The field of quality is very important for a company under current conditions. It is necessary to continuously improve the quality of provided services. Even though metallurgy is focused on production, not on providing services, even in these companies great variety of services exists, which is important to improve all the time. One of these production supporting services are the repairs. This article analyses and solves the problem of insufficient promptness of the repairs in a metallurgy company.U suvremenim uvjetima poslovanja područje kvalitete vrlo je važno za kompaniju. Neophodno je kontinuirano poboljšanje kvalitete pružanih usluga. Iako su metalurške kompanije fokusirane na proizvodnju u njima postoje velik broj različitih usluga koje je potrebno unaprjeđivati cijelo vrijeme poslovanja. Jedna od tih usluga koje podupiru proizvodnju je održavanje. U članku se analizira i daje rješenje problema nedovoljno brze reakcije službe održavanja u metalurškim kompanijama

E. Weiss

L. Mixtaj

M. Andrejkovič

R. Weiss

Z. Hajduová

English

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M. ANDREJKOVI^, Z. HAJDUOVÁ, L. MIXTAJ, E. WEISS, R. WEISSIMPROVEMENT OF PROCESSES IN METALLURGY COMPANYReceived – Prispjelo: 2010-02-05Accepted – Prihva}eno: 2010-03-25Professional Paper – Strukovni radINTRODUCTIONThe importance of quality improvement is nowadaysundeniable. Many companies understand quality in dif-ferent ways. By using methodology DMAIC in SixSigma the possibilities for improvement in the repairprocesses in the metallurgy company should be pointedout. This article is focused on the problem of length ofthe repairs for the purpose of quality improvement, be-cause the quality of provided service is being consid-ered. With respect to the size of the company, the repairsare provided by an independent department. In 2008there was an increased amount of prolongations of pro-duction downtimes resulting in creation of productionloss. For this reason in this article the possibilities ofelimination of this problem will be pointed out. In thetheoretical part of the article the focus will be on theproblem of the method six sigma and the basic tools forquality improvement.BASIC TOOLS OF IMPROVEMENTPareto´s diagram is a diagnostic tool that can be usedfor a quick and simple determination of crucial errors,items or tools. For its construction the primarily abso-lute frequency is used. Its construction results from theempirical principle 80-20. Pareto´s diagram originatesfrom the use of Pareto´s principle; however its first usein practice is attributed to J.M.Juran. Pareto´s diagramcould be understood as an extension of cause-and-effectdiagram or at least be based on it. 1.The process of data arrangement, data classificationand data tabulation helps to determine the most importantproblems that are needed to be removed. The construc-tion of Pareto´s diagram is quick and simple. The cause ofeach error is carefully examined and recorded into the fre-quency table. According to this table, the individual cate-gories are sorted decreasingly. The height of the columnis then equivalent to the frequency of given category. Atthe same time these categories are depicted on the hori-zontal axis from the most frequent to the least frequent.The proportionality of the category division is shown byso called Lorenz curve that represents cumulative relativefrequency of the given categories 2, 3.During the analysis of possibilities for improvementit is necessary to identify all impacts that influence thephenomenon, which needs to be improved. All potentialimpacts that can actually influence the monitored pro-cess it reflects.For determination of each individual cause of theproblem the most frequent method used is brainstorming.Correctly and carefully created Ishikawa diagram shouldquickly identify the causes of quality problems and sub-sequently use the correct repairs for their elimination 4.QUALITY AND ITS IMPROVEMENTGitlow, 5, defines quality as “an assessment ofproduct or service to the customers or users. “ El-Haikand Yang, 6, defines quality as the ratio of attributesthat given product has and our expectations we have forproduct or service. For this reason it is necessary to referMETALURGIJA 50 (2011) 2, 141-144 141The field of quality is very important for a company under current conditions. It is necessary to continuously im-prove the quality of provided services. Even though metallurgy is focused on production, not on providing ser-vices, even in these companies great variety of services exists, which is important to improve all the time. One ofthese production supporting