|2006 Anodizing Conference Abstracts|
A New Approach To Pulse Anodising: Decreasing Energy Consumption – Increasing Productivity
A. D. Juhl, AluConsult; K. Burfelt, SAPA Profiles DK; and P. Weldingh, Lokalenergi
Most anodising job shops use DC or pulse anodising with pulses in milliseconds. The process time for forming a 20 µm anodic oxide layer with these methods is normally in the area of 60 minutes. By using slow square-formed pulses, this process time can be decreased by as much as 50 precent and at the same time the total energy consumption in the anodising tank can be decreased by as much as 30 percent.
The present work will show how an existing anodising line can be optimised with a few simple guidelines. To provide the necessary contact, several parts of the anodising equipment were improved before implementing pulse anodising. Several current densities and pulse periods were tested to find the parameters that provide the most optimal productivity and, at the same time, the lowest energy consumption.
The aluminium alloy was a 6082, and four different profiles were processed in order to investigate whether the geometry had some influence on the pulse parameters.
Anodizing by Current Density: The Challenges and Rewards
Steve Brisk, Stylmark
Aluminum anodizing firm Stylmark converted its anodizing line from volt/line to amps/sq. ft. Along with the attendant mechanical changes, some process changes also are discussed, as are both the challenges of implementation encountered and the proof of the expected gains actually obtained. The updated line has reduced anodizing times by 25 percent, limited end-for-end and coating variations, and a new ergonomic clamp system allows for better flow of current density.
A Practical Guide to the Production of Anodized Finishes
Arthur Brace, Ph.D. and Ted Short
Anodizing industry consultants Dr. Arthur Brace and Ted Short are developing training modules that soon will be available to the anodizing community. These modules, which include a number of practical issues on the anodizing plant, equipment, and processes, can be put to use training plant personnel and customers or end users. The presentation includes an overview of these important training tools and explains how to use them effectively.
Cogeneration for Anodizers
Darrin Moorman, I Power Energy Systems, LLC
Combining heat and power, cogeneration is a means to put to productive use what otherwise might be wasted. For example, AAC member Highland Plating installed a cogeneration system that produces energy for the plant and yields heat as a by-product that is used to maintain elevated tank temperatures. Darrin Moorman of I Power Energy Systems—the company that developed and installed the cogeneration system for Highland—presents this case study and explores further options available to anodizers.
Effect of the Anodic Oxide Properties on the Kinetics of the Electrolytic Coloring Process
Yar-Ming Wang, Hong-Hsiang (Harry) Kuo, Rohan Akolkar
Materials & Processes Lab, GM R&D Center
Kinetics of the tin electrodeposition reaction during the electrolytic coloring of porous anodic oxide films on aluminum is studied as a function of the oxide properties, e.g., the thickness of the porous oxide layer, and the surface resistance offered by the barrier oxide layer. In the present study, the thickness of the porous oxide layer is controlled by the anodization time, and the surface resistance offered by the barrier oxide layer is controlled by the anodization voltage and the anodization bath temperature. Steady-state polarization measurements are employed to characterize the dependence of the coloring kinetics on the oxide properties. Measurements indicate that the kinetics of the electrolytic coloring process can be accelerated by: (i) reducing the surface resistance of the oxide film by growing the oxide at a lower anodization voltage, or at a higher bath temperature, or (ii) growing a thinner porous oxide layer by decreasing the anodization time. The electrochemical measurements are supported by gravimetric analysis (using calibrated x-ray fluorescence spectroscopy) and optical spectrophotometry to determine the tin content and the color shade of the electrolytically-colored alumina samples.
Emerging Trends in Chemical Regulation
Charles Simmons, Law Offices of Charles T. Simmons, LLC
The regulatory climate in the United States may be seen to vary according to the whim of each successive administration, but U.S. regulations often are looked upon by observers in other countries as a bellwether, an indicator of future global trends. Precautionary principles serve as an example of the direction being taken by regulators worldwide; other risk analysis factors also are discussed.
How to Realize Significant Cost Savings with Filtration and Purification
Charles Schultz, SERFILCO Ltd.
Over the last two to three years, the use of filtration on anodizing acids and associated solutions has increased significantly. There are now many thousands of process tanks operating with continuous filtration on a wide variety of anodizing applications – the number increases each week. New technology has enhanced the efficiency of anodizing processes, reduced disposal and waste treatment costs and significantly improved process control, while improving quality and lowering operating expenses.
