Application of Finite Elements on Non-Linear Deformation of Flexographic Photopolymer Printing Plate

摘要

Printing offers the possibility of producing mass quantities of a wide variety of electronic components and devices quickly and at lower cost. Flexography is mainly used for packaging applications, but is also a potential method for the micro manufacture of electronic devices, smart packaging and RFID. Fine solid lines of high quality are essential to enable printing of ink tracks for electronic applications. Plate characteristics are among a number of process parameters that will influence print line quality, which will affect the electrical performance of printed tracks. Deformation of the photopolymer plate is an important factor in determining the line quality. Therefore, an investigation into plate deformation is vital. A numerical model of close multiple lines has been developed and used to examine its deformation under a range of printing conditions. An Ogden constitutive model was used to describe the response of the photopolymer plate material. A series of uniaxial tension and pure shear experiments was carried out to provide mechanical properties of the photopolymer. In validation of the material model, numerical results agree well with the experimental data in both simple tension and pure shear. Numerical models were then used to determine the change in line profile, as the deformations occur on a microscopic level and cannot be assessed experimentally. The simulations yield information on line width increase due to plate deformation. However, the predicted line width is smaller than that of printed line measured using image analysis. The difference in line width is due to ink spreading and by relating the numerical results with those from the printed copy; the proportion of increase in line width due to the deformation of the printing plate has been quantified at 53 to 69%.