Lean production has become a widespread production system to address the need of being more productive. Since three decades ago that some big automotive manufacturers started to adopt lean, many SME’s has adopt it and enjoy the outcomes. Literature have investigated the successful implementation of lean in these organizations, yet, very few papers have addressed the challenges toward adopting lean.

In this thesis research a plastic package manufacturer is chosen as the case of study to implement some initiatives of lean production and study the challenges and outcomes of lean adoption. The efforts during the making the changes were focused on adopting the SMED and Root-Cause Analysis techniques, and also to reduce defect rate in one of the products.

The findings indicate before any effort to implement lean production techniques, some social issues must be considered to reduce the risk of failure. The Rosti AB case indicated that promoting motivation among operators and resolving mistrust between managers and operators is essential to encourage them to participate in improvement changes.

In order to promote motivation and eliminate mistrust to encourage operators to participate in improvement changes it is necessary to empower them in decision makings in improvement implementations.