Redesign of the Curing Area of the Tire Manufacturing Process

sustainability

Article Redesign of the Curing Area of the Tire Manufacturing Process

Florin Stîngă , Irina Severin * , Ioana Alina Mitrache and Elena Lascu Faculty of Industrial Engineering & Robotics, University Politehnica of Bucharest, 060042 Bucharest, Romania; ﬂ[email protected] (F.S.); [email protected] (I.A.M.); [email protected] (E.L.) * Correspondence: [email protected]; Tel.: +40-726-283-850

Received: 26 June 2020; Accepted: 19 August 2020; Published: 25 August 2020

Abstract: In this study, the production efficiency of a company’s manufacturing flow decreased, and therefore specific improvement actions on the tire manufacturing process were implemented. Additionally, the process improvement plan started with a deeper understanding of the activities, by using the SIPOC method (suppliers, inputs, process, outputs, customers). In order to identify the root-causes and the opportunities for improvement, quality instruments, such as the Ishikawa and Pareto quality tools, were used. The tire manufacturing process was reorganized using the 5S method, then the process was standardized and maintained through specific working procedures drafted on the standard operating procedure format. A particular device was designed for unlocking spring vents. Finally, the implementation of the redesign project shows added value as the entire manufacturing process improved by identifying weaknesses and correcting them. In addition to this, a different objective of the same company used in this case study is linked to adapting to market regulation requirements (the Economic Commission of Europe), with the aim to remain competitive. Therefore, well-defined processes and a strategy based on continuous improvement are needed. The methodology may be transferred to other industries.

Keywords: process improvement; quality tools; improvement plan; quality operating procedure

1. Introduction In the field of production, including in tire manufacturing, a continuous development approach implies critical problems identification and prioritization [1]. Organizational performance takes into account two main factors: (1) behavioral quality management practices, which include the commitment of management, employees, customers, and suppliers, and (2) technical quality management practices, including strategic planning, process management, benchmarking, and the analysis of information [2]. The role of management is essential for the improvement of quality, as well as for the commitment to understanding the needs and to innovating the business processes [3]. According to ISO 9001: 2015, understanding and managing the correlated processes within a management system support the increase of the organization’s efficiency, effectiveness and resources economy, the final aim being to obtain the desired results [4]. The continuous improvement of quality and processes is a fundamental strategy in an organization, and such an approach brings many benefits regarding the optimization of the manufacturing time, cost reduction, and improvement of the overall activity. Process management aims to monitor and control the processes defined in an organization [4]. Quality management practices, effectively supported by top management, lead to processes efficiency [5]. Performance management can incorporate essential management models and practices to achieve the objectives [6,7]. The processes improvement depends on the management’s commitment and the employees’ efficiency. The relationship between management and the rest of the employees, focused on processes

Sustainability 2020, 12, 6909; doi:10.3390/su12176909 www.mdpi.com/journal/sustainability Sustainability 2020, 12, x 2 of 22

Sustainability 2020, 12, 6909 2 of 22 The processes improvement depends on the management’s commitment and the employees’ efficiency. The relationship between management and the rest of the employees, focused on processes innovation,innovation, improvement and development, finally finally leads leads to efficiency efficiency and good quality for the products [[8].8]. The organization should determine the opportunitiesopportunities for improvementimprovement and thereforetherefore implementimplement thethe neededneeded actions.actions. The development of opportunities should be identifiedidentified byby analyzinganalyzing the qualityquality managementmanagement system system and and considering considering the th processe process results. results. The The process process outcomes outcomes should should be continuouslybe continuously measured measured and and monitored monitored using using data data extraction extraction techniques techniques [9]. [9]. Globalization and competitiveness in the marketsmarkets are growing, adding pressure onon companiescompanies to reducereduce costscosts andand toto adaptadapt rapidlyrapidly toto consumerconsumer preferences or marketmarket regulations [[10].10]. To have a successful improvementimprovement strategy, strategy, all all stakeholders stakeholders should should be be considered, considered, and and dedicated dedicated objectives objectives and measuresand measures should should be targeted be targeted [11], [11], including including processes processes streamlining, streamlining, too. too. The main pillars for processprocess improvementimprovement maymay bebe seenseen inin FigureFigure1 1..

Figure 1. Process improvement.

Considering thethe accelerated accelerated evolutions evolutions that that organizations organizations must must compete, compete, rigorous rigorous attention attention should beshould paid tobe numerous paid to factorsnumerous affecting factors them, affecting along withthem, their along processes. with their In this processes. sense, companies In this havesense, to paycompanies attention have to their to pay products’ attention quality, to their to products’ control the quality, deadlines to control of manufacturing the deadlines and of delivery, manufacturing as well asand the delivery, costs linked as well with as the rapidcosts linked development with the of rapid the market development and the of increasing the market and and di ffithecult-to-meet increasing demandsand difficult-to-meet [12]. demands [12]. Many studies show how qualityquality managementmanagement methods are usedused successfullysuccessfully inin businessbusiness development [13], [13], and and in in order order to to remain remain competitiv competitive,e, it is it necessary is necessary to continuously to continuously consider consider the theadaptation adaptation of business of business models models [14]. [Developing14]. Developing a sust aainable sustainable strategy strategy [15] involves [15] involves focusing focusing on three on threesignificant significant areas of areas interest: of interest: (1) environment (1) environment protection protection by respecting by respecting the norms the in norms the field, in the(2) social field, (2)responsibility social responsibility by adopting by adopting a correct a correct strategy strategy regarding regarding business business ethics, ethics, and and (3) (3) economiceconomic responsibility [[5].5]. The development and and improvement improvement of of processes processes ma mayy by by structured structured in infour four main main stages, stages, as asproposed proposed in inFigure Figure 2 2[16].[ 16 ].The The first first step, step, process process planning planning and and organization, organization, consists consists of nomination of a team for identifying thethe processprocess activitiesactivities andand forfor detectingdetecting thethe needneed forfor improvement.improvement. The secondsecond stage, stage, the the process process enhancement, enhancement, concludes concludes the process the process capability capa analysisbility byanalysis collecting by datacollecting from thedata process from activities.the process The thirdactivities. stage, The process third evaluation, stage, process uses quality evaluation, assessment uses methods, quality suchassessment as brainstorming, methods, such Ishikawa as brainstorming, charts, and ParetoIshikawa charts, charts, for identifyingand Pareto thecharts, problems’ for identifying root causes. the Theproblems’ fourth root stage, causes. process The improvement fourth stage, and proc monitoring,ess improvement consists of and implementing monitoring, the consists identified of solutions,implementing updating the identified the procedures, solutions, and standardizingupdating the theprocedures, process. Finally, and standardizing one may consider the process. the fifth stage,Finally, aiming one may to sustain consider the the process fifth stage, performance aiming byto monitoringsustain the andprocess continuous performance improvement by monitoring [17]. and continuous improvement [17]. Sustainability 2020, 12, 6909 3 of 22 Sustainability 2020, 12, x 3 of 22

Figure 2. Stages of improvementimprovement process.

