Cleaning of melt blown dies, melt blown die blocks
Liquid polymer under high pressure comes out of a spinning beam (die beam, die block) in the melt blown process (spinning fleece process) and will be blown and spun through high speed hot air and cold air into fine fibres (micro fibres), which will be collected by a takeup mesh and carried away. Nonwoven micro fibre fleece fabrics are produced by this method, which, depending on the application, could be produced in different densities, thicknesses, absorptivity, strengths and merged into several layers. Besides of the well-known fleece shirts and fleece jackets, other typical products are extremely light but high efficient respiratory filters, cabin filters and fuel filters, and also large absorption and isolating stuff, such as diapers, cushion fleece, or isolating mats. Single use clothes or vacuum cleaner bags are also manufactured out of micro fibres fleece.
The cleaning of these spinning beams or die beams, which are frequently several meters long, requires a very delicate cleaning process, due to the extremely fine die holes and geometries. The fully automatically working thermal cleaning system VACUCLEAN by SCHWING heats up the tools slowly and gently, whereas a big portion of the cold polymer inside and outside will melt and flow out. The proper cleaning of the spinning beam will take place at approximately 450 °C within 8 to 30 hours, depending on the size and geometry of the tool, by means of controlled pyrolysis and oxidation under a vacuum atmosphere.
By this method any thermal or mechanical damage is excluded and a perfect cleaning quality without carbon remains is always assured.