An overview of continuous filtration systems, enhanced by airless agitation, including details on sizing appropriate systems and a review of various case histories, together with a comparison between filtered and unfiltered solutions will make the case for continuous filtration systems to eventually become the most widely used method of reducing operating expenses and improving process control in the anodizing industry.
Hybrid Nanostructure of the Anodic Oxide for Polymer Bonding: A Case Study
J. Runge, CompCote International, Inc., Elmhurst, Illinois; A. Gilbert, Mercury Marine, Inc., Fond du Lac, Wisconsin; G. Kriesch, Walgren Co., Grand Rapids, Michigan; and J. Pernick, IHC Corp., Detroit, Michigan
Mercury Marine, Inc., the world leader in engineering, building, and providing marine power, is always looking for a means to increase the corrosion protection of the finish on their marine engines. In addition, they seek to eliminate the use of hexavalent chromium from their finishing processes for their products. The engine housings, aluminum die castings, have been conversion coated, electrodeposition primed (EDP) and then finish lacquered. As an alternative finishing process, hard anodizing (Type III) was considered and tested by Mercury Marine. Two fundamental negative attributes of the Type III finish were encountered: 1) the hard anodic finish did a poor job of protecting sharp edges of the machined surfaces of the die castings; and 2) the hard anodic finish did not EDP very well or consistently.
Walgren Company, a manufacturer of turnkey finishing systems worldwide, was involved through the course of investigation for alternative processes. Walgren is working with Mercury Marine to set up a finishing system, from cleaning through e-coating. In the course of designing the new line, which would have included large chillers and a high power rectifier, Walgren suggested the use of an emerging technology for anodizing aluminum, CompCote®, which would dramatically reduce the need for the chillers and would use lower power rectifiers. In addition, CompCote® was an interesting alternative because the finish contains islands of conductive polymer integrated throughout the finish; it can sustain a static charge and therefore has better throwing power with EDP, and provides actual sites for chemical bonding with subsequent polymer finishes.
Samples were run at various thicknesses by IHC Corporation in Detroit. During subsequent coating, the samples consistently exhibited complete coverage with EDP at thicknesses as high as 20µ. Upon consideration of key performance factors, an optimum potential finish sequence was developed utilizing thin CompCote (3-5µ) together with EDP. Samples show no evidence of corrosion after six months in tide-exposure testing at the Gulf of Mexico.
This presentation shows how a consortium can work together to solve an industrial problem. Through scientific anodizing process innovation and finish engineering know-how, the use of this hybrid nanostructure is being investigated to solve a design challenge and fulfill a performance requirement.
Improving the Anodizing Coating Properties with Cryogenic Treatment
Mike G. Wilfley and George A. Calboreanu, Ph.D.; A.R. Wilfley & Sons Inc.
Comparative investigations between standard anodized coatings and anodized with an additional cryogenic treatment were conducted. The benefits of the cryogenic treatment in 7075 hard anodized and 2024 anodized coatings are presented. The cryogenic treated coating had a significant lower amount of cracks, the cracks were shorter and with smaller crack facets openings than the identical material standard anodized only.
The wear performance of 2024 standard anodized and 2024 anodized with an additional cryogenic treatment was evaluated using a Taber Model 503 Abraser. The tensile and compressive stresses developed during such test at the contact surface were established using the Hertzian theory of elastic contact. The wear rates were calculated by finding the area losses of the anodized coatings at the OD, center, and ID of the wear track. The remaining anodized coating areas were determined from SEM views using a CAD Area Measurement System. The additional anodized 2024 cryogenic treated had an impressive 88% - 633% better wear performance than the standard 2024 anodized coating.
Measurement Technique for Determining the Quality of Anodic Seal
Ralph Delfonso, Fischer Technology, Inc.
In addition to measuring anodize thickness, it is equally important to measure the sealing quality of the anodic oxide. Sealing quality determines weather resistance of the finish. This session is an informative description of methods ASTM B 457-67 and DIN EN ISO 12373-5 including advancements and the instrument and technology used to perform these test methods.
Measuring the Thickness of Anodize on Aluminum with Eddy Current
Changqing Lee, Oxford Instruments Coating Measurement
The eddy current method is one of the most frequently used methods to measure the thickness of anodized aluminum. The eddy current method is a nondestructive method of determining coating thickness. When a conductive substrate is subjected to an AC magnetic field from a probe, eddy currents occur in the material in proportion to the frequency and resistivity. The induced eddy currents generate an opposing magnetic field which alters the circuit reactance and the output voltage of the probe. The change in output voltage is used to calculate coating thickness. There are various types of instruments, such as hand-held and bench-top units, that are capable of measuring anodize thickness.
