CemeCon, a coatings technology provider based in Horseheads, N.Y., now offers systems that can be operated by new users after just a few weeks of training—and these systems are even more capable than earlier models, according to Sales Manager Ryan Lake.

The third factor to consider, according to Lake, is the ability to develop proprietary coatings. He explained that contract coaters are more or less forced to offer standard products. “We don’t know what’s coming through the door each day. … We can make tweaks with our pretreatment, our post treatment, or cleaning, depending on the size of the tool and the geometry, to optimize in different ways. But we don’t have the same flexibility as a tool manufacturer.” Lake added that there also isn’t a huge difference between materials available from the competitive coaters. Whereas, “when you bring coating in house, you can do whatever you want. And with HiPIMS, you can sputter almost any element on the periodic table.”

Evans said Inveio coatings can consist of various combinations of titanium aluminum nitride, titanium chromium nitride, and aluminum oxide. Inveio is used for indexable inserts, where CVD predominates. Evans reported tool life improvements of 30 percent to 50 percent, strictly due to the coating. For solid-carbide tools, where a thinner coating is needed to preserve a sharper cutting edge, Sandvik Coromant has a proprietary PVD process called Zertivo. The touted benefit again is the ability to manipulate the coating process at the micro level. This is said to yield improved adhesion between substrate and coating, optimized for each grade. Here it’s titanium nitride, or a titanium carbon nitride coating. “We’re starting to see some aluminum oxide type coatings with the PVD processes,” Evans said. He added that Zertivo is now being applied to all new carbide grades.

In one comparison (a 6 mm carbide endmill machining 62 HRC cold-work steel, with vc = 170 m/min, fz = 0.11 mm, ae = 0.05 mm, ap = 0.05 mm), the SteelCon coated tool lasted 1,050 minutes, versus a competing TiAlSiN-coated tool’s 590 minutes, and an AlTiN-coated tool’s 405 minutes. In general, said Lake, SteelCon delivers “the ability to run tools anywhere from 10 to 30 percent longer than even our previous coatings, or run 10 to 30 percent faster than what they have been doing.”

Brian Shaffer, vice president for operations and quality at Better Edge, added that you also need to consider the expected volumes of specific coatings. “Recipes are very expensive, especially in the high-performance arena we like to play in. So we have to do enough testing to prove the recipe is worth it to our customer’s bottom line, and ask ourselves if we will have enough volume to fill the unit to make it worth running.”

Weigand attributed this success to SteelCon’s excellent thermal stability and insulation, which “hardly lets any heat into the tool, but dissipates it via the chip. This is particularly advantageous for materials that are themselves very poor heat conductors, such as stainless steel, nickel-based alloys and titanium. Without SteelCon, the high temperatures that inevitably arise during machining of the hard materials would damage the tool and embrittle the carbide.” Like other HiPIMS coatings, SteelCon is “highly wear-resistant,” due to the excellent adhesion of the coating and its high hardness and toughness, said Weigand. “This combination of properties results in significantly longer tool life and excellent machining results.”

* Source: Statistical Report 2013 published by the International Tungsten Industry Association (ITIA)

Steed explained that this capability is especially useful for coating the indexable inserts used in the heavy-duty machining of rails, switches, pipes and crankshafts, as well as in the rotary peeling of cast iron and ferrous materials. “These operations often require a large number of cutting inserts capable of holding up to maximum working speeds and providing high-quality machining. Higher coating thicknesses significantly extend their tool life—the key to economic efficiency. The correlation in such applications is almost linear—and that’s where this coating, which we call FerroCon Quadro, comes into play.”

New Technology That Achieved an Innovative Recycling System– A bold challenge to achieve the oxidation wet-chemical process –

Lake said the first of three factors to study is financial: How much are you spending on outside coating services? “If it’s $200,000 to $250,000 per year, there’s definitely a financial reason to look at bringing it in-house.”

