[en] Today's industrial companies are faced with increasing complexity due to rapid technological developments, shorter product life cycles and globalisation. In this new and changing environment, companies must be able to quickly adapt, and many have had to migrate from a make-to-stock (MTS) environment to a make-to-order (MTO) environment. According to some studies (Chakravorty, 2001; Darlington et al., 2015; Modi et al., 2019; Riezebos et al., 2003), the theory of constraints (TOC) and its drum-buffer-rope (DBR) production planning and control system (PPCS) has been shown to be a valid methodology for responding to the problems of MTO environments. However, other studies (Atwater & Chakravorty, 2002; Pretorius, 2014; Wu & Yeh, 2006) have detected difficulties in implementing TOC-DBR. To overcome some of these issues, Lizarralde (2020) has developed a systematic decision-making process to apply DBR in MTO scenarios, proposing a change in the first two steps of the TOC methodology. This doctoral thesis was born with the aim of completing the systematic process of implementing the TOC-DBR methodology in MTO environments. In the theoretical framework, no article has investigated the systematisation of the third step of the TOC methodology. After a systematic literature review of the TOC-DBR methodology, it becomes evident that two factors, protective capacity and protective inventory, play a key role in absorbing system variability when implementing the third step of the methodology. Furthermore, to design the systematic implementation process of the third step, a specific literature review has been conducted in the field of tactical and strategic processes to integrate the strategic vision of the organisation into the TOC-DBR operational model. As a result, the researcher has developed three novel implementation phases to apply to MTO environments: 1) Model configuration phase: Through the designed steps, a manager designs a solution for the implementation of the third step of the TOC-DBR methodology. 2) Operational model phase: A manager follows specific steps to control order entry and manage both bottleneck (BN) and shipping time buffers and capacity buffers. With these steps, the manager ensures that the system remains stable in the defined time interval. 3) Tactical Sales and Operations (S&OP) phase: Steps are taken to reconcile the organisation's strategic plans with the execution phase. For this purpose and based on the continuous improvement process of the demand-driven adaptive enterprise (DDAE) model, the deviations of the operational phase are analysed. Taking into account these deviations, it is necessary to return to the configuration phase of the model and re-analyse the design of the solution and propose improvements to ensure that the system remains stable over time and to guarantee operational performance. These three phases have been included in a systematic implementation process, which enables the implementation of the third step of Goldratt's TOC methodology. This systematic process has been developed through four case studies (CSs) based on two companies in the Basque Country with different MTO scenarios. For this purpose, this thesis employs a sequential mixed methods approach using a holistic, multiple-CS approach. This design is a research approach that involves the use of qualitative and quantitative methods in sequential order. As a result of our research, four theoretical contributions have been made. For example, some of the contributions has been to analyse the impact of protective capacity on the application of step three of TOC-DBR in MTS and MTO environments or defining the level of protective capacity as a strategic factor or decision for organisations operating in MTO environments. On the other hand, a practical contribution has also been made that integrate the monitoring and management of the level of protective capacity in the TOCDBR methodology via the concept of capacity buffer used in the DDAE model. Interestingly, another unexpected practical contribution has also emerged throughout the research process. This key contribution relates to the need to integrate the operational phase with the strategic phase in the systematic process and is presented as follows: Creation and description of the systematic process of implementing the third step of the TOC-DBR methodology for MTO environments integrating the S&OP process via the DDAE model. This integration combines two complementary methodologies: the TOC-DBR model and DDAE model.

