Anodizing is one of the most common surface treatments of aluminum. In all anodizing processes, the basic reaction is conversion of the aluminum surface to aluminum oxide. The aluminum part, when made anodic in an electrolytic cell, causes the oxide layer to become thicker, leading to better corrosion and wear resistance. For decorative purposes, the oxide layer formed on the surface can be dyed. In aluminum anodizing processes, the basic reaction is a conversion of the aluminum surface to aluminum oxide, including Type I (Chromic acid anodizing), Type II (Sulfuric acid anodizing), Type III (Hard coat anodizing).

Below are ten best practices to keep in mind when anodizing:

1. Surface Preparation: Thorough cleaning of the metal surface before anodizing to remove any contaminants, oils or oxides is imperative. Common methods include alkaline cleaning and acid etching.
   • • Learn more: The pretreatment processes prior to anodizing are critical in not only cleaning the aluminum, but also in creating a variety of colors and finishes. Learn more about the effect of pretreatment on the appearance of anodic coating. short.pfonline.com/anodizepretreat

2. Alloy Considerations: Different aluminum alloys respond differently to anodizing. It is important to keep this in mind when setting finish and performance expectations.
   • • Learn more: Alloys with higher silicon concentrations can inhibit the growth of anodic oxide films under galvanostatic and potentiostatic conditions. short.pfonline.com/intermetallicspec
3. Quality Control: Consistent monitoring of your anodizing process through regular titrations will help maintain the desired coating thickness, color consistency and surface finish.
   • • Learn more: Having trouble with spotting defects when anodizing? This overview of the various causes of white spots and potential solutions may help. short.pfonline.com/anodizewhitespots
     • Learn more: Understanding the differences in cracking and crazing in anodic coatings, and insights for mitigating defects in anodized parts: short.pfonline.com/crackcraz
   4. Maintain Anodizing Parameters: Anodizing parameters such as bath temperature, current density and voltage are critical for consistency and quality. Deviations from recommended parameters can lead to uneven coating or poor adhesion.

• • • Learn more: Sulfuric acid anodizing bath makeup. short.pfonline.com/sulfanodiz
    • Learn more: The 720 Rule describes the relationship between the amount of current passed through an aluminum surface and the resultant anodic oxide thickness produced over time. short.pfonline.com/720rule

• • • Learn more: Aluminum sulfate is the preferred buffer to prevent burning of parts in an anodizing bath. short.pfonline.com/sulfbuff

5. Sealing: Proper sealing helps in closing the pores of the anodized layer and enhances the corrosion resistance and durability of the coating. 
   • • Learn more: Is a cold seal right for your anodizing operation? short.pfonline.com/coldseal
     • Learn more: Sealing of anodized aluminum is considered to be the most important of all the various steps in the anodizing process. Learn how to select the best anodizing seal process: short.pfonline.com/selectseal
6. Dyeing: Take care to adhere to proper dyeing techniques to achieve uniform and vibrant colors and make sure the dye is compatible with the anodized coating for long-lasting results.
   • • Learn more: How to minimize fading of anodized colors. short.pfonline.com/anofade
7. Racking Considerations: Properly designed and maintained racking aids in achieving uniform coating thickness and prevents uneven coloration.
   • • Learn more: What are the most common racking problems for platers and anodizers? This helpful clinic will help you avoid the common pitfalls: short.pfonline.com/rackingpitfalls

8. Ventilation: Ensure proper ventilation in the anodizing facility to control fumes and maintain a safe working environment. Proper ventilation also aids in controlling temperature and chemical concentrations.
   • • Learn more: Read about pollution control for anodizing: short.pfonline.com/pollano

• • • Learn more: Considerations for the ventilation of metal finishing tanks. short.pfonline.com/opentank

9. Preventative Maintenance: Regularly inspect and maintain anodizing equipment, including rectifiers, tanks and filtration systems. Well-maintained equipment contributes to consistent anodizing results.
   • • Learn more: Tips for optimizing your anodizing line: short.pfonline.com/anomaint

10. Waste Management: Implementation of effective waste management practices and compliance with environmental regulations is critical for conserving resources, controlling costs and minimizing the environmental impact of the anodizing process.
    • • Learn more: Read about one anodizer’s success in conserving water and reducing waste after implementing a zero liquid discharge facility: short.pfonline.com/0discharge

These are just a few tips to help ensure a successful anodizing process with consistent and high-quality results. Always consult with anodizing experts and follow industry standards in order to keep up with the latest advancements in anodizing technology.

The definitions

CAA is mainly used for the protection of critical structures with joints. The corrosion resistance is excellent relative to the thickness of the coating, which usually lies in the range of 0.08 – 0.2 mil. The oxide film is softer and is formed without any significant fatigue loss of the material. The film is easily damaged and is light opaque gray in color. When this film is sealed in a dichromate seal, a greenish color appears.

The process is voltage controlled with a ramping at the beginning of the process, increasing up to 40 volts depending on the type specified. Type I and Type IB are specified in the military specification MIL-PRF-8625F. Type I are conventional coatings produced by about 40 volts, and Type IB are coatings produced by a voltage of 20 to 22.

Fig. 1. The FIB-SEM cross-section images at different magnifications for TFSA coatings are on the left and the CAA coatings are on the right, both on EN AW 2024. Photo Credit: all images courtesy of AluConsult

However, TFSAA forms a coating using voltage in a low concentration of sulfuric acid, which leads to a low electrical conductivity and with less chemical attack of the coating. This results in thickness in the same range as CAA films. However, the thickness is more dependent on the anodizing time.

The two coatings have distinct differences in morphologies, as shown in Figure 1. The thickness of the two coatings is about 0.108 mil (2.74 micrometers). The images show a smooth interface between the TFSAA coating and the aluminum substrate (on the left), whereas the CAA coatings show a rougher interface. Both texture and grains in the CAA coating are found to be much coarser than for the TFSAA.

