Infrastructure development for Gresik Smelter Project requires a substantial amount of precast spun piles. The current factory capacity of 50 piles/day does not meet the minimum project's daily needs of 80 piles/day. The current production line still shows an imbalance output on each existing work station, which caused a numerous problems such as delays, bottle necks and ineffective production flows leading to a reduction in production capacity. This study is conducted using the Line Balancing method, Process Activity Mapping and Root Cause Analysis. Using this method, you can find out the existing conditions of each work station, understand the production flows and identify waste by grouping the stages of the production process into activities that are Value Added, Non Value Added and Necessary but Non Value Added. The Takt Time value needed is 15 minutes/unit, the results of this study indicate there are 4 work stations with Station Time above Takt time and have an NVA value of 14.71%. After analyzing and improving the 5 research variables the NVA value can be reduced to 4.58% and the overall Station Time has a value under 15 minutes/unit resulting on the fulfillment the target of 80 piles/day.