Engineers working in industries that use fast-running machinery will almost certainly be familiar with the demands for ever-greater productivity to increase competitiveness and reduce costs. We have seen numerous situations where a thousand cycles per minute appears to be the norm - particularly in packaging applications. Unfortunately, cycle rates such as these cannot be reached using traditional methods.
In many cases, the power of servo motors can reach maximum levels, offering high dynamic speed and power to do the job. Fast cycle times require ultra-fast changes of position set values, which unfortunately may stimulate mechanical resonances in a machine, leading to losses in quality. For this reason, automation experts are looking into more ‘intelligent’ options to give the opportunity to increase speed and save time.
The most common initial reaction is to think about the control loops of existing drives, but without measuring the behaviour of the fluid being transported, it is difficult to implement. Moreover, the cost of the necessary system sensor(s) can be prohibitive.
Therefore, designers may consider generating an optimised profile. The drawback with this approach however, is that you then create a dedicated system. Any change of movement, even slight alterations in speed or position, will require a new profile. In modern production situations, we would expect a method that is flexible and somewhat more adaptable to production changes.
Our PSD series of servo drives offers the potential to provide a solution and has been designed to address some of industry’s most challenging applications.
One that is frequently seen is the need to move open containers filled with liquids as quickly as possible between positions A and B. The PSD series of servo drives can help avoid the stimulation of resonance altogether. In addition, in systems like these, effective vibration suppression can be the key to further process improvements.
If nothing is done, the liquid being moved is likely to spill from its container, especially if cycle rates are increased with the higher speed and the acceleration profile resulting in more turbulence of the liquid.
Effective vibration suppression will help allow increases in acceleration and also remove the frequencies responsible for the turbulence. This results in a motion profile with the same cycle rates as before but with really stable fluid during movement.
Depending on the application, different methods of controlling / suppressing vibration are available, each delivering the same impressive results in terms of stability, high dynamics and productivity.
We have worked successfully with manufacturers in a range of industries to control challenging applications; fluids is just one example. Outcomes have typically delivered faster machine cycle times due to reduced fluid settling time and through this, up to 20% greater productivity.
Learn how using the latest drive technologies to suppress vibration can boost your packaging line or production system.
Article contributed by Hermann Kamphues, product manager drives, Electromechanical & Drives Division, Parker Hannifin Corporation.