services are the repairs. This article analyses and solves the problem of insufficientpromptness of the repairs in a metallurgy company.Key words: Metallurgy Company, Process Improvement, Six Sigma, RepairsUnapre|enje procesa u metalur{koj kompaniji. U suvremenim uvjetima poslovanja podru~je kvalitete vrloje va`no za kompaniju. Neophodno je kontinuirano pobolj{anje kvalitete pru`anih usluga. Iako su metalur{kekompanije fokusirane na proizvodnju u njima postoje velik broj razli~itih usluga koje je potrebno unaprje|ivati ci-jelo vrijeme poslovanja. Jedna od tih usluga koje podupiru proizvodnju je odr`avanje. U ~lanku se analizira i dajerje{enje problema nedovoljno brze reakcije slu`be odr`avanja u metalur{kim kompanijama.Klju~ne rije~i: metalur{ke kompanije, unaprje|enje procesa, six sigma, odr`avanjeISSN 0543-5846METABK 50(2) 141-144 (2011)UDC – UDK 669.14:3394:669.18:672:914:913.0=111M. Andrejkovi~, Z. Hajduová, Faculty of Business Economies, Univer-sity of Economies, Bratislava, Ko{ice, L. Mixtaj, E. Weiss, R. Weiss,BERG Faculty Technical University of Ko{ice, Slovakiato Juran’s definition of quality, which says that quality isfitness for use.In the beginning of quality improvement, the basictools for improvement are used: histogram, develop-ment diagrams, correlation diagram, Pareto diagram,Ishiwawa diagram, regulation diagram and controlsheets. The history of modern quality improvement be-gins with Shewharth regulation diagrams 5. Conse-quently, he managed to create PDCA cycle, whichgained its success later. Gradually, TQM quality im-provement system was used in practice. A newest ap-proach to quality improvement is the Six Sigma method,whose crucial aspect of success is the ability to imple-ment to the assessment economical and other character-istics besides quality 6, 7.SIX SIGMA A DESIGN FOR SIX SIGMANowadays, Six Sigma represents the most increasingmanagerial company system for improvement. One of themain principles of this methodology is reaching only „3,4PPM“. This phrase determines a situation, when for everymillion of products produced, there are only 3,4 discor-dant products (supposing normality of error distribution)8. The key aspect of success of this methodology is,contrary to its predecessors, the fact that it implementsinto the processes of project assessment not only the qual-ity assessment, but also economical and other character-istics, which are commonly used in company’s practice.Consequently, it interconnects and compares these char-acteristics, getting the synergistic effect from their utili-zation 9. By using DFSS methodology it gets evenhigher synergic effect, due to using the tools of classicmethodology Six Sigma early in the phases of projecting,designing and research. DFSS represents discontinuedconstant improvement. By this method we get ahead oftime compared to Six Sigma improvement and the costsare reduced due to the fact that the repair costs and costsof changes in design are in the early phases incomparablylower than in the phases of production or sale 6.PROCESS MAPS ANDDEVELOPMENT DIAGRAMSIn theory, it is possible to encounter the terms as pro-cess maps and development diagrams. According toseveral authors they are even synonyms. Gitlow definesdevelopment diagram as “graphical (picture) represen-tation of the flow of various operations of the processused for documentation of this process.” 5. Construc-tion of development diagram can provide important in-formation about the process that can help people con-cerned to understand, modify or improve the process.Standard symbols, introduced by American NationalStandards Institute, are used for construction of devel-opment diagrams 10.Fitzgerald et al. defines two types of development di-agrams 11:– System development diagram – graphically repre-sents the order of operations creating process– Project development diagram – represents theplan of area, usually containing the flow of workand goods, equipment distribution, storage areas,warehouses, etc.Gitlow claims the following advantages of using de-velopment diagrams opposed to using written or verbaldescriptions. According to them the functions of com-munication tool, planning tool provide a systematicoverview, define tasks, depict internal relationships,support logical correctness, facilitate breakdown re-moval and document the system 5, 12.IMPROVEMENT OF REPAIR PROCESSESIn the metallurgy company the breakdown of the de-vices occurs regularly. Such situations are not rare. Thebreakdown repair is executed either by employees of thedepartment where the breakdown occurred, if the break-down is easily reparable, or by