Reasons to make the switch

One of the reasons for anodizers to change from the CAA process to the TFSAA process instead of boric sulfuric acid anodizing (BSAA) is because of the license fee to Boeing. Another reason is the idea of the easy change if they already are running Type II sulfuric acid anodizing — same equipment and process. Unfortunately, this is often a mistake because the two processes vary more than expected.

Having a lower concentration of sulfuric acid gives a less conductive solution, leading to a TFSAA coating with a 33% higher coating density than the CAA coating with comparable thickness (see Figure 1). For dimension and fatigue- sensitive applications, this variation can be critical. Controlling coating thickness is critical for both corrosion and mechanical properties, but also the morphology of the oxide is of great importance. This is true for Type II, also, where variation in the oxide structure leads to variations in color and properties.

CAA replacement

Besides Type I and Type IB, other processes are available, such as Type IC, with BSAA as the NADCAP-approved process. Type IIB — thin sulfuric acid anodizing — is the other alternative for the replacement of chromic acid. This process can also be named Type IC because the type is classified by non-chromic acid anodizing used as an alternative for Type I and Type IB.

The confusion is obvious, and according to MIL-PRF-8625, the difference can be found in the coating weight. Type IC has a coating weight of 200 – 700 mg/ft², whereas Type IIB enables coating weight up to 1,000 mg/ft² as a maximum.

For the fatigue-sensitive parts, the BSAA has long been the only fully implemented alternative to CAA, according to Naval Air Systems Command (NAVAIR). The TFSAA is an alternative, also, and new improvements enhance the TFSAA process. It meets the process control test of MIL-PRF-8625F but has still not been fully implemented in all specifications.

Challenges

Measuring thicknesses below 0.28 mil (7 micrometers) is always tricky and critical because the deviation in the measuring device is in the range of the layer thickness that needs to be measured. Therefore, Type IIB is defined

Fig. 2. This shows TFSAA with various sealers on 2024-T3 aluminum after exposure to 1,000 hours of ASTM B 117 salt spray. 

more by coating weight than by thickness compared to Type II anodizing, where thickness is the preferred test and often the only control done.

The sealing process is another deviation between the two sulfuric anodizing processes because the hot water sealing process is insufficient to pass the corrosion test when using a TFSAA coating (see Figure 2).

Some of the programs for aerospace call out the low chrome concentration seal with less than 0.02 ounce per gallon. This sealing solution can be difficult to maintain and control compared to the conventional 5% sodium dichromate seal.

In Figure 2, it is obvious that the TFSAA still needs a sealer with chrome to pass the corrosion resistance test, as the conventional hot water sealing is insufficient.

The porous layer formed and sealed with the low concentration of sodium dichromate does not have enough active chromate, and the corrosion inhibitor is the layer to protect against corrosion. Therefore, these layers are often non-conformant to the MIL-PRF-8625. Many anodizers have a dichromate seal in their process line but often, this is the 5% dichromate seal and therefore, a new process tank must be included with new procedures in place.

These are only some of the deviations anodizers face when changing from chromic acid anodizing. To transition well, time and openness to change must be invested. Sometimes, more tests and changes must be performed to prepare for the transition.

About the Author

Anne Deacon Juhl

Anne Deacon Juhl has a Ph.D. in pulse anodizing. During her studies, she established a personal network in Europe, the U.S., and Scandinavia. As a consultant within the field of aluminum finishing, she has worked with many kinds of chemical and electrochemical surface treatments, such as anodizing, coatings, electroplating, and electroless plating, with 25 years of experience in the industry.

Lorin Industries Inc., a global producer of coil anodized aluminum, now offers building information modeling (BIM) files for its anodized aluminum colors and finishes, which are available for direct download from its website. This feature of the website, the company says, enables architects, engineers and contractors to directly access BIM files which enable streamlined and collaborative design and build processes. For those architectural firms that use RIB’s SpecLink software, Lorin’s products can be specced directly from RIB.

The benefits of anodized aluminum for architectural applications are far ranging, according to Lorin. Anodized aluminum reportedly provides a durable solution that does not chip, flake or peel. The company says this durability combines with natural beauty to bring long-lasting aesthetics to products ranging from cladding and roofing systems to interior panels, decorative applications and other possibilities. Lorin also maintains that the colors and finishes of its anodized aluminum contribute to its appearance.

Architects, engineers and contractors looking to integrate Lorin’s anodized aluminum into their next project can visualize its impact on their projects using BIM. To streamline this process, the company now offers BIM files for its finishes directly on its website. BIM is notable for enabling a collaborative approach to design and build, representing both the functional systems, such as electrical and HVAC systems, and the aesthetic aspects of a project, such as roofs and walls. 

Alufinish (Andernach, Germany) and Columbia Chemical (Brunswick, Ohio) are combining their sales and service capabilities and resources for the U.S. market in a move that offers an expanded line of products and services to a broader base of customers.

The collaboration will offer processes for the surface treatment of aluminum alloys. The two companies will cover the entire process from pre-treatment to anodizing and coating.

“By combining the experience of our companies, we will be able to offer a high-quality service for equally high-quality products in future,” says Stephan Zegers, managing director of Alufinish.

“This collaboration reflects our shared commitment to delivering innovation and excellence,” says Brett Larick, president of Columbia Chemical. “By combining our strengths, we will be able to offer unparalleled service and drive further growth for the surface treatment of aluminum alloys in the U.S. market.”

The two companies plan to kick-off their collaboration at the Aluminum Extrusion Technology Seminar from April 30 to May 2 in Orlando, Fla., U.S. Visit both companies at the Alufinish Booth 120.            

