We’ve written several articles on this site about Cartesian robots, but let’s take a step back and define exactly what makes a robot a Cartesian robot, as opposed to another type of robot or multi-axis system. First, a Cartesian system is one that moves in three, orthogonal axes — X, Y, and Z — according to […]
FAQs + basics
What is a direct drive motor?
A direct drive motor is any motor — rotary or linear — in which the load is connected directly to the motor, without mechanical transmission elements such as gearboxes or belt and pulley systems. In other words, the motor directly drives the load. Direct drive rotary motors Rotary direct drive motors are often referred to […]
How does the number of stator phases affect stepper motor performance?
Stepper motors move in discrete steps when current is applied to coils in the stator. The size of the step is determined, in part, by the number of phases in the stator. In general, the more stator phases, the smaller the basic step angle and the higher the motor’s resolution. Stepper motors come in three basic types […]
How to specify linear motion components for vacuum applications
Vacuum applications are common in the manufacturing of semiconductors, liquid crystal and plasma displays, fiber optics, and aerospace components, where linear motion systems are used for the positioning, handling, and alignment of critical equipment. Although vacuum applications are often likened to cleanroom applications, in the category of “special environments,” there is a critical difference between […]
What are goniometer stages and where are they used?
The term “goniometer” can refer to a type of device that measures angles or to a device that rotates objects to a precise angular position. The former type, for measuring angles, is widely used in physical therapy to measure the range of motion of joints, such as the wrist or knee. This type of goniometer […]
How raceway geometry affects profiled rail guide performance
In the context of profiled rail guides with recirculating balls, the raceway geometry defines how the load-carrying balls are positioned relative to the raceways of the rail and the bearing (aka “carriage” or “slide”). The two most common raceway geometries are referred to as circular arc and Gothic arch, but some manufacturers have adopted a […]
Beam deflection equations for linear systems
When a linear guide, such as a round shaft or profiled rail, deflects or sags, the bearings that travel along the guide experience edge loading (a higher load concentrated at the ends of the bearing), which can cause rough, irregular movement, increased wear, and reduced bearing life. And when a linear guide is incorporated into […]
What benefits do dovetail slides offer versus other linear bearing types?
Dovetail slides are a type of plain linear bearing — along with boxway slides and plain bushings made of plastic, composite, or bronze — that rely on direct contact between sliding surfaces to support a load. These differ from modern rolling element linear bearings, which use balls or rollers to reduce friction between the load-bearing […]
What are the benefits of a rotating ball nut (aka driven nut)?
When you think of a ball screw assembly, you probably envision a screw shaft with a motor connected to one end. The motor turns the screw, and the ball nut travels along the length of the screw shaft. An alternative setup is to hold the screw shaft stationary and rotate, or drive, the ball nut […]
What’s the difference between dynamic load capacity and static load capacity?
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 […]