In orderorder to to develop develop the the manufacturing manufacturing system system in a sustainable in a sustainable environment, environment, it appears it important appears toimportant evaluate to the evaluate system the and system to understand and to understand the performance the performance level in level the in industry, the industry, by taking by taking into accountinto account the mentioned the mentioned stages whichstages are which part ofare three part major of three areas: major economic, areas: social economic, and environmental. social and Ourenvironmental. project has focusedOur project mainly has onfocused the economic mainly on area the by economic addressing area how by addressing to comply with how the to comply market regulationswith the market (Economic regulations Commission (Economic for Europe Commission (ECE)) and for aimingEurope to (ECE)) improve and process aiming performance. to improve processIn theperformance. manufacturing environment, organizations remain competitive when they are able to effectivelyIn the solve manufacturing problems that environment, occur in production organization processes,s remain such competitive as production when bottlenecks, they are inability able to toeffectively produce, solve poor productproblems quality, that highoccur production in producti costson processes, [18]. such as production bottlenecks, inabilityProcess to produce, management poor isproduct backed qu upality, by measurement high production and analysis costs [18]. activities, and is led by leadership and strategicProcess processmanagement planning, is backed paying greatup by attention measurement to the customerand analysis and marketactivities, [5]. Inand the is industry led by withleadership very highand strategic competitiveness process planning, between paying companies, great theattention improvement to the customer of processes and market is essential, [5]. In thereforethe industry systems with ofvery methods high competitiveness are integrated, betw in ordereen tocompanies, help identifying the improvement the factors of and processes activities is foressential, improvement therefore [ 19systems]. Quality of methods tools help are tointegrat optimizeed, in manufacturing order to help time,identifying streamline the factors processes, and minimizeactivities for losses, improvement increase productivity [19]. Quality and tools consequently help to optimize improve manufacturing quality. Organizations time, streamline that use qualityprocesses, instruments minimize are losses, more increase efficient, productivity flexible, and manageand consequently to deliver qualityimprov productse quality. at Organizations reduced costs. that useProcess quality optimization instruments [18 are] refers more to efficient, eliminating flexible, costs and with manage low quality, to deliver eliminating quality products correction at operations,reduced costs. waste, overproduction, bottlenecks, and to optimizing time. After identifying the componentsProcess thatoptimization slow down [18] the refers processes to eliminating or lead to costs high with manufacturing low quality, costs eliminating or high production correction times,operations, one may waste, continue overproduction, to the stage where bottlenecks, the methods and are to identified,optimizing thus time. optimizing After theidentifying productivity the andcomponents streamlining that theslow processes down the [20 processes]. or lead to high manufacturing costs or high production times,The one main may benefitscontinue ofto the applying stage where continuous the methods improvement are identified, are related thus optimizing to improving the productproductivity quality, and improvingstreamlining manufacturing the processes [20]. times, optimizing costs, streamlining processes, and increasingThe main competitiveness. benefits of applying continuous improvement are related to improving product quality, improving manufacturing times, optimizing costs, streamlining processes, and increasing 2. Case Study competitiveness. 2.1. Starting Situation The case study, the process of tire manufacturing, presented multiple problems that need to be solved in order to improve the performance. Sustainability 2020, 12, x 4 of 22

2. Case Study

2.1. Starting Situation The case study, the process of tire manufacturing, presented multiple problems that need to be Sustainability 2020, 12, 6909 4 of 22 solved in order to improve the performance. The starting point is given by the process deeper analysis, implemented by a dedicated team, to identifyThe the starting process’ point activities is given [16], by using the process the mappi deeperng method analysis, of implementedprocesses (suppliers, by a dedicated inputs, process, team, tooutputs, identify customers) the process’ [20]. activities [16], using the mapping method of processes (suppliers, inputs, process,The outputs, purpose customers) of the team [20 ].is to monitor and identify possible problems in the manufacturing process.The purposeThis team of works the team closely is to monitorwith the and quality identify manager possible to establish problems and in the validate manufacturing the improvement process. Thisplan. team works closely with the quality manager to establish and validate the improvement plan.

2.2.2.2. DescriptionDescription ofof thethe TireTire ManufacturingManufacturing Process Process TheThe tire tire manufacturing manufacturing process process is is organized organized as as presented presented in Figurein Figure3. The 3. Th maine main stages stages present present the followingthe following areas: areas: mixing–compound–components–building–curing–ﬁnishing. mixing–compound–components–building–curing–finishing.

FigureFigure 3.3. MainMain stagesstages ofof thethe tiretire manufacturingmanufacturing process.process.

ProcessProcess mappingmapping isis a tool for showing showing series series of of events events that that produce produce an an end end result result (Table (Table 1).1). A Aprocess process map map shows shows the the steps steps of of activities activities and and peop peoplele who who are are involved involved in, and it ooffersﬀers aa wayway toto understandunderstand thethe processprocess andand thethe areasareas where where improvement improvement should should be be relevant. relevant. TheThe representationrepresentation revealsreveals thethe inputsinputs andand thethe outputsoutputs forfor eacheach stagestage ofofthe theprocess process and andthe theassociated associatedinternal internalsuppliers suppliers andand customers.customers.

SustainabilitySustainability 20202020,, 1212,, 6909x 5 of 22

Table 1. Mapping process of tires’ manufacturing Table 1. Mapping process of tires’ manufacturing Suppliers Input Process Output Customers Suppliers Input Process Output Customers Supply ProductionProduction Supply departmentProductionProduction plan plan Supply Supply ma materialsterials MaterialsMaterials request request department departmentdepartment DiDifferentfferent types types of of Compound MixingMixing area area Raw materials Raw materials Mixing Mixing process process Compound area mixedmixed rubber rubber area Compound DifferentDifferent types types ofExtrudingExtruding of rubber of Components Compound area RubberRubber sheets sheets Components area area of mixedmixed rubber rubber bandsrubber bands area Components ExtrudingExtruding the the Components areaRubber Rubber sheets sheets TireTire components components Building Building area area area componentscomponents TheThe carcass carcass (without Tire CarcassCarcass (without the final BuildingBuilding area area Tire components the final shape and CuringCuring components manufacturingmanufacturing shape and tread treadpattern) pattern) CuringCuring The carcass The carcass Curing Curing proc processess Final Final tire tire Finishing Finishing area area Control,Control, CompliantCompliant and and non- FinishingFinishing area area Final Finaltire tire measurementmeasurement and and StorageStorage non-compliantcompliant tirestires testingtesting of tires of tires

InIn connectionconnection toto FigureFigure3 3,, in in Figure Figure4 ,4, the the tire tire manufacturing manufacturing process process is is presented. presented.

Figure 4. Description of the tire manufacturingmanufacturing process [[21].21]. The two main ingredients of the tire are natural rubber and synthetic rubber. In addition, chemicals, The two main ingredients of the tire are natural rubber and synthetic rubber. In addition, textile materials and steel cord are used. The ingredients are combined depending on the type of tire chemicals, textile materials and steel cord are used. The ingredients are combined depending on the being manufactured. type of tire being manufactured. Mixing—The mixing area is organized vertically and represents a process where various types Mixing—The mixing area is organized vertically and represents a process where various types of rubbers are obtained for the next stage of the process. The materials obtained in the mixing area of rubbers are obtained for the next stage of the process. The materials obtained in the mixing area are made of natural rubber, synthetic rubber and various chemicals. The materials can be of several are made of natural rubber, synthetic rubber and various chemicals. The materials can be of several types depending on the type of tire [22]. The ingredients are mixed by applying mechanical work, types depending on the type of tire [22]. The ingredients are mixed by applying mechanical work, and blended so as to obtain a homogeneous mixture. and blended so as to obtain a homogeneous mixture. Compound—Ingredients are brought together in the required composition of rubber compound, Compound—Ingredients are brought together in the required composition of rubber compound, so as to obtain the diﬀerent mix of ingredients in accordance to the concerned component properties. so as to obtain the different mix of ingredients in accordance to the concerned component properties. Sustainability 2020, 12, 6909 6 of 22

