This research of study was made Presteel Oy. The aim of the study was to find out how to develop the process of production and improve it by means of Lean philosophy methods. The theory part of this study considered to develop methods for the manufacturing process based on the Lean philosophy. The experimental part of the study concentrated on the process of production. The main result of the study was that the importance of employers and know-how in the improvement of production quality is significant. In addition versatile know- how generates flexibility in the production and improves internal customer service thinking. The efficiency of the production could be improved by utilizing the Lean methods. The best results is new layout in the production.