Finite element modeling and analysis of relief images pressing technological process on paper materials. Relief stamping method
|Keywords||Relief stamping, paper, cardboard, polyurethane, stamp, pressing|
|Programs in use||LS-DYNA, SolidWorks|
Description of relief stamping method
Elements used in relief stamping: a metal stamp with an engraved image, paper material or paperboard, a polyurethane plate. The relief image on the polyurethane is obtained by pressing the paperboard by the stamp into the polyurethane.
Fig. 1. Manufacturing scheme of the relief stamping process
Fig. 2. Photo of a stamp with a set of engraved test images
The stamping process is followed by a by-effect - tension of paper material (Fig . 3). In addition, as a result of created pressure elastic material "leaks" outside the stamp area and bursts the paperboard by the stamp perimeter (Fig. 4).
Fig. 3. The result of paperboard side tension during the stamping process
Fig. 4. The result of tension and breach by the stamp contour
Modeling of the relief stamping process is done for two different metal stamps (Fig. 5). The large stamp is the one with three columns of type-setting elements: square, rectangular and hemispherical. The small stamp is the one with a single column of type-setting elements (rectangular).
Fig. 5. Stamp profiles
|Sheet of paper. Contours of z-axis deformations.||Polyurethane mat. Contours of z-axis deformations.|
|Sheet of paper. Contours of z-axis deformations.||Polyurethane mat and sheet of paper.
Contours of z-axis deformations.
During the relief stamping process thinning of a perforated sheet occurs, which can lead to paper rupture. The paper thinning typical for the studied process is represented in Fig. 6. The initial (paper) thickness is equal to 0.1 mm. The most probable rupture zones are located in the areas of connection of the paper with side surfaces.
Fig. 6. Variation of paper thickness (mm)
The large stamp. Displacement field (m). Paper sheet
The large stamp. Distribution field (m). Polyurethane base plate