Safe Torque Off, or STO, is a drive-based safety function that stops the drive from providing power to the motor, without interrupting power to the drive. Activating the STO function produces an uncontrolled stop, meaning the motor coasts to a stop based on the system’s inertia and friction. The STO function also prevents an unexpected […]

If you design, install, or troubleshoot motion control systems, you’re probably familiar with PID (proportional-integral-derivative) control, which uses feedback to detect errors between the desired position and the actual position and applies corrective commands to compensate for those errors. Although PID control is the most common type of industrial controller, it does have limitations. First, […]

For rolling element bearings, the L10 life calculation is an easy way to determine the bearing’s expected travel life. But for plain bearings, determining life expectancy is not so straightforward. Plain bearing life is based on the amount of wear the bearing experiences, which depends on factors that are unique to each application, such as […]

New mounting bracket fits size 25 programmable and absolute shaft encoders Encoder Products Company (EPC) has introduced a new linear measurement solution: a bracket that fits all of EPC’s size 25 shaft encoders with 2.5 in. flange mounts, including absolute and programmable encoders. The bracket works with: The Model MA63S absolute encoder. With resolution up […]

Most linear guide and screw manufacturers offer online tools to help engineers with product sizing and selection. But these tools can sometimes be more in-depth – or alternatively, more simplified – than is needed at the current design or selection phase. In these cases, the easiest and fastest solution is to do the sizing yourself. […]

There are few linear motion applications in which the load is perfectly centered over the supporting bearing. On the contrary – the majority of applications involve loads that are cantilevered, meaning they are offset from the bearing and induce a moment load. In this context, the term “bearing” can mean a single bearing or a […]

In motion control, there are typically two types of positioning that can be used for a linear or rotary axis: relative, in which each position is based on a previous position, regardless of the actual position of the axis; or absolute, in which each position is referenced to a home, or zero, point. Axes that […]

A linear voice coil motor (also referred to as a “voice coil actuator” or “linear DC motor”) is a simple yet very precise type of electric motor, consisting of just two primary parts – a coil and a magnet. When current is applied to the coil, a force is generated. The magnitude of the force […]

The load-to-motor inertia ratio is a critical parameter in servo motor sizing and performance. As we discussed in a previous article, one of the most significant effects of using a gearbox in a servo system is its ability to help optimize the inertia ratio. Why inertia ratio is important If the motor inertia is too […]

SMAC Moving Coil Actuators reached a cycle rate of 2400 ppm (40 Hz) with their new LCB model electric actuator, meeting the target set by several leading packaging OEM’s. The fastest pneumatic actuators generally reach a peak speed of 1200 ppm. By doubling the speed of pneumatic actuators, SMAC can greatly improve the efficiency of […]

Worm gears are often used for their ability to provide large speed reduction and high torque multiplication. But their self-locking properties can also be beneficial in many applications.  In a worm gear assembly, the worm is typically the driving component. Self-locking means that the gear cannot drive the worm. In other words, back driving is […]

Linear motors are generally classified by the construction of the motor’s primary part: ironless or iron core. In an ironless linear motor, the windings of the primary are embedded in an epoxy resin, whereas the windings of an iron core linear motor are mounted in an iron lamination stack. The lamination contains teeth, or protrusions, […]

Helical gears and spur gears are two of the most common gear types and can be used in many of the same applications. Spur gears are simple and inexpensive to manufacture, but helical gears offer some important advantages over spur gears. The teeth of a helical gear are set at an angle (relative to axis […]

Microstepping is a method of controlling stepper motors, typically used to achieve higher resolution or smoother motion at low speeds. Stepper motors move in discreet steps, or fractions of a revolution. For example, a stepper motor with a 1.8 degree step angle will make 200 steps for every full revolution of the motor (360 ÷ […]

A planetary gearbox offers high torque transmission with good stiffness and low noise, in a more compact footprint than other gearbox types. The planetary gearbox design is fairly simple, consisting of a central sun gear, an outer ring (also referred to as an internal gear, because its tooth face inward), planetary gears, and a carrier. […]

Ball screw rigidity depends not only on the screw shaft and ball nut, but also on the thrust bearings and on the ball nut and bearing housings. Where: Rtot = Rigidity of the screw system (N/μm) RS = Rigidity of the screw shaft (N/μm) RN = Rigidity of the ball nut (N/μm) RB =  Rigidity of the […]

Guide Master was developed to meet market demands for precision applications such as semiconductor, LCD, LED, and secondary battery production processes. The masterpiece of precision guides Features of Guide Master linear guide include: Higher load capacity: With 8 rows of needle bearings in its octagonal design, Guide Master has more points of contact between post and […]

Spur gears are a type of cylindrical gear, with shafts that are parallel and coplanar, and teeth that are straight and oriented parallel to the shafts. They’re arguably the simplest and most common type of gear – easy to manufacture and suitable for a wide range of applications. The teeth of a spur gear have […]

Air bearings offer numerous advantages over mechanical bearings such as profiled linear guides and crossed roller slides. But they are still considered by many designers and engineers to be a high-cost solution, primarily for niche applications that require extreme precision. However, their benefits include more than just high precision, and cost is being driven down […]

The length of a V-belt can be specified in several ways, including outside length, effective length, and pitch (or datum) length. Outside length is measured around the belt’s outer diameter with no tension, but is only an approximation and is not useful for sizing or selection. Effective length is measured at the effective outside diameter […]

As a pulley rotates, centrifugal forces act on the pulley, and if its mass is not evenly distributed around the axis of rotation – that is, if it is unbalanced – these centrifugal forces will also be unbalanced and cause the pulley to vibrate. (Uneven mass distribution can be due to imperfections in machining or […]

There are three characteristics that indicate when a servo system is properly tuned: response time, settling time, and overshoot. Response time is the time it takes the system to reach a specified percentage of the target value, while settling time is the time it takes for the target value to be settled, within a specified […]

Like servo motors, stepper motors are available in both rotary and linear designs. When an application requires force (rather than torque) output and can operate in open loop control, a linear stepper motor is often the preferred solution. Although linear stepper motors are available in both variable reluctance and hybrid designs, the more common version is […]

Like many terms used in the linear motion industry – “heavy duty,” “miniature,” and “corrosion-resistant,” to name a few – there is no industry standard that specifies what constitutes a “high speed” linear actuator. Nevertheless, there are some general guidelines that manufacturers follow when classifying and marketing their actuators as high speed. These guidelines are […]

Resonance occurs when the resonant frequency (also referred to as the natural frequency) of an object or system is equal or very close to the frequency at which it is being excited. This causes the object or system to vibrate strongly and can result in unexpected – and sometimes catastrophic – behavior.  When one oscillating object or system (a […]