Advantages and Disadvantages of Linear Rail 3D Printers


Linear rails are a popular motion component in modern 3D printers. As the name suggests, they consist of a rigid steel rail along with a carriage slide that contains a recirculating ball bearing.

A cut-away depiction of a linear rail and its recirculating ball bearings. Source: Linear Motion Tips

A cut-away depiction of a linear rail and its recirculating ball bearings. Source: Linear Motion Tips

They are designed to facilitate the sliding motion of the carriage while keeping it restricted to linear directions.

For this reason, 3D printers featuring linear rails are, supposedly, considered high-quality machines and their price tag generally reflects this belief.

Let’s take a look in detail at the advantages and disadvantages of these printers to understand if the investment is really worth:





Linear rails flex significantly less than linear rods, due to factors such as shape and metal stiffness. This higher stiffness translates into cleaner print surfaces and edges.


One is enough

As we mentioned above, linear rails don’t allow for any rotation in the carriage. This means that, unlike for linear rods, a single rail will be enough to achieve a strict linear motion and create a simpler, lighter, more nimble assembly, which will also reduce 3D print ringing.


Higher precision, smoother motion.

Linear rails are also usually manufactured to much tighter tolerances than linear rods. This higher precision translates to reduced play and binding (when the bearings catch and don’t roll smoothly), yielding smoother, more consistent motion.


Easier mounting

Unlike rods, linear rails are fairly easy to mount. The rails and carriage both have regularly spaced mounting holes, so a couple of bolts will have everything locked down.





As we said, linear rail 3D printers are expensive. Any decent linear rail will easily cost several times more than a comparable combination of linear rod and bearing.



Since the ball bearings in linear carriages are not locked in, linear rail 3D printers require an extra level of attention to prevent the carriage from falling off the rail.


Are linear rail 3D printers worth?


There’s no doubt that, under a performance perspective, linear rail 3D printers are far more precise and reliable than their counterparts. Their price, however, makes them difficult to recommend to everyone. If you’re on a tight budget and don’t need the best possible performance, linear rails may not be the best choice.



Categories: Design & Process