Prediction of Tooltip Error in Cnc Milling Machine By Using Variation Simulation Analysis (Vsa) and Finite Element Analysis (Fea)
The main objective of this research work is to study the tolerance analysis combined with Variation Simulation
Analysis (VSA) and Finite Element Analysis(FEA) used to predict the position error of tooltip in CNC Milling machine
(MT-250). For a given CNC machine 3D model is created then Geometric Dimensioning and Tolerancing model (GD and T)
is applied to CNC mill structure. GD and T model is applied individually to each and every sub-component of milling
machine such as base, lower table, working table, upper body, head. Variation Simulation Analysis (VSA) is used to predict
the amounts and causes of variation. In order to find the tooltip displacement in given working volume kinematic analysis is
combined with VSA analysis studied. In addition to above FEA analysis is also done on given milling machine. In static
analysis deflection due to self-weight and in dynamic analysis (modal analysis) deflection at each node due to vibration are
considered. Final result shows that the highest possible error point in the given work volume as well as roll of different subcomponent
on position error of tooltip was indentified. As per result the highest contributor to the tooltip error is lower table
which is assembled to the base then upper body and head. Finally working table having major effect where as base and
workpiece plays a minor role in position error.
Keywords- GD and T, VSA, FEA, Tolerance, kinematic analysis and Tooltip deviation..