Components—During this process, all components are prepared for the curing stage. In compound area, the following components are obtained: tread sidewall, liner, filler, bead, steel belt, plies, chafer. Building—The building process involves two operations: the first one, where the tire carcass is obtained by assembling inner liner with sidewalls and body plies, and the second one, where inflated carcass is applied on the belt and tread components. All parts from components area are used in the building sector, and the output of this process is a carcass, the semi-finished product. Curing—The curing process is used to obtain the final shape of the tire and the tread pattern. It involves the chemical cross-linking of rubber and vulcanizing agents, the result being an elastomer. Curing is performed using heat and pressure in the mold of tire. Finishing—In this manufacturing stage, final measurements are implemented. The tire is measured for force variation (uniformity measurement) in conditions of automatically mounted on wheel halves, inflated, and then run on a simulated road. Tire balance measurement means similar tires automatically mounted on wheel halves, and then rotated at high speed [23].

2.3. Identifying Improvement Opportunities Identifying opportunities for improvement begins with understanding the process by mapping it. The production ﬂow is presented, the activities are analyzed and monitored. Finally, possibilities for developing the process are identiﬁed [18].

2.4. Identifying Problems The team responsible for monitoring activities in all stages, gathering opinions of all employees implied in the manufacturing process, finalized the identification of issues. Mapping the manufacturing processes, many problems can be identified, but among the critical ones, there are bottlenecks that lead to the interruption of production [24] and eventually lead to decreased production capacity, decreased performance and increased costs [18]. Following the analysis mentioned above, several problems were identified in the newly established area for preparing the molds for the curing process. The team dedicated to this project identified several interruptions, due to various causes that delayed the preparation of the molds for the curing process. Taking into account the newly established area in the factory, several problems appear and lead to the extent of the manufacturing time; consequently, productivity decreases. The main objective targets are identifying the root causes of blockage leading to production shutdown, identifying productivity decrease, and slowing down the capacity of the entire production system. This type of problem leads to higher costs, but also to an inefficient process, as the expected results are not achieved [25].

2.4.1. Root Cause Analysis The causes that lead to the process slowing or even blocking can be multiple, starting from problems related to workers, working methods, procedures, and mode of operation, to the used equipment and how equipment is handled. Following the application of the Ishikawa diagram [20], the possible causes that lead to the occurrence of blockage in the curing area are identiﬁed. The mold washing machine is essential for the curing process, because each mold must be washed before entering in the curing cycle. The machine wear contributes to process slowdown, as maintenance should be frequent. Lack of procedures lead to errors in the machine settings. Sometimes, washing substances are not appropriately dosed; consequently, the molds are not washed well and cannot be used in the curing process, so the washing process should be repeated. All these issues can lead to increased tire manufacturing time, or may even block manufacturing for certain types of envelopes. As can be seen in Figure5, following the performed monitoring and analysis, the curing process was slowed down or blocked, due to several possible causes. Sustainability 2020, 12, x 7 of 22

Ishikawa diagram: the diagram was used for detecting the causes which lead to blockages of the curing process. These causes are identified as follows: without a procedure for setting the machine, the operators set the washing program arbitrarily, or use an inappropriate quantity of chemical solution. The lack of procedure and operating mode can definitely lead to the problem. Non- standardized activities lead to increased processing time, production blockage and losses with non- Sustainabilityconform 2020 products, 12, x [26]. 7 of 22 After analysis, the causes related to people can be revealed, such as lack of training, insufficient Sustainability 2020, 12, 6909 7 of 22 staff,Ishikawa lack of diagram:motivation, th eor diagram carelessness. was used for detecting the causes which lead to blockages of the curing process. These causes are identified as follows: without a procedure for setting the machine, the operators set the washing program arbitrarily, or use an inappropriate quantity of chemical solution. The lack of procedure and operating mode can definitely lead to the problem. Non- standardized activities lead to increased processing time, production blockage and losses with non- conform products [26]. After analysis, the causes related to people can be revealed, such as lack of training, insufficient staff, lack of motivation, or carelessness.

FigureFigure 5. 5.Ishikawa Ishikawa diagram.diagram.

IshikawaPareto chart: diagram: following the diagramdetermination was usedof the forcauses detecting that lead the to causesthe problem, which the lead Pareto to blockagesmethod of the(Figure curing 6) was process. applied, These in order causes to identify are identified the associated as follows: roots. without a procedure for setting the machine, the operators set the washing program arbitrarily, or use an inappropriate quantity of chemical solution.40 The lack of procedure and operating mode can100% definitely lead to the problem. Non-standardized activities35 lead to increased processing time, production90% blockage and losses with non-conform products [26]. 80% 30 After analysis, the causes related to people can be revealed, such70% as lack of training, insufficient 25 Figure 5. Ishikawa diagram. staff, lack of motivation, or carelessness. 60% 20 50% Pareto chart: following determination of the causes that lead to the problem, the Pareto method (Figure6) was applied,15 in order to identify the associated roots. 40% (Figure 6) was applied, in order to identify the associated roots. 30% 10 causes 20% 40 5 10%100% percent 35 0 0%90% 80% 30 70% 25 60% 20 50% 15 40% 30% 10 causes 20% 5 Figure 6. Pareto chart. 10% percent 0 0% After monitoring and analyzing the process, the main issues appear due to the activities in the mold preparation area. As seen in Figure 6, the main causes leading to the problems were identified, grouping the causes in function of their occurrence during the monitoring period. After identifying the causes using the Ishikawa diagram, the Pareto diagram was used to highlight the 80% causes generating problems. The dedicated team made the classification of the causes by monitoring the

Figure 6. Pareto chart.

After monitoring and analyzing the process, the mainmain issues appear due to the activities in the mold preparation area. As seen in Figure 66,, thethe mainmain causescauses leadingleading toto thethe problemsproblems werewere identified,identified, grouping the causes in functionfunction ofof theirtheir occurrenceoccurrence duringduring thethe monitoringmonitoring period.period. After identifying the causescauses using the IshikawaIshikawa diagram,diagram, the Pareto diagram was used to highlighthighlight the 80% causes generating problems. The The dedicated dedicated team team made made the classification classification of the causes by monitoring the Sustainability 2020, 12, 6909 8 of 22 activities for two weeks. Several issues have been identified, such as lack of procedures, workspace organizational problems, lack of training, machine settings and wear, insufficient staff, carelessness or storage of the molds. The first three causes lead to nearly 80% identified problems (Figure6). The lack of procedures attracts many problems related to time, quality of tires, process stability, delivery of activities’ outputs and the training of new employees. Several non-documented activities in the curing area were identified, such as:

lack of procedures for mounting and dismantling the molds, • washing molds at the washing machine, • washing mold rings on the machine, • sand blasting of the sidewalls of molds, • unlocking spring-winds of molds, • transport of molds in the hydraulic presses, these leading to production time increase and to • ineﬃcient process.