John Tartagia, Ph.D, Stork Climax Research Services
New Generation of Process Controllers for Type II Anodizing
Dipl.-Ing. Frank Munk, Munk GmbH
Combining the advantages of both human flexibility and standardized operation by automation, the presentation focuses on a special process controller system designed for the Type II aluminum anodizing process. The known systems available are either general remote control panels to control the rectifier or fully automated plant control systems. The presented system offers the anodizer the option to automate his process without making the investment into a hoist control system. Dedicated aluminum process controllers are the interface between the flexible hoist operation system and the standardized process operation. Calculation of process time, calculation of active surface area, readjusting the process voltages, those standardized operations are taken away from the operator to allow more time to increase quality and productivity. The presentation gives an idea of what is possible and affordable for today’s service companies willing to take the challenge of increasing productivity to stay competitive.
New Methods for Non-Contact Anodize and Coating Measurement
Joseph Price, CTO; Sensory Analytics, LLC
An innovative new suite of fixed and portable systems designed to provide measurement and control solutions for the anodization process are now prepared for commercial introduction. These systems provide a coating thickness result that is totally independent of substrate thickness weight or geometry, does not require any correction factors and provides NIST traceable results for measurements performed on abstract shapes, holes, curves, edges and channels. This technique excels over traditional alternate solutions currently employed in the field because it does not require direct contact with the specimen, which broadens the applicability of this system over current contact-based solutions.
Recycling Increases Plant Profitability
C. Tom Philipp, Enviroscience Inc.
The steel industry has recycled hazardous waste pickle liquors into value-added products for many years. The anodizing industry should convert their non-hazardous filter cakes into value-added products. Case histories will be presented showing the anodizing industry the economic and environmental benefits of recycling. Recycling of secondary materials (filter cake and ATH) is beneficial and cost effective. Recycling can be the financial incentive to elimination of excessive POTW surcharges.
Charles Simmons, Law Offices of Charles T. Simmons, LLC
OSHA’s hexavalent chromium rulemaking is being challenged by both sides. The effects of OSHA’s new chrome PEL on anodizing are variable. However, whether the PEL will be upheld or lowered is up to the Third Circuit Court of Appeals, the same Court that ordered OSHA’s rulemaking in a suit brought by Public Citizen. The rule, the litigation, and possible outcomes will be discussed.
Chronic Whole Effluent Toxicity (WET) is another contentious issue that won’t go away. Although the Court of Appeals for the D.C. Circuit decided the test variability issue in EPA’s favor, questions of validity and applicability remain. Current WET issues and the possibility of bringing a Supreme Court challenge will be discussed.
What will the new Roberts Court do to environmental regulation? On June 19 a divided Supreme Court narrowed the Clean Water Act term “waters of the United States” to “relatively permanent bodies of water.” The Court recently agreed to hear a dispute brought by 12 states and other groups who argue that EPA did not have the authority to refuse to regulate certain greenhouse emissions under the Clean Air Act. Fearing a possible rollback of federal environmental laws, activists are pushing for more state authority. The Supreme Court – a lasting legacy of the Bush Administration – it’s views on environmental regulation and how it might handle the chrome PEL and chronic WET will also be addressed.
Restriction on the use of Certain Hazardous Substances in Electrical and Electronic Equipment (otherwise known as RoHS)
Roman Kostiuk, Clariant (Canada), Inc.
This European regulation that took effect on July 1, 2006 will certainly be of interest to anyone involved in the supply and manufacture of electronic equipment. This presentation will therefore focus on the following subject matter:
Solving an Aquatic Toxicity Problem with the Use of a Multi-Step Process Wastewater Recycle and Reuse System
Don Deemer, Environmental Resources Management (ERM)
Terry Snell, The William L Bonnell Co., Inc.