Steelhead has made Veterans Metal’s processes much more efficient by integrating iPads and a QR code system. Plant Manager and Navy veteran, Randy Wayand, uses the new system on Veterans Metal’s shop floor. Photo Credit: Steelhead Technologies

When Andrew Kossowski acquired the former DHS Enterprises (Clearwater, Florida) in September 2020, the 27-year-old shop was 100% manual with no ability to track efficiency or performance quality. From the beginning of his ownership, however, Kossowski envisioned a complete makeover of the entire business. His first step was to complete the National Aerospace and Defense Contractors Accreditation Program (NADCAP) accreditation for Anodizing and Quality Management System in the old shop, which the shop accomplished in August 2022. It also obtained a Lockheed certification for various other processes at that time. The next step was starting from scratch with new equipment,moving out of the old 5,000-square-foot facility and building a new 15,000-square-foot building, including a complete digital transformation end to end.

The new company, Veterans Metal, contains no paper trails but instead, full digital traceability. When the new shop officially opened with a ribbon-cutting ceremony at its new location in August 2023 in Largo, Florida, it was already well on its way to becoming paperless, proving to Kossowski that it pays off to dream big. 

By implementing Steelhead Technologies’ customizable ERP software, the 16-employee shop — which offers its customers a variety of finishes including anodizing, chem film and passivation — has found that it can more easily maintain its demanding NADCAP certification while eliminating Excel spreadsheets and traveler carts. Steelhead combines quoting systems, scheduling and invoice tracking for the shop.

“The process that we captured from the last time we worked on the part is already in the software,” Kossowski explains. “I used to type the same information three times. And then I had to use a pen and paper to write things down. The worst thing about pen and paper is that people can write whatever they want.” But now, with the shop’s use of iPads and QR codes, part tracking is much more accurate and avoids human error, he adds.

Working without paper has made Kossowski consider how much time was wasted filling out forms. “We can be better by doing other things like focusing on the job, how to make the part properly and focusing on strategy in processing the part.”

The entire project — from the initial regular meetings to discuss Veterans Metal’s needs through the development stages and testing of the software to the integration of the technology — was completed in about 10 months. Although it has only been implemented for a short time so far, Kossowski is already ecstatic about the impact Steelhead has had on his business.

A perfect pair

Finding job shop software specifically for anodizing or the metal finishing processes Veterans Metal offers for the military, automotive and marine industries was

Even though the shop had not yet implemented Steelhead at 100% capacity, it completely stopped using paper to document NADCAP on Sept. 1, which was made possible by QR technology. Photo Credit: Veterans Metal

challenging for Kossowski, simply because there are not many options on the market, he says. Therefore, when he discovered Steelhead at the International Manufacturing Technology Show in 2022, he was anxious to learn more about its offerings. After a long discussion about goals and objectives, both the shop and software developer felt they were a great match for one another.

According to Chet Halonen, sales engineer at Steelhead, the project was promising from the get-go. He says the team discussed Kossowski’s goals for digital integration and all the functionality that Veterans Metal was looking for.

Kossowski has similar sentiments about their initial meeting. “I immediately realized they were exactly what I was looking for,” he comments. He adds that he was impressed with the people he met, including Halonen and later the CEO, Jeff Halonen. “They have done a marvelous job. I particularly like their project management approach and the implementation of the project,” he says.

With an undergraduate degree in aeronautical science and a graduate degree in computer science, Kossowski had a good understanding of the language Steelhead spoke. He had also managed many large-scale projects and programs in the corporate world before his time at Veterans Metal and after his military career in the U.S. Air Force, where he worked primarily in testing and quality assurance for the manufacturing and refurbishment of a variety of aircraft.

He also respected that Steelhead’s staff knew its products well. The sales staff understood the technical aspects of the product and could answer his questions intelligently. “That was really important to me from a confidence perspective and getting the project done.”

According to Halonen, Steelhead has been excited about working with the team at Veterans Metal from the beginning and describes the shop as “leading the charge” in the NADCAP space. Although it is the software company’s first time developing programs specifically to adhere to this certification for a customer, it is no stranger to this certification. Its team of 11 full-time developers understand the importance of NADCAP and how it influences its customers. As a result, the company had been working toward building infrastructure around this demanding accreditation prior to working with Veterans Metal.

However, the Steelhead company itself is not NADCAP accredited. “Veterans Metal is our customer, and we work to its requirements, and they are responsible for being NADCAP accredited,” Halonen says. “At the end of the day, we are not doing NADCAP processing. So, we don’t have any formal ties with it or the Performance Review Institute (the organization that administers the accreditation).”

From planning to beta testing

Because of the robust documentation and adherence to procedures that are necessary for NADCAP audits, Veterans Metal understood digitizing its entire ecosystem would be a challenge that would take time, patience, trial and error, and persistence. But in the long run, it would be worth the work; going

These parts at Veterans Metal are ready to be anodized after being loaded in Steelhead software. Photo Credit: Steelhead Technologies

paperless not only adds efficiency to the shop floor, but also produces more reliable and predictable data that is valuable to the shop and its aerospace and defense customers. 

Kossowski also intended for Steelhead to mold a new way of thinking for Veterans Metal. “There's no point in spending money on software that will only replicate what you had before,” he explains. “There's a lot of bells and whistles when it comes to technology, and I want to take advantage of those without customizing the software to a point where it's unrecognizable. So that was a priority for me and my team to not ask Steelhead to modify anything to fit some old way of thinking.”

Therefore, from the beginning, Kossowski was open to being a beta tester for the technology, which pleased Steelhead and gave the shop the privilege of helping customize the software. They agreed to begin a rollout on Jan. 1, 2023, (at the old shop because the new one was not built yet) with the additional help of Veterans Metal employees who were knowledgeable about various aspects of the shop’s production process. The team set out to meet one to two times per week.

The team’s digitization goals included eliminating paper travelers on the shop floor, tracking parts throughout every stage of processing as well as enabling awareness of the areas of the company that are making money and losing money. It was also critical for the software to integrate many systems, including inventory tracking and quoting.

Veterans Metal tanks are used in the metal finishing process with QR codes for NADCAP tracking and repeatability via Steelhead. Photo Credit: Veterans Metal

As Halonen and the software team consulted with the shop’s team members, they gradually built features and modules for the software. Then, the entire group went through a two-month testing process on site at the shop to ensure the software functioned properly and contained the necessary elements.