“One of the tasks of our department is to strengthen the material flow from ore and scrap to the manufacture of cemented carbide tools, which are the final products. Our solution was to establish a recycling technology and a recycling center in the U.S. [discussed below]. The Sumitomo Electric Group started recycling tungsten in the 1980s. At that time, a recycling process called the “zinc process” was used to recycle scrap into raw material powder while retaining its constituents. In 2011, Sumitomo Electric developed a new chemical process to recycle scrap into tungsten trioxide (WO3), making great strides in recycling. Today, the recycled volume is equivalent to the weight of the cemented carbide tools sold by the Sumitomo Electric Group in Japan. However, this does not necessarily mean that Sumitomo Electric products accounted for 100% of the collected scrap. Part of the scrap was exported as valuables or melted with steel scrap. Of the total scrap generated in Japan, an estimated 30% is returned to our group. As the first step, we hope to increase the percentage to about 50%. To this end, we must expand both the collection capacity and the processing capacity. In terms of achieving stable supply, we are studying the possibility of investing to acquire interests in mines in addition to promoting recycling,” said Okamori.

But now—and you probably saw this coming—CemeCon’s HiPIMS is able to reliably achieve a 12-µm thick PVD coating. Steed said that’s because CemeCon is uniquely able to synchronize the cathode pulses with the substrate table, thereby “actively managing and limiting” the residual stresses of the coating. “We’ve even tested coating as thick as 25 microns,” added Lake, “though not in production. Even 12 was unheard of as recently as three years ago.”

Originally developed for the hardened steels used in mold making, CemeCon’s SteelCon coating is now being applied broadly, reported Manfred Weigand, product manager for round tools. That includes stainless steel, nickel-based alloys, titanium alloy, quenched and tempered steel (42CrMo), and cold-work steel (1.2379).

Should you coat in-house? Factors to consider include costs, supply chain issues and the ability to make proprietary coatings

So is it worth adding more to the mix? Shaffer pointed to Balzer’s Tisaflex, which he said had proven successful “in hardened steels and other difficult to machine materials. That’s another recipe we may one day consider bringing in-house if we have enough demand.” The lesson here is that cost considerations go beyond getting a vessel.

Lake listed control of the supply chain as the second most important factor in deciding whether to coat in-house. “That way, the tools never leave their facility, they never leave their control, they shorten their lead times. That is often a goal.” Shaffer enthusiastically agreed: “Full control of the process gives us a competitive advantage—being able to offer better lead times. We just started a program we call ‘Rapid Edge’ that offers high-performance coated specials in just three days.”

Steed also noted that in addition to being thick and tough, the FerrCon Quadro coating is very smooth and the thickness is evenly distributed, which provides optimum wear resistance. In fact, it appears smoothness is a feature of not only HiPIMS, but CemeCon PVD coatings in general. Shaffer said they have an older, pre-HiPIMS, CemeCon sputtering unit that “still outperforms the Oerlikon Balzers in applications where we need an excellent surface finish. We’ve seen this with seven flute finishing endmills and some reaming applications.”

“Recycling of cemented carbide scrap is important partly because it is highly effective in terms of environmental conservation. The percentage of tungsten contained in ore is less than 1%. Meanwhile, the percentage of tungsten contained in cemented carbide tools is about 85%. From the viewpoint of refining efficiency, it is far more environmentally friendly to extract tungsten from the scrap of cemented carbide tools. It should also be noted that global tungsten reserves are estimated at about 3.2 million tons. Thus, the resource is likely to be depleted in the near future. Global competition for tungsten will intensify. We must further expand the scope of recycling to protect Japan’s manufacturing industry. While such efforts partly reflect our business strategy to encourage customers to use Sumitomo Electric products, we will publicize the importance of recycling through activities to foster motivation and raise awareness with the SDGs in mind,” said Nakao.

