of several components: an electric box that generates ultrasonic waves, a converter (which uses piezoelectric ceramics to convert ultrasonic waves into mechanical vibrations, which are then strengthened by a booster, and then transmitted to the welding head. The booster is used for cooling It has two advantages. In this way, it is not necessary to loosen the compressed air interface when replacing the welding head and the cooling will be more efficient. The working principle of the vortex booster: firstly guide the compressed air (maximum 10bar) to the booster and perform pre-cooling . Then relax it and use the Joule-Thomson effect to continue to reduce the air temperature (see the technical column). There are also such intuitive examples in daily life: cooling soda, creamy ice cream or whipped cream squeezed out of a pressure bottle When the snow machine throws artificial snow to the ski resort. The welding head suitable for the booster has a special shape of the mold cavity, which is suitable for the Rank-Hellsch vortex tube. The low pressure zone with fast vortex circulation will cool the center The air is separated from the hot air on the wall surface of the welding head. Then, the cold air flow from the center of the welding head directly reaches the tip of the welding head. In this way, the riveting point is cooled faster; the cooling efficiency is improved. Practice shows that with the patented cooling process, the robot supports The cycle time of ultrasonic riveting is reduced by nearly half, sometimes even less than two seconds.