Manufacturing landscape
The current manufacturing landscape is characterized by high number of different type of wastes. The term waste is not only limited to material waste but there are many other types of waste, such as manufacturing time, human effort, waiting time etc. Reducing the waste and at the same time assuring that the desired level of product quality is being produced is essential for the profitability and competitiveness of manufacturing companies. At the same time because of the increased market demand for new products the product life cycle of the products has been reduced and manufacturers forced/ perused to develop and produce products at faster rate eliminating also to zero the time for optimizing their production systems leading to high number of product defects and waste.
Quality improvement
Manufacturers to assure and improve product quality are implementing at least one quality improvement method. Manufacturing systems are characterized by high uncertainty and volatility and therefore adjustments always will be needed. Traditionally, such methods are Six Sigma, Lean, Lean Six Sigma, theory of constrains and total quality management. Those methods are well established in the manufacturing systems for decades and served well their purpose, but there are numerus issues with those methods that made them unable to cope with the manufacturers requirements and the current technological advancements such as all the digital technologies coming with the Industry 4.0 (artificial intelligence, machine learning, digital twins, vision systems etc). This is due to the fact that all the traditional quality improvement methods have been developed without the knowledge of all the data driven digital technologies and therefore they cannot take full advantage of phenomenal capabilities of those technologies. Those facts have contributed to the search for alternative solutions for quality improvement methods that can harvest the full potential of Industry 4.0 technologies. To this extent in 2020 an old an approach called Zero Defect manufacturing (ZDM) was brought back to life, in a modernized version by Foivos Psarommatis [1].
Effects of quality
The quality of a product can have effects on more than one level, such as direct cash losses and the waste of resources that hurts the environment. Companies that make things must use quality management to keep or improve their operational, financial, and environmental success. Poor quality can hurt society as a whole and hurt a business’s reputation by making people unhappy with the goods and service. But digital technologies must be combined with human factors like Industry 4.0 enablers and smart workplaces to reach the hard goal of zero defects.
What Zero Defect Manufacturing is?
ZDM is far more than a quality improvement approach, it is also a way of thinking. ZDM is a toolbox for assuring that the produced quality is the desired one maintaining the desired performance of the production system. This toolbox contains some of the tools traditional quality improvement methods suggests, but also new ones have been added based on the technological capabilities. The difference is how those tools are used and combined in order to achieve the desired results. ZDM is composed out of four main ZDM strategies named “Detect”, “Predict”, “Repair” and “Prevent”. Those strategies are classified into two categories, the triggering strategies “Detect” and “Predict”, which are those that they identify that there is an issue and the action strategies “Repair” and “Prevent” that are there to mitigate the issue with the best possible way. Another critical aspect of ZDM is the fact that imposes that 100% of the products are inspected for assuring the desired quality, something that was not the case for the traditional quality improvement methods. More specifically, the ZDM strategies needs to be implemented in pairs, always one triggering with one action strategy. This create 3 possible ZDM pair strategies Detect-repair, Detect- Prevent and Predict- Prevent. This means that if you detect that there is a quality issue then there are two options either to repair the problem, if possible or to take preventing actions for assuring that in the near future you will not have the same quality problems. The ultimate tool of ZDM is the Predict – Prevent, because using the Industry 4.0 technologies we can predict when in the near future a defect or a quality issue might arise and therefore make preventive action prior to that event and avoid creating the problem. The difference is that in this case there is not defect generated, predictive approach, whereas in the case of detecting a defect the defect has been already generated, corrective approach.
How to efficiently achieve ZDM
The implementation of ZDM is a complex procedure that requires changes in the peoples mindset and methods used. Most of the R&D efforts are focused on the development of those digital technologies for either detecting or predicting a defect or in general an event in the production or in the value chain of the manufacturing company. Those technologies are crucial for the implementation of ZDM, but without the proper orchestration, no optimum solutions can be provided in the manufacturing company as a hole. Manufacturing systems are dynamic systems, but many times are being seen as static, meaning that when something happens you need to adapt the schedule in order to accommodate the new parameters into the schedule. More specifically, the key for the successful implementation of ZDM is the adoption of dynamic scheduling tool that will be able to handing all those disruptive events that happens in the production based on information not only from the production but from the entire corporation and value network. A disruptive event can be from a defected product where the repairing tasks need to be scheduled, to the prediction of the defect that the preventing actions needs to be scheduled with time constraints or to the new order that has arrived to the production. In other words, anything that happens in the production affects that planned schedule and therefore, the production needs to be re-scheduled in order to accommodate in the most optimum way the new parameters, otherwise non optimal schedules will be followed leading to longer times, more resource consumptions and higher costs and environmental impact.
Benefits of ZDM
The ZDM approach is the key towards manufacturing sustainability and zero waste production all it takes is adoption of the new ideas, technologies and a proper orchestrator to lead you towards success and profitability conserving at the same time the environment.
[1] Psarommatis, F., May, G., Dreyfus, P.A. and Kiritsis, D., 2020. Zero defect manufacturing: state-of-the-art review, shortcomings and future directions in research. International journal of production research, 58(1), pp.1-17.
