Advanced Technologies for Industry 4.0: A Challenge for Plasma Scientists

Abstract

The society is facing the fourth industrial revolution, often referred as Industry 4.0. Industry 4.0 refers to the concept of factories in which machines are augmented with wireless connectivity and sensors, and in a broader sense to development of production processes that are compatible with the major concept. The compatibility is assured in practical cases only where the processes are reliable enough and any deviations from prescribed parameters manageable. Furthermore, the applied technological processes should be compatible with major trends and policies such as environmental sustainability, low carbon footprint etc. Plasma technologies are among technologies that have been recognized as key enabling technologies in several EU regions including Slovenia. Traditional plasma reactors are often “black boxes” with adjustable and traceable discharge parameters (like type of discharge, voltage and current, types of gases and their flows etc.) but plasma parameters (fluxes of reactive species onto the products upon plasma treatment, temperatures of reactive species and products, etc.) are not monitored. In order to meet standards of Industry 4.0, plasma reactors will have to be equipped with numerous sensors integrated into a smart control system. There is hardly any correlation between discharge and plasma parameters in industrial reactors employing complex gases. Several examples of spatial and/or temporal variation of plasma parameters at constant discharge parameters will be presented. Such variations should be managed by smart production lines according to Industry 4.0. The problem is manageable only upon installing numerous sensors into plasma reactors. These sensors should monitor at least the energy fluxes onto the surface of treated materials, but preferably also the fluxes of different reactive species. The latter is currently regarded impossible for industrial size reactors due to the lack of appropriate sensors. The development of reliable and inexpensive sensors of plasma radicals therefore represents a major challenge for plasma scientists. The next challenge is a development of smart reactors capable of sustaining uniform plasma parameters in the entire volume and independently from the type of the materials and/or products installed into the reactor.