QR scanning changes perspective

As a result of the close partnership with Veterans Metal, Steelhead created the Certification Scanner Line for the shop (now on the market for any NADCAP metal finishing shop). This technology streamlines data entry and employs advanced algorithms to ensure data accuracy. The systems are designed to flag anomalies and deviations from industry standards without human intervention. Everything is done at the click of a button with a QR scanner gun and integrated system.

In a NADCAP environment where operator instruction and time tracking are required, like at Veterans Metal, the Scanner Line is most valuable. Here, all different parts from multiple customers are loaded onto a rack that has a QR code, as do the stations. A handheld scanner is used to instruct operators on when to move parts and to where, while simultaneously recording all the processing history required by NADCAP, military and other accreditations, Jeff Halonen explains.

Through Steelhead, certifications are fully digital and can be created in a fully automated fashion, pulling information from processing, receiving, inventory, specifications, measure data, photos and more. The digital certifications can be sent to customers directly from the platform.

The software team started automating the invoicing/quoting process first since Veterans Metal wanted to use QR codes for this in the new shop where it was slated to move at the end of July. So, getting an early start, the developers integrated the existing Excel spreadsheets with algorithms Kossowski himself created into the new software. Now, when performing a preliminary inspection, the department uses QR scanners and iPads instead of tracking everything on paper.

Training and champions

Backing up to Aug. 3, the day of Veterans Metal’s ribbon cutting ceremony, the shop also held its first training session for all Veterans Metal employees with Steelhead present. In addition to the five to six hours of training the software developers conducted that day, training continued throughout August via several video conference calls. The company set up 50-inch TV screens on the shop floor and provided an environment for remote interaction with Steelhead.

Veterans Metal employees were provided in-depth training as part of the implementation of Steelhead’s software. Photo Credit: Steelhead Technologies

Training has been conducted in stages as the technology for each department has been rolled out. To aid in a smooth training process, Kossowski assigned two champions and funneled training through them. One champion, who is the assistant office manager, heads up the quoting, shipping and receiving and invoicing departments while the other, who is the plant manager, focuses on quality inspections, racking and packing the process line. By dividing training between two champions, they had the opportunity to ask questions, determine any bugs and make enhancements to the application prior to introducing the training to the rest of the team.

The all-employee training sessions with Steelhead were also valuable. If there were additional questions, employees didn't have to wait for an answer from the champion; they could ask Steelhead on the spot.

A bright future

Thrilled with how the software has made the shop’s NADCAP documentation so much more efficient, which improves the overall workflow and time savings on the shop floor, Kossowski and the Veterans Metal team are excited to continue working closely with Steelhead — a company that can keep up with their fast pace.

Because the shop is an early adopter of the software and Steelhead is an early-stage company, Kossowski believes there is still a lot of growth potential ahead for the partnership. For example, he plans to increase capacity from the old shop’s 100,000 parts processed per month to potentially three million parts and to increase the number of employees to 30.

“We’re going to add more NADCAP accredited services with the support of Steelhead software — we’re not done,” he says. “We have a lot to offer Steelhead because we’re growing. And they are not set in their ways. They can adapt and be flexible right now.”

Triplex Plating CEO Jamie Baldwin and COO Jesse Baldwin received the 2023 Top Shops award for Plating/Anodizing at SUR/FIN 2023.
Source: Products Finishing

Products Finishing’s 2024 Top Shops Benchmarking Survey is now open as of February 1. The annual program was created to aid finishing shops in measuring their key operating metrics and assessing how their business compares to others in the industry.

Each year the Top Shops program takes its core mission of continuous improvement to heart, seeking ways to further improve the benchmarking survey and the resulting reports. This year, the Top Shops program offers a fresh approach tailored to meet the needs and time constraints of industry professionals. This year’s surveys are designed to offer participants the benefits of benchmarking and recognition without overwhelming them with an exhaustive list of questions.

Core questions offer simplified but cohesive approach

Recognizing the value of finisher’s time, Gardner Intelligence has revamped its survey structure for 2024. The survey’s core questions, constituting fifty percent of the survey, are tailored to provide valuable insights to the majority of participants. Respondents are urged to complete the core survey by April 30, 2024, to receive a customized benchmarking report, and the chance to earn Top Shops status, and be recognized as an honoree.

Digging deeper

After completing the core survey, participants can opt-in to modules of additional benchmarking questions, delving deeper into specific aspects of their operations. Whether it’s profiling, operations, technology, business strategy, or human resources, participants have the flexibility to select modules based on their business priorities.

Why Participate?

Participants in Top Shops benchmarking program receive a customized report showing how their responses compare to other facilities. This allows participants to better assess strengths and weaknesses, and to determine areas for future improvement. In addition, companies that rank in the top 20% of scores are recognized as Products Finishing Top Shops and celebrated in Products Finishing magazine, through PF’s various media channels and at industry events. 

Photo Credit: Protolabs

Digital manufacturer Protolabs has expanded its CNC machining capabilities again to enable accelerated anodizing and chromate plating on aluminum components. From time of quote to manufacturing to shipping, the company says customers can get custom machined parts with plating in as fast as four days.

“While traditional finishing processes like anodizing have been around for a while, never have manufacturers been able to consistently produce parts as fast at scale as we have at Protolabs,” says Greg Thompson, global product director of Protolabs’ CNC machining. “An engineer can have fully anodized or plated parts on their desk within a few days of placing an order.”

Anodizing and plating help prevent corrosion, strengthen parts and improve cosmetic appearance. All plating options for machining are available to customers when they upload a 3D CAD model on the company’s website.

Eligible materials include aluminum 6061/6082 and 7075. For anodizing, three specific types are offered: Type II (Class 1, Class 2) and hard-coat Type III (Class 1); for chromate plating, Type II is available.