employees of maintaindepartment. These employees are assigned to the break-downs based on the waiting list which determines the or-der of repairing each of breakdowns.At 2008 there was executed approximately the sameamount of breakdowns than in 2007. Also the averagevalue of repair did not change since 2007. On the con-trary, there was an increased amount of loss caused bybreakdown downtimes. For this reason an improvementteam was created and its task was to identify the causesof such increase of loss in downtimes and remove theircauses.For improvement of repair process it will be usedDMAIC methodology, which is a part of Six Sigma. Forthis reason each step of improvement are determined bythis methodology.DefineIn the beginning it is necessary to define all the facts.In this project of improvement we focus on the processof devices repair in the metallurgy company. The pro-cess of repair consists of several steps is presented in thefollowing map, Figure 1.The arising of a breakdown is also understood as anidentification of the breakdown by the operating person-nel. Immediately after identification of the breakdownthe personnel determines its seriousness. If the break-down is not complicated, the repair will be executed bythe operating personnel, who have the basic skills for re-pairing common breakdowns of devices. If the break-down is serious (complicated), the personnel will reportto maintain department. This report contains, besidesthe description of breakdown, its priority. Based on thisinformation, the dispatcher places the given report intothe system of breakdown reports in the appropriate or-der. In this system the repairs with a high priority arepreferred. Consequently a team is dispatched to repairthe device according to the waiting list. In some cases it142 METALURGIJA 50 (2011) 2, 141-144M. ANDREJKOVI^ et al.: IMPROVEMENT OF PROCESSES IN METALLURGY COMPANYis possible that the repair will not be executed immedi-ately, but after some time due to the occurrence of moresignificant breakdowns. The repair priority is repre-sented on a scale 1 to 5, where 1 is the highest priorityand 5 is the lowest one.MeasureThe loss can be understood in this case as every de-crease of revenues due to the production downtime.The development of loss caused by the downtime ofdevices and tools in 2008 increased approximately in30 %. The amount of this loss is represented in Figure 2.In 2008 there was reported approximately the sameamount of breakdowns as in 2007.The structure of every breakdown according to theirrepair priority is represented in the following graph. InFigure 3. can be seen that in 2007 there where 30 % ofbreakdowns with the highest priority. In 2008 this cate-gory represents approximately 55 %.Also the average time, which elapsed from reportingthe error till the correction, was found out. By compari-son was found out that errors identified as critical havebeen repaired in average of next 3 hours. Errors identi-fied as the least serious were corrected in average ofnearly 1,5 days (32,56 hours - non-stop operation).AnalyzeThe observed increase in breakdowns with the high-est priority is suspicious. For this reason we decided toevaluate retrospectively, if the degree of assigned prior-ity was appropriate. There were created three groups,i.e. a group where the repair priority was assigned right.The second group represents breakdowns, whose repairpriority was undervalued, i.e. the priority assignmentwas lower than it should have been. The third group ismade of breakdowns, whose repair priority was overval-ued, so they should have had a lower priority than onerecorded in the breakdown system. The ratio of thosegroups is in the following graph. We can see that in 2008there are up to 50 % of breakdowns that were overval-ued, Figure 4.Based on the results, it was found out that the prob-lem of increase the loss from failures is caused by over-valuing repair priority. Thus it is necessary to create asystem of assessment of breakdown repair priority thatwould be more objective.For these groups the finding of the average length of re-pair has been held again. It was found out, that mistakes,whose priority of repair was overestimated, had signifi-cantly lower average value than those ones who were prop-erly assessed in terms of their priorities. This means thatthe corrections could have been made also later.ImproveFor improvement of this condition it is necessary, aswe wrote in the previous part, to improve the system ofpriority assignment of breakdown repair. Until now thissystem was based solely upon objective assessment. Incase we wanted to improve the