Change is sweeping through the bearing industry, says Snyder, and today
superior technology is the key to success and survival.
Design News: How has global competition affected the bearing industry?
Snyder: The first thing it has done is open the door for new producers with much lower costs. In applications or industries where bearings are a cost-sensitive item, it's a very easy entry for people with lower costs. And of course for the more mature bearing companies, who have a big technology base, the problem is to take advantage of their technology and come in at a competitive price. So global competition has caused the bearing industry to focus much more on manufacturing cost. But it has also opened up a big new customer base. And because those people want to catch up in a hurry, it creates a tremendous opportunity for makers of high-technology products.
Q: Why has bearing service life become a selection criteria?
A: Before, we used fatigue life. Maximum load determines fatigue life, so you select a bearing to handle maximum load. If the bearing doesn't fail, it means you've got a bearing in there that's much bigger than it needs to be. Also, the bearing's going to run a little hotter, because it's bigger, and you've got a bit more weight. Today we ask questions like, "how noisy is it?" Your failure criteria are totally different. Failure happens when the bearing's not useful in the application anymore, for whatever reason.
Q: How will attempts to develop a stress limit as part of a bearing life equation affect the industry?
A: If we're going to utilize stress limit, we'd better be sure we know what the loads really are. If you utilize the stress limit, you've got the potential to downsize. You can run faster, which means you may be able to run at a lower temperature at the same speed. You've got less weight in the total application; you've got less total cost in it. But the downside is, you've got to understand the application conditions. What is the load cycle? What is the misalignment? Because if you're starting to utilize a stress limit, and you underestimate the loads, you could be in for some big hurt.
Q: How will advances in coatings, such as diamond-like carbon coatings, affect bearing performance?
A: We're looking for bearings that are going to last better under poor lubrication conditions, and under conditions where you've got a lot of contaminant, be it solid or liquid. These diamond-like coatings are very, very hard. Because they are hard, we don't see the same surface deterioration that we might with a conventional steel bearing. It's a continuation of a trend to try to get more hardness into the surfaces of the bearings.
Q: What are the primary factors that shorten bearing life?
A: Many customers have come to us and asked us to participate in a failure analysis. And what we see is that probably the two most important causes of bearing failure are poor lubrication conditions and mishandling. The former may mean selecting the wrong lubricant, not maintaining it properly, not changing it, not changing the filter, or letting water get into the lubricant. And mishandling could mean just leaving a bearing open on the bench overnight before you install it. Then, because of high humidity, you get some rust on it. Any mishandling can have a dramatic impact on a bearing, and its performance in an application.
Q: How have inexpensive computers and software affected bearing design ?
A: We can do things very quickly as compared to what we used to do. Before, you'd come up with a design on a piece of paper, go back and make prototypes and samples, then go to the lab and test. Now you can simulate the bearing on a computer. You only test once. It's a final verification test as opposed to testing to arrive at a final design. That helps tremendously in manufacturing. Because before we go to manufacturing, we've got that design finalized. Using 3-D models we can look at the assembly techniques to try to eliminate bottlenecks. Computers and software have really shortened time to market.