During the past decades, there have been an acceleration of customers’ needs of customized products. This have pressured many companies in offering customized products in order to reach customer satisfaction and keep growing and expanding their market share. Nowadays the competitive pressure between companies with the same product segment is increasing and the market requirements are changing rapidly. To handle this competition, many manufacturing companies are focusing on mass customized production. However, mass customization has been a topic of interest for many researchers. The focus has been in studying and understanding the complexity and the constrains that a company encounter when dealing with mass customized production in mostly the automotive industry. One of the constrains that have been less highlighted by researchers were the effects that mass customized production has on the output variation of production lines. Therefore, the purpose of this thesis is to investigate how to minimize output variations in mass customized production within assembly lines. To do that the researchers focused on studying the output variation in whitegoods industry instead of the automotive industry that captures most of the existing research. The study includes two main research questions. The first question was to identify the factors that affect the output variation in mass customized production. While the second question was to identify applicable solutions that can be used to stabilize the output. To ensure the reliability and validity of the research findings, the researchers used multiple case study combined with literature reviews. To answer the research questions several data collection techniques were used in the multiple case study conducted on two lines. Those data collection techniques were participating observations, document reviews, a semi-structured interview and many conversations with the affected persons. The findings from the case study for research question one showed consistency with the theories described in the theoretical background. This was evident because similar problems when it comes to output variations were defined in the theories. One problem was about the simplification of assembly line balancing problem that was evident in both case studies. This was an effect of the missing product family classification which created a high output variation because of the use of only one line balancing for all product variants. Another problem identified included functionality problems of machines because of performing wrong assembly or the use of the wrong component. There was as well the problem of missing or delayed components which was an effect of the lack of structure in the material picking and the deliveries performed for both lines. A combination of those factors created the experienced output variation on both lines. To deal with those problems and minimize the output variation, a solution approach was defined in the second research question. This approach was created together with the case company with the help of the theoretical background and it presents several steps to follow when attacking and resolving similar problems as presented above. The most important conclusion of this thesis is that, when dealing with output variation in mass customized production where people are performing the assembly, it is essential to provide the right conditions for them to ensure that they have the right knowledge base to perform the requested assembly.

Purpose: The problem with the construction industry is inefficient material handling that creates waste in form of unnecessary activities that do not increase the value of the product. The construction industry is accused of production delays, exceedance of budget and difficulties in having a high quality. The aim is to find opportunities for improvements to make the material handling on a construction site at deliveries, material storage and material transports more efficient. Method: A qualitative case study of an organisation was carried out to achieve the aim of the report. The methods used in this study was unstructured observations, semi structured interviews and document analysis. Findings: A checklist for material handling based on the theories of Muda, 5S and JIT within Lean has been designed as an improvement and is intended to be used at a construction site. The checklist is based on the collected empirical study and consists of three parts, based on the issues of the study, which were deliveries, material storage and material transport. The purpose of the checklist is to improve the material handling at a construction site by identifying and eliminating wastes in terms of waiting, transport, storage and defects. Implications: By using the checklist, follow the delivery plan, improve the construction site plan and improve the contract between the suppliers and the company that have been concluded from the study result, waste in deliveries, material storage and material transport can be reduced. The recommendation is to follow the suggestions for improvement to make the material handling more efficient and reduce waste on a construction site. Limitations: The limitations that have been made in the study is to identify the wastes in the material handling moments that have been used in the study during the different material handling processes. The communication between workers, in what way the company plans their work activities, work environment and quality of work is not included in the study. / Syfte: Problemet i byggbranschen är ineffektiv materialhantering som skapar slöserier av resurser i form av onödiga aktiviteter som inte ökar värdet på slutprodukten. Byggnadssektorn anklagas för förseningar, budgetöverskridande och svårigheter att hålla en hög kvalitet. Målet är att hitta förbättringsmöjligheter för att effektivisera materialhantering på en byggarbetsplats vid leveransmottagning, materiallagring och materialförflyttning. Metod: För att uppnå studiens mål har en kvalitativ fallstudie av en organisation genomförts. De datainsamlingsmetoder som har använts är strukturerade observationer, semistrukturerade intervjuer och dokumentanalys. Resultat: En checklista för materialhantering baserad på teorierna Muda, 5S och JIT inom Lean har utformats som ett förbättringsförslag och är tänkt att användas på en byggarbetsplats. Checklistan är gjord utifrån studiens insamlade empiri och består av tre delar som utgår från studiens frågeställningar leveransmottagning, materiallagring och materialförflyttningen. Syftet med checklistan är att effektivisera materialhanteringen på en byggarbetsplats genom att identifiera och eliminera slöserierna i form av väntan, transport, lager och defekter. Konsekvenser: Genom att använda checklistan, följa leveransplanen, uppdatera APD-planen och förbättra kontraktet mellan leverantörer och företag som har framtagits i studiens resultat kan slöserier inom leveransmottagning, materiallagring och materialförflyttning minskas. Rekommendationerna blir att följa förbättringsförslagen för att effektivisera materialhanteringen och reducera slöserier på byggarbetsplatsen. Begränsningar: De avgränsningar som har gjorts i studien är att identifiera de valda slöserier inom Muda som behandlades i studien under olika materialhanteringsmoment. Kommunikationen mellan arbetarna, på vilket sätt företaget jobbar med att planera olika arbetsmoment, arbetsmiljö och arbetskvalitet ingår inte studien.