The Filter Fabric Division of Tamfelt Oyj manufactures filter fabrics for pulp and paper, mining and chemical industries. The division has 133 employees, of which two are production planners. One production planner is in charge of production planning of weaving and warping and the other is in charge of sewed final products. This final project work focuses on researching and developing the work of the production planner at the sewed final product unit. Production of sewed final products is small batch production where sales order is the driving force. Delivery times must be kept as short as possible, efficiency of the manufacturing capacity must be taken into account while keeping the inventory values as low as possible. The work of the production planner is made interesting by these challenges. The production planner in question co-operates with the production planner of weaving and warping, the supervisor of sewing department, and sales and purchasing departments. There are lots of challenges and changes at the working life of today. Developing one’s own work can contribute to increased job satisfaction. The hectic work schedules call for discarding all redundant and ineffective activities. This final project work tests how soft system methodology performs as a research method when the research problem in one’s own work. Soft system methodology enables analysing unspecified problems. It is even possible to change the research subject during the research work. The research problem on this final project work is defining the delivery time of sewed products. Delivery time, to be set by the production planner, is problematic due to the fact that loading of the manufacturing capacity affects the delivery capability. Delivery time can vary even for same for same product and same-sized production batches. During research, the salesmen of the unit filled in a questionnaire and some other relevant employees were interviewed. Several new problems were discovered. There was not enough time to research all of those on this final project work. However, in the future, new research can be started in order to solve the new problems that turned up. Soft system methodology as a research method is well suited for the research subject of this paper. Even the definition of the research subject was complicated to do. Soft system methodology takes into consideration all interest groups that can have an influence on the problem. The major results of this research include some developing changes to the work of the production planner. Above all, this research brings forward several new issues. For these new problems, new research can be started.