There is hardly anything in this world that some man cannot make a little worse and sell a little cheaper, and the people who consider price only are his lawful prey.
John Ruskin 1819-1900
ANODISING = ADDING VALUE TO ALUMINIUM
Aluminium is an exceptional, modern material. It is lightweight, does not suffer from destructive corrosion and can be fully and repeatedly recycled. It is rapidly replacing more traditional materials such as steel and stainless steel across a whole range of industries.
Anodising is simply the best way to protect aluminium – allowing the natural metallic aspect of aluminium to be protected against the effects of pollution and corrosion for the lifetime of the project or product.
Anodising is the transformation of the surface of the aluminium into a structured oxide layer. Anodised aluminium remains pure aluminium, allowing it to be fully and repeatedly recycled through simple re-melting.
Anodising brings considerable added value to the material, giving it exceptional properties such as resistance to corrosion, resistance to abrasion and durability.
Anodising enhances the esthetic quality of aluminium over the very long term – the authentic metallic lustre of the metal is fully preserved in a perfectly homogenous surface, which can coloured to achieve the required surface finish.
Anodising is a technology which has already existed for 80 years and its exceptional performance has been proven in the most hostile and aggressive environments. Traditionally based on the batch process, flat rolled aluminium can also anodised in coil form prior to transformation, permitting lighter gauge metal to be treated and guaranteeing maximum and economy with perfect homogeneity of aspect.
A batch anodising line consists of a series of vertical treatment baths. For architectural applications, baths will be typically some 7 – 8 meters long (to permit the economical treatment of profiles), 1.25 -2.0 metres wide (to permit the treatment of sheets) and 500 mm depth to permit the treatment of pre-fabricated sections.
Extruded, cast or sheet aluminium, in semi-finished or finished form, is attached to a conductive rack with clamps. The aluminium is then immersed in the various treatment baths to undergo a series of chemical and electrochemical processes. After the final treatment stage, the anodised parts are removed from the rack and packed for shipment to the customer.
The above diagram is a representation of the batch anodising process.
Through its two plants in the UK (Heywood Metal Finishers in Huddersfield and LHT Anodisers in Uxbridge), United Anodisers is able to offer dimensional capabilities in batch anodising:
Maximum length 7 meters (U.S.: 23 feet)
Maximum width 2 meters (U.S.: 6,56 feet)
Max section depth 500 mm (U.S.: 19,7 inches)
These dimensions may vary according to treatment (please ask for further information)
Colours available
Natural (clear) in a range of different gloss levels
Champagne – Light Gold (Regency Gold 1) - Medium Gold (Regency Gold 2) - Dark Gold (Regency Gold 3)
Bronze – obtained by electrolytic colouring (Anolok I process) available in references 541, 543, 545, 547 and 549.
Black – obtained by electrolytic colouring (Anolok I process) in reference 54B
Blue Grey – obtained through interference colouring (Anolok II process, unique to United Anodisers) in references 717, 713, 715 and 717
A wide range of other colours are available using Sanodal dyes (different shades of yellow, red, green, orange and blue) and or using the Sandalor process (a combination of organic dyes and electrolytic colouring).
Please contact us for further information.
Advantages
Small batch sizes possible
Greater treatment flexibility
Can be used on aluminium in all its forms (profiles, sections, castings and sheets)
No maximum metal thickness
Can be applied on unfinished, semi-finished or finished aluminium
No limit in anodic film thickness
Disadvantages
Compared to continuous anodising, the process is less automated and the metal requires more handling
Higher cost
Prefect homogeneity of surface aspect for large surface areas more difficult to achieve
Continuous anodising can only be applied to flat rolled aluminium, whilst still in coil form.
A continuous anodising line consists of two de-coilers, an entry accumulator, a series of horizontal chemical and electrochemical treatment cells, an exit accumulator and a re-coiler.
Metal to be treated is place on a de-coiler and is pulled through the anodising line at a constant speed determined by reference to the parameters of the treatment to be realised
The entry accumulator permits the metal to be fed into the line when the de-coiler is stopped (when the treatment of the coil is finished) and the next coil is attached by staples.
The exit accumulator permits to stock the metal feeding from the line the coil when the re-coiler is stopped to permit the coil to be removed once treatment is complete.
Continuous anodising lines are designed to operate for days without stopping with only a minimum production team; line stops are required only for periodic or annual maintenance or product changeovers. Continuous anodising lines can be fully automated according to very precise production parameters. This type of anodising permits very uniform treatment across every coil.
Dimensions available
Coil width
1000mm – 2000mm
(US: 39 to 78 inches)
Metal thickness
0.3mm – 3.5mm
(US: 0,012 to 0,138 inches)
Maximum/minimum coil weight:
10 tons/2.5-3.0 tons
Minimum/Maximum anodic
film thickness:
Sub-micronic - 25 microns
(US : up to 0,00099 inches)
These dimensional possibilities may vary according to treatment (please check with us)
Colours available
Natural or clear anodizing – in different aspects
Gold – obtained by chemical mineral colouring– available in the following shades: Champagne – Light Gold (Gold 20), Medium Gold (Gold 30) and Dark Gold (Gold 40)
Bronze – colour obtained through electrolytic colouring with a wide range of shades from Light Bronze to Dark Bronze/Black. Available in references: Bronze 20, Bronze 30, Bronze 40, Bronze 50, Bronze 60, Bronze 70, Bronze 80 = Nearly Black
Colour and texture combinations: Stainless steel look-a-like – Alunox
Decorative Grey
Black
Red, Blue, Green Sanodal colours available on demand
Advantages
• Automated process with minimal handing
• Economy
• Uniformity of treatment parameters
- Within the same coil (both over the length and the width)
- From coil to coil
-
From production batch to production batch (reproducibility) • Homogeneity of gloss levels
• Homogeneity of colour
• Fully compatible with textured finishes such as perforated metal, tread plates, stucco effect, hammered effect
• Surface can be filmed after treatment
• Pre-anodised material can be cut, folded or pressed with appropriate equipment and expertise
Limitations
• Process can only be applied to flat rolled aluminium in coil form – not applicable for sheets, profiles or castings
• Higher volume means less flexibility in smaller treatment volumes
• 25 micron maximum
• Minimum production order = half coil
• Transformation after anodising is limited (for example, deep drawing or heavy embossing is impossible)
