Hello,
Have you searched the forum for this? I was able find similar thread.
community.dynamics.com/.../using-routing-link-codes-in-mrp-planning-in-microsoft-dynamics-nav.aspx
community.dynamics.com/.../component-flushing-methods-in-microsoft-dynamics-nav.aspx
community.dynamics.com/.../using-low-level-codes-in-microsoft-dynamics-nav.aspx