Rotary tables are positioning devices that are oftentimes used in precision manufacturing applications. More specifically, they are tools that hold parts on rotating axes, which increases productivity, accuracy, and repeatability. It seems simple enough, but there are various types of rotary tables. So how do you choose which one is best for you? Let’s go through three common kinds of rotary tables – air-bearing, oil hydrostatic, and mechanical-bearing – to assist you in answering that question.
Air-Bearing Rotary Tables
In many cases, air-bearing rotary tables will be the answer. This is due to the fact that they have the capacity to run longer than other kinds. These are exactly what they sound like; with air-bearing rotary tables, parts float on air above the table. With this, there are no contacting parts to wear the machine down, resulting in decades of maintenance-free motion. That is a significant benefit to any piece of air-bearing equipment, but these rotary tables are specifically beneficial for certain applications.
Maximizing metrology productivity can be challenging, but utilizing air-bearings can assist in boosting turnover. Additional industries such as optics, assembly lines, and light machining and grinding, can use them to increase accuracy and productivity as well.
Oil Hydrostatic Rotary Tables
Similar to air-bearings, oil hydrostatic rotary tables do not have any contacting mechanical parts, as they float parts on oil. These rotary tables are most commonly used for grinding and machining when smooth and repeatable motion is a necessity. They provide high load capacity and can be useful when extreme stiffness is necessary.
Mechanical-Bearing Rotary Tables
Mechanical-bearing rotary tables are a bit different from the other two. Just as the name suggests, this type of rotary table does have moving, touching mechanical parts. And while this does sometimes result in a shorter life than the air-bearing or oil hydrostatic tables, many organizations will still pick these out of the others. Why? They still offer high performance.
These rotary tables can be used in most applications and provide superior performance in radial, axial, and angular error motions. In all, mechanical-bearing rotary tables do the job; however, it is possible that they will not last as long as other types.
Which is Best?
The answer to the question, “Which one is best?” is the ever-hated, “It depends!” In general, air-bearing rotary tables will provide the highest accuracy for the longest amount of time. The lack of touching mechanical parts allows this type of rotary table to last decades. However, if you need a stiffer hold, oil hydrostatic could be the better choice. And in other cases, mechanical-bearing rotary tables could be best. All in all: It depends.