One company that you might say is obsessed with creating proprietary cutting-tool solutions, to include coating, is Sandvik Coromant, whose U.S. headquarters is in Mebane, N.C. The company’s Inveio coating uses a patented chemical vapor deposition (CVD) process to manipulate the grain structure such that it is “more perpendicular than any other aluminum coating on the market,” according to Doug Evans, development specialist. This uniformly perpendicular structure is stronger than other CVD coatings, he said, using a unique illustration. “If you lay an egg on its side and apply pressure to it, you’ll easily break it. But if you can stand that egg up, you get much better compression forces and it takes a lot more pressure to break. The same is true if you can get that aluminum grain structure to stand straight up.”

Specialty tool manufacturer and regrinder Better Edge, Scottdale, Pa., coats its product with equipment from CemeCon and Liechtenstein-based Oerlikon Balzers. Plus, Better Edge’s Kabrlyn Coating Technologies division offers coating services to other tool manufacturers. Likewise, CemeCon, Balzers and other firms that make coating vessels generally offer coating as a service, too, and these companies can offer useful perspectives on whether to take coating in-house.

Sandvik Coromant not only patents its coating processes, the company also builds its own coating vessels (not to mention creating specialized pre- and post-processing routines). Evans said 90 percent of the tools Sandvik sells have been coated using its own equipment.

Cemented carbide scrap is classified into two main categories: solid hard scrap and powdery soft scrap. The former includes used or defective cutting tips, drills and dies/molds, while the latter refers to powder sludge generated during grinding and polishing at manufacturers of cemented carbide materials and cemented carbide tools. The sorting and collection of such scrap are crucial processes in the completion of a recycling system. When Sumitomo Electric started to recycle scrap in the 1980s, it also started to collect scrap. Recycling collection boxes are made available to customers, which use cemented carbide tools. The boxes, which are used to sort cemented carbide tools and other materials, are collected periodically. The company also accepts scrap from competitors’ products. It has also started collection by using a home delivery service. All the cemented carbide scrap collected is transported to the Igetalloy Scrap Center for sorting. The entire collection process is undertaken by Sumitomo Electric Tool Net, Inc., which sells cemented carbide tools. Shinji Nakao, General Manager of the Environment and Resources Sales Dept. of Sumitomo Electric Tool Net, has been engaged in the collection from the outset.

The Japanese government has set the procurement of rare metals as a national project due to changes in the environment surrounding rare metals. From the latter half of the 20th century to date, the framework of the global economy has changed significantly due to the rise and development of emerging countries, including China. Global production and consumption have accelerated, resulting in the expansion of consumption of rare metals. Against this backdrop, there has been a rising tide of resource nationalism (the belief that the resources available in a country should be managed and developed by that country) among producing countries. Tungsten is no exception. Previously, Japan imported much of its tungsten from China, which accounted for more than 80% of the global production volume. Today, tungsten is a mineral subject to export control in China. The production volume in other countries, including Vietnam and Russia, is limited. It is evident that tungsten will be depleted in the near future. Under these circumstances, the Sumitomo Electric Group has embarked on the recycling of tungsten. This is a challenging project to free the company from dependence on imports and achieve a stable supply by recycling tungsten. The Administrative Dept. of the Advanced Materials Business Unit is responsible for procuring metallic materials for cutting tools, including tungsten. General Manager Yoshimitsu Okamori is one of the members who have led the efforts to recycle tungsten.

For example, said Shaffer, in late 2020 Better Edge invested in an Oerlikon Balzers arc technology coating unit with “TiN, AlTiN, AlCrN, and TiAlN recipes that allowed us to keep 99 percent of our business in-house. We still have the odd case of extremely long tools that need to be shipped out, or a recipe we don’t offer, such as TiB2 or diamond.”

Achieving cleanliness is another cost consideration, noted Shaffer. “We found that investing in a superior cleaning unit helps tremendously in decreasing coating vessel downtime by reducing arcing errors.”

