Motion Control

Precision Ball Screws

Thomson Industries (Radford, VA) has introduced miniature metric precision ball screws in three interface styles: flanged, threaded, and rounded. The FSI metric ball screws are flanged, and the RSI style is rounded. Both feature a multi-liner ball return system that provides smooth operation and increased load capacity. The miniature ball screws are available in a range of standardized diameters from Ø6 mm – Ø14 mm. Flexible ball nut mounting configurations and rapid prototyping are options for the ball screws.

Posted in: Products, Manufacturing & Prototyping, Motion Control


Servo Drives

The MR-J4-TM multi-network servo drives from Mitsubishi Electric Automation (Vernon Hills, IL) are available with Ether Net/IP™ and EtherCAT® interfaces. The drives feature dual 100BASE-TX Ethernet ports in line, tree, and star topologies; One-Touch Auto-Tuning; 2.5 kHz speed frequency response for short settling time; high-resolution 4,194,304 pulse/revolution absolute encoders; and Advanced Vibration Suppression Control II for vibration suppression on both the load and the machine base. The drives also come with add-on instructions for EtherNet/IP networks using ControlLogix® or Compact - Logix® controllers.

Posted in: Products, Manufacturing & Prototyping, Motors & Drives


Advantages of Servo Motor and Direct Drive Technology

For many years, stepper motors have been the most popular type of electric motor designed into instrumentation for a wide variety of reasons. Stepper motors have become increasingly commoditized, and can be sourced easily. In addition, the growing “maker movement” has simultaneously made them more popular and reduced their cost. Unlike servo motors, stepper motors don’t require tuning to optimize their performance. What’s more, scaling and motion commands are typically quick and simple to execute using stepper motors. Servo motors often require a bit more expertise in executing complicated (torque, velocity, or position) loop closures. Finally, micro-stepping allows most modern drive electronics to step or increment a stepper motor to a resolution of 50,800 steps per revolution or higher.

Posted in: Articles, Motion Control, Motors & Drives


An Inside Look at Electromechanical Power-Off Braking Options

Making the right choice between spring set and permanent magnet brakes can impact safety, durability, maintenance, and performance. Power-off brakes are designed to hold or stop motion in the absence of power. Adding an electrical current releases the brake, freeing the load for motion. Given the safety ramifications of keeping a system locked in place until it is powered up, motion control system designers tend to specify power-off brakes more often than power-on brakes. There are, however, two different failsafe brake technologies: one uses compression springs to hold its load in place, and the other uses permanent magnets. Each has specific strengths and weaknesses, and knowing the difference can impact safety, durability, cost, and performance.

Posted in: Articles, Motion Control, Electronic brake controls, Springs, Magnetic materials


Multiphysics CAE of a Shock Absorber

Figure 1. CAE simulation of a shock absorber. Shock absorbers are important parts of vehicles. The shock absorber is used to observe the vibrations from shock loads due to irregularities of the road surface, and operates without affecting the stability, steering, or handling of the vehicle. Generally, for light vehicles, cylindrical coil springs are used as suspension elements. The application described in this article attempts to analyze performance of a shock absorber with different suspension springs. This analysis includes comparative modeling and analysis of solid height, damping performance, oscillation capabilities of closed coil conical and cylindrical compression springs, and a suggested suitable design for improved performance.

Posted in: Application Briefs, Motion Control, Dampers and shock absorbers, Springs, CAD, CAM, and CAE, Performance tests


Rotary Valve

RotaVal Ltd. (Wiltshire, UK) introduced a heavy-duty rotary valve for use where solids handled and operating conditions combine to cause abrasive erosion within the valve. It has on-site component replacement. The valves are used in discharging materials such as cement, PFA, granite dust, silica sand, and mineral powders under adverse pressure conditions. Standard valves are manufactured in cast iron, SG iron, Ni-hard, and carbon steel. The replaceable body liner can be hard chromed or ceramic coated. Rotor shaft sealing options include various types of gland packing, mechanical seals, and air or grease purge.

Posted in: Products, Motion Control


Voice Coil Actuator

The LAH15-19-000A linear voice coil actuator from BEI Kimco (Vista, CA) provides low hysteresis/ low friction with bi-directional position control. It is suited for applications where low friction and high force accuracy are needed. The low-friction design features a patent-pending symmetrical flex circuit that prevents friction caused by movement. A solid brass ball cage with captured steel balls also reduces friction. The actuator offers a hysteresis of 10 mN. Other features include a peak force of 4.7 N, a total stroke of 7.4 mm, and a compact size of 38 mm in diameter by 48.3 mm in length.

Posted in: Products, Motion Control


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