When choosing a screw to provide mechanical motion to your machine, you’ll likely encounter two options: acme screws and ball screws. Both acme screws and ball screws function by transforming rotational motion into linear motion. Each of these screws is useful for different functions, but before purchasing one, you’ll need to decide which is best for your machine. To help you choose the right type of screw assembly for your application, learn to identify the differences between acme screws and ball screws.
What Is an Acme Screw?
An acme screw is a particular type of lead screw with a trapezoidal thread along its shaft. The shaft is fitted with a nut, which can move back and forth along the shaft as it rotates.
Advantages:
- Less expensive than ball screws
- Preferred choice for vertical applications and those with low load ratings
- Self-locking – no additional brakes needed
Disadvantages:
- Lower efficiency than ball screws
- More friction between the screw shaft and nut
- Shorter life cycle than ball screws
What Is a Ball Screw?
A ball screw is similar to an acme screw in that it also consists of a screw shaft and nut. However, it differs in that it also includes ball bearings. Located between the shaft and the nut, the ball bearings roll through the threads of the screw to aid in the smooth motion of the nut along the shaft.
Advantages:
- Friction is minimized by the ball bearings
- Higher efficiency than acme screws
- Able to support heavy loads
Disadvantages:
- More expensive than acme screws
- Have the tendency to back drive, which must be fixed with brake system or preloading
- Often louder than acme screws during operation
The differences between acme screws and ball screws make each type of screw assembly best for certain applications. As a ball screw manufacturer, Wedin International, Inc. manufactures and repairs both ball screws and acme screws. Contact us, and we’ll be happy to provide you with quality parts for your machine.