If you’re on the market for a ball screw, you’ve undoubtedly noticed that there are two distinct varieties. These are referred to as rolled and ground ball screws. Though they perform comparable roles, there are a few differences between ground and rolled ball screws that should be noted. Here is a guide to ground vs. rolled ball screws: the differences.
A grasp of the two distinct manufacturing processes used to fabricate these components is the key to understanding both the strengths and limitations of rolled and ground ball screws.
What is Ground Ball Screws？
Ground screw threads are manufactured using an abrasion process that typically takes place in a horizontal setup in which material blanks rotate on their long axis between two machining centers while extremely hard abrasive cutters designed to cut a few threads at a time carve the threads from the cut blanks.
The lead screw and ball nut’s internal and external threads are cut using a similar process. This progressive abrasive machining technique needs the material blanks to be cut to final length before grinding. Internal and exterior threads are ground using different cutter sizes and styles, but the fundamental procedure remains the same.
Advantages of Ground Ball Screws
Ground ball screws will be much quieter in operation than their rolled counterparts. The mating ball nut is ground and paired with the ground screw ensuring ball-to-screw contact is optimised.
What is Rolled Ball Screws？
Rolled screws are manufactured via a procedure known as rolling, which includes the plastic deformation of metal. This technique improves the screws’ mechanical qualities, making them stronger and more durable than their chopped counterparts. The rolling process also produces a better surface polish, which can benefit the screw’s performance in a variety of applications.
Advantages of Rolled Screws
- Increased Strength: The rolling process aligns the grain structure of the metal, resulting in improved tensile strength and fatigue resistance.
- Cost-Effectiveness: Rolling is a more efficient manufacturing method, reducing material waste and production time, which translates to lower costs.
- Better Surface Finish: The rolling process produces a smoother surface, which can enhance the screw’s performance and reduce friction during installation.
- Precision: Rolled screws can be manufactured to tight tolerances, ensuring consistent quality and performance.
Ground vs. Rolled Ball Screws: The Differences
Manufacturing Process
A rolled ball screw is created by pushing round blank bar material through rotating tool dies. As the blank material passes through these rolling dies, threads develop as it is pushed out of the way. Rolling dies exist in a range of forms and sizes to accommodate the various pitches connected with ball screws.
Threads of a rolled ball screw
Ground ball screw is manufactured by way of grinding away the material of the blank bar to form the ball screw threads. The blank bar material is machined by two machining centres which grind a few threads at a time.
Accuracy
In terms of accuracy, ground ball screws rank substantially higher than rolling ball screws. This is because the threads of a ground ball screw have been created more accurately and smoothly than that of a rolled ball screw. When a screw is more precise, the nut glides more smoothly down its shaft. Increased precision isn’t always a good or negative thing; depending on the application, a rolling ball screw can be highly accurate and yet be an excellent choice for your project.
Cost
When comparing ground vs. rolled ball screws, you’ll notice a big pricing discrepancy. Because of their efficient production process, rolled screws are generally substantially less expensive than ground screws. Despite their higher price, ground screws are frequently preferred over rolled screws for use in machines requiring high precision because they provide more accuracy.
Conclusion
During the fabrication process, rolled ball screws and precision ground ball screws differ in a few ways. Ground ball screws are manufactured using an abrasive grinding technique, whereas rolled ball screws are made with rolling dies.
The cost of the two types of ball screws is normally different. Rolled ball screws are often more affordable and accessible than ground ball screws. Ground ball screws, on the other hand, are preferable for machinery that demands higher precision due to their greater accuracy.