In industry, it is common to need to transport products by vibrating conveyors driven by electromagnetic vibrators.
THE PERFORMANCE OF LINEAR VIBRATORS AND FEEDERS
Linear vibrators or linear drives, also called Lung Link Units, are located after the vibratory feeders and their incorporation is essential or advisable in most applications. The linear vibrator is the linking element between the Sorting Unit and the Receiving Station or process line. It also regulates the variable flow rate of the Selection Unit and ensures the presence of the part available at the Receiving Station, as required by the sequence of the automatism associated with the machine or work point supplied. On the other hand, it allows defining a linear feed speed of the parts already positioned, as well as controlling the start and stop of the vibratory feeder, incorporating a saturation sensor.
A Lung Link Unit consists of a rectilinear or linear vibrator to which is attached a guide, also called a channel, through which the previously positioned parts advance, managed by a controller. Normally also supported by a conveyor belt system.
CRITERIA FOR CHOOSING ONE OF THESE VIBRATORS
In this equipment, the electromagnetic vibrator is the driving element that propels the parts forward. It consists of two elastically connected masses (active mass and reactive mass) and one or more electromagnets.
A particular vibrator model is designed for a range of applications and is bounded within certain limits. Several criteria must be considered when choosing the vibrator model, among which the length (longer for higher speed) and the width of the linear vibrator, which is related to the torque.
The mass ratio must also be considered, as the vibrator is a unit consisting of two masses, spring-loaded together and elastically isolated from the outside. The lower (reactive) mass is generally 2 to 3 times heavier than the upper (active: aluminium plate + guide) mass. Vibration amplitude and linear velocity are inversely proportional to the masses. The reactive mass therefore has a lower amplitude and a lower linear velocity.
Another point to consider is the guide, which must have sufficient rigidity to vibrate in unison with the aluminium plate and not acquire its own vibration that could interfere with that of the vibrating system. Finally, the installed power of the vibrator, absorbed by different causes, must be considered in order to satisfy all performance requirements.
MODELS OF LINEAR VIBRATORS
At TAD we have the widest range of linear vibrators on the market with the VL-30, VL-60, VL-70 and VL-80 models, which allows us to cover the whole spectrum of applications related to our activity. We produce, for example, special multi-channel straight vibrators with multiple channels in order to maintain high cadences. The type of link-lung unit to be used in each application is defined according to the geometry and position of the workpiece to be conveyed.
This equipment always offers an efficient, reliable and cost-effective solution, with an almost unlimited lifetime, as its components are very robust.