In any motion system, understanding the type and direction of applied and resultant loads is important for determining bearing life and analyzing deflection. In linear motion systems, we typically use Cartesian coordinates (X, Y, and Z) to define the placement and direction of loads. But for rotating components such as screws, rack and pinion drives, […]
Slides + guides (all)
Motion basics: What are degrees of freedom (DOF) and how many are there?
To identify the position of an object in three-dimensional space, we use a coordinate system that defines three axes: X, Y, and Z. If the object is a point mass, we only need three coordinates (X, Y, and Z) to locate its position. But a rigid body can both move, or translate, along these three […]
Motion basics: What is ball conformity in linear guides and screws?
In linear guides and ball screws, load-carrying balls or rollers can ride on planar (flat) raceways, as with non-recirculating linear roller bearings, or in curved raceways, as with ball screws and profiled rail guides. When a ball or roller rides on a planar raceway, the contact between the rolling element and the raceway will be […]
Motion basics: What is differential slip and how does it affect linear bearings?
Linear bearings that use balls or rollers are typically chosen for their ability to carry high loads with very low friction. But rolling elements — including linear bearings — are not friction-free. One of the factors that contributes to friction in linear bearings (along with properties such as surface roughness, elastic hysteresis of the materials, and […]
Mechanical properties of materials: Hardness
Hardness is a common specification for linear shafts and guides — especially those used with ball and roller bearings, where the guide encounters extremely high loads over very small areas. The hardness of a bearing surface can significantly affect the life of the system and is often accounted for by applying a hardness correction factor […]
What is cage creep and why does it matter?
Several types of non-recirculating linear bearings use a cage to contain the rolling elements, maintain consistent spacing between them, and ensure even load distribution. But in each of these non-recirculating designs, the cage “floats” between the two moving components, meaning that it’s not constrained and can gradually move away from its intended, centered position. This […]
PMM miniature slides are compact and low-friction for accurate linear motion
Compact – Smooth – Accurate PM’s miniature ball slide Type PMM is a compact and robust solution for smooth and accurate linear motion that fits in narrow spaces to transfer light to moderate loads. The slides where developed for the semiconductor industry and medical devices where they are used for accurate positioning of samples under […]
Mini nanopositioning stage designed with voice coil motor and air bearing slide
Cleanroom-compatible, this new high performance noncontact miniature linear slide from PI is suited for applications like wafer inspection, scanning/metrology, fiber alignment, laser micromachining and marking, autofocusing, and genome sequencing. PI’s air bearing motion product line is expanding again. The new A-142 high performance compact nano-positioning and linear alignment stage is designed with a voice coil […]
Ball spline preload: How, why, and when it’s applied
Like other linear motion components where rolling elements ride in raceways, ball splines can be supplied with preload. In the case of a ball spline, the main purpose of preload is to reduce angular backlash — clearance in the rotational direction — when torque is applied. Without preload, ball splines have a small amount of […]
Slide ways feature stable motion at high to low speeds
NB Slide Ways are non-recirculating linear motion bearings used primarily in optical and measurement equipment where high precision movement is required. The SV style consists of 2 roller cages with precision rollers in a cross arrangement and four rails with V-shaped raceways. The SVW has one rail with V-shaped grooves on both sides and 2 […]