The addition of quick-turn plating builds on the digital manufacturer’s portfolio for CNC machining, which includes advanced anodizing and chromate plating capabilities with flexible lead times. Customers with AS9100 and ITAR needs can access Protolabs’ precision machining capabilities and those with more complex, high-requirement parts can tap into the company’s digital network of manufacturers at Hubs.

“We’ve promised our customers more capabilities across all our service lines this year, and our machining service is leading the way,” says Rob Bodor, Protolabs president and CEO. “Through our unique manufacturing model that pairs a network of global manufacturers with our digital factories, we can comprehensively serve the prototyping and production needs of our customers.”

Brakes
Photo Credit: All images courtesy of MacDermid Enthone

Making a vehicle go is important. But, making it stop is critical and surface finishing plays an important role in making sure brake systems perform effectively and withstand the elements and harsh conditions that the road and the weather expose them to. Products Finishing recently sat down with Rene van Schaik, global strategic accounts director, MacDermid Enthone Industrial Solutions, to hear his insights into the many important ways that surface finishing protects and enables automotive brake systems.

Rene van Schaik, global strategic accounts director, MacDermid Enthone Industrial Solutions

PF: Can you talk a bit about the various chemistries involved in coating brake system components?

RS: It’s important to understand that there are different types of brake systems used, depending on the class of vehicle. There are floating brake caliper systems, fixed brake caliper systems, and drum brakes. Drum brakes are typically for lower end vehicles, though we see them growing in use for electrical vehicles. Fixed brake calipers are relatively expensive — but they’re the best ones there are — they have large aluminum calipers. And then there are floating brake systems with floating calipers, these can be either cast iron, or cast iron aluminium mixtures.

For aluminum components, anodizing products and conversion coatings are used to help adhere certain paints or lacquers. For the cast iron caliper components, there are different zinc plating systems or zinc alloy plating systems.

But, when you look at the brakes as a whole, it’s more than the calipers. There are caliper housings and brackets, and there are also bolts and pins that go into the brake system. There are pistons, brake pads, tubes and fittings — all of which require coatings. So, for example, on fasteners, it would be an alkaline zinc or an alkaline zinc nickel. On calipers, it would be acid zinc or acid zinc nickel, because the acid systems have different plating characteristics than the alkaline ones. The plating initiation is a lot faster, which is needed for these cast iron materials. Pistons, for example, would require hard chrome or electroless nickel.

PF: I'm sure you also have to consider how the coatings on different parts interact with each other, correct?

RS: That’s really important, yes, as they’re connected to each other. So, there’s a very strong trend, for example, to zinc nickel as opposed to pure zinc. And a lot of that has to do with increased use of aluminum for lightweighting for electrical vehicles or improving fuel economy. It takes certain coatings that can work in combination with aluminum. Zinc nickel is a very good one that’s compatible with aluminum.

Brakes

PF: When it comes to brakes, reliability is paramount. Can you talk about the role coatings play in terms of corrosion and wear resistance?

RS: Obviously, safety is a very big requirement. Corrosion protection is a key factor, as you mentioned, and wear resistance as well. Brake fluid compatibility is another consideration. If the incorrect coating is applied, it might dissolve when in contact with these brake fluids. So, that's why we use inorganic sealants typically as opposed to organic sealants.

Coating adherence toward a paint or a powder coating also needs to be considered. This contributes to wear resistance to stone chipping, for example. In addition, as the brakes push into the disk, there’s a lot of heat generated. So, resistance to temperatures is also required. In addition, you need to consider UV resistance and weathering fastness.

Finally, don’t forget the appearance. Since most of the designs today are open wheel designs, you can actually see the brakes. Especially with luxury vehicles, people are showing off their brake systems. Sometimes you see colorful brakes — bright green, gold, black, blues. Or they need to be uniform silver. Back in the 80s, even the most iconic cars had closed wheel designs, but today with more open wheel designs, the appearance of the brakes has become quite important.

PF: The final finish isn’t the only chemistry involved — can you talk a bit about the importance of pre-treatment in finishing brake systems?

RS: Everything starts with pretreatment, and that’s even more valid for cast iron or cast aluminum materials compared to steel or standard aluminum components. That’s because these casting materials have certain roughness or holes in them that needs to be pretreated in a specific way to ensure that you can have a uniform good finish after plating.

The pretreating sequence is important. For cast iron caliper components, it’s very important to have an ultrasonic positioned after the pickling, to get rid of any contamination or filth that might be entrapped in these holes of the cast iron. These absolutely have to be removed from these cavities prior to the plating process. Otherwise, they get trapped underneath the plating layer and then you get all sorts of delayed defects afterwards.

The same is valid for cast aluminum. The pretreatment is necessary for the anodizing process to be efficient. If the layer is not smooth, then the anodizing layer can’t build in a sophisticated way, and then it will be non-uniform and the appearance won’t be very nice.

Unfortunately, what we’ve seen since the start of the pandemic, and during the supply chain interruptions, is that the casting quality has gone down in recent years. But, even with more challenging casting qualities, our products need to provide a consistent quality and help our customers meet certain first pass yield standards. So, it’s increasingly important, from that point of view, that we also help advise the customers on the pretreatment line design and layout, and also, in certain cases, provide auxiliary equipment that can provide quality, sustainability or economic advantages for customers.

PF: How have brake systems evolved in recent years? Are emerging applications like electric vehicles, hybrids, and new energy vehicles changing the way we think about brakes? If so, what does that mean for the surface finishing solutions involved?

RS: The automotive industry is evolving and there are a lot of new trends coming. While some of these trends have been around for many years, the world wasn’t ready for them. But today, in some regions more than others, you can see that it’s really pushing through. In Europe and Asia, there are a lot of electrical vehicles already on the road. In some parts of Europe, 50% of the cars on the road today are already electrical. In the future, there will be even more changes such as hydrogen systems.