The workspace organization appears to be very important; it directly influences the activity in the working area and adds a lot of benefits in terms of efficiency. After monitoring and analyzing the process, opportunities for organizing workspace were identified, such as:

no delimitation of workspaces and pedestrian routes, • lack of labels for shelves of molds stored, • incorrect storage of tools, • incorrect storage of used screws and trash in the workspace. • Lack of training and insufficient staff—The main identified problems were the blockages of curing activity, long lost time for some activities, which means lost production time. When a manufacturing process stops for an unplanned event, it accumulates downtime of production. Besides the problems related to the working procedures and organizational workspace, in this area, other problems generating the process blockage were found, such as problems in the washing machine molds. Each mold must be washed before entering the curing cycle, but unfortunately, the machine has poor capacity for washing all the molds necessary for the curing process. Therefore, the number of molds washed and prepared for entry into the curing cycle was monitored for 15 days (Figure7). Several causes were found to be related to the washing machine: no working procedure was drafted, and each worker sets the machine in a different way. Moreover, the quantities of the cleaning substances were different. As seen in Figure7, the number of washed molds was not the same every day, and the expected results were not achieved, with an impact on shut down production.

2.4.2. ECE Changes on the Sidewalls of Molds The abbreviation ECE comes from Economic Commission for Europe, which helps to standardize regulations in member countries. The ECE regulations include rules regarding sidewall symbols, tire markings, speed index and load index, durability and tire noise. In accordance with ECE regulations, the company must modify the sidewalls of the molds with the ECE symbols to show compliance with the European norm. The sound produced by tires can be considered a sort of environmental pollution. That is why this regulation also refers to the noise that tires make. In Table2, the ECE symbol can be identiﬁed by inserting the letter “E” or “e”, followed by a numeric code in a rectangle or a circle. The letter represents the ECE, and the number indicates the country where the tire was registered. As seen in Figure8, each country has its own number [26]. Sustainability 2020, 12, x 8 of 22 activities for two weeks. Several issues have been identified, such as lack of procedures, workspace organizational problems, lack of training, machine settings and wear, insufficient staff, carelessness or storage of the molds. The first three causes lead to nearly 80% identified problems (Figure 6). The lack of procedures attracts many problems related to time, quality of tires, process stability, delivery of activities’ outputs and the training of new employees. Several non-documented activities in the curing area were identified, such as: • lack of procedures for mounting and dismantling the molds, • washing molds at the washing machine, • washing mold rings on the machine, • sand blasting of the sidewalls of molds, • unlocking spring-winds of molds, • transport of molds in the hydraulic presses, these leading to production time increase and to inefficient process. The workspace organization appears to be very important; it directly influences the activity in the working area and adds a lot of benefits in terms of efficiency. After monitoring and analyzing the process, opportunities for organizing workspace were identified, such as: • no delimitation of workspaces and pedestrian routes, • lack of labels for shelves of molds stored, • incorrect storage of tools, • incorrect storage of used screws and trash in the workspace. Lack of training and insufficient staff—The main identified problems were the blockages of curing activity, long lost time for some activities, which means lost production time. When a manufacturing process stops for an unplanned event, it accumulates downtime of production. Besides the problems related to the working procedures and organizational workspace, in this area, other problems generating the process blockage were found, such as problems in the washing machine molds. Each mold must be washed before entering the curing cycle, but unfortunately, the machine has poor capacity for washing all the molds necessary for the curing process. Therefore, the number of molds washed and prepared for entry into the curing cycle was monitored for 15 days (Figure 7). Several causes were found to be related to the washing machine: no working procedure was drafted, and each worker sets the machine in a different way. Moreover, the quantities of the cleaning substances were different. As seen in Figure 7, the number of washed molds Sustainabilitywas not the2020 same, 12, 6909every day, and the expected results were not achieved, with an impact on9 shut of 22 down production.

Sustainability 2020, 12, x 9 of 22

Table 2. Economic Commission for Europe (ECE) countries symbols [26]. Figure 7. Number of washed molds per day. Code Country Code Country E1 Germany E21 Portugal Table 2. Economic Commission for Europe (ECE) countries symbols [26]. E2 France E22 Russia CodeE3 CountryItaly E23 Code Greece Country E1E4 Holland Germany E24 E21 Ireland Portugal E2E5 Sweden France E25 E22 Croatia Russia E3E6 Belgium Italy E26 E23 Slovenia Greece E4E7 Hungary Holland E27 E24 Slovakia Ireland E5 Sweden E25 Croatia E6E8 Czech Belgium Republic E28 E26 Belarus Slovenia E7E9 HungarySpain E29 E27 Estonia Slovakia E8E10 CzechYugoslavia Republic E31 E28 Bosnia and Herzegovina Belarus E9E11 Great Spain Britain E32 E29 Latvia Estonia E10E12 YugoslaviaAustria E34 E31 BosniaBulgaria and Herzegovina E11 Great Britain E32 Latvia E12E13 Luxembourg Austria E37 E34 Turkey Bulgaria E13E14 Switzerland Luxembourg E40 E37 Macedonia Turkey E14E16 SwitzerlandNorway E43 E40 Japan Macedonia E16E17 Finland Norway E45 E43 Australia Japan E17 Finland E45 Australia E18 Denmark E46 Ukraine E18 Denmark E46 Ukraine E19E19 Romania Romania E47 E47 South South Africa Africa E20E20 Poland Poland E48 E48 New New Zealand Zealand

Figure 8. ECE symbols [27]. Figure 8. ECE symbols [27]. The initial code is followed by a two-digit series. This refers to the series of regulations for tire The initial code is followed by a two-digit series. This refers to the series of regulations for tire certification, in line with different standards depending on the category. certification, in line with different standards depending on the category. For example, “02” is regulation for passenger tires and “00” for commercial tires vehicles. Other For example, “02” is regulation for passenger tires and “00” for commercial tires vehicles. Other specific information, such as noise limits or wet traction, may be revealed as a second ECE symbol. specific information, such as noise limits or wet traction, may be revealed as a second ECE symbol. As seen in Table2, tires that meet the regulations regarding noise and wet traction limits may have the As seen in Table 2, tires that meet the regulations regarding noise and wet traction limits may have second ECE symbol [27]. the second ECE symbol [27]. The manufacturer has to comply with European regulation, so the ECE symbol visible on the tire sidewall proves the product certification. The company must receive the approval of the independent laboratory after performing the tests and confirming the validation of setting in place the manufacturing process. As a result, the ECE mark may be applied on the manufactured tires. Sustainability 2020, 12, 6909 10 of 22

The manufacturer has to comply with European regulation, so the ECE symbol visible on the tire sidewall proves the product certification. The company must receive the approval of the independent laboratory after performing the tests and confirming the validation of setting in place the manufacturing Sustainability 2020, 12, x 10 of 22 process. As a result, the ECE mark may be applied on the manufactured tires. AccordingAccording toto thethe managementmanagement requirements,requirements, thethe changeschanges mustmust bebe mademade byby weekweek 1515 withwith thethe applicationapplication ofof thethe ECEECE normnorm (Figure(Figure9 9).). ModificationsModifications to to the the moldmold sidewallssidewalls areare mademade byby thethe supplier,supplier, whowho hashas agreedagreed toto aa planplan forfor allall changes.changes. TheThe moldsmolds sidewallssidewalls mustmust bebe preparedprepared forfor sendingsending toto thethe suppliersupplier forfor ECEECE modificationsmodifications and,and, forfor thisthis process,process, aa planplan dependingdepending onon thethe productionproduction planningplanning mustmust bebe followed.followed. The main issue in this process isis preparingpreparing thethe numbernumber ofof moldsmolds plannedplanned forfor modificationmodification andand sendingsending themthem toto thethe supplier.supplier.

