Today’s motion automation applications demand effective linear motion transfer systems, such as leadscrews and ballscrews. Although leadscrews are often seen as less expensive substitutes for ballscrews, making a decision on which type of screw to use is a lot more complicated than focusing solely on cost.
The basic difference between ballscrews and leadscrews is that a ball screw uses ball bearings to eliminate the friction between the nut and screw and lead screws do not. Lead screws use deeper helical threads and a mating nut, which is usually made of a polymer composite or bronze. The rolling nature of ball screws eliminates the sliding friction associated with lead screws.
What are the advantages/
disadvantages of leadscrews?
- Leadscrews cost less.
- Leadscrews are less cost-effective in the long run due to maintenance costs.
- Leadscrews are self-locking and do not require a braking system.
- Leadscrews are generally less efficient, requiring greater torque and a larger motor and drive.
- Leadscrews have higher friction and run a hotter temperature.
- Most lead screws are not well suited to high throughput, high speed applications or those with continuous or long cycle times.
- Leadscrews in general are self-lubricating.
- Leadscrews can be less noisy.
What are the advantages/
disadvantages of ballscrews?
- Ballscrews require braking systems.
- Ballscrews are available in higher accuracy grades for greater positional accuracy.
- Ballscrews are more efficient, requiring less torque.
- Ballscrews have lower friction and run at cooler temperatures.
- Ballscrews require grease or oil lubrication to achieve design life.
- Ballscrews can have higher noise values.
- Ballscrews require braking mechanisms to eliminate back driving.
- Ballscrews are available in rolled & ground types
- Ballscrews can be adjusted to increase/decrease preload.
How does my application dictate which one to use?
Generally speaking, ballscrews are better for applications that require smooth motion, efficiency, accuracy, precision, and prolonged continuous or high-speed movement. Traditional leadscrews are more suitable for transfer applications for which speed, accuracy, precision, and rigidity are not as critical.
Of course, there are always trade-offs to be made depending on your application. In addition to materials, assembly design, and accuracy, important variables to consider include wobble error, noise, maintenance, efficiency, and longevity. In most cases, evaluating the load, accuracy, and lead for your application will most generally answer the question of ball screw vs. lead screw. If you are still unsure on which one to use in your application, please contact our friendly expert team today.