As I mentioned before with brakes, we have to distinguish between low end, mid class and high end vehicles. I think that still applies whether it’s an electrical vehicle or not. And the other thing that we should bear in mind is that there’s a difference between the brake systems between the rear axle usage and front axle usage. So, in today’s combustion engine, there’s a difference between front and rear. And in the electrical vehicles, we also see it as a difference.

When we really look at the brake systems, I talked about the fixed calipers and the floating brake calipers and the drum brakes — will those significantly change? No, that’s not something we should expect to see in the short term.

For floating brake calipers, a trend that we do observe in light of light weighting is that maybe the bracket is made of cast iron and then it’s combined with an aluminum housing. And of course, zinc nickel is important as I mentioned earlier, to avoid contact corrosion.

You also see regenerative braking used on new cars, meaning brakes are used less and therefore the corrosion resistance has to be even higher and longer. So again, that is the explanation why it would go to zinc nickel as opposed to zinc.
So one of the trends that we observe with electrical vehicles is that drum brakes are rising in popularity a little bit again. While drum brakes were typically only used in low end vehicles for a long time, we are now are seeing mid class electrical vehicles are equipped with drum brakes in the rear axle usage. And as part of that, we’re seeing more closed wheel designs or semi closed wheel designs again. That’s partially to improve the aerodynamics for the driving distance of course, but also to make the use of drum brakes less visible.

Other new designs include wheel hem consisting of an inner aluminum carrier and an aluminum brake disc. This avoids flash rust on the disk and also reduces noise. Because electric vehicle engines are very quiet, there’s a high focus on the brake systems to have no sound at all.

The other trend we haven’t even spoken about is autonomous driving. For fully autonomous driving, the brake systems can work with very small calipers that can be fully integrated inside of the wheel. Because the emotions are eliminated, there’s no speeding, there’s no emergency braking.

PF: As these trends continue to evolve, all that R&D work continues, right?

RS: Absolutely. That’s why our company is very much involved, not only with at applicator level and the tier ones, but also at the OEM level. We want to know where these trends are going because products are not developed from one day to the next. Sometimes they take years. We need to know early in the game where it’s going and what we need to develop to help the industry to give the new materials the right characteristics to ensure safe performance.

Besides the two facility additions it has completed since its inception, it recently finalized an exterior building refurbishing. This consisted of the addition of new windows for improved visibility and curb appeal.
Source (all photos): Ace Anodizing and Impregnating Inc.

Because the finishing industry can be highly competitive, most shops in this market seek to provide products and services that bolster their reputation and outshine other finishers. However, sometimes excellence occurs naturally while simply being a customer-focused organization, which is the case for Ace Anodizing and Impregnating Inc. (Hillside, Illinois). This Products Finishing Top Shop not only considers itself an expert in the finishing industry after more than 60 years in business but also, living up to its name, an “ace” in the customer service department. Its team does this by offering turnkey work and flexibility that is not the usual services found at most finishing shops.    

“Our customers are trying to do more with less people,” says Mike Battaglia, V.P. sales and marketing at Ace. “So, the more of a resource you can be, the more value you can bring, even if it isn’t directly related to something you do.”

He explains that the company sees itself more as a project manager than just a finisher. Therefore, the team often gets involved in the initial design stage of a customer’s project to engineer around any potential finishing barriers and design issues. This way, it gets a true understanding of a product’s end use to provide the correct coating.

A coat of many colors

As its name states, Ace Anodizing and Impregnating Inc. provides anodizing, powder coating with a chromate conversion pretreatment and vacuum resin

The company’s precision cutback saw system is designed for production cutting of bars or extrusions to close tolerances. The system uses a computer controlled back gauge for accurate sawing performance and i mproved throughput.

impregnation capabilities, but offers a lot more than what is implied and to a colorful customer base as well.

The company’s anodizing processes include bright dip anodizing, Type II anodizing, Type III hard coat anodizing and two-step architectural anodizing in clear and a variety of colors. With two anodizing lines, Ace can process small and large parts. It also does vacuum resin impregnation, powder coating, chromate conversion and precision cutback sawing.

Ace’s newest capability is the ability to offer Type III, clear or black anodizing on parts up to 282 inches long. The powder coat system is designed to run parts as large as 24 ft. by 10 ft. by 8 ft. All processes are completed in its original facility, which, after a couple of expansions, now stands at 85,000 square feet.

The components of this large tank, which were fabricated from heavy gauge steel, were to spend their service life as integral tanks in a heavy duty parts washing system. Ace’s customer had specific requirements for the coating, such as the application of a iron phosphate pre-treatment and a fluropolymer custom color, all of which were necessary to guarantee the coatings performance and meet the design requirements. They also had specific requirements for packaging to protect the parts through shipping and rigging prior to the system installation. The company’s ability to powder coat and oven cure large, heavy parts enabled it to powder coat each of the eight 500-lb, 14’ L x 4’ W x 8’ H tanks and related components in five days. 

The third-generation, family-owned business serves an intentionally diverse customer base comprised of recreational, medical, aerospace, defense, ordnance, cabinetry, architectural, infrastructure, RV and marine industries, to name a few. Battaglia describes the facility’s range of work. “No job is too small or too large. We have the flexibility to adjust our capabilities to the needs of our customers. The industry is constantly evolving, and so is Ace.”

Part jobs range anywhere from an inch to 282 inches long. “We can anodize and powder coat small parts or a tank that’s 20 ft. long,” he says.

According to Battaglia, the company provides some unique processes that are hard to find in the industry. This includes large part hard coating in clear or black (and any type of anodizing for large parts) and chromate pretreatment on all powder coatings. “Some companies that have their own powder coating operations send us their jobs to pretreat,” he says.

Bright dip anodizing is another increasingly difficult process to find, which

The company’s anodizing processes include bright dip anodizing, Type II anodizing, Type III hard coat anodizing and two-step architectural anodizing in clear and a variety of colors. With two anodizing lines, Ace can process small and large parts.

Ace provides.  

The company’s wide range of work that spreads across many industries is strategic, according to Battaglia. “Customer diversity is good because we are not dependent on one industry,” he explains. “We’re able to shift our focus if one industry seems to soften.”

