When a linear motion application requires high thrust force and rigidity along with good positioning accuracy, a preloaded ball screw assembly is often the best choice. Manufacturers offer ball screw preload amounts ranging from just 1 or 2 percent for applications where backlash would be detrimental, up to 10 percent or greater for applications that […]
FAQs + basics
Gallery: Rod style actuator variations and uses
Linear actuators can generally be classified as either slider style or rod style. With a slider style actuator, the motion is constrained to the limits of the housing length and the load is mounted to a slider or table. With a rod style actuator, motion is produced by a rod that extends and retracts from […]
Stepper motors: Differences between permanent magnet, variable reluctance, and hybrid types
Stepper motors are commonly used in linear motion applications for their precise positioning capabilities and good holding torque. And while the basic operating principle is the same for all stepper motors, there are differences in operation and performance between the three primary types: permanent magnet, variable reluctance, and hybrid. Permanent magnet stepper motors Permanent magnet […]
Can a linear actuator provide the rigidity and accuracy of a linear stage?
Although there are no industry standards that define linear actuators and linear stages, generally accepted terminology indicates that a linear actuator is typically constructed with an aluminum extrusion or base, while a linear stage is typically built on a flat, machined steel or granite base. This distinction implies that linear actuators can provide longer strokes […]
Why use a multi-start ball screw?
The easiest way to get higher speed from a ball screw assembly (within the screw’s critical speed limit, which is based on diameter, length, and end fixity) is to use a higher screw lead. But increasing the lead of the screw has a drawback: as the lead increases, the number of effective turns in the […]
Lead screw selection: What should I consider besides diameter and lead?
Once you’ve gone through the process of sizing a lead screw, you know what diameter and lead will provide the required load capacity, speed, and back driving torque for the application. But there are hundreds — maybe thousands — of lead screw designs on the market. Beyond the basics of diameter and lead, how do you […]
Lead screw sizing in 4 steps
Lead screw sizing is a bit of a hybrid exercise, with similarities to the process of ball screw sizing, but incorporating some of the considerations that come with sizing a plain bearing. While many factors are involved in the selection of a specific lead screw assembly, lead screw sizing — choosing the right diameter and […]
PV Equation: How to calculate the PV value for a lead screw application
Lead screws rely on sliding friction between the nut and the screw to convert rotary motion into axial (thrust) force to move a load. Most lead screw designs use either a carbon steel screw with a bronze nut, or a stainless steel screw with a plastic nut. In either case, there are no recirculating balls […]
Which timing belt tooth profile should I use: Trapezoidal, curvilinear, or modified curvilinear?
Timing belts — also known as synchronous belts or toothed belts — are most often used in transporting, indexing, and positioning applications where high torque or force transmission and high acceleration rates are required. Unlike V-belts, which rely on friction between the belt and the pulley for power transmission, timing belts have positive engagement between […]
Does my system need high accuracy or repeatability (or both)?
Question: “I’m designing a new linear motion system. Should I design it for high accuracy or repeatability? Or both?” Before we answer this question, let’s define accuracy and repeatability for linear systems… Accuracy In linear motion, there are two generally categories of accuracy – positioning accuracy and travel accuracy. Positioning accuracy specifies the difference between […]