Rolling element linear bearings, such as round shafts and bushings, profiled rail guides, crossed roller slides, and even ball screws, have two load capacity specifications — dynamic load capacity and static load capacity — which are based on different operating parameters and performance criteria and are independent of each other. To accurately size and select a […]
Applications
LINAK linear actuators in medical sit-to-stand lifts facilitate rehabilitation
By 2050 there will be two billion people older than 60, according to the WHO … and 2035 will see a 12.9 million shortage of healthcare professionals. Fortunately, some new linear-motion technologies could help satisfy some of the growing need for healthcare, especially in the segment of the industry dedicated to patient rehabilitation. Consider one […]
When should you use a ball spline?
A ball spline is a type of rolling bearing linear guide, similar to a round shaft and bushing assembly, but with a critical distinction in its operation. The shaft of a ball spline is much like a linear guide shaft, except that the spline shaft has grooves along its length. The spline nut (analogous to […]
Shape-memory alloys linear actuators: A new option for positioning
Now, one new actuator uses bundles of SMA wire made of specialty nickel-titanium alloy for reliable linear motion. Dean Pick, P.Eng. • President | Kinitics Automation Shape-memory alloys (SMAs) are those materials that respond to temperature changes by changing form factor. Originally funded by the U.S. Navy, SMA technologies were first commercialized by Raychem Corp. […]
When should you lubricate a lead screw?
It’s expected that a ball screw, with metal-on-metal rolling contact between the balls and the raceways, will require periodic lubrication with either grease or oil. One of the advantages that lead screws have over ball screws is that they can often operate without lubrication — eliminating maintenance and the potential hazards that come with using […]
When is resolution important for linear systems?
Accuracy and repeatability are standard specifications that describe how a linear motion system behaves along its travel and how closely it reaches the intended position. Resolution, on the other hand, is less often included in performance data for linear motion systems, but it can be equally important as accuracy and repeatability in some applications. In […]
Linear motion designs see wider adoption of linear direct drives
Direct drives are a motion-control technology projected to see high rates of adoption in coming years, according to market research by the ARC Advisory Group. That’s due in part to an array of industries driving for higher throughput and more accurate processes. According to Brian Scott, applications engineer at Nippon Pulse America Inc., linear shaft […]
What type of motor is a servo motor?
The short answer is: There is no single “type” of servo motor. The term “servo” simply means the motor operates in a closed loop control system that uses feedback from an encoder or resolver (typically integral to, or mounted on, the motor) to compare the motor’s actual position, velocity, or torque to the commanded value. […]
Linear motion applications for piezo actuators and piezo motors
Piezo actuators and motors are often the preferred technology when an application requires movements of a few millimeters or less with high resolution. And while these small-scale applications don’t typically attract the same level of attention as those that require massive 100 mm diameter ball screws or enormous 12-meter gantries, applications in the single- and […]
How to calculate the effect of preload on ball screw axial deflection
In a recent post, we looked at the methods for inducing preload in a ball screw assembly and the effects it has on performance. One of those effects is that preload reduces axial deflection (displacement) and increases rigidity. But preload also increases the applied load on the screw assembly and reduces life. To determine the […]