Turnkey tales

As a 20-year veteran in the finishing industry (12 of those years with Ace), Battaglia says Ace is a company focused on getting things done; it has reacted and adjusted quickly to change. Management has responded to customer needs in big ways such as investing in additional processes and equipment which necessitated facility expansion. It also began offering value-added services, or turnkey work, that speaks volumes to its customers.

“If there’s a service that we don’t want to add as one of our core competencies, then we form a strategic alliance with outside sources to provide it,” he explains. “Then, we offer customers the opportunity to either work directly to the provider, or we will turnkey it for them.”

So, if a customer is running into a problem where it can’t find a source for a certain finish, Ace can do some research for the customer to find the solution.

Bright dip anodizing is a process Ace offers that not many finishing shops provide.

Ace can also take a project from start to finish. For instance, if the customer does not want to buy extrusions, the shop will deal directly with an extruder, purchase the material, bring it in the warehouse and stock it, cut the raw extrusions to precise lengths, finish it and ship it to meet the customer’s specifications. In these cases, Ace acts as a one-stop shop because the customer’s only touch point is the finishing shop. In addition, the customer was not stuck with excess inventory that is the wrong color, wrong length or the wrong finish. Instead, Ace keeps the inventory for the customer and the customer sends Ace its orders as needed.

Staying on top of the game

Reinvesting in the business and evaluating options for continuous improvement are ways Ace lives out its Top Shops title, according to Battaglia.

“The business has changed, the customers are more sophisticated, competition is more sophisticated, and the days of just trying to stay status quo are gone,” he explains. “You’ve got to be coming up with new and creative ways to lower costs, keep good employees and improve your processes.”

Battaglia says Ace’s owner not only does all these things, but he genuinely cares about his employees. Because the staff feels appreciated, in return, it prides itself on producing a quality product. Employees also self-evaluate for process improvement.

To assess the business regularly, the finishing shop finds great value in participating in PF’s Top Shops benchmarking survey each year. “The survey forces us to look outside of our building to see what other finishers are doing,” Battaglia says. “And while we are an industry leader, there are some things out there that others are trying that may be a fit or spark an idea for something we can do differently.”

This perforated aluminum panel is used in an architectural application requiring an anodized finish, Type II, Class II, with lightfast, UV stable coloring.

Like many manufacturing companies, Ace is faced with ongoing obstacles such as employee recruitment and the increasing costs of retaining good employees. Cost containment and dealing with rising prices within the supply chain, increased environmental regulations and economic uncertainty are other business challenges.

As there will always be issues to confront within the market or the business itself, change is inevitable as well. The finishing shop strives to adapt as much as possible to the ebbs and flows. Sometimes, that is in the form of building expansions. Besides the two facility additions it has completed since its inception, it recently finalized an exterior building refurbishing. This consisted of the addition of new windows for improved visibility and curb appeal.

This cooling apparatus for a combine or mining equipment has been powder coated at Ace.

Q: In the last year, the industry is moving rapidly to change over to decorative trivalent from hexavalent. As an applicator, we find there is no shortage of information, but the topic is so complex, we don’t even know where to begin, specifically when deciding between chloride and sulfate-based systems. Can you provide an overview of the topic and a review of what factors we may want to consider as we evaluate our choices?

A. It is quite common to be at a loss for where to begin when sifting through the large volume of information available regarding this transition. When talking with other applicators in your situation, I have found it helpful to provide an overview that offers a basic history on the usage of trivalent chromium, the important industry testing that has occurred to validate its usage, and then offer a comparison of the two types of systems and factors to consider when selecting what is right for your situation. 

Due to the amount of focus currently on this topic in the industry, I would be remiss if I did not first address a common misunderstanding between decorative trivalent plating and hard chrome plating. Decorative trivalent chromium is not the same as hard chrome plating, nor is the availability of technology the same. That is a topic in and of itself. For the purposes of this article and your question, we will be discussing information related only to decorative chrome plating.

History and Testing of Trivalent Chrome

To begin with a basic history, many people don’t realize that decorative trivalent chromium has been used in exterior applications for decades. Specifically, it has been used in the over-the-road trucking industry for well over 30 years, with the heaviest usage being on truck bumpers and stacks. In the beginning, trivalent chromium was chosen primarily for its operational efficiencies as it offered better coverage and less burning than hexavalent chromium. From an appearance standpoint, the earlier versions of decorative trivalent chrome were quite a bit darker (average L* value of 74-75) than hex chrome (average L* value of 81-83) which unfortunately tarnished its reputation for a while. However, as with other plating processes over time, the technology has advanced and the color value and appearance of trivalent plating systems on the market today is much closer to hexavalent (with L* values ranging from 76-82 depending on which process you choose).

Over the years, extensive testing has been completed to gauge the performance of decorative trivalent plating in the field. In the mid-1970s, CASS testing and mobile performance tests were conducted by ASTM International (formerly known as American Society for Testing and Materials). Plated in accordance with ASTM-B-456, testing was performed on steel 4 x 6 inch panels that were mounted on truck trailers traveling primarily in the rust belt. Extensive data is available for these tests, but a brief summary revealed microporous hexavalent chromium and trivalent chromium performed best in long-term outdoor exposure in these real-world tests and both performed identically in the protection and appearance ratings. As mentioned, the ASTM tests were conducted in the mid-1970s.

More recently, however, USCAR conducted a three-year field test study of trivalent chromium deposits. USCAR (United States Council for Automotive Research, LLC) is a collaborative automotive technology company whose member companies include Ford Motor Company, General Motors and Stellantis. Their primary goal is to strengthen the technology base of the United States auto industry with research and development. In 2020, USCAR released the findings of its “Final Assessment of Decorative Trivalent Chromium Exposure in Winter Environments” study. A summary of the study was published in the March 2020 issue of Products Finishing.

