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, […]
Applications
Piezo motors vs. voice coil actuators for micron and sub-micron positioning
Applications that require micron or sub-micron level positioning with extremely smooth motion and control often call for a direct drive system — linear motor, piezo motor, or voice coil actuator. Linear motor stages are typically used when high forces are needed over stroke lengths greater than a few hundred millimeters. But for high-precision applications with […]
How to account for rack and pinion inertia during system design
Rack and pinion drives are often used in applications that require stroke lengths beyond the practical limits of ball screws and thrust forces that exceed the capabilities of belt drives. And in some applications, rack and pinion systems can also provide lower total inertia than a suitable ball screw or belt drive alternative, which can […]
Linear motion basics: 13 fundamental topics you need to know
Whether you’re new to designing and sizing linear motion systems, or you could just use a refresher, we’ve gathered all the articles that cover mechanical concepts used in linear motion systems and put them together here, as a sort of “linear motion basics” reference guide. Unlike our curated lists of articles that address sizing and […]
What factors contribute to friction in linear motion systems?
Designers and engineers typically try to avoid or mitigate friction in linear motion systems. Although friction isn’t always bad — in some applications, it can provide a damping effect and help improve servo tuning — when it comes to linear motion systems, it increases the amount of force required to move a load, creates heat, […]
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 […]
How to account for belt and pulley inertia during system design
In order for a motor to accelerate or decelerate a load, it must overcome the load’s inertia, or resistance to change in motion, as explained in Newton’s First Law. In belt-driven linear motion systems, the motor has to overcome not only the inertia of the applied load, but also the inertia of the belt, pulleys, […]
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 […]
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 […]
A guide to stainless steels for linear motion components
For applications that involve corrosive environments, designers of linear motion systems can take precautions such as using covers to protect vulnerable components, ordering parts with special coatings or platings, and strategically placing sensitive components within the machine or system to minimize their exposure to hazardous liquids or fumes. But some applications — due to the nature […]
