Surface treatment of aluminium extrusions

Transcription

1 Surface treatment of aluminium extrusions

2 Contents Anodising 2 3 Lacquering 4 Mechanical/Chemical Surface Treatment 5 Other Surface Treatments 6 Contacts and Samples 7 In its natural state, aluminium has an attractive and corrosion resistant surface. The surface treatment of aluminium is mainly carried out for aesthetic reasons or because special characteristics are required. Characteristics that can be changed and improved by surface treatment are things like resistance to corrosion, surface structure, hardness, durability, ability to reflect and electrical insulation. In this brochure we present the most common methods of surface treatment we use, divided into four main groups: ELECTROCHEMICAL anodising ORGANIC lacquering MECHANICAL grinding and blasting CHEMICAL polishing and burnishing Anodising Suitable for decoration or improved surface protection. Anodised extrusions are used in a wide range of architectural and decorative applications where a beautiful and resistant surface is required. The process increases the thickness of the natural oxide layer. This improves resistance to mechanical wear and corrosion at the same time as electrically insulating the surface. The thickness of the layer is determined by surface requirements and the application. Standard colours for indoor and outdoor use are shown on the page opposite. Staining The anodised layer can be stained in many colours. Depending on the method used, the durability achieved can be suitable for both indoor and/or outdoor applications. Recommended layer thicknesses when anodising Layer thickness µ Applications 25 Surface exposed to severe corrosion or wear, especially outdoors in corrosive environments 20 Severe or normal exposure outdoors, e.g. construction materials, vehicles and boats. 20 Severe indoor attack by chemicals, in damp air e.g. the food industry 15 Fairly severe wear indoors, e.g. railings or ornamental finishes outdoors 10 Normal exposure indoors or outdoors in a dry and clean atmosphere. For reflectors, fittings, ornamental edging on vehicles, sports equipment 5 Normal indoor exposure 2

3 Anodising Standard colours Natural Nickel silver Light bronze Medium bronze Dark bronze Black Light red Medium red Dark red Light gold Medium gold Old gold Printing techniques do not allow the exact shades to be shown which is why deviations can occur. Request a colour sample from our Customer Service Department (see p. 7). 3

4 Mechanical surface treatment Special surface finishes can be achieved by mechanical treatment such as polishing, grinding and blasting. These methods remove small blemishes from the surface, give a uniform appearance and provide the opportunity to create various reflecting and decorative surfaces. Here are some examples of grinding and glass blasting. For further examples, contact Customer Service! Heavy grinding Light grinding Glass blasting Chemical surface treatment Chemical surface treatment can be applied as pretreatment before anodising or lacquering as well as to remove surface unevenness and create a shiny surface. Here are two examples of polishing. Environmentally sustainable and chrome-free processes are available to give high resistance to corrosion for surfaces where the ability to conduct electricity is required. Contact Customer Service for more examples and further details. Glasblästring + kemisk polering Kemisk polering 4

5 Lacquering Powder lacquering of aluminium extrusions is a solvent-free and environmentally sustainable method that provides a wide spectrum of colours. It gives good corrosion characteristics and a durable and low-friction surface. Powder lacquer is resistant to UV light and is therefore also suitable for outdoor use. The whole spectrum of RAL and NCS colours is available. Select the colour you want using a standard colour chart. We have access to both vertical and horizontal lacquering plants for efficient production and consistently high quality. Powder lacquering of aluminium extrusions gives access to the whole spectrum of colours. 5

6 Other surface treatments Screen printing Screen printing on aluminium extrusions provides a durable and decorative finish. It can be applied to both untreated and anodised surfaces. Improved durability is achieved if printing is done before the last anodising step; final sealing. The pores in the oxide layer absorb the printing ink and the pores are finally sealed to give extra protection against wear. Foiling A foil film can be applied to the majority of extrusions to protect the visible surface against damage during mechanical treatment, transport and assembly. 6

7 Surface and colour sample Printing techniques do not allow the faithful reproduction of the shades of colours and surfaces so the pictures in this brochure can only provide an indication of what is possible. Request surface samples from Customer Service. Visible or not? Obviously, greater demands are made on an extrusion s visible surfaces than on those that cannot be seen. Mark visible surfaces with a dotted line on the design drawings to avoid misunderstandings and problems. Optimal extru- sion design The surface structure and appearance of an extrusion can be optimised as early as the design stage. The design impression, surface finish and characteristics can be improved through décor tracks, grooves etc. Other treatments Apart from surface treatment, HAP has resources for all the usual machining and assembly techniques used for aluminium extrusions and components. Our plants have special equipment including CNC longbed and multioperational machines. For larger volumes or special commissions, we can set up customised and highly automated production lines that can also include surface treatment. 7

8 Inforema AB / Originalbyrån i Växjö AB At your service! Please contact our officices or visit our homepage for further information regarding customer support and technical assistance. Hydal Aluminium Profiler AB Box 236, SE Vetlanda Tel: +46 (0) hap@hydal.com