FigureFigure 9.9. ECEECE modiﬁcationsmodifications planning.planning.

AccordingAccording toto thethe agreedagreed planplan betweenbetween thethe tirestires plantplant andand thethe supplier,supplier, ECEECE modificationsmodifications willwill bebe plannedplanned asas inin FigureFigure9 .9. For For planning planning compliance, compliance, the the tires’ tires’ company company must must send send 50 50 sidewalls sidewalls per per weekweek toto thethe suppliersupplier toto bebe modified.modified. AsAs seenseen inin FigureFigure9 9,, the the supplier supplier modified modified the the received received sidewalls sidewalls andand respectedrespected thethe agreement,agreement, butbut thethe companycompany werewere notnot ableable toto sendsend thethe agreedagreed numbernumber ofof sidewallssidewalls accordingaccording toto thethe planning.planning. TheThe problemsproblems come come due due to the to lack the of lack organization of organization and process and standardization. process standardization. From discussions From withdiscussions the operators, with the the operators, main issue the was main the moldsissue was identification the molds in identification the deposit. Duein the to deposit. many molds Due into themany deposit, molds lack in the of deposit, procedures, lack andof procedures, lack of labels and on la theck of shelves, labels on much the timeshelves, was much spent time searching was spent the correctsearching molds. the correct molds.

3. Improvement Plan 3. Improvement Plan The improvement must be correlated with the results’ analysis from the monitoring stage. The improvement must be correlated with the results’ analysis from the monitoring stage. The The areas for actions are identified and the objectives for improvement are directly related to the main areas for actions are identified and the objectives for improvement are directly related to the main issues found, i.e., standardization in the mold preparation area for the curing process, drafting of issues found, i.e., standardization in the mold preparation area for the curing process, drafting of working procedures, increased number of molds washed per day. working procedures, increased number of molds washed per day. 3.1. Implementation of 5S Method 3.1. Implementation of 5S Method In order to organize the activity and the working space of the mold preparation area, the In order to organize the activity and the working space of the mold preparation area, the improvement method 5S was implemented. improvement method 5S was implemented. Sort step—In the first step of 5S, a broad investigation of all items in the working area (materials, Sort step—In the first step of 5S, a broad investigation of all items in the working area (materials, tools, equipment, furniture etc.) is implemented, so as to separate what needs to be present versus tools, equipment, furniture etc.) is implemented, so as to separate what needs to be present versus what may be removed. what may be removed. Before sorting the items, analyzing the area of molds’ preparation, several irregularities were Before sorting the items, analyzing the area of molds’ preparation, several irregularities were identified, as seen in Figure 10, such as a lack of labels on shelves and on the screw drawers. Different identified, as seen in Figure 10, such as a lack of labels on shelves and on the screw drawers. Different types of screw dimensions lead to increase in the mold assembly time. types of screw dimensions lead to increase in the mold assembly time. Organizational problems were identified in the area around the washing machine, too, such as lack of layouts for washing machine trolleys and lack of layouts for containers with chemical solutions of washing machine (Figure 11); these affected the mold washing activity. In the tool trolley area, as seen in Figure 12, organizational problems were found, such as a lack of layouts for operator trolleys and trash. At this stage, all objects were identified and sorted. Objects that can be removed were stored, as seen in Figure 13. Finally, in the sorting stage, all objects were identified, and their status to remain in the molds’ preparation area or to be eliminated was decided. Sustainability 2020, 12, x 11 of 22

Straighten—Setting in order consists of arranging all objects in the right place so as to allow efficient use. In this phase, the ordering operations were carried out in the area. Working tools, mold components,Sustainability 2020 fixing, 12, x screws and other equipment must be located close to the area where these11 ofare 22 used. Through all these organizational measures, employees spend less time looking for parts and Sustainability 2020, 12, 6909 11 of 22 itemsStraighten—Setting for their activities. in order consists of arranging all objects in the right place so as to allow efficient use. In this phase, the ordering operations were carried out in the area. Working tools, mold components,Lack fixing of labelsscrews on and shelves other equipment must be Lack located of labels close on to the the screw area wheredrawers these are used.Sustainability Through 2020, 12all, xthese organizational measures, employees spend less time looking for parts11 andof 22 items for their activities. Straighten—Setting in order consists of arranging all objects in the right place so as to allow efficient use. In this phase, the ordering operations were carried out in the area. Working tools, mold components,Lack fixing of labelsscrews on and shelves other equipment must be Lack located of labels close on to the the screw area wheredrawers these are used. Through all these organizational measures, employees spend less time looking for parts and items for their activities.

Lack of labels on shelves Lack of labels on the screw drawers

Figure 10. Workspace analysis inin thethe assemblyassembly areaarea ofof molds.molds.

LackOrganizational of layouts for problems washing weremachine identiﬁed trolleys in the area around Lack theof layouts washing for machine, containers too, such as lack of layouts for washing machine trolleys and lack of layouts for containers with chemical solutions of washing machine (FigureFigure 11 10.); theseWorkspace aﬀected analysis the mold in the washingassembly activity.area of molds.

Lack of layouts for washing machine trolleys Lack of layouts for containers

Figure 10. Workspace analysis in the assembly area of molds.

Lack of layouts for washing machine trolleys Lack of layouts for containers

Figure 11. Workspace analysis in the washing machine area.

Lack of layouts for operator trolleys Trash storage

Figure 11. Workspace analysis in the washing machine area. Figure 11. Workspace analysis in the washing machine area. In the tool trolley area, as seen in Figure 12, organizational problems were found, such as a lack of Lack of layouts for operator trolleys Trash storage layouts for operator trolleys and trash. At this stage, all objects were identiﬁed and sorted. Objects that can be removed were stored, as seen in Figure 13. Finally, in the sorting stage, all objects were identiﬁed, and their statusFigure to remain 11. Workspace in the molds’ analysis preparation in the washing area machine or to be area. eliminated was decided.

Lack of layouts for operator trolleys Trash storage

Figure 12. Workspace analysis tool trolley area.

FigureFigure 12. 12.Workspace Workspace analysis analysis tool tool trolley trolley area. area. SustainabilitySustainability 20202020,, 1212,, 6909x 1212 ofof 2222

Sustainability 2020, 12, x 12 of 22

FigureFigure 13.13. SortingSorting objects.objects. Straighten—Setting in order consists of arranging all objects in the right place so as to allow The screws ordering was done by sorting each screw and placing them according to the size eﬃcient use. In this phase, the ordering operations were carried out in the area. Working tools, mold (Figure 14), so as to avoid searching and choosing the right screw for the assembly and mounting of components, ﬁxing screws and other equipment must be located close to the area where these are used. molds on vulcanization presses. Through all these organizational measures, employees spend less time looking for parts and items for Figure 13. Sorting objects. their activities. The screws ordering was done by sorting each screw and placing them according to the size (Figure 14),14), so as to avoid searching and choosing the right screw for the assembly and and mounting mounting of of molds on vulcanization presses.

Figure 14. Ordering the screws by size.

After sorting the screws according to size, to facilitate quick access, they were placed in trays, and these were placed on shelves near the area where they were used (Figure 15).

Figure 14. OrderingOrdering the the screws screws by size.

