The　thin-walled　part　is　extensively　applied　to　the　plentiful　industries　including　automotive　and　aerospace,　which　inevitably　suffer　the　force-induced　deformation　during　milling　due　to　their　low　stiffness　characteristics.　This　leads　to　a　reduction　in　machining　accuracy　and　even　results　in　component　damage.　To　address　the　issue,　a　deformation　prediction　model　without　iteration　considering　the　IUCT　(Instantaneous　Undeformed　Chip　Thickness)　update　is　proposed.　First,　based　on　the　stiffness　equation,　the　node　division　method　is　applied　to　tool-workpiece　deformation　model,　in　which　solution　scale　is　reduced　to　improve　the　model　efficiency.　Then,　to　establish　an　iterative　model　for　the　actual　deformation,　the　coupling　effect　among　the　milling　force,　radial　cutting　depth,　IUCT　and　deformation　need　to　be　considered　into　the　prediction　model.　Next,　a　non-iterative　deformation　prediction　method　is　proposed,　in　which　the　milling　force　model　is　reconstructed　to　obtain　the　generalized　deformation　formula　of　the　closed-form　solution.　Moreover,　the　impact　of　the　IUCT　update　on　both　milling　force　and　deformation　is　analyzed.　Finally,　the　correctness　of　the　proposed　method　is　verified　through　flank　milling　experiments,　which　shows　the　average　accuracy　of　deformation　can　reach　97.5　%.　The　accuracy　and　efficiency　of　the　proposed　method　are　verified　in　different　scenarios　by　comparison　with　other　methods.　©　2025