Humankind has seen many industrial disasters and one can implicate these were the result of negligence of safety standards, incompetent working style or an occurrence of an on-site accident. If proper guidelines and a set of rules based on functional safety are followed, then most of these accidents and the associated loss of life & other valuable resources could be avoided. International organisations, like ISO, ANSI, OSHA etc, are playing an important role in the field of industrial safety assurance, which majorly covers two aspects when it comes to safety during product development. The first aspect covers the safety of components, irrespective of the projected malfunctions, which means the machine component remains safe and does not harm itself & its surroundings even after some malfunction occurs. Whereas, the second aspect authenticates the correct system behaviour by developing all the possible use case scenarios and performing rigorous testing so as to be prepared & to avoid the worst situation. Both these aspects make sure that the overall safety of the work system is maintained and tries to minimise & control the rate of damage due to system failure.
Different age of the industrial revolution and its role in safety assurance
The first industrial revolution transformed hand production methods by the introduction of machines and the rise of mechanised factory system to make the life of humans easy & faster in the production. Then came the second industrial revolution, which led to the development of electrical units and machine tools, so that the production can be levelled up at the mass production level. After that the third industrial revolution arrived, which focused on the introduction and development of the Programmable Logic Controller (PLC), to overcome safety problems associated with the mass production era. Currently, the fourth industrial revolution has open doors to digitalisation, connected systems and safe automation with use of the Internet of Things (IoT) and has connected man with machine. One can understand from the first industrial revolution till today, that the end-result of all these revolutions has only one motive, and that is to use state-of-the-art technology to make sure of the development of a safe & sound industrial workplace environment.
This has made major manufacturing companies from various sectors, like the automotive, pharma, oil & gas, etc, to take transit from old-school practices and be more open towards the modern manufacturing approach. This concept of becoming the smart factory has led manufacturing systems to be designed in a smarter way and the machines installed in the system to have capabilities to interact with the operator & other machines in the production environment to have self-diagnostic features to access its own health with the use of sensor systems & to showcase a safety point of view by having capabilities to warn its work environment if any failure occurs.
Safety loopholes in modern manufacturing
We are seeing manufacturing processes get more and more automated, which means more robots performing multi-assembling operations, Automated Guided Vehicles (AGVs) performing logistics operations and automatic conveyor systems working with sensors & feed mechanism. These operations are not always fully automated and require some guidance & orientation from the operator, and this raises a scenario where both man & machine are interacting and working hand-in-hand with each other. This further implies that this man-machine collaborative system must be made safe & robust so as to avoid fatal incidents like injuries & death in case of machine failure and also, to increase the machine operator confidence.
State-of-the-art safety measures
Companies and their equipment manufacturers are working hard to make sure that the functional safety of their manufacturing units & equipment is maintained at the optimum level and furthermore, exploring more solutions so as to decrease the rate of accidents in the industry. Some of the state-of-art-solutions available today, that are helping us reach the ultimate goal of functional safety in various circumstances, are described below:
Safety Programmable Logic Controller (PLCs): Safety Programmable Logic Controller (PLCs) are used in industries that are designed to achieve two major objectives – firstly, try to not fail and secondly, if unavoidable, fail in an anticipated way as per the design. IEC 61508 is the international standard for the functional safety of the Electrical and Programmable Electronic Safety systems. Safety PLC should be designed and tested in such a way so as to make it capable of detecting 99% potential failures.
Lockout Tagout: Lockout Tagout is a safety procedure that is done in a scenario of maintenance & service of machine equipment. The sole aim is to make the machine and its environment inactive at the time of maintenance procedure, so that scenario of unexpected starting of the machine and hurting the employee performing machine service could be minimised.
Speed and Motion control of Variable Frequency Drives and Servos: This is a safety procedure that allows safe operation by reduction of speed if the machine encounters the presence of humans in its working environment. For example, we can see three different colour zones based on the distance between the man and machine in the illustration above. When the machine encounters the human in the yellow zone, it reduces its speed and activates the buzzer as an indication to vacate the workspace, followed by further decreasing its speed in the orange area and finally coming to a stop position in the red zone. The distance sensors are placed in the front and back of the AGV to take control of the vehicle in the case of human interference.
Muting of safety devices: This safety procedure makes sure that there is no human presence in the machine work area. Muting sensors are installed at the entry/exit area which are connected & only allow pallet movement. If they encounter any other movement, it immediately switches off the system and the machine operation comes to a halt. This is mostly used in the areas of robot operation where the robots are guarded in the cage to restrict unwanted movements or in automatic conveyor systems.
Use of IoT sensors with computer vision: Advancements in the sector of machine vision and sensor technologies have established their importance in the manufacturing world. We now have different sensors that can govern slight changes, like motion, velocity, leakages, etc, and their integration with IoT has made the information transfer process simpler & more accessible. Different machine data is captured on a real-time basis to monitor, govern and make changes in the machines even from remote positions. Installation of automatic scanners to identify operational flaws, heat sensors like infrared cameras to govern overheating hazards, etc, are some of the important applications towards functional safety in industries.
Industrial safety is a continuous process and newer technologies in the field of Machine Learning & data science are strongly establishing a strong foothold. One can see that these technologies will further help enhance the man-machine trust, develop concepts of safe working with cobots and an overall optimised work environment. 5G infrastructure is on the verge of getting rolled out soon and this means that it will bring in opportunity for safer, faster & a quick response for overall communicating infrastructure – hence, a forward step in the direction of enhanced safety and increased efficiency in the industries. Also, the rise of Artificial Intelligence is further enhancing security and making industries safer. The above-mentioned safety technologies will make the manufacturing world safe & sound. Apart from this, we need to keep in mind the challenges, like scalability, cost of implementation and knowledge transfer from already established industrial players to the newcomers, as the saying goes, “Knowledge is worth nothing if it is not shared”.