After sorting thethe screwsscrews according according to to size, size, to to facilitate facilitate quick quick access, access, they they were were placed placed in trays, in trays, and andthese these were were placed placed on shelves on shelves near near the areathe area where where they they were were used used (Figure (Figure 15). 15). Sustainability 2020, 12, x 13 of 22 Sustainability 2020, 12, 6909 13 of 22 Sustainability 2020, 12, x 13 of 22 Sustainability 2020, 12, x 13 of 22

Figure 15. Place the screws in trays.

Shine—In the cleaning phase,FigureFigure the trash 15. PlacePlace was the thecollec screws screwsted, in in as trays. trays. well as useless things, cloths, broken Figure 15. Place the screws in trays. screws and worn parts to be thrown away (Figure 16). Shine—InShine—In the the cleaning cleaning phase, phase, the the trash trash was was collec collected,ted, as as well as useless things, cloths, broken Shine—InStandardize—The the cleaning aim phase,of the standardizationthe trash was collec phaseted, was as wellto implement as useless andthings, reinforce cloths, of broken good screwsscrews and worn parts to be thrown away (Figure 1616).). screwshabits in and the worn working parts area; to be this thrown is why away the phase(Figure was 16). documented and maintained. Standardize—The aim of the standardization phase was to implement and reinforce of good Standardize—The aim of the standardization phase was to implement and reinforce of good habits in the working area; this is why the phase was documented and maintained. habits in the working area; this is why the phase was documented and maintained.

Figure 16. Trash disposal.

Standardize—TheLabels were created aim and of applied the standardization Figurefor the 16. screws Trash phase arrangeddisposal. was in to trays implement (Figure and 17) or reinforce storage of lockers good Figure 16. Trash disposal. habits(Figure in 18). the The working creation area; of this labels is why ensures the phase efficiency was documented when searching and maintained. for the needed screws and Labels were created and applied for the screws arranged in trays (Figure 17) or storage lockers maintainingLabels were the habit created of order,and applied too. for the screws arranged in trays (Figure 17)17) or storage lockers (Figure 18). The creation of labels ensures efficiency when searching for the needed screws and (Figure 1818).). The The creation creation of of labels labels ensures ensures effi eﬃciencyciency when when searching searching for for the needed screws and maintaining the habit of order, too. maintaining the habit of order, too.too.

Figure 17. Labels on the trays.

Figure 17. Labels on the trays. Figure 17. Labels on the trays. Sustainability 2020, 12, 6909 14 of 22 Sustainability 2020, 12, x 14 of 22 Sustainability 2020, 12, x 14 of 22 Sustainability 2020, 12, x 14 of 22

FigureFigure 18. 18. Labels LabelsLabels for forfor storage storage locker locker screws. screws. Figure 18. Labels for storage locker screws. Dedicated areas are established, with drawn layo layoutsuts for the containers with chemical solutions DedicatedDedicated areas areas areare established,established, withwith drawn drawn layo layoutsuts for for thethe containerscontainers withwith chemicalchemical solutionssolutions for the molds washing machine (Figure 1919).). forfor the the molds molds washing washing machine machine (Figure (Figure 19). 19).

FigureFigure 19. 19. Layouts Layouts for for the the containers containers with with chemical chemical solutions. solutions. Figure 19. LayoutsLayouts for for the the containers containers with with chemical chemical solutions.

Similarly,Similarly, areasareas withwith drawndrawn layoutslayouts forfor thethe moldsmolds washingwashing trolleys,trolleys, as as seenseen in in FigureFigure 20, 2020,, helphelp to to standardizeSimilarly, the areas activity with in drawn the area, layouts and to for carry the moldsout the washing mold washing trolleys, process as seen regularly. in Figure 20, help to standardizestandardize the the activity activity in in the the area, area, andand toto carrycarry outout thethe moldmold washingwashing process process regularly.regularly. regularly.

FigureFigure 20. 20. Layouts Layouts for for washing washing machine machine trolleys. trolleys. Figure 20. LayoutsLayouts for for washing washing machine machine trolleys. trolleys. Labels for shelves with molds are essential for the curing process. Many molds of different sizes LabelsLabels forfor shelvesshelves withwith moldsmolds areare essentialessential forfor thethe curingcuring process.process. ManyMany moldsmolds ofof didifferentﬀerent sizessizes with Labelsparticular for shelvesspecifications with molds are stored are essential in the mold for tharea,e curing so in process.order to avoidMany wastingmolds of time different after moldsizes withwith particularparticular speciﬁcationsspecifications are are storedstored in in thethe moldmold area,area, soso inin orderorder toto avoidavoid wastingwasting timetime afterafter moldmold withcleaning, particular detailed specifications labeling appears are stored essential in the (Figure mold area, 21). so in order to avoid wasting time after mold cleaning,cleaning, detaileddetailed labelinglabeling appearsappears essentialessential (Figure(Figure 21 21).). cleaning,Sustain—This detailed labeling step involves appears implementing essential (Figure good 21). behaviors and habits in activities. Changing the Sustain—ThisSustain—This step step involves involves implementing implementing good good behaviors behaviors and and habits habits in in activities. activities. Changing Changing the the habitshabits isis definitelydefinitely veryvery difficultdifficult andand appearsappears toto bebe thethe majormajor actionaction forfor thethe effectivenesseffectiveness ofof thethe 5S5S habitsmethod is implementation. definitely very difficult and appears to be the major action for the effectiveness of the 5S methodmethod implementation. implementation. Sustainability 2020, 12, 6909 15 of 22 Sustainability 2020, 12, x 15 of 22

Sustainability 2020, 12, x 15 of 22

Figure 21. LabelsLabels for for shelves shelves with with molds. molds.

TheSustain—This workers will step tend involves to operate implementing as in the past, good so behaviors the main objective and habits is into activities.change those Changing habits. Forthe habitsupdating is definitely the good veryhabits, di ffia culttraining and appearstopic named to be one the majorpoint lesson action (OPL) for the was effectiveness chosen to of present the 5S themethod new implementation.organized habit on eachFigure aspect 21. Labels of an for equipment, shelves with molds.machine, operating mode or testing procedure.The workers OPL presents, will tend in to comparison, operate as inprevious the past, versus so the improved main objective working is to organization, change those so habits. as to The workers will tend to operate as in the past, so the main objective is to change those habits. stimulateFor updating people the goodto procee habits,d correctly a training (Figure topic named22). one point lesson (OPL) was chosen to present the For updating the good habits, a training topic named one point lesson (OPL) was chosen to present new organized habit on each aspect of an equipment, machine, operating mode or testing procedure. the new organized habit on each aspect of an equipment, machine, operating mode or testing OPL presents, in comparison, previous versus improved working organization, so as to stimulate procedure. OPL presents, in comparison, previous versus improved working organization, so as to people to proceed correctly (Figure 22). stimulate people to proceed correctly (Figure 22).

Figure 22. OPL examples.

