The global site of the UK's leading magazine for automation, motion engineering and power transmission
13 July, 2024

Twitter link

Sub-$500 electric cylinders challenge pneumatics

20 January, 2014

A US specialist in moving coil actuators, SMAC, has announced a family of electrically-driven linear actuators that, it claims, take the technology into areas that were previously the domain of pneumatic cylinders. It says that the CBL cylinders, with prices starting at less than $500, overcome some of the limitations of pneumatic devices, particularly in packaging applications.

The electric cylinders offer long cycle lives at high cycle rates. SMAC says they will operate for more than 100 million cycles, compared to the 10–20 million cycle lives of many air cylinders. The electric devices can operate at more than 2,000 cycles per minute, it adds, while pneumatic cylinders rarely exceed 1,000.

The long operating lives are the result of a carriage-free design with built-in linear bearings, including lube rings. The main items subject to wear in the electric cylinders are their guide bushings, which can be repaired easily and quickly in the field. This reduces waste compared to the air cylinders, which need to be replaced completely when they fail.

The electric cylinders’ strokes can be set via an electrical interface. Users simply type in the required speed, position, acceleration and force, allowing precise adjustments in a fraction of the time needed for pneumatic cylinders, with no manual readjustments required. This is said to result in savings in time and costs, and increases in throughput due to reduced downtime.

The cylinders’ velocity, position, and force can be varied independently and simultaneously. A patented “soft-land” function allows accurate sensing of product location, as well as precise force control.

No external switches or sensors are needed to check the cylinder movements or position, allowing significant reductions in wiring and installation costs.

SMAC says that its electric cylinders have many advantages over pneumatic actuators

The cylinders are said to offer consistent actuation times, with variances in cycle times of as little as 1ms, compared to 20ms or longer for conventional pneumatic cylinders. They can achieve acceleration rates up to 50G, says SMAC.

The electric cylinders also have environmental attractions. The power consumption of 35mm-diameter versions is as low as 1.5A, 24V. SMAC contrasts this with the energy-draining air consumption of air cylinders and the inefficiencies of producing and transporting compressed air.

It adds that the electric cylinders are also much quieter than pneumatic devices and, because they’re electric, they do not produce the process exhausts of pneumatic cylinders. This makes them suitable for use in clean rooms and in locations where Control of Substances Hazardous to Health (COSHH) regulations apply.

The first model in the CBL series has a diameter of 35mm and stroke lengths of 10 and 25mm. It will be followed by other variants with diameters from 15–75mm.

  • To view a digital copy of the latest issue of Drives & Controls, click here.

    To visit the digital library of past issues, click here

    To subscribe to the magazine, click here



"Do you think that robots create or destroy jobs?"



Most Read Articles