If you’re involved in ball screw sizing or selection, you’ve probably noticed that there are several different standards that govern various aspects of ball screw design, from lead accuracy and load capacity to ball nut tolerances and rigidity. Fortunately, in many cases, these standards are in harmony and provide the same (or virtually equivalent) specifications. […]
FAQs + basics
Profiled rail accuracy: When accuracy class doesn’t tell the whole story
You’ve chosen a profiled rail and bearing for a high-precision application — machining, cutting, or metrology, for example. The bearing (aka carriage, or runner block) has good load capacity and rigidity, so it should provide long life and low deflection. But when you integrate the assembly into your application, you notice that the system doesn’t […]
What is sub-divisional error (SDE) in linear encoders?
To determine the position of a linear axis, an encoder read head travels along a scale and “reads” changes in light (for optical encoders) or magnetic field (for magnetic types). As the read head registers these changes, it produces sine and cosine signals that are shifted 90 degrees from each other (referred to as “quadrature […]
Selecting shafts for linear bearings: two things you need to know
In a round shaft linear bearing system, the shaft acts as the inner raceway of the bearing and plays a significant role in the wear and life of the system. Both recirculating and plain linear bearings as well as track-roller wheel-based linear bearings can use a wide variety of shaft materials, depending on the application […]
What is a gimbal and how is it used?
In simple terms, a gimbal is a pivoting platform that allows an object to rotate around one or more axes. They’re often found in photography and videography applications to stabilize cameras, as well as in navigation systems for ships. In these applications, two or more gimbals are mounted together with orthogonal axes (axes mounted 90 […]
How do roller pillow blocks compare with traditional round shaft bearings?
Round shaft guides are typically used with plain (composite, plastic, or bronze) or recirculating ball style linear bearings. But another type of round shaft bearing — referred to as a roller block or roller pillow block — offers better stiffness than plain bearings and higher speed capabilities than recirculating ball types. Instead of balls, a […]
What are roller chain wear indicators?
Rollers chains, as a mechanical power transmission method, and like any mechanical system, are subject to wear over time and with continued use. Just how much it wears depends on a number of factors including whether or not the chain is properly lubricated and the amount of loading, among other things. So how does one […]
Tribology basics for linear bearings
Tribology is the study and application of the principles of friction, lubrication, and wear between two surfaces in relative motion. In linear bearing systems, those two surfaces are the bearing element and the guide raceway. Friction and wear The term “wear” generally refers to deterioration, but when discussing tribology principles in relation to bearings, it refers […]
What are hexapod robots (also referred to as Stewart platforms)?
Multi-axis systems can be designed and built with either serial kinematics or parallel kinematics. In systems built on the principle of serial kinematics, one axis sits on top of another axis, and each axis is driven individually, independent of the others. Cartesian robots are a good example of serial kinematic design. In parallel kinematic systems, multiple axes […]
What are some options for quieter chain operation?
Chain and sprocket drives are a traditional power transmission/motion technique. In general such drives tend to perform admirably well in harsh environments and feature high wear resistance and fatigue strength. Among one of the persistent down sides is the noise generated by chain and sprocket systems. There are a few common causes of noise in […]