Linear Stages

Different Kinds of Linear Stages and Their Applications

When it comes to providing precise linear motion for a motion solution or a work automation solution, nothing gets the job done better than high-precision linear stages. Just like any other type of high-end machinery, there exist many different kinds of linear stages, each with its own unique traits, characteristics, and industry applications. Let’s get to know each of them and how they’re used in today’s industries.

Direct Drive Linear Motor Stage

This particular linear stage is known not only for being capable of very fast, very smooth, and very precise movement on a single plane, but also because it has the vaunted trait of being maintenance-free. This is all thanks to how the linear motors that power its movements are made and designed. Linear motors, without getting too technical, are motors that are able to directly translate electricity into linear movement, all without an intermediary structure between them that could cause friction, and thus result in wear and tear.

Such a feat is done through the clever use of charged magnets and air bearing guideways. As a result, the main moving parts involved in a direct drive linear motor stage do not actually come in contact with one another. Without friction, not only are the movements of a direct drive linear motor stage that much more precise, but also much more repeatable and sustainable.

Because of this unparalleled precision, repeatability and reliability, the direct drive linear motor stage is well-suited for industry and research positioning and scanning applications, such asprecision automation, micro-assembly, and biotechnology. It is also seeing use in industries that require fine laser beam control, optics, lens testing, and photonics alignment. 

XY Stage

The XY stage is a linear stage designed to provide precise motion to an affixed payload in two planes of movement, hence its name. As such, it is perfect for jobs and positioning applications that require movement in two axes. In its simplest and crudest configuration, an XY stage is essentially just two single-plane stages bolted together so that they are perfectly orthogonal, to properly facilitate movement between the two axes.

This is useful up to a point, but is usually not advisable for the most precision-demanding of tasks. For those, a more nuanced and deliberate configuration is needed, where the orthogonal orientation of both stages are precision-machined into their component parts, combining them much more effectively and securely. An example of this configuration is where the two stages are placed on top of each other, with the top of the lower axis stage serves as the base for the upper axis stage.

XY stages can be designed with a wide range of guideways and motors, with the air bearing guideway/linear motor setup affording the most accurate and reliable results.

Like the direct drive motor stage, the XY stage sees use as a motion solution component in industrial measuring technology and microscopy. It is also used in industries that require precise optical inspection tasks and laser processing.

The Microscope Stage

As its name implies, the microscope stage is a linear stage that contributes to the overall precision of an automated digital microscope. Simply put, it is a speciallydesigned XY stage that has an extremely low profile, as well as an open aperture in the middle to accommodate another linear stage meant to control the focus of a digital microscope’s objective lens. It is usually powered by stepper motors and lead screws, although recent developments have allowed newer microscope stages to employ linear motors.

But how does the microscope stage actually help a digital microscope be more accurate? Simply by precisely moving the sample or specimen to be examined by the microscope in the XY planes, in conjunction with the linear stage that focuses the microscope’s objective lens. In this manner the specimen is always in focus, allowing for a consistent and clear view at all times.

As they are purpose-built for microscopes, microscope stages see heavy use in any industry that requires up-close and accurate inspection of small objects, such as in the medical and electronics manufacturing industries.

The Screw-Driven Stage

This particular style of linear stage provides linear motion through the use of a stepper motor pulling a drive nut along a screw shaft. Depending on the type of screw shaft and how fine the thread pitch – i.e., the distance between the screw shaft’s grooves – the speed and precision of the linear motion can be modified according to the motion solution owner’s exact specifications. This gives the screw-driven stage a degree of customization that its other counterparts cannot boast.

Among its peers, the screw-driven stage is one of the more affordable linear motion solutions available, as the parts involved in its construction and design are simple, inexpensive, and easy to replace. The way it functions also makes this particular stage invaluable when it comes to motion solutions that require vertical movement.

When it comes to industrial applications, screw-driven stages are seen mostly in automation and inspection systems, laser machining, and jobs that require vertical lift. Some specific sub types of screw-driven stages, especially the more compact ones, see use in the medical field, mainly for examination and diagnosis.

The Air Bearing Stage

The air bearing stage offers a high level of precision that other linear stages can be hard-pressed to emulate, especially when combined with a linear motor actuator. This is because it uses a thin layer of air in order to completely eliminate friction from its main moving parts.

By using air bearings, the stage can average out any errors or faults of its flat planar guideway, providing a level of precision that tops even that of mechanical guideways, with resolutions up to less than 1 nanometer. The fact that a cushion of air is preventing any moving parts from coming into contact with each other also completely eliminates any friction-based wear and tear, which helps the owner save on parts maintenance and replacement costs.

Due to its ability to provide an extreme level of precision in its movements, air bearing stages are used for industries that require high precision laser machining applications, especially those that require smooth arcing and circular movements. They are also precise enough to be of use when it comes to the assembly of fiber optic manufacturing equipment.

The Gantry System

The gantry system type of linear stage can be considered as the bigger and more heavy-duty version of the XY linear stage. It is capable of extreme levels of accuracy and repeatability, thanks to the optimized encoder locations and ironless, cog-free linear motors that come standard with this particular system. Because the latter component ensures that the movements are facilitated in a contactless manner, operation noise as well as velocity ripple is reduced.

Besides all these stellar advantages, the gantry system also sports one unique advantage over its counterparts, namely its ability to have other motion stages – such as rotary tables and miniature linear stages – mounted onto its frame for added functionality and modularity. This makes the gantry system perfect for high-accuracy and high-duty cycle industry applications, such as imaging, automated parts inspections, material dispensing, and 3D printing.

In Conclusion

Linear stages offer the very best in precise motion solutions. The fact that there exists many different types means that any industry or business – no matter their size, resources, or main product/service – can benefit from them.

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