Improvement of Efficiency and Reduction of Waste in the Precast Plate Production Process Using the Lean Construction Method

— PT. X is one of the largest Hollow Core Slab precast concrete industries in Indonesia, where to realize this vision, they continue to develop products and improve productivity performance by trying to improve service quality, production processes, and delivery of products to customers at minimal cost and on time. To achieve this goal, a Lean Construction method is need to eliminate waste and identify activities that can affect product value added. The study began with the identification of waste using a questionnaire, then analyzed by selecting the mapping tool in the Value Flow Analysis Tool and analyzing the root causes of improvement suggestions using the bizagi modeler. The results showed that the most critical wastes that affected productivity were defects (30.67%), improper processing (22.67%), and unnecessary movements (17.33%). The lead time required for the whole process is 1970.06 minutes and after repair is reduced to 1941.36 minutes by combining the printing process to making the hole joint shear connector and column coupling reducing the value added by 28.7