The real difference between ball screw and trapezoidal screw

“Ball screws and trapezoidal screws are not interchangeable in many cases, and there is always a trade-off between accuracy, stiffness and load capacity. I have also heard that there is not necessarily a perfect match between specifications and performance. I hope to compare them. A mature perspective to understand the real difference between them."

There are some differences between the application of ball screws and lead screws. Original equipment manufacturers' applications often require "appropriate" products, and lead screws are often the right choice. Trapezoidal Screw products are easily adapted to specific applications to achieve the desired performance while keeping costs to a minimum. In some cases, life testing is required during the design phase, but for OEMs, doing this extra work in the early stages can help reduce product costs. The Ball Screw can run continuously, withstand much higher loads and achieve faster speeds, and it is worthwhile to increase the cost. For the end user, the ball screw has good predictability and is therefore the best choice for ensuring fast integration and reliability. For example, factory automation systems rely heavily on ball screw technology. Of course, there are many original equipment manufacturer application systems that also require ball screws, such as the machine tool industry. For original equipment manufacturers, the technology is determined by performance and cost, not predictability.

The main difference between a ball screw and a Lead Screw is the way the load is carried between the moving surfaces. The ball screw uses recirculating ball bearings to minimize friction and increase efficiency, while the lead screw utilizes a low coefficient of friction between the sliding surfaces. Therefore, the lead screw usually does not reach the efficiency of the ball screw (about 90%). A simple analysis of the tribological mechanism (researching wear and friction) reveals that the predictability of sliding friction is necessarily lower than that of a transmission using recirculating ball technology. The fatigue life equation (such as L10 life) is very reliable within its scope of application. In summary, ball screw and trapezoidal screw have fundamental differences in their application fields because of their differences in their ability to predict performance and life.

Although ball screws have various advantages (load, stiffness, efficiency, duty cycle, predictability), they are costly. Although they are cost effective compared to other translational Linear Motion schemes, the ball screw design is more complex, requiring a hardened precision Bearing surface and a ball circulation device. The size of the lead screw is very flexible, the design is very flexible, the noise is small under the correct use, the corrosion resistance is good, and the self-locking function can be configured to meet the vertical application requirements. They play an important role in many applications, and of course there are some limitations.