While we often talk about the importance of keeping contamination out of linear motion components such as linear guides and screws, when these systems are used in a cleanroom, the goal is just the opposite — to keep these components from introducing contamination into the environment. What exactly is a cleanroom? According to ISO 14644-1:2015, […]
FAQs + basics
How do miniature profiled rail guides compare to their full-size counterparts?
The basic distinction between “standard” and “miniature” profiled rail guides is the width of the guide rail: profiled rails with a width of 15 mm or less — and the carriages that fit on them — are generally considered “miniature” by bearing manufacturers. (However, some manufacturers also produce 15 mm rail guides in standard versions, as we’ll […]
When is encoder resolution specified in bits, and what does that tell us?
Absolute encoders — whether rotary or linear — track the position of an axis by assigning a unique value to each position on the encoder, so that no matter where the axis being measured is located, its exact position can be determined. And because each position is uniquely identified, this holds true even if the […]
What’s the difference between minimum incremental motion (MIM) and resolution?
When we talk about the positioning capabilities of a linear motion system, we typically talk about accuracy and repeatability, and in some applications — especially those driven by stepper motors — we may also be concerned with resolution. But accuracy and repeatability define a system’s ability to reach its commanded position and to do so over […]
Linear bearing seals: Types, options, and applications
Seals for recirculating linear bearings serve two functions — keeping contamination out and keeping lubrication in — to ensure the system operates properly without premature wear or failure. Because sealing is so critical to linear bearing systems, manufacturers offer a variety of sealing designs and materials to meet a wide range of applications and environments. […]
Ball screw seals: Types, options, and applications
Ball screws are used in a wide range of applications, many of which expose the screw and nut assembly to harmful contamination in the form of dust, chips, or liquids. And like any bearing that uses metal balls (or rollers) on metal raceways, ball screws can experience abrasive wear when exposed to solid contaminants, while […]
Belt driven actuators for a wide range of applications
Belt driven actuators are the workhorses of the electromechanical world, offering longer stroke lengths and faster speed capabilities than screw driven designs, with less inertia and better resistance to contamination than rack and pinion drives. And although linear motors boast better positioning accuracy than belts, the price-performance ratio of a belt driven actuator is difficult […]
How to size a spline shaft: Shaft strength in bending and torsion
Choosing a shaft for a traditional linear ball bushing is relatively easy — choose the appropriate diameter, material, and hardness, check the dimensional accuracies and tolerances, and if the shaft is unsupported, perform a beam deflection calculation. But because spline shafts can withstand both radial and torque loads, it’s important to ensure the shaft strength […]
How to calculate bearing life for a ball spline
A ball spline is much like a linear ball bushing and shaft, but with axial grooves along the outer diameter of the shaft and the inner diameter of the nut. These grooves prevent rotation of the bearing (referred to as a spline nut) and allow the ball spline to transmit torque. Because a ball […]
What is stepper motor resonance and how can it be avoided?
The discrete, step-by-step movements that give a stepper motor its accurate positioning capability can also lead to some undesirable performance characteristics — namely, vibration and audible noise due to resonance. Stepper motors naturally exhibit small vibrations with each step, due to the inertia of the moving rotor, which causes the motor to slightly overshoot (or, […]
