At the beginning of the production street, on both the top and bottom side of the machine a facing material (for example steel from a steel coil) is introduced. Depending on the application and the constructive demands of the final product, the facing material firstly is profiled after being fed into the machine. All is then transported to the lay down, after a pre-heating step and/or a plasma- or alike treatment. The facings always have to be preheated to guarantee a good reaction profile of the adhesive system. Without pre-heating the chance of so-called heatsink occurs. Heatsink means that the warmth, which the adhesive system develops during curing, flows away too fast to get the adhesive well and fully cured. Directly after pre-heating, a dosing unit applies the liquid components A and B separately as droplets or stripes onto the surface. A moving wiper or weeping plate mixes the two components. Between both facings an insulating core of PUR, PIR, EPS or MW is now introduced. The facings with adhesive are than pressed onto the core material.
At low surrounding temperatures the sandwich element can be post-heated in a conveyor to guarantee a conditioned curing of the PUR system. Hereafter the panels are cut to tailor made sizes. Adequate testing of the delamination values can be carried out just after 24 hours because the adhesive system is than fully cured.