Precision motion systems are critical in applications that require highly accurate automated positioning. These include a range of modern fields, from laser processing and automated liquid handling to microscopy and photonics.
One of the most recognized constituent modules of these motion systems is the translation or linear stage. Simply put, a translation stage is a component that allows for precise automated positioning along just a single straight line. It is also possible to combine multiple linear stages in order to create XY or XYZ stages, which, as you can imagine allows for the translation of the load along multiple axes of motion.
The six degrees of freedom
To better understand the process of linear motion or translation, it is important to point out that in the context of robotics and engineering, the movement of a body is said to have 6 degrees of freedom. Three of these degrees of freedom are rotational, and the remaining three are translational or linear.
The rotational degrees of freedom include rolling (side-to-side tilting on the x-axis), pitching (forward-backward tilting on the y-axis) and yawning (left-right turning on the z-axis). Conversely, the translational degrees of freedom are surging (forward-back linear motion on along the x-axis), swaying (left-right linear motion along the y-axis), and heaving (up-down linear motion along the z-axis).
Restraining the other 5 degrees of freedom
As you can imagine, a successful translation requires that 5 of the object’s 6 degrees of freedom are restrained—all 3 rotational degrees of freedom, and 2 translational degrees of freedom. This is what linear stages do.
There is a wide array of standard linear motion systems available in the market today. Some of the most popular ones are the following:
- Air bearing stages – Air bearing stages are known for producing the highest level of accuracy when it comes to translation. The bearings typically glide in a very thin layer of air that is just 10 percent of the thickness of hair.
- Screw-driven stages – Unlike many stages that use linear motors to achieve the desired linear motion, screw-driven stages are usually powered with a stepper motor. The two common types of lead screws that screw-driven stages use are friction screws and ball screws.
- Direct-drive linear motor stages –Unlike conventional stages that use belt-drive, leadscrew, and rack and pinion technologies, directdrive systems use linear motors.They are advantageous because they are typically less bulky, don’t suffer wear, are less noisy, and can achieve greater speeds and accuracy.
These linear stages employ a range of positioning technologies. Depending on the ability of the manufacturer, they can be custom-designed according to a client’s specific requirements. To make sure that you will be provided with modules that perfectly fit the systems they need to be integrated into, consider getting these components designed and engineered by a motion system supplier with many years of industry experience. The manufacturer should have a good track record when it comes to delivering optimal solutions to complex challenges.
