For almost half a century, Zygo Corporation has been a global leader in the design and manufacture of advanced optical metrology systems and ultra-precise optical components and assemblies.

Zygo takes its core philosophy of bridging the gap between academia and industry seriously. How seriously? Zygo is Latin for “bridge.”

With that bridge in mind, Zygo — with its optics division and metrology division — has expanded its automotive metrology expertise over the years to include the inspection of gears and other gear-related parts.

“Our involvement with gears is quite recent; we were involved in some very unique applications in the early 2000s,” said Michael Schmidt, market development manager for the Zygo Corporation. “One was with the space shuttle’s aileron gears and another common application was with helicopter transmission gears. For the helicopter manufacturer, Zygo made sure that the superfinishing processes maintained its stability. More recently, we’ve been working with automotive OEMs on EV transmissions and their tight specifications. Though this movement into gears may seem new, one of Zygo’s major markets is automotive metrology.  We’ve been providing our technology to automotive component manufacturers for almost 30 years. From high-value, low-volume components to integration into production lines for 100 percent inspection, all major OEMs and Tier I/II suppliers rely on Zygo instruments worldwide.”

A ground hypoid planetary gear. (Courtesy: Zygo)

EV Gears

Now, Zygo is moving into the inspection of gears associated with electric vehicles, according to Schmidt, and the software that Zygo offers makes it even easier for customers to interpret the nuances of an inspection.

“We’re delving more into EV gears now because of the market need for quieter, more efficient gear systems,” he said. “And probably one of the reasons a lot of customers are coming to us now is they’re finding the contact stylus solution sometimes just isn’t right for the application. The 3D capability gives them more information on the surface, not just the surface texture, but also other contributing factors from the surface that will provide smooth operation of their products — specifically, what peculiar things are they seeing from their processes that they’ve never seen before? They can now visualize this on the 3D data in front of them, and it gives them a lot of ideas.”

Schmidt said Zygo’s customers license non-contact 3D optical profilers ranging from a bench-type system to a fully automated system.

“Our flagship system, the Nexview™, is a fully automated system,” he said. “This allows the customer to have a system for all their users and is able to be pre-programmed to run measurement sequences for each of their products automatically. The technology that we’ve invested in over the last 30 years in our microscopes allows us to use custom-designed objectives, which were designed specifically for the automotive market.”

Gear tooth geometry of a hypoid planet gear. (Courtesy: Zygo)

Passion for metrology

It all boils down to how Zygo is passionate about metrology, according to Schmidt.

“We always say our passion is metrology,” he said. “From the product standpoint, our product team wants to enable our customers to measure everywhere. And what that means is a lot of people are accustomed to measuring stuff in the metrology lab. We, as a company, decided a long time ago, let’s try to move the metrology from the well-controlled metrology lab to the production floor where it makes the most sense. We want to be next to those grinding machines. We want to be next to milling machines on the production floor. But the key takeaway is that we’re very passionate about the metrology and offering the right solution.”

As the industry moves into the EV world, it’s more important than ever that Zygo keeps its metrology solutions on the cutting edge, according to Schmidt.

“From the transition from internal combustion engine transmissions to EVs, our technology has always been there,” he said. “They’ve caught up to us, and now we’re traveling onwards together to help each other. We’re going to help them try to solve some of the solutions that they have. EV is creating challenges for a lot of EV transmission manufacturers, as we know, from reducing noise to preventing catastrophic deterioration of the gears because of the high torques that are on all the components in the EV transmission nowadays. We’re being called on because of the innovations that we’ve implemented, the investment in better algorithms, field stitching, and vibration mitigation.”

The Zygo ZeGage™ Benchtop OpDcal Profiler. (Courtesy: Zygo)

Expertise difference

Making this transition to EVs happen takes a workforce that’s up to any and all challenges, according to Schmidt.

“As with many of the top companies, I’d have to say the best investment that we have is our people,” he said. “Without the people, we just wouldn’t be the company that we are today. So, it’s that combination of my colleagues developing better innovations for processing with the  creation of better tools so that they can make these EV gears smoother, more robust, and optimize manufacturing.”

