By Ken Korane
We recently had the opportunity to meet with Thomas Witzler, Managing Director of NKE Austria, to get his take on a couple engineering trends affecting the bearing industry in general and his company in particular.
One promising area of development, he said, is the much-talked-about area of “smart” bearing-units that incorporate bearing hardware and sensor electronics in a single package. “We’re in the midst of what’s called the fourth industrial revolution, Industry 4.0,” said Witzler. OEMs want to build more intelligence into their machines, and that requires more data. “And for that, you need sensors. Coming from a bearing background, it’s obvious that bearings are quite sensitive elements of any machine. It makes sense to integrate sensors with the bearings,” he said. Coming from a bearing background, it’s obvious that bearings are quite sensitive elements of any machine. It makes sense to integrate sensors with the bearings,” he said.
The problem with current sensor-bearings on the market, however, is that they also require a sizeable cable to transmit data to a controller, he continued. And that takes up space, slows installation, and can complicate maintenance and reliability.
As a better alternative, NKE engineers are developing wireless sensor-bearings that have the same size as conventional bearings and need no cables. Witzler expects commercial products on the market within the next two years.
“We’ll start with temperature sensors because that’s easiest,” he said. Measuring vibration is another obvious need, as is torque. He expects the first units will be installed in applications where machine failure is costly, either in terms of damage to the equipment or in downtime and lost production. But even if the price tag for a complete smart-bearing system is one to two thousand Euros, if a machine failure costs 50 thousand Euros and insurance is expensive, the economics are more than reasonable, he added.
And he expects costs to drop as the technology matures and enjoys wider acceptance. “I think it’s like in the IT sector. When Bill Gates developed DOS, people said no machine will have ever run MB memory because it’s too expensive. Today, your cell phone has more,” said Witzler.
Another open issue is how to handle data coming from the bearings. Converting pure data directly into information that controls decision making and machine actions is not yet feasible. But NKE is working with development partners on the intricacies of linking bearing sensor data into customers’ standard information platforms and existing IT infrastructure, to help optimize machine performance, improve plant operations and add value to the customer.
Witzler is also seeing heightened interest from OEMs who are in the process of developing new machines. “They’re willing to pay extra to get more information out of a prototype that they don’t necessarily need once the machine goes into regular production,” he said.
These emerging technologies are coming together in a way that will change industry, he emphasized. “I think personally, 4.0 smart machines may be positioned for a big jump. So let’s invest in sensors, because sensors are close to bearings and bearings are what we know. We want to be part of the wave to come.”
Another interesting topic, and how it relates to the future of bearings, is 3D printing. But here, Witzler is a bit more cautious. “If we talk about cages and materials like plastics, I think we are close.” NKE is already investigating materials that can handle the temperatures and offer the necessary precision to work in bearings. “It’s not going to be large-scale production at the moment,” he noted. But for small quantities of special cages, that could be an ideal solution. “We think that plastic cages will be the first step, brass cages might follow.”
However, he’s not convinced that bearing rings will be 3D-printed anytime soon. NKE has tested rings made using additive-manufacturing techniques and found the results wanting. It’s difficult to obtain the necessary hardness and proper density of the product, and the material absorbs the lubricant, he explained. “So it’s a little bit of a dead-end road at the moment.”
And if you consider heat treatment, he continued, either you need a printer that operates at high temperatures, around 800° C, with an enriched atmosphere, or you print a part and then heat treat it. “But with those temperatures and energy requirements, that’s quite a tricky, specialized process and few people really have the expertise,” he said.
Nonetheless, the concept is enticing, Witzler noted. Today, it’s not unusual to produce steel in one location, ship it halfway across the globe where it is forged into a bearing, and then sent off to yet another location where it’s actually needed. The beauty of the concept is users could economically make a viable product when and where it is needed, and save a lot of time and money. And 3D printing can produce structures that would be impossible using current, classic manufacturing methods, he added.
The technology will definitely come, but initially it’s going to be for specials and small lots, and with different materials. “Bearings are a rather conservative industry. I don’t think that 3D printing will replace large-scale mass production using standard bearing steel in the near term,” he said. But the technology and capabilities are constantly improving. Ultimately, different materials — perhaps ceramics — could be a solution for 3D-printed bearings, added Witzler.