USCAR wanted to better understand the corrosion performance of trivalent chromium in CASS, calcium chloride, and real-world winter conditions with a focus on general corrosion, high chloride corrosion as well as color and color stability. The main goal was to identify whether sulfate or chloride should be used industry-wide for the U.S. car manufacturer’s supply chain. As part of the three-year field study, chloride systems were tested against the sulfate systems, and the data determined chloride systems performed better in high chloride corrosive environments than the sulfate systems. With respect to the specific performance in high chloride regions, the study found that chrome loss was more prevalent on sulfate-based chemistries than on chloride-based chemistries. The study revealed that 13 of 14 chemistries with significant chrome loss were sulfate systems. Again, these test results are specific to the USCAR field study, but the information is worthy of reference and consideration for any decorative plater working with automotive OEMs.

Recently, heat exposure testing was performed by a third-party Tier 1 supplier on automotive exhaust tips. The testing compared hexavalent chromium against a popular trivalent chloride system, trivalent sulfate system, and a newer technology trivalent system with reclaim abilities. The results of the testing revealed that after heat cycling the sulfate system’s color degraded to become less white and less blue than the chloride-based systems. In other words, the chloride systems behaved similarly to hexavalent chromium systems. The results were comparable to those obtained in the USCAR field study. Follow up salt spray testing post-heat exposure also showed delamination and pitting on the sulfate sample. It is worth noting that the automotive sector is interested in the results of the heat exposure data and further testing will be completed.

Uses of Trivalent Chrome

Initially, trivalent chromium was used for its operational efficiencies, however, today we find it is primarily the regulatory drivers such as REACH, OSHA (employee exposure), and EPA (wastewater, emissions, PFAS) moving the process forward. This has led the automotive industry to further sharpen its focus and enhance testing on the performance of trivalent chromium plating. As a result, applicators are increasingly becoming aware of the color stability and corrosion performance differences between the two systems.

When evaluating the choice between chloride and sulfate-based decorative trivalent systems, there are several factors to consider. Appearance and corrosion performance, plating rate in microns per minute, and anode type and functionality are all central to the evaluation.

Appearance or color is often the first consideration. Though we know both sulfate and chloride trivalent are not quite as white as hexavalent chromium, the good news is both are very near in color, almost to the point of being indistinguishable to the average eye. Based on the supplier, different systems can offer varying levels of L*a*b* values, so we often recommend applicators send in samples to be processed in the actual chemistry, request finished samples for evaluation, or ask to visit shops using the process to see the production line. Again, we encourage any applicators doing heavy work with automotive OEMs to review the USCAR field study summary in depth when considering performance factors. In terms of color stability, when referencing the USCAR field study, the data shows chloride systems are more color stable than sulfate systems. A related critical performance characteristic is corrosion resistance, and the data from the field study revealed chloride systems ranked higher in providing better corrosion resistance, especially in high chloride corrosion environments.

The next thing to highlight is the operational comparison of the plating rate in terms of microns/minute. This is a key consideration for applicators when deciding whether to install sulfate or chloride. When making the switch from decorative hexavalent to trivalent, many shops look at their existing line layout and timing and want to be able to maintain as close to the same process and plating speed they had with hexavalent plating to maintain their efficiency. Chloride systems have a plating rate that is identical or slightly faster than hexavalent chromium, averaging 0.1 to 0.25 microns per minute. Sulfate systems plate at half the speed of a hexavalent system, averaging .04 to .08 microns per minute. For applicators with return automatic lines, the speed is a very important factor to consider when choosing a sulfate system, as a larger tank size or possibly a new line might need to be constructed to accommodate switching to the slower plating speed. With a hoist line, you would need to add additional stations to account for the longer plating time with sulfate. This can be a concern based on your building footprint and floorspace limitations. If choosing a chloride system, speed will be less of an issue as it does not require additional plating time when converting from hexavalent chromium, so you will not need to lengthen your plating tank on a return automatic line or add another station on your hoist line.

A final operational difference to consider is the anode type and functionality. Anodes for chloride baths are graphite and have an extremely long life. I am aware of a shop that has had the same graphite anodes for 25 years. Sulfate baths require mixed metal oxide anodes which are typically replaced every few years. These anodes can be quite expensive, and they are also more delicate and require special shielding to ensure they do not get damaged or scratched. If the surface does get scratched, the electrolyte can begin building slight amounts of hexavalent chromium which, in turn, will lower the efficiency of the bath drastically. If you go in this direction, it can be helpful to note that most high-volume trivalent sulfate applicators will keep an additional set of MMO anodes on hand to accommodate this concern and prevent downtime if the surface gets damaged.

Conclusion

With the increasing and ever-tightening regulations and controls on hexavalent plating for both environmental and worker exposure, the benefits of making the switch can quickly be realized by the applicator. All things being equal, when switching to either chloride or sulfate decorative trivalent baths from hexavalent, trivalent offers better throwing power, is extremely tolerant to current interruption, is not prone to burning or nickel show, offers increased production and decreased rejects, and will greatly enhance employee safety.

As a final point of summary, as indicated in your question, the industry is indeed moving rapidly on this front. It is important to be aware that OEMs are actively changing process standards and developing new color standards. Specs are being reviewed and revised on a regular basis to specifically call out trivalent chromium. Collaborative efforts are also happening across the industry: AIAG is reviewing related quality requirements of the applicators, and a workgroup of ASTM’s B08.10 subcommittee is in the process of developing new thickness testing standards for trivalent chrome. On a global level, we are aware of numerous decorative trivalent RFQs circulating and Tier suppliers and automotive OEMs that are seeking platers who have already made the conversion to decorative trivalent chromium. This industry movement has led applicators to begin rapidly installing baths and preparing to make line adjustments to accommodate the transition. Your review of this information as you evaluate your choices in this decision is well timed.  

About the Author

Photo Credit: Columbia Chemical

Mark Schario

Mark Schario serves as Chief Technology Officer for Columbia Chemical at Columbia Chemical. For more info, visit columbiachemical.com.