2. The ultrasonic plastic welding surface design
In order to make the ultrasonic energy concentration, shorten the welding time and improve the welding quality in the process of plastic welding, the structure of the ultrasonic welding horn surface needs to be specially designed.
(1) When two plastic parts need to be welded in a plane, if a convex edge of a certain cross-sectional area is designed on the welding surface of a welding part, the ultrasonic vibration energy can be concentrated in the welding process and the welding time can be shortened. After melting, the convex edge is evenly spread over the welding surface, so as to produce a firm connection strength and reduce the deformation of the welding surface. It would be better to use a triangular energy seeker instead of a rectangular one. There are several welding surfaces for different applications.
(2) The disposable plasma separator is to put the whole human blood into the plasma cup and do high-speed rotating movement on the separator to separate the plasma from the whole blood. The product was originally sealed by rubber sealing ring and outer sealing aluminum ring, and later we used ultrasonic welding machine to seal the connection, please review below picture. For the original design, it used in aluminum ring sealing process, and the aluminum ring is rolled and pressed at the same time, although the welding effect is ok. But after a period of time, deformation will occur when the rubber ring and top cover are combined with the cup body, and it is easy to occur the phenomenon of loose sealing, leakage in the process of using, resulting in the waste of blood resources. However, the use of ultrasonic welding completely avoid the phenomenon.
(3) The ultrasonic welder can also be used for packaging plastic bottle large-volume parenteral (LVP) infusion bags. As a new substitute for glass bottles, LVP packaging has been widely used in the field of LVP packaging, which is characterized by light weight, no need to recycle, and less particle precipitation. In our designing the ultrasonic horn, how to fuse the bottle cap and the bottle body seal is a big technical difficulty. In this process, we also use ultrasonic welding technology, please review below picture. Because polypropylene is easy to absorb energy, we use a metal supporting mould at the bottom of the bottle body to reduce the amplitude of the bottle mouth in the welding process, thus reducing the absorption of energy. Most of the ultrasonic energy is converted into heat energy, and the lower bonding surface of the bottle mouth and cap is melted and fused into one. After adopting ultrasonic bottle mouth welding, the product has beautiful appearance and reliable sealing. Now we are developing automatic multi – station welding production line to meet the needs of users.
Post time: Apr-07-2022