FINISHING TECHNOLOGY
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COMPUTERIZATION and AUTOMATION OF ANODIZING PLANT
Several kinds of control ways are available, especially to integrate the anodising rectifiers in the automatic plants...
Mario Leoni - ELCA S.r.l. - Brescia, ItalyAbstract
Several kinds of control ways are available, especially to integrate the anodising rectifiers in the automatic plants.
Manual control:
It is the simplest control way. Parameters are adjusted manually by the operator.
Automatic Local control:
Obtained using a dedicated process computer installed on the equipment.
Different programmable devices can satisfy the requirements of any special process
Automatic Remote control:
It is obtained interfacing the equipment with a general external control system (PLC) by means of analogue signals or digital peripherals or programmable device with serial communication line.
Fully integrated automatic control:
By using the local process computer (APC or Elca Ramper or the Elca digital control) and with the supervision of the general control system (PLC), based on digital information exchange via serial communication line.1.
INTRODUCTION
Current rectifiers are necessary to perform the electrolityc oxidation of the aluminum and the technical features of the equipment have continuously been modified in the last years. Since the oldest, simplest type without any stabilization had been commissioned, the request for improved regulation charachteristics and control possibilities has greatly increased. The introduction of the SCR-based technology allowed the construction of fully electronic controlled rectifiers, practically with infinite control possibilities.
Let us briefly summarize the main control types of converters nowadays used in anodizing.
• Manual control
• Automatic Local control
• The automatic control
• Fully integrated automatic control
ANODIC COATING FORMATION ON ALUMINUM WITHOUT A "BARRIER LAYER"
Arthur W. Brace, Great BritainAbstract
This contribution provides convincing evidence that coating formation does not commence with formation of a uniform film but with the random growth of anodic oxide nuclei which progressively spread to cover the whole surface. These nuclei are considered to be associated with defects in the atomic lattice structure. It is also shown that it is unlikely that the porous structure develops from attack of the electrolyte. Publshed data is critically analysed to demonstrate that published values for cell and wall sizes are mean values which have a normal statistical distribution with a variance of approx. ±25%. Published sources are also used to show that nitial anodic oxide formation commenences from random centres. The implications of these findings are considered.
This paper has been written after an involvement of the author in the anodizing industry for over 50 years. With it comes a feeling of disappointment at the continued acceptance of the "barrier layer" theory which, as a personal judgment, at the anodizing shop floor level has been found to be inadequate and misleading. At the academic level, contributions seem to have become of increasing intellectual sophistication but of increasingly limited help to the production anodizer. Whilst the "barrier layer" has been researched to the ndl degree, only limited attention has been given to factors affecting film quality. There is no explanation offered as to why, under controlled constant conditions, the anodic film can change from a homogeneous film to a degraded one that "chalks" badly on exposure when the thickness exceeds 20 µm.
Another problem has been the academic obsession with 99.99% purity aluminum. The author is unaware of any papers on the morphology of coatings produced on the main materials anodized by industry, e.g., 1050, 5050 and 6063. These alloys behave differently from 99.99% in anodizing, so it is highly probable this will affect the morphology and properties of the coatings produced.
The development of industrial processes
The production of an anodic oxide film on aluminum was established in a patent by Pollok (1) in 1896. Tbe coating produced was what became known as a "barrier layer" coating. Subsequently, the process was used in the production of electrolytic condensers.
Plants were set up in the 1920s to serve the infant electronics industry.
The introduction of processes producing relative1y thick, porous anodic films on aluminum also began in the 1920s, with the publication of a series of patents. The first of these was developed al the National Physical Laboralory in England.(2). It covered the use of a chromic acid electrolyle in a cell in which aluminum was the anode and direct current was used. Il has remained in use for many years for the protection of aircrafl and defense components.
ALUPROGETTO:
THE BEAUTY OF STRUCTURAL ALUMINIUM IN THE CONSTRUCTION FIELD.
A REVIEW OF SIGNIFICANT APPLICATIONS
Mario Conserva - Edimet SpA - Italy ALUPROGETTO is an Edimet international award included for the first time in the collateral events of METEF 2006, devoted to existing structures totally or mainly made of aluminium.
The competing sections considered in ALUPROGETTO were:
-bridges and gangways
-civil and industrial structures (buildings, sheds, hangars, stairs, platforms, self-supporting façade claddings)
-mobile structures for temporary uses
-elements of street fittings with a structural value
The initiative was carried out with the support of prestigious organizations and associations
ANCE - Italian Association of Building Construction;
Assomet - Italian Association of Non Ferrous Metal Industries;
Polytechnic of Milan - Faculty of Design and Building Environment;
IED - European Institute of Design;
Uncsaal - Italian Ass.of Architectural Alu and Steel Manufacturers;
IASS - Int. Association for Shell and Spatial Structures;
Cermet - Call project;
EAA and Centroal;
AFFG - Aluminium for Future Generations project
THE JURY
The Jury appointed for the selection and assignment of the Awards was:Ernesto Carretta, Technical Assistance for Industry – Metra Spa, Brescia, Alessandro Chiarato, Director of IED – European Design Institute, Milan , Antonio Citterio – Studio Citterio and Partners, Milan , Aldo Colonnetti, Director of Ottagono Magazine, Bologna , Mario Conserva, Managing Director – Edimet Spa, Brescia , Sergio Croce, Professor of Technical Architecture – Milan Polytechnic, Claudio De Albertis – Ance - National Ass. of Building Construction, Milan , Pietro Gimelli – General Director Uncsaal – Constructors of Frames in Aluminium, Steel and Alloys, Milan , Gian Carlo Giuliani,– Redesco Srl, Milan, Italy & Member of the Advisory Board of IASS, Madrid, Spain, Alberto Seassaro, Head of the Faculty of Industrial Design – Milan Polytechnic , Giorgio Valentini – Studio Valentini, Milan.
THE SHOW
The 27 selected works, coming from Italy, UK, Brazil, Netherlands, Spain and Japan, were displayed during the four days of the Metef 2006 exhibition in a devoted area to the attention of designers, architects, engineers and techical operators.
The ALUPROGETTO show was visited by about 1500 operators.
ADVANCED CAPABILITIES OF ELECTROPHORETIC PAINTING FOR SPECIALIST ALUMINIUM COATING APPLICATIONS
Electrophoretic paint deposition is a well established application method for the coating of metals. In particular is its ability to coat complex shapes with a consistent layer thickness...
Peter Hope, MIMF. - LVH Coatings Ltd. - Birmingham, UKAbstract:
Electrophoretic paint deposition is a well established application method for the coating of metals. In particular is its ability to coat complex shapes with a consistent layer thickness. Aluminium, by its versatile forming methods, is an ideal substrate for electrophoretic painting – especially for the anodic method during which a level of protective anodising takes place that is advantageous for adhesion and corrosion resistance.
Electrophoretic painting is readily automated. It has very high material utilisation efficiency with negligible pollution. For appropriate applications it has unmatched
productivity and cost effectiveness.
Advances in electrophoretic painting technology have enabled a wide range of decorative and functional finishes to be applied. Environmental resistance can be increased by state-of-the-art anti-corrosion treatments and UV light absorbent chemistry. Mechanical resistance is enhanced by utilising nanocomposite and viscoelastic properties. Electroconductive materials enable multi-layer coating. Wear and friction can be controlled with dry lubricants. UV curing technology reduces energy consumption and low temperature processing preserves metallurgical attributes.
Such functional properties can be combined with an extensive palette of decorative effects in single or multi-layer applications.