Abstract: In a process and apparatus for the production of panels, plates or sheets are cemented on opposite sides of an intermediate layer of honeycomb with transverse openings constituted by a network of strips of constant width defining the openings. The edges of the strips defining the network are cemented on opposite sides of the layer and the plates or sheets are applied on the cemented edges. Two lateral parallel grooves are formed intermediate the thickness of the longitudinal edges of the intermediate layer with the layer contracted, such that the strips are flat against each other. Then these grooves are used to guide the layer when the layer is pulled out to form the openings. The necessary reduction of the width of the layer is effected by inserting two lateral convergent guides in the grooves on opposite edges of the layer, and forcing the layer to move in the direction of convergence of these guides.