3.2. Standardization of Activities through Working Procedures FigureFigure 22.22. OPL examples. The process standardization implies drafting the necessary procedures for the activity, in order 3.2. Standardization of Activities through Working Procedures to increase productivity and reduce production times, but also to improve organizational performanceThe process [28]. standardization implies drafting the necessary procedures for the activity, in order to increase productivity and reduce production times, but also to improve organizational performance [28]. Sustainability 2020, 12, 6909 16 of 22

3.2. Standardization of Activities through Working Procedures The process standardization implies drafting the necessary procedures for the activity, in order to increase productivity and reduce production times, but also to improve organizational performance [28]. The activities standardization consists of procedures’ drafting following activities organization, presents regulated working practices, helps to better understand the activities, and facilitates continuous improvement. For drafting working procedures, the area of mold preparation was monitored for three weeks, to identifySustainability best practices 2020, 12, x and to standardize processes. 16 of 22

The first stepThe activities in carrying standardization out the procedures consists of proced has beenures’ todrafting monitor following the activity activities for organization, several consecutive days, to observepresents howregulated each working operator practices, from eachhelps shiftto better works. understand In order the toactivities, identify and the facilitates problems and to find the optimalcontinuous solutions, improvement. theworking procedures of the operators were timed. Based onFor the drafting problems working found procedures, in each the particulararea of mold case,preparation operators was monitored were invited for three into weeks, meetings to to identify best practices and to standardize processes. identify the appropriateThe first step solutions. in carrying As out no the procedures procedures werehas been applied to monitor for the the respectiveactivity for operations,several each operator workedconsecutive as hedays, thought, to observe so how a lot each ofworking operator fr timeom each and shift energy works. were In order spent to ineidentifyfficiently. the To facilitateproblems the and understanding to find the optimal of solutions, the processes the working and procedures their standardization, of the operators were documentation timed. using the standard operatingBased on the procedure problems found (SOP) in was each chosen.particular SOP case, isoperators a set of were step-by-step invited into instructions meetings to to clarify identify the appropriate solutions. As no procedures were applied for the respective operations, each (through accurateoperator worked descriptions) as he thought, the operations so a lot of wo torking be performed time and energy during were the spent production inefficiently. process necessary to carry out anTo activity facilitate in the a understanding more efficient of way,the processe and tos and save their time. standardization, SOP represents documentation an instruction using manual, which explains,the standard with operating images procedure and text, (SOP) step was by chosen. step, how SOP is to a performset of step-by-step the activities instructions of ato specificclarify process. The dedicated(through accurate team descriptions) has discussed the operations with the operatorsto be performed about during the encounteredthe production problems.process After necessary to carry out an activity in a more efficient way, and to save time. SOP represents an monitoringinstruction the activities manual, which in the explains, area ofwith preparation images and text, of step the by molds step, how for to perform the hardening the activities process for 15 consecutiveof a specific days, process. the dedicated team established improvement measures together with the quality manager. TheseThe measures dedicated team were has validated discussed bywith top the management. operators about the encountered problems. After The activitiesmonitoring ofthe the activities operators in the fromarea of severalpreparation shifts of the were molds monitored for the hardening to identify process the for problems15 of consecutive days, the dedicated team established improvement measures together with the quality the process,manager. and toThese find measures better were solutions. validated Atby top the management. end of the monitoring, several opportunities for improvementThe regarding activities theof the standardization operators from several of activities shifts were weremonitored identified. to identify One the problems may conclude of the that the work processesprocess, related and to tofind the better preparation solutions. ofAt thethe moldsend of needthe monitoring, to be standardized. several opportunities for An exampleimprovement of regarding the standard the standardization operating ofprocedure activities were for identified. unlocking One may spring-vents conclude that the is provided. work processes related to the preparation of the molds need to be standardized. Spring-ventsAn are example small of valves the standard allowing operating the procedure air from for theunlocking mold spring-vents to be removed is provided. during Spring- the curing process. Forvents drafting are small thevalves procedure, allowing the the air activitiesfrom the mo wereld to be monitored, removed during and the the curing time process. was registered For for several consecutivedrafting the daysprocedure, and duringthe activities the variouswere moni shifts.tored, Opportunitiesand the time was were registered identified for several for improving the time orconsecutive for the working days and during operation the va mode,rious shifts. as seenOpportunities in Figure were 23 identified. for improving the time or for the working operation mode, as seen in Figure 23.

Figure 23. Unlock spring-vents and device solution. Figure 23. Unlock spring-vents and device solution. At step 4 of the procedure below, initially the mold segments were placed directly on the At stepworktable 4 of the for procedure cleaning. Due below, to the initially cylindrical the shape mold of segmentsthe mold segments, were placed they were directly not in on a fixed the worktable for cleaning.position Due during to the the cylindricalcleaning operation. shape of the mold segments, they were not in a fixed position during the cleaningAs seen operation.in Figure 23, the operator used to fix with an object and re-position frequently the part, wasting time and leading to increased cleaning time for the unlocking of spring-vents. The solution As seen in Figure 23, the operator used to fix with an object and re-position frequently the part, to this issue was to create a support for the mold segments (Figure 24). Considering that the mold wasting timesectors and have leading different to sizes, increased the support cleaning should time be designed for the according unlocking to the of larger spring-vents. size of the existing The solution to Sustainability 2020, 12, 6909 17 of 22 this issue was to create a support for the mold segments (Figure 24). Considering that the mold sectors haveSustainability different 2020 sizes,, 12, thex support should be designed according to the larger size of the existing17 of 22 mold segment.Sustainability SOP, given 2020, 12 in, xFigure 25, may be considered an example; the processes may be improved17 of 22 and mold segment. SOP, given in Figure 25, may be considered an example; the processes may be then documented in a standardized way. improvedmold segment. and then SOP, documented given in inFigure a standardized 25, may be way. considered an example; the processes may be improved and then documented in a standardized way.

FigureFigureFigure 24.24. 24. Support Support of of segmentssegments segments of ofmolds. molds.

GeneralGeneral informationinformation aboutabout thethe procedure,procedure, generalgeneral safetysafety rulesrules andand possible possible dangers dangers

Description of operations Description step by step of operations step by step

Figure 25. Cont. Sustainability 2020, 12, 6909 18 of 22

Sustainability 2020, 12, x 18 of 22

Description of operations step by step

Approvals from Engineering, quality, HSE, R&D and production

Figure 25. Unlock spring-vents SOP. Figure 25. Unlock spring-vents SOP.

4. Improvement4. Improvement Plan Plan Results Results A results analysis takes into account data analysis and the actions carried out previously, A resultscorrelated analysis with the takes processes’ into account performance data and analysis the products and the quality actions [4]. carried out previously, correlated with the processes’Improving performance the processes in and the thecuring products area taking quality more [measures4]. to minimize process blockages, Improvingas seen in the analysis processes and inmeasurement the curing phase, area takingthrough more Ishikawa measures and Pareto to minimize diagrams, were process mainly blockages, as seendue in the to several analysis factors. and measurement phase, through Ishikawa and Pareto diagrams, were mainly due to severalImprovement factors. measures were taken for each factor mentioned above. Due to the lack of working procedures, all activities in the molds’ preparation area were monitored, then the standard operating Improvement measures were taken for each factor mentioned above. Due to the lack of working procedure was documented and, applying the 5S method, the workspace organizational problems procedures,were solved. all activities Considering in the that molds’ the major preparation identified problem area were responsible monitored, for the then process the standardblocking was operating proceduredue wasto the documented washing machine, and, applying after the theimprovem 5S method,ent plan the implementation, workspace organizational the number of problems molds were solved.washed Considering daily was that meas theured major for identiﬁed15 days. problem responsible for the process blocking was due to the washingAfter machine, applying after the the procedures improvement and organizing plan implementation, the workspace, the the number number of ofwashed molds molds washed is daily was measuredhigher and for almost 15 days. the same every day, as given in Figure 26; this shows the benefit result of the improvement and the process standardization. After applying the procedures and organizing the workspace, the number of washed molds is higher and almost the same every day, as given in Figure 26; this shows the beneﬁt result of the improvement and the process standardization. Sustainability 2020, 12, 6909 19 of 22 Sustainability 2020, 12, x 19 of 22