When we last covered cutting tool coatings in detail (ME August 2019: “Better Tool Life through Advanced Chemistry”), the hot new technology was high-power impulse magnetron sputtering (HiPIMS). HiPIMS is an advanced form of physical vapor deposition (PVD) that achieves a nearly complete ionization of the coating metal. But the process requires controlling more than 100 parameters. At the time, tool manufacturers were just beginning to recognize the benefits of coatings produced by the method—but many still were leery about attempting it themselves.

CemeCon’s president, Marjorie Steed, observed that the intense competitive pressure caused by the COVID-19 pandemic pushed tool manufacturers to seek new ways to distinguish themselves. “They asked, ‘How can we promote our specialty products? How can we prove that our tools perform better than before, or better than our competitors?’ This search for new technology led to a surge in demand for the HiPIMS process, and it has continued as things move forward.”

As discussed in the 2019 article, PVD is a better technique than CVD for a number of reasons—unless the application requires a thick coating. Lake explained that’s because stress builds within a PVD coating as it gets thicker, and that leads to poor adhesion and premature failure. “The arc technique has always topped out at between four to five microns, unless you did special things to further relieve the stress. Traditional sputtering maxed out at eight, maybe ten, at the absolute most.”

Ideally you’d physically isolate coating from grinding, Lake added, because the latter puts particulates into the air. Otherwise, “you run the high risk of coating voids on your tools, because the particulate gets on your tools. They go into the chamber, and then the coating doesn’t adhere. But we have customers that have coating equipment perhaps only 20 feet (6.1 m) from the grinder and they are still successful. We would advise a separation. But we also know sometimes reality doesn’t allow that to happen.”

The company’s latest operating software makes it relatively easy to control the multitude of factors that govern the HiPIMS process, Lake explained. He recounted a recent installation in which a customer sent staff members to CemeCon for two-week training sessions, followed by another two weeks in-house. “None of them had ever done coating before, yet they were [soon] up and running.” As he put it, CemeCon is “able to train anyone that has interest in the technology. If they can figure out how to successfully make quality cutting tools, they can learn how to do coating.”

Japan depends on imports for most of its energy and mineral resources. At present, there are no mines in Japan that produce rare metals, including tungsten. For this reason, ensuring the stable supply of energy and mineral resources is one of most important national issues. Against this backdrop, the Ministry of Economy, Trade and Industry formulated the New National Energy Strategy in 2006. It mentioned the need to step up efforts to promote recycling of metallic mineral resources. The Guidelines for Securing Resources, which were established in 2008, set out a policy to support the acquisition of important resources, including rare metals. In the following year, the Strategy to Secure Rare Metals was published. In 2012, five minerals— neodymium, dysprosium, tantalum, cobalt and tungsten—were selected as priority minerals to be recycled. A national project is under way to secure these rare metals. Why are rare metals so important? Although they are consumed in small quantities, they are indispensable materials in the manufacture of LCD TVs, mobile phones and vehicles. In fact, they are essential in maintaining and strengthening the international competitiveness of Japan’s manufacturing industry. Notably, global demand for rare metals is expected to increase in the fields of nextgeneration vehicles, motors and storage batteries, which are expected to come into widespread use in the building of a low-carbon society. In terms of the use of tungsten, cemented carbide accounts for about 61% of the global market on average. In Japan, the percentage of cemented carbide is particularly high (about 76%).* Derived by mixing WC with cobalt (Co), cemented carbide achieves high hardness, high wear resistance, and high heat resistance. Cemented carbide tools, such as drills, and cemented carbide inserts for cutting tools have achieved high-speed machining and revolutionized the operation of manufacturing and machining sites. In Japan, the Sumitomo Electric Group has become one of the pioneering companies of this technology. Cemented carbide tools are crucial for many manufacturers. It is safe to say that these tools are the lifeline of manufacturing and machining. Tungsten is an essential material in the production of these tools.