Loren McCune, Bon L Manufacturing Company
George Patrick, Patrick Engineering Associates
The Bon L Manufacturing Company operates an aluminum anodizing plant in Newnan, Georgia. Process wastewater discharges from the plant were historically treated via a conventional physical-chemical treatment system. Treated wastewaters were discharged under the terms of an NPDES permit to an urban drainage ditch with a seasonal dry weather flow of zero. One of the conditions of the NPDES permit was to monitor for aquatic toxicity. Since the receiving stream was a small stream that had no flow during dry weather periods, the aquatic toxicity test had to be conducted with 100 percent treated wastewater and no dilution. The treated effluent consistently failed the aquatic toxicity test. Extensive biological and chemical testing concluded that several chemicals in the treated wastewater were contributing to the toxicity, including high concentrations of salt (primarily sulfate from the use of sulfuric acid), metals (primarily nickel), and refractory organics (primarily surfactants). Because several different classes of chemicals were contributing to toxicity, no single treatment process was capable of removing all the causes of aquatic toxicity. The solution involved source control, water use reduction, waste minimization, and design and installation of an upgraded process wastewater treatment system. The upgraded process wastewater treatment system consisted of several different conventional and advanced physical and chemical treatment processes. The resulting treated effluent was determined to be of sufficiently good quality that it could be reused in the manufacturing operations, thereby eliminating the discharge to the small tributary and substantially reducing the facility’s demand for fresh water.
Technical Bulletins Serve to Educate and Inform
Richard Mahn, Houghton Metal Finishing Co.
Over the past 12 years, the Council has released a series of Technical Bulletins covering a wide range of anodizing topics. Taken together, these 17 bulletins combine to yield a distinctive desktop reference that aids countless anodizers in their day-to-day operations. Topics run the gamut from “Aluminum Alloy Reference for Anodizing” to “Specifying Anodized Aluminum” to the most recent Bulletin, “Waste Treatment of Spent Dye Baths.”
The Impact of Copper on the Bright Dip Process
Melvin L. Todd, Potash Corp.
The general theme of this presentation is to investigate the role that copper plays in the production of NOx gases during the bright dip process. Copper is a typical component in most bright dip or R-5 formulations. Copper aids in the brightening mechanism by plating on the surface of an aluminum part. The copper concentration is greater in the low recesses of the part. Thus, the copper protects these regions from additional attack from phosphoric acid, which reduces the bright dip reaction rate in the copper-plated recessed areas of these parts.
At normal concentrations, copper has a positive impact on the brightening process. However, copper has a catalytic effect on the decomposition of nitric acid. One of the by-products of this reaction is NOx gas. This paper explores the relationship between copper concentration and NOx gas production. The effectiveness of copper replacement products will also be investigated. The tendency of these replacements to generate NOx gases in the bright dip reaction will also be determined. Ion chromatography (IC) using purge and trap technology will be used to collect and quantify the NOx gases produced.
The Spectrum of Integral and Non-Integral Colors for Different Hard Anodizing Processes
Leonid Lerner, Sanford Process Corporation
Today, many companies employ a number of different hard anodizing processes, from High Voltage (HV) to a variety of Low Voltage (LV) processes. Hard anodizing has different integral colors depending on coating thickness, type of aluminum alloy, electrolyte temperature, anodizing voltage, current density and other more or less significant factors.
The current work explores the physics of color and evaluates the industry’s decades-old tenet, “the darker the coating, the harder it is.”
Toughness: The Key to Improved Anodic Oxide Finish Performance
Jude Mary Runge, Ph.D.; CompCote International, Inc.
Comparative testing of typical sulfuric acid anodic oxide finishes to a novel composite anodic finish by way of conventional Taber Abrasion, Pin-Disk Friction and Microhardness Testing, as well as unconventional Torque and Charpy Impact Testing have brought to light the importance of the engineering property of fracture toughness. Test performance differences and comparative microstructural analysis indicate enhanced wear resistance is a function of higher toughness rather than hardness. Increased cohesive strength and reduced surface roughness of the composite finish due to modifications to the finish microstructure resulted in lower friction and reduced wear in even dissimilar wear couples. The results indicate the importance of understanding the anodizing process and the synergy between process, microstructure and engineering properties to bring innovation and improvement to our mature industry.
Trends in Aluminum
Stephen Johnston, Alcan, Inc.
The presentation begins with a view of the factors driving global production of primary aluminum for the past hundred years, along with trends affecting aluminum shipments worldwide for the past quarter century. The current economic situation is assessed in light of conditions specific to various regions of the world. With an understanding of the foregoing fundamental factors, the current aluminum situation is analyzed. Primary production, mill shipments and orders, consumption, and inventories are examined. Considerations resulting from smelters’ closures, expansions, and restarts are presented. Trends in aluminum pricing, especially relative to competing materials, are addressed.
(Name in bold represents presenter)