What is a Screw Wear Life
The wear life of Power Screw and nut drive systems are difficult to predict theoretically. The number of variables involved in such a prediction is large; load, speed, screw material, nut material, surface finishes, lubrication, duty cycle, operating temperature, and environmental factors such as the presence of abrasive contaminants, corrosives, vibration, etc… (See equation 1 in Figure 49) and our understanding of how these factors interact is limited. Because of this, the only proper approach to evaluating the service life of Power Screws is to thoroughly life test each application prior to final specification and production. However, even under laboratory conditions, results may vary quite markedly as rubbing friction and wear are notoriously capricious. Test life cycle variations of two or three to one are not uncommon.
A general understanding of the wear mechanism, some simple design, and operating guidelines, and recommendations for life testing will help you get the best performance from your screw and nut drive system. To learn more about screw wear life, check out our article Wear Life of Power Screws.
FIGURE 37