Figure 26. WashingWashing machine mold SOP. Analyzing the results of the improvement plan (Figure 26) within 15 days, we can see a 39% Analyzing the results of the improvement plan (Figure 26) within 15 days, we can see a 39% increase in the number of molds (blue versus red column). The solutions sustained, and the obtained increase in the number of molds (blue versus red column). The solutions sustained, and the obtained results will be supported through the continuous adaptation of the working procedures, training, results will be supported through the continuous adaptation of the working procedures, training, and internal audit actions. A new iteration may be applied similarly, identifying the problem, then the and internal audit actions. A new iteration may be applied similarly, identifying the problem, then root causes and then implementing an improvement plan. the root causes and then implementing an improvement plan. The planning evolution of the ECE changes can be noticed due to the organization of workspace The planning evolution of the ECE changes can be noticed due to the organization of workspace through the 5S method and creating labels on the shelves of molds. As seen in Figure 27, in order through the 5S method and creating labels on the shelves of molds. As seen in Figure 27, in order to to make possible the changes, an extension of 2 weeks, (week 16 and 17) was adopted, in which the make possible the changes, an extension of 2 weeks, (week 16 and 17) was adopted, in which the remaining sidewalls were modiﬁed until the improvement measures were taken. remaining sidewalls were modified until the improvement measures were taken.

Figure 27. ECE modifications modiﬁcations planning. Project Implementation Project Implementation In Figure 28, the project summary may be followed. One may see the identiﬁed problems by the In Figure 28, the project summary may be followed. One may see the identified problems by the team of 3 members who monitored, analyzed, and proposed solutions to improve the process. team of 3 members who monitored, analyzed, and proposed solutions to improve the process. The project implementation was carried out over three months. The team responsible for The project implementation was carried out over three months. The team responsible for implementing the improvement project, consisting of 3 members, worked closely with the operators of implementing the improvement project, consisting of 3 members, worked closely with the operators the two work shifts to understand the problems and identify optimal solutions. Improvement solutions of the two work shifts to understand the problems and identify optimal solutions. Improvement were approved by the quality manager, closely involved in the project, too. The three-week monitoring solutions were approved by the quality manager, closely involved in the project, too. The three-week phase was required to collect data from the process, followed by another three weeks to implement monitoring phase was required to collect data from the process, followed by another three weeks to 5S, OPL, and draft procedures. Procedures were implemented, and then a stage of monitoring and implement 5S, OPL, and draft procedures. Procedures were implemented, and then a stage of collecting data from the process to verify the project progress followed (Figure 29). monitoring and collecting data from the process to verify the project progress followed (Figure 29). Sustainability 2020, 12, 6909 20 of 22 Sustainability 2020, 12, x 20 of 22 Sustainability 2020, 12, x 20 of 22

Figure 28. Project implementation. Figure 28. Project implementation.

Figure 29. Stages of project. Figure 29. Stages of project. The results cancan bebe seenseen inin reducingreducing the the time time for for each each of of the the activities activities in in the the area area of of preparation preparation of The results can be seen in reducing the time for each of the activities in the area of preparation ofmolds molds by by up up to to 25%, 25%, increasing increasing the the number number of of washed washed molds molds by by 39%,39%, streamliningstreamlining andand facilitating of molds by up to 25%, increasing the number of washed molds by 39%, streamlining and facilitating work, standardizing processes, facilitatingfacilitating employeeemployee trainingtraining andand ensuringensuring workerworker safety.safety. work, standardizing processes, facilitating employee training and ensuring worker safety. Comparing the the situation situation before before with with those those afte afterr the the improvement improvement and and the theobtained obtained results, results, one Comparing the situation before with those after the improvement and the obtained results, one mayone maynotice notice the theimprovement improvement of the of thetimes times for for carryin carryingg out out various various activities activities in in the the area area of of mold may notice the improvement of the times for carrying out various activities in the area of mold preparation, and the increase of the number of wash washeded molds that led to the main main objective, objective, removing preparation, and the increase of the number of washed molds that led to the main objective, removing blockages from the process.process. Furthermore, followin followingg the improvement process, the activities were blockages from the process. Furthermore, following the improvement process, the activities were standardized by performing the procedures and the workspace was organized, which led to the standardized by performing the procedures and the workspace was organized, which led to the reduction of working times by up toto 25%.25%. reduction of working times by up to 25%. 5. Conclusions 5. Conclusions 5. Conclusions The case study presents the process-based approach, through which the organization continually The case study presents the process-based approach, through which the organization monitorsThe thecase processes study presents and maintains the process-bas their improvement.ed approach, Thus, continuousthrough which improvement the organization has been continually monitors the processes and maintains their improvement. Thus, continuous continually monitors the processes and maintains their improvement. Thus, continuous improvementsupported by thehas quality been supported management by system the quality and the management tools used to system keep processes and the andtools product used to quality keep improvement has been supported by the quality management system and the tools used to keep processesunder control. and product For increasing quality the under management control. For system increasing efficiency the and management effectiveness, system processes efficiency of deeper and processes and product quality under control. For increasing the management system efficiency and effectiveness,understanding, processes monitoring, of deeper and managing understandi areng, focused monitoring, on. and managing are focused on. effectiveness, processes of deeper understanding, monitoring, and managing are focused on. Within the improvement plan, the processes were carefullycarefully monitored, in order to identify their Within the improvement plan, the processes were carefully monitored, in order to identify their steps. Quality Quality tools tools were were used, such as suppliers,suppliers, inputs, process, outputs, customers (SIPOC) for steps. Quality tools were used, such as suppliers, inputs, process, outputs, customers (SIPOC) for mapping processes and identifying interactions between processes. Furthermore, quality tools such mapping processes and identifying interactions between processes. Furthermore, quality tools such Sustainability 2020, 12, 6909 21 of 22 mapping processes and identifying interactions between processes. Furthermore, quality tools such as Ishikawa and Pareto diagrams were used to identify the causes that lead to problems. After identifying the problems and their associated root causes, steps have been put in place to make processes more efficient and leaner, with improved production times. An essential role of the applied methods was also the good habits maintenance and the high level of rigor in carrying out the activities. Activities standardization realized by drafting the necessary procedures, adopting the SOP model (standard operating procedure), in which images and text were used with the description of each stage of the activity to facilitate the processes understanding by the operators. The process improvement made possible the ECE modifications, too, so the company was able to achieve its objectives in the tire market, and in relation to the competitors. Finally, one may consider the quality management an essential in performance development of processes with support of top management and contribution from all employees through engagement and focus on continuous improvement. The sequences of the proposed methodology may be applied in other industries or services [29–31].

Author Contributions: Conceptualization F.S., I.S., Methodology F.S., I.A.M., E.L., validation F.S., drafting—original draft preparation F.S., writing and review I.S., supervision I.S. All authors have read and agreed to the published version of the manuscript. Funding: This research received no external funding. Acknowledgments: This work was funded by [the European Social Fund from the Sectoral Operational Program Human Capital 2014–2020], through the Financial Agreement with the title “Scholarships for entrepreneurial education among doctoral students and postdoctoral researchers (Be Antreprenor!)”, grant no. [51680/09.07.2019—SMIS code: 124539] and APC was partially funded (8.7%) by grant no. [51680/09.07.2019—SMIS code: 124539]. Conﬂicts of Interest: The authors declare no conﬂict of interest.

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