MECHANICAL PRETREATMENTS
Unwanted surface damage, defects, and irregularities must be mechanically removed before anodic treatment. Different surface effects (gloss, brushed, or matte) can be achieved through mechanical pretreatment by brushing, grinding, polishing, and various blasting processes.
Different pretreatments give the workpiece interesting and very different design and surface effects.
Part Sizes:
Polishing: on request
Brushing: 3000 x 1500 mm; on request
Grinding: on request
Various blasting processes: Up to a length of 6500 mm possible; on request
The following pretreatments are possible according to ÖNORM C2531 and DIN standard 17611:
A0 = E0 = unprocessed, anodized and compacted
Anodic oxidation is carried out after degreasing without any further pretreatment. The surface finish resulting from the previous treatment remains intact; that is, grooves, scratches, file marks, corrosion defects present before treatment, etc., remain visible. Furthermore, previously undetectable surface defects may become visible.
This method is chosen when the surface treatment serves only the purpose of corrosion protection and the parts are not visible.
A1 = E1 = ground, anodized and compacted
Sanding produces a relatively uniform, somewhat dull-looking surface. Any surface defects are largely removed. However, it does not create a flat surface. Therefore, particularly deep scratches cannot be repaired. Depending on the abrasive grain, coarse to fine sanding marks will be visible after treatment. With non-parallel sanding directions (e.g., on frames), apparent differences in brightness will occur due to differently directed reflections.
A2 = E2 = brushed, anodized and compacted
Brushing creates a uniform, bright surface – unlike A1. The brush strokes are visible after treatment. Grooves, scratches, file marks, and existing corrosion defects are only partially removed. A fine brushed finish is achieved. Surface damage is not removed. Press marks are removed.
A3 = E3 = polished, anodized and compacted
Polishing creates a shiny, polished surface. Grooves and scratches, file marks, existing corrosion and other surface defects are only partially removed. Bridge marks may become clearly visible after this treatment.
A4 = E4 = ground, brushed, anodized and compacted
This treatment method combines processes A1 and A2. Mechanical surface defects are eliminated, resulting in a uniformly glossy surface. Grooves, scratches, inclusions, etc., are no longer visible, unlike with previous treatment methods.
A5 = E5 = ground, polished, anodized and compacted
This treatment combines processes A1 and A3. The surface acquires a smooth, even more glossy appearance. Surface defects such as grooves, scratches, inclusions, etc., are removed.
A6 = E6 = specially pickled, anodized and compacted
A clean surface is essential for consistent treatment with various processes. Therefore, contaminants, oils, greases, coolants, abrasives, as well as rolling, pressing, tempering, and casting skins must be removed during chemical pretreatment.
This results in a highly matte aluminum surface. Surface defects such as grooves, scratches, inclusions, etc., are smoothed out, but not always completely eliminated.