Implementing the PDCA $($Plan$-$Do$-$Check$-$Act$)$ cycle within a production company can lead to significant improvements in efficiency, quality, and overall performance. Let's break down how it might be applied in a case study scenario:

$1.$ Introduction Continuous improvement is a set of repetitive actions, which are designed to increase the capacity to meet the re quirements. It is one of the eight quality management princi ples. Actions concerning continuous improvement include $($BAGI$$SKIJ$.2004,$ IMAI M$.2007)$: $$ analyzing and evaluating the existing situation to the identify the area for improvement, $$ setting targets that relate to improvement, $$ searching for solutions to achieve the objectives, $$ evaluation of these solutions and making a selection, $$ implementation of solutions, $$ measurement, verification, analysis and evaluation of the results of implementation to determine whether the ob jectives have been achieved, $$ formalizing changes. Using the principle of continuous improvement is associat ed with using consistent, comprehensive organizational ap proach to improve the achievements of the organization, ensuring the participation of people skilled in the use of methods and tools of continuous improvement, the constant products, processes and systems improvement, understood as the goal of every person in the organization, establishing the objectives and reference state to direct the continuous im provement, and also the recognition and accepting the im provements. William Edward Deming, a prominent American research er$,$ similarly to Japanese, believed that management staff and all employees should be involved in the process of continu ous improvement. He created $14$ principles that later became the basis of the philosophy of quality in the organization and continuous improvement cycle PDCA $($Plan $-$ Do $-$ Check $-$ Act$),$ called the Deming wheel. Deming cycle is a sequence of actions that aim at improvement. This cycle is also de signed to solve quality problems and implement new solu tions. PDCA model is extremely versatile and it can be suc cessfully used in any type of business. Owing to this cycle, an enterprise experiences an $80\%$ reduction of costs of $$problems$$ of the order of $20$ to $30\%$ of the initial level $($e$.$g$.$ the product quality defects$)$ on average $($PRACA ZBIOROWA $2014).$ Most often it is used $($UCZAK J$.,$ MATUSZAK$-$FLEJSZMAN A$.2007)$: $$ in the process of continuous improvement, $$ during the implementation of changes, $$ during a downtime between one phase of a project and the next, $$ during the implementation of a new solution, $$ during the review of a process improvement Before the PDCA cycle is begun, it is essential to ensure that the existing standards are stable $($IMAI M$.2007).$ The cycle is the so called SDCA $($Standardize $-$ Do $-$ Check $-$ Act$)$

$($JAGUSIAK$-$KOCIK M $2014).$ Only when the cycle functions $($this means that the standard has been implemented$)$ and stabilized$),$ it can increase, improve standards, by means of PDCA cycle. Figure $1$ shows the PDCA model, indicating a possible critical area. Fig $1.$ PDCA cycle with indicating the critical area The first step of Deming cycle $-$ "Plan" $($P$)$ is associated with recognizing the possibility of changes, namely, its im provement and scheduling it$.$ It sets the objectives for im provement and designs an action plan which will enable this objective. It is necessary to identify the problem, analyze the causes affecting it$,$ generate solutions, and develop a plan of implementation. During this step, every action can be supported by tools and methods such as Ishikawa dia gram, Pareto$-$Lorenz diagram, process mapping or brain storming. In the next step $-"$Do$"($D$)$ the developed plan in order to make changes in the process is implemented in a company $($in order to raise its productivity or quality and to eliminate the causes of problems$).$ It takes place with the support and understanding of the management. In this phase, tools such as an action scheme, benchmarking, flow diagram or check sheet can be used. "Check" $($C$)$ step equals checking, testing, whether solu tions introduced to a company brought adequate results. The measurements are taken and they are compared with the values folded in the plan. Control sheets, control charts, process capability indices can be used to help. If the imple mentation of solutions proved to be appropriate, it is fol lowed by $4$ PDCA cycle step $-$ "Act" $($A$),$ if not $-$ one shall return to step $1-$ "Plan" $($P$)($this is a critical area in the pro cess of improvement$).$ The last step of the PDCA cycle "Act" $($A$)$ is connected with the application of the implemented solutions. When these solutions are proven, they are considered the norm and lead to standardization and monitoring of the activities. This step may be necessary in case of tools such as process map ping, an action scheme or benchmarking $($FRANZ J$.$ K$.,$ LIKER J$.$ K$.2016.,$ KIRAN D$.$ R$.2016).$ PDCA cycle is contained in a circle and never ends. The knowledge gained from the last stage becomes the