[eu] Gaurko enpresa industrialek konplexutasun handiagoari aurre egin behar diote, garapen teknologiko azkar, produktuen bizitza ziklo labur eta globalizazioaren eraginez. Ingurune berri eta aldakor horretan, enpresak uneoro egokitzeko gaitasuna izan behar dute, eta askok biltegiratze ekoizpeneko ingurunetik (MTS) eskaerape ekoizpeneko inguruneetara (MTO) aldatu behar izan dute. Zenbait ikerketen arabera (Chakravorty, 2001; Darlington et al., 2015; Modi et al., 2019; Riezebos et al., 2003), mugen teoria (TOC) eta bere ekoizpenaren plangintza eta control sistema (PPCS), drum-buffer-rope (DBR), MTO inguruneen arazoei erantzuteko baliozko metodologia dela frogatu dute. Hala ere, beste ikerketa batzuek (Atwater & Chakravorty, 2002; Pretorius, 2014; Wu & Yeh, 2006) zailtasunak atzeman dituzte TOCDBR metodologia ezartzerako orduan. Arazo horietako batzuk gainditzeko Lizarraldek (2020) DBR MTO inguruneetan aplikatzeko prozesu sistematiko bat garatu du non TOC metodologiaren lehen bi urratsetan aldaketak proposatu diren. Doktorego tesi hau MTO inguruneetan TOC-DBR metodologia inplementatzeko prozesu sistematikoa osatzeko helburuarekin jaio da. Marko teorikoan ez da TOC metodologiaren hirugarren urratsaren inplementazio sistematikoa ikertu duen artikulurik aurkitu. TOC-DBR metodologiaren berrikuspen bibliografiko sistematikoa egin ondoren, argi geratzen da bi faktorek, babes ahalmenak eta babes inbentarioak, funtsezko eginkizuna betetzen dutela sistemaren aldakortasuna xurgatzeko, metodologiaren hirugarren urratsa ezartzerakoan. Horrez gain, hirugarren urratsaren inplementazio prozesu sistematikoa diseinatzeko, prozesu taktiko eta estrategikoen alorrean berrikuspen bibliografiko espezifikoa egin da, erakundearen ikuspegi estrategikoa TOC-DBR funtzionamendu ereduan txertatzeko. Ondorioz, ikertzaileak hiru inplementazio fase berri garatu ditu MTO inguruneetan aplikatzeko: 1) Ereduaren konfigurazio fasea: Definitutako urratsen bidez, kudeatzaile batek TOC-DBR metodologiaren hirugarren urratsa ezartzeko irtenbidea diseinatzen du. 2) Eredu operatiboaren fasea: Kudeatzaile batek urrats zehatzak jarraitzen ditu eskaeren sarrerak kontrolatzeko eta botila lepo (BN) eta bidalketa buffer denborak eta baita gaitasun bufferrak kudeatzeko. Urrats hauekin, kudeatzaileak sistema egonkor mantentzen dela ziurtatzen du zehaztutako denbora tartean. 3) Salmenta eta operazio taktiko (S&OP) fasea: Erakundearen plan estrategikoak exekuzio fasearekin bateratzeko urratsak definitu dira. Horretarako, eskariaren arabera lerrokaturiko negozio eredu moldagarriaren (DDAE) etengabeko hobekuntza prozesuan oinarrituta, fase operatiboaren desbideraketak aztertzen dira. Desbideratze horiek kontuan hartuta, beharrezkoa da ereduaren konfigurazio fasera itzuli eta irtenbidearen diseinua berriro aztertu eta hobekuntzak proposatzea, sistema denboran egonkor mantendu dadin eta funtzionamendu errendimendu egokia bermatu dezan. Hiru fase hauek inplementazio prozesu sistematiko batean gehitu dira eta, horri esker, Goldratten TOC metodologiaren hirugarren urratsa praktikan jarri da. Prozesu sistematiko hau, MTO ingurune desberdinak dituzten Euskadiko bi enpresatan oinarritutako lau kasu azterketen (CS) bidez garatu da. Horretarako, tesi honek método misto sekuentzialaren ikuspegia erabiltzen du CS anitzen ikuspegi holistikoa erabiliz. Diseinu hau, metodo kualitatibo eta kuantitatiboak ordena sekuentzialean erabiltzen dituen ikerketa ikuspegia da. Ikerketaren ondorioz, lau ekarpen teoriko egin dira, adibidez, MTS eta MTO inguruneetan TOC-DBR-ren hirugarren urratsa ezartzean babes ahalmenaren inpaktuaren analisia edo babes ahalmenaren definizioa faktore estrategiko bezala MTO inguruneetan jarduten duten erakundeentzat. Bestalde, TOC-DBR metodologian babes ahalmen mailaren jarraipena eta kudeaketa integratzen duten ekarpen praktiko bat ere egin da, DDAE ereduan erabiltzen den gaitasun buffer kontzeptuaren bidez. Interesgarria da ikerketa prozesuan zehar ustekabeko beste ekarpen praktiko bat ere agertu dela. Funtsezko ekarpen praktiko honek prozesu sistematikoan fase operatiboa eta fase estrategikoa integratzeko beharrari egiten dio erreferentzia eta jarraian aurkezten da: DDAE ereduaren bidez S&OP prozesua integratzen duten MTO inguruneetarako TOCDBR metodologiaren hirugarren urratsaren inplementazio-prozesu sistematikoa sortzea eta deskribatzea. Integrazio honek bi metodologia osagarri uztartzen ditu: TOCDBR eredua eta DDAE eredua.