People who aren’t in the know often assume that all screws are created more or less equal. In fact, ball screws are quite different from lead screws. Ball screw buyers should read on to find out about the key differences between the two to ensure that they are purchasing the right type of mechanical linear actuator.
What Are Ball Screws?
Ball screws are mechanical devices used to turn rotational motion into linear motion. They’re composed of screw shafts, ball nuts, and recirculating ball bearings that reduce friction and allow a highly efficient transfer of power.
What Are Lead Screws?
Lead screws are also mechanical actuators that translate rotational into linear motion, but that’s where the similarities end. Instead of ball bearings, they utilize sliding screw shafts with threaded nuts that move directly against each other. As a result, lead screws produce higher friction and greater energy losses.
Differences in Efficiency
Ball screws are far more efficient than lead screws. While even the highest quality lead screws average only 44% efficiency, ball screws typically boast rates of 90% or better. The reason ball screws consistently deliver higher efficiency is that their design allows them to minimize friction, which can be vital for high-precision, high-repetition applications.
Differences in Performance
Ball screws offer significant performance advantages in most applications. If efficiency, precision, accuracy, or speed are top concerns, they’re obvious choices. Lead screws are only suitable solutions for simple applications that don’t require high performance.
Differences in Complexity
Ball screws are much more complex than lead screws. As a result, it’s very important to purchase them from a reliable manufacturer. The quality of the design, engineering, and materials used in the fabrication of ball screws can significantly impact their performance.
Lead screws are much less complex. Their comparatively simple design makes them less expensive and helps to reduce the amount of noise produced during ordinary operation. However, it also increases friction and reduces maximum load specifications.
When to Use Ball Screws
Use ball screws whenever precision, accuracy, efficiency, or speed are top priorities. They’re much better in high-performance applications. Examples include robotics, automated industrial equipment, vehicular power steering systems, semiconductors, and aerospace applications.
When to Use Lead Screws
Some situations call for the use of lead screws instead of ball screws. This may be the case if the application requires resistance to back-drive. Back-drive is most common in vertical applications when loads are stopped and holding mechanisms fail, and unfortunately, it’s most common with high-efficiency linear actuators.
Where to Find Ball Screws
Since lead screws are less complex, less efficient, and less expensive, buyers have some wiggle room when it comes to choosing a manufacturer. The same can’t be said of ball screws. These complex pieces of equipment must be made from high-quality materials and manufactured to specific engineering specifications.
The best way to buy ball screws is to find a reputable online industrial parts dealer. Buyers should look into a company’s reputation before placing an order and consider other factors such as whether they also provide repair services and protective devices such as rubber or leather baffles. Choose a manufacturer that offers guarantees of quality in addition to competitive pricing.
