Anodizing hall deals with the aluminium surface finish by anodic oxidation – anodising. Anodizing hall is equipped with a state-of-the-art, fully automated data recording line with dimensions of 3m x 0.5m x 2.2m , including the sewage treatment plant. The quality is guaranteed by chemical agents from the top supplier of such agents, Alufinish. The line meets standard TL 212 with improved technology for alkaline resistance of pH 13.5. The line is fully designed to comply with the requirements of the automotive industry.
Aluminium surface finish – anodising
Anodic oxidation or anodising is a type of chemical thermal surface finish of aluminium products (abbreviation of Aluminium Electrolytic Oxidation). Due to the passage of direct current a thin layer of aluminium oxide, Al2O3, with a thickness of 5–30 µm is created on the surface of the aluminium parts. This layer does not oxidise, and thus it protects the aluminium itself from oxidation. It is used, for example, in the aircraft and automotive production or where the aluminium is used as an exterior, such as in aluminium windows.
Anodic oxidation of finished aluminium products increases their resistance to weather conditions as well as to mechanical abrasion resistance of the surface layer. Thermal and electrical conductivity is also reduced, as is surface roughness, for example after chip-forming machining, because the elimination of microfissures on the aluminium surface structure leads to an increase in surface mechanical strength. Anodic oxidation also significantly increases products’ lifetimes. Apart from this protective function, anodic oxidation also has an aesthetic role because it allows the anodised subject’s surface to be substantially highlighted, including possible colouring , providing them with the required appearance.
The part surface goes through treatment before anodic oxidation. To remove grease and impurities remaining on the surface after previous mechanical treatments, the parts undergo a degreasing process in degreasing baths.
Before anodic oxidation, the aluminium surface is submerged in the E0 bath. Bathing in the E6 bath integrates the surface and provides it with a satin matte finish.
Before anodic oxidation itself, it is necessary to clean the surface with a special agent from the Alufinish company. This provides the optimal environment for anodic oxidation.
Before anodising, the part surface also goes through mechanical pretreatment. This treatment is not only effective but flexible, allowing for adjustment for different product lines.
To apply the glossy anodic oxidation, our company uses top robotic polishing technology from the Cimotec company – Robocel 400GT. This machinery was developed specially for polishing roof beams and other straight or slightly curved decorative laths. It is possible to use fixed, revolving, and tilting polishing equipment to treat the components.
After mechanical polishing, electrolytic polishing follows in line of anodic oxidation. Connection of these two technologies results in the final glossy surface with values from 200–600 Gu used in the automotive industry.
Aluminium surface treatment
Natural anodising, pretreatment E0 – surface degreasing and cleaning Mechanical grinding E1 – surface pretreatment before anodic oxidation Mechanical brushing E2 – surface pretreatment before anodic oxidation Mechanical polishing E3 – surface pretreatment before anodic oxidation Combination of pretreatments E4/E5 – brushing and grinding / grinding and polishing Natural anodised coat, pretreatment E6 – satin matte finish design Black anodised coat, pretreatment E0/E6 or E6/EV6 – after anodic oxidation the implementation of ‘C’ colours (according to the Qualanod standard) in the required shade Electrochemical polishing E7 – without mechanical pretreatments Electrochemical polishing E8 – before anodic oxidation, the parts are ground and/or polished to give them that very glossy surface
– 3D CNC bending – 5-axis CNC milling – Robotic and manual polishing – Laser marking or engraving