Full-field strain analysis after the forming process is based on the precise measurement of initially squared grid patterns. This means that the sheet metal has to be marked before forming. Marking has to fulfil the following requirements:
- perfect transfer of sheet metal strain to the grid
- high visibility and contrast of the grids after intense tool contact
- low impact on the tribological behaviour of the sheet metal
- high precision grids
Different stencils are available with grid spacing of 1–2.5 mm so that the appropriate marking can be applied for the corresponding forming process. The ViALUX marking sets cover the whole line of materials used in forming technology. In addition to the electrolytic marking equipment a new printing methodology was developed for practical use for non-conducting materials.
The 2.0 mm grid contains additional reference points in variable order. This 3-point codung simplifies the identification of the grid stitches in each 3D image set and therefore helps to reduce the time for evaluation and linking single measurements.
The XL format marking stencils cover a triple larger marking area compared to the standard stencil. Thus, they enable large-scale marking in one step. By means of digital printing techniques, these DigiGrid XL marking grids are flexible and can be adjusted to the customer's wishes.
Electrolytic marking equipment
The E1 electrolyte is a standard etchant for many ferrous and non-ferrous metals. A proven selection of print colours is available for sheet metals with organic coating, plastics or other materials. Electrochemical grid marking is well proven at elevated temperatures up to 230°C. Special printing colours are available for higher forming temperatures.
E1 Electrolyte is suited for the electro-chemical marking of a number of ferrous and nonferrous materials. N2 Neutralyte, R3 Stencil-cleaner, and the coating of the stencil grids are harmonized to the E1 Electrolyte. In addition, ViALUX also supplies the electrical equipment that is necessary for marking.