We all know weld or knit lines can be a problem for plastics part, but how far do you go to investigate how significant they will be in Moldflow? In this talk we will review tools and workflows in simulation that analysts can use to help investigate and reduce/eliminate product performance issues related to weld lines. The importance of mesh, material and processing factors, results interpretation, custom plots, API scripts & Helius PFA/Advanced Materials Exchange workflows will all be presented in the hopes that users go beyond just looking at weld line or weld surface plots for more informed decision making and risk reduction.