FINISHING TECHNOLOGY
Per accedere a questo contenuto e' necessario essere abbonati. Registrati qui.
To read this article you have to subscribe. Please click here. ...
THE APPLICATION OF REVERSE OSMOSIS
IN ALUMINIUM FINISHING PLANTS
...The application of Reverse Osmosis in Aluminium Anodizing and Painting lines is nowadays an ecological and economical sustainable technology...
Vincenzo Longo, Mauro Novelli , Tecam, ItalyAbstract
The application of Reverse Osmosis in Aluminium Anodizing and Painting lines is nowadays an ecological and economical sustainable technology for the deionized water production.
Some of rinses in Aluminium Finishing lines have the necessity to be performed with deionized water in order to guarantee the best quality of the final production.
A Reverse Osmosis plant is applied in most of the cases to replace the traditional Exchange Ionic Deionizer.
A Reverse Osmosis plant represents an ecological and economical sustainable choose benefitting the water saving, the drastic reduction of chemical products consumption and avoiding pollutants introduction in environment coming from the resins regeneration.
Working 24 hours per day the Reverse Osmosis plant produces deionized water without interruption due to regeneration cycle.
The quality of the deionized water produced by Reverse Osmosis, is constant in terms of conductivity, the Exchange Ionic Deionizer tend to increase the water conductivity even more approaching the regeneration time at the resin bed end of cycle.
Compared with an Exchange Ionic Deionizer double line (for continuous production 24 h/d), the Reverse Osmosis plant has lower Capital Expenses (CAPEX) and lower Operative Expenses (OPEX) too, generating economic benefit from installation.
TCP - INDUSTRIAL APPLICATION OF ECOLOGICAL
PRETREATMENT WITHOUT CR 6+
...Chemical treatment prior to painting is the key element of many production lines...
E. Kokalj, Surtec International, GermanyAbstract
Chemical treatment prior to painting is the key element of many production lines. Having a direct influence on final quality and visual aesthetics any errors in this industrial segment can lead to long term impact on paint adhesion and corrosion protection. Aware of this, the majority of manufacturing facilities adopt a conservative approach, remaining with only proven and entrenched technologies such as phosphating and yellow chromating (Cr6+).
Fundamentally chemical pre-treatment prior to painting of steel substrates is divided into either Zn-phosphating, for high end markets such as automotive (utilizing separate degreasing and grain refinement), or Fe- phosphating (one step cleaner-coater) for indoor equipment such as appliance and HVAC. Similarly architectural aluminium and Al alloy pre-treatment is typically dominated by hex-chromium passivation.
Primary advantages of these traditional technologies are simplicity, economy of use and visual appearance. Having long established acceptance, these older technology application methods are well known and understood.
Recently, as with many chemical treatment sectors, changes are occurring to meet higher environment standards and improved health protection in the work place. In addition, part recycling now plays a bigger role, especially in the automotive and electronic sectors.
Two basic standards restricting the use of Cr6+ exist: ELV, directed at automotive and WEEE, directed towards the electronic industry. Many of countries are also reducing tolerance of Ni, Zn, Mn, PO4 ...This situation is forcing all chemical suppliers to start development of new generation metal pre-treatment chemicals .
THE ALUMINUM BRIGHTENING PROCESS,
TECHNIQUES, FINISHES AND TRENDS
...an extensive review of the actual chemical and electro chemical techniques has been done in this article...
Toni Aztarain , Albert Forns, Antonio RuizBarcelonesa de Drogas y Productos Químicos, Spain
Abstract
Aluminum brightening processes have been studied and discussed in many publications, an extensive review of the actual chemical and electro chemical techniques has been done in this article.
Brightening technologies are normally difficult to manage, and work in a narrow range of parameters, one of the objectives is to clarify the operation and characteristics of each technology in order to obtain better results and save cost.
Implementation of those techniques is explained and the operation parameters discussed in terms of the quality obtained and plant operation. Temperature and chemicals use to be the main functions to control and study.
Future technologies and trends are exposed and must be deeply investigated in the future. Explanation of investigation lines should be considered to avoid future customer, laws or environmental problems.
BASIC DESCRIPTION
The aluminum brightening process is based on removing material from the substrate base achieving a smooth surface with a few microns of roughness. There are two classical methods to obtain this finishing, the mechanical polishing through machining the surface, and the chemical interaction to remove the substrate. The object of this paper is to discuss the actual techniques and future trends in the chemical and electro chemical aluminum removal.
Since the first introduction of anodizing in the industry by the 1920’s the polishing processes have been present in many companies. Were first achieved by mechanically polishing the surfaces to obtain a specular mirror–like finish and subsequently the electro chemical processes were used as well. The appearance and serveability of Aluminium is clearly a function of the pre-treatment applied, hence selecting the right pre-treatment will fit your customer expectations, save your company time and money and saving to the environment tons of chemicals.
CAUSTIC SODA RECOVERY FROM EXTRUSION DIES:
CASE HISTORY
Massimo Masiero, Italtecno, ItalyAbstract
In aluminium extrusion industry, the cleaning of extrusion dies is conventionally afforded by use large quantities of caustic soda cleaning solution, which needs to be regularly disposed by external companies.
The more and more stringent environmental Laws and the increasing ecological costs, have brought to the natural conclusion that the caustic solution should be recycled instead of being wasted.
It is described the case of an European extruder, where a new technology for recycling caustic soda has been implemented on a full industrial scale and very successfully.
The reasons which led to this choice are listed. Also, the results of implementing this technology will be detailed, along with the change on operations, the beneficial cost effects, the dramatically reduced impact on a complicated urban environment.
HARD COATING OF THE CAST ALUMINIUM ALLOYS
BY DIFFERENT ANODIZING PROCESSES
Leonid M. Lerner, Sanford process, USAAbstract
Most cast aluminum alloys do not accept anodic coating well. The coating is unattractive, poor in abrasion resistance and inconsistent in results achievable.
This first phase of our study was designed to identify different processes available for successful hardcoating of cast aluminum alloys. In later studies we intend to expand on this foundation and examine other facets of hard anodizing cast alloys,
including evaluation of micro hardness of the film material and the thickness of the film material using optical micro system analysis. In this study we employed two different power supplies and four different processes. The samples that were processes were 5” diameter round disks of 380 cast aluminum alloy, 380 die cast
parts and 390 die cast part. The same amount of Ampere-Minutes was used in each process run.