L-Shaped Air Flush Spray Mixing Heads for the Production of Lightweight Automotive Components

摘要

In the automotive manufacturing industry polyurethane can be used for manufacturing a broad variety of components including "sandwich" panels that present, all together, a lightweight and structurally rigid component that, in time, have substituted heavier parts made with more traditional materials. In the automotive industry such properties are essential for components like trunk floors, rear shelves, sky roofs, and others. The purpose of this paper is to offer a view on the latest technical achievements in terms of lightweight automotive composite components made of sprayed polyurethane over a core composed of fiberglass layers and honeycomb paper, using the latest version of the Cannon LS 10 mixing head. Thanks to the developments of the new mixing head, an efficient distribution of sprayed material is achieved at a very fast pace and highly reduced waste. Furthermore, by means of a hydraulically operated stroke adjuster and washing valve, along with the redesigned geometry of some components, this mixing head can be flushed without solvent, while the cleaning piston allows less frequent washing of the head. Processes that allow lower curing temperatures are also possible. In this way, molds that operate at lower temperatures can be utilized. This consents reducing the energy consumption involved in the process. The use of improved chemical formulations cuts processing time, requiring short and efficient spray stretches. This modern head, therefore, can reach more than 200 g/s flow rate, while maintaining the optimal mixing ratio. Moreover, larger areas can be covered with an optimized surface-spray tip distance, spray angle and flow rate. The Cannon group has developed two state-of-the-art laboratory booths at Cannon USA (Cranberry, PA) and at Cannon Afros (Caronno Pertusella, VA, Italy), which are cooperating to develop this technology. This allows this equipment manufacturer to closely work with well-known raw material suppliers and mold manufacturers, continuously improving the technologies to keep up with increasingly faster productions and lower energy consumptions while, for the same reason, new chemicals are developed.