The　influence　of　a　balanced　structure　on　the　rotation　effect　of　a　build-up　system　was　investigated　using　an　orthogonal　array,　which　can　efficiently　reduce　the　total　number　of　experiments.　Based　on　mechanical　analysis,　four　primary　influence　factors　of　the　balanced　structure　were　specified,　including　the　thickness,　material　and　shape　of　the　balanced　platen,　and　the　height　of　the　bearing　outer　ring.　Finite　element　method　(FEM)　was　employed　to　investigate　the　relationship　between　four　factors　and　the　maximum　differential　of　the　horizontal　side　force　(F-m)　on　a　force　transducer　in　the　measurement　of　different　orientations.　We　found　that　by　decreasing　the　F-m,　less　rotation　effect　of　the　build-up　system　would　be.　The　results　of　FEM　simulations　and　the　related　assumption　were　validated　by　orthogonal-array　experiments　results.　Furthermore,　FEM　simulations　for　the　effects　of　the　height　of　the　bearing　outer　ring　demonstrated　that　the　magnitude　of　F-m　initially　decreases　with　increasing　the　height　of　the　bearing　outer　ring,　but　then　levels　off.　(C)　2014　Elsevier　Ltd.　All　rights　reserved.