The more information Zygo’s equipment can gather from the gear leads back to the customers’ processes, according to Schmidt.

“A lot of people think it’s, ‘Oh, OK, we’re just going to check Ra.’ First of all, we supply all ISO 2D profile parameters, but the true value is the ISO 3D, or areal, parameters,” he said. “But we offer more than that. Some of the projects I’ve been involved in are helping our customers better understand their process and finding a balancing act with regards to attaining the right surface texture on both sides of the gear while maintaining the gear tooth profile and height. Sometimes, one flank is ground or polished to a certain level, while the other side is not. Then we provide that quantitative feedback to make their small adjustments, rotations, pressures, whatever, to that machining process. That almost-instant feedback the Zygo tool provides gives them the closed-loop feedback they require to quickly get their parts within spec.”

And that’s not just the quantitative values, but the qualitative visuals Zygo provides its customers, according to Schmidt.

“Experienced process engineers find some of the most value from our tools, especially the 3D maps we acquire from their parts, “he said. “Sometimes, the parameters are within specification, but the gears are still generating too much noise. They can look at the 3D topography map we produced and determine what might be amiss. Sometimes they’ll see remnants from the previous one or two processes (e.g., skiving or hobbing), which is feeding through to the final process, causing the texture to be multidirectional rather than the planned texture lay.”

Zygo’s Flagship 3D Op2cal Profiler, the Nexview™ NX2. (Courtesy: Zygo)

Impressive resume

With more than 50 years of experience in the metrology field, Zygo has picked up an impressive amount of evidence to back that up.

“Anybody who walks into Zygo, from the lobby, you can see something that we call the ‘Patent Wall,’” Schmidt said. “It’s the number of patents that we have in metrology. It’s a very, very long wall, and we still don’t have enough hallway space for all the patents. We have, I think about 400 to 500 patents related to metrology and optics.”

The seed for all those patents began in 1970 when the company’s three founders started an optical company with the goal of bridging academia and industry. The company’s first products were the production of some of the best plano optics for parallel surfaces, according to Schmidt.

“And then, it dawned on them, ‘We’ve got to measure these optics,’ and, as we know with manufacturing, you can’t make it if you can’t measure it,” he said. “So, our first engineer, came up with the first commercial laser interferometer, and that’s where the metrology division started.”

Zygo later expanded that product line with consecutive innovational advancements into the products offered today.  Released in the 1990s was their next innovation, the Coherence Scanning Interferometer (CSI), commonly known as an optical profiler, a major breakthrough because of the extremely high measurement precision.

“That’s pretty much one of the product lines I mostly work within the gear realm, because it’s a non-contact optical profiler,” he said. “It’s almost like using a stylus, but rather than touching the surface, we just use light.”

Surface roughness of a ground EV gear. (Courtesy: Zygo)
Surface waviness of a ground EV gear. (Courtesy: Zygo)

Looking to the future

As Zygo moves into the future, Schmidt expects EVs to dominate the market, whether it be hybrid, battery-electric, or hydrogen powered. This means there will be more opportunities for the company to offer its state-of-the-art metrology services. And another important capability Zygo has is to measure thin films as well.

“There are other capabilities we’ve developed, which we think will become important as manufacturers determine their best manufacturing processes and further develop their product lines,” Schmidt said. “One being the ability to measure film layers. There may be a point in the future where coating technologies will be required to even further improve gear robustness.  With Zygo CSI technology, we already have that covered with the ability to measure films and their bottom and top topographies. These will be very useful to process engineers to ensure coatings are homogeneously applied, or even tribological lubrication testing.  Some of the current EV motors will be well over current internal combustion counterparts’ RPMs. The effects on the lubricants and the gear surfaces will need to be better understood to increase lifetime.”

“The future of automotive will be exciting and we are seeing that now with this paradigm shift in the industry towards electric vehicles, he said. “Zygo will continue to grow our relationships with our current and future customers, providing new, innovative solutions to ensure both our partners and Zygo are successful. In the end, it will make their own customers happy with their purchases, I’m looking forward to it. We’ll be ready.”