This thesis investigates how material handling affects assembly operators’ availability for value-adding work and develops a fact-based foundation for improving internal logistics in a make-to-order production environment. This thesis investigates how material handling affects assembly operators’ availability for value-adding work and develops a fact-based foundation for improving internal logistics in a make-to-order production environment. A case study was conducted at a manufacturing company operating with high product variation and customer-specific orders, involving quantitative time studies (frequency analysis and time measurements) and qualitative interviews. The results show that approximately 20% of the assemblers’ working time is currently occupied by material handling tasks, reducing their capacity for core assembly work. A scenario analysis indicates that reorganizing internal logistics, by assigning material handling to dedicated logistics personnel, can significantly increase production capacity and reduce non-value-added time, especially at higher production volumes.  This would, however, incur additional staffing costs and require careful planning. Interviews with assemblers reveal generally positive expectations about focusing more on assembly (e.g. improved work continuity and ergonomics), coupled with some concerns about monotony and increased supervision with a new logistics setup. Concrete improvement proposals are presented based on the findings, including implementing a dedicated line-feeding system and improving material supply routes. The study contributes quantitative data and analysis to support decision-making for internal logistics organization.  By transferring material handling away from assemblers, the company can potentially meet its increased production targets with existing assembly resources. Recommendations for further work include evaluating specific line-feeding methods and addressing human factors in the transition to ensure sustained productivity and operator satisfaction.