current situation withoutMETALURGIJA 50 (2011) 2, 141-144 143M. ANDREJKOVI^ et al.: IMPROVEMENT OF PROCESSES IN METALLURGY COMPANYFigure 1 Process map of repairsFigure 2 Loss development caused by breakdownsFigure 3 Structure of reported breakdowns with respectto their importance in years 2007 and 2008Figure 4 Assessment of suitability of the priority of repairsthe change of the assessment system; we would need toincrease the amount of employees of repair department.That would represent additional financial costs. Theproduction loss would be reduced at the expense of addi-tional costs. During the analysis of this solution wefound out that the benefit of such a solution would beonly negligible.The given situation is caused by the changeability ofassessment. Employees are assessed based on their pro-ductivity and if the devices are stopped it resulted withdecreasing of production. Each department has definedproduction goals, based on above mentioned assess-ment. For this reason each operating personnel tries toacquire the repair as soon as possible resulting in over-valuing the repair priority.Thus the only way is the change of priority assess-ment system. To make the assessment objective, it shouldbe executed by an independent person, who would onlyevaluate the priority of these breakdowns. Due to the un-interrupted working time, such a person would have towork non-stop, so for a 3 shift working time it would benecessary to have at least 10 people available during themonth. If this activity was executed by a repair dis-patcher, his working load would significantly increase,while the time for transport in the area is long due to thelimited speed of vehicles, local conditions and the size ofthe area. The transport from the center of the factory toany point would last up to 30 minutes. For this reason thisstep would be financially demanding.For determination of an objective priority assessmentwe decided to create a unified assessment questionnaire,in which the personnel will, based on the given questions,determine the degree of priority for breakdown repair. Inthis questionnaire the personnel determines the prioritybased on the following questions:1. Does the breakdown cause stop of production?2. Does the breakdown endanger the safety of em-ployees?3. How many employees are affected by this break-down?4. What is the estimated value of a daily loss?Based on the answers is assigned the repair priorityand the waiting list for repairs is created.ControlTo verify that the situation was remedied, there wasused an indicator for false repair assessment. This indi-cator will be monitored for individual weeks and indi-vidual manufactories. This way it would be possible toidentify potential manipulations with the assessmentsystem. Consequently, the ratio of false repair assess-ments will be monitored by the p-diagram. The volumeof the loss from the repairs has decreased about 15 % incomparison to the previous year after introduction ofnew steps.CONCLUSIONIn this article we pointed the possibility of utilizationof Six Sigma method in the metallurgy company. Spe-cifically we applied methodology DMAIC for improve-ment of repair processes. The repairs are executed con-stantly in this company, thus their coordination is veryimportant. For this reason the company can this way in-crease their quality level of repair services, where speedis one of the aspects of quality. The level of quality wasconsidered to be already high in present time.The use of DMAIC algorithm for the case of servicesis unusual. Adaption of this procedure to the followingconditions is considered to be the greatest contributionof this article. These adjustments can also be used forfurther improvement projects that will be dealing withquality of service. Therefore the scientific contributionof this article is in the adaptation of the original method-ology DMAIC, which was primarily designed for theneeds of improving product quality.REFERENCES1 W.E. Deming, The new Economics for Industry. MIT, Cen-ter for Advanced Engineering Study, Massachusetts, 1993,p 248.2 M. Tká~, [tatistické riadenie kvality, Ekonóm, Bratislava,2001, p 312.3 T. Ryan et al., Statistical Methods for Quality Improvement.John Wiley & Sons, New York, 1988.4 K. Ishikawa, Guide to Quality Control, Asian ProductivityOrganization, Tokyo, 1983, p 226.5 H. Gitlow et al., Tools and Methods for the Improvement ofQuality, Irwin, Boston, 1989, p 605.6 B. El-Haik – K. Yang, Design for Six Sigma: A RoadmapFor Product Development, McGraw Hill, New York, 2003,p 624.7 I. Liberko, J. Na{~áková, L. 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