There are two load capacity specifications for recirculating linear guides and ball screws—static load capacity and dynamic load capacity. Most engineers are familiar with dynamic load capacity, since this is the value used to calculate bearing life. But it’s also important to consider the component’s static load capacity in order to avoid premature bearing failure. Here’s a […]
Applications
Why RMS torque is important for motor sizing
Servo motor performance is highly influenced by the motor’s ability to dissipate heat and avoid thermal overload, which can damage internal components and even demagnetize the magnets. Internal thermal sensors can protect the motor during operation, but proper sizing and selection are the first step to ensuring that the motor is not at risk of thermal […]
Round shaft or profiled rail for linear motion? How to choose
Updated May 2019 || When designing a linear motion system, engineers have two primary choices in recirculating linear guides — round shaft or profiled rail. Choosing the wrong linear motion system can be a costly mistake, resulting in design or structural changes, poor machine performance, or oversized components with higher costs. Although both round shafts and […]
The difference between inertia and momentum
The concepts of inertia and momentum are often confused — possibly due to the similarity of their definitions. Inertia is generally described as an object’s resistance to motion, with momentum being the tendency of an object to continue moving. Both have implications for linear motion applications, but while inertia is a fundamental sizing parameter, momentum […]
A selection guide for linear systems
Gone are the days when machine designers and builders had to choose between constructing their own linear system from scratch or settling for a limited range of pre-assembled systems that, in most cases, were an imperfect fit for their application. Manufacturers today offer systems based on a range of drive mechanisms—ball screws, belts, rack and pinions, linear motors, […]
Linear motion tips for food and beverage applications
It’s not hard to understand why applications in the food and beverage industry are especially challenging for linear motion systems. Food processing and packaging equipment must simultaneously meet high throughput requirements and withstand harsh environments, while safely handling and processing products which are at constant risk for spoilage or dangerous contamination caused by environmental factors or improper handling. Add to this […]
Don’t ignore these three things when mounting linear guides
Linear rail guides are designed for applications that call for precise motion with high load-bearing capability. But improper mounting can add unnecessary loads, reduce life, and undermine the inherent travel accuracy of the linear guide system. Understanding and following the three mounting specifications described below will help ensure your installation achieves the desired accuracy and doesn’t succumb […]
How to avoid ball screw buckling
Imagine two columns—one short and wide and the other long and narrow. As you begin to put weight on them, the long, narrow column gradually begins to bend, to the point that it becomes permanently deformed and eventually breaks, while the short, wide column handles the weight with ease. In the same way the long, […]
How to determine if a screw will back drive
Screw assemblies are generally preferred over belts or linear motors in vertical applications. This is because a screw will prevent the load from catastrophically crashing if there’s a loss of power to the motor. But a vertical load can still cause a screw to back drive, allowing the load to drop, albeit at a slightly […]
Breaking down linear bearing construction
As with most complex products or systems, specifying and applying profiled rail bearings doesn’t require that you know every detail of linear bearing construction. But having a basic understanding of the various design types and geometries can help you choose a product that enhances, rather than detracts from, the performance of your machine—especially in applications that […]