With increases in the use of multi-layered materials in the aerospace industry to reduce weight while still meeting strength requirements, the study of inter-layer burr formation in drilling of a multi-layered material becomes more important. Inter-layer gap formation due to material bending by drilling thrust force has significant effect on inter-layer burr formation. A finite element model for inter-layer gap formation in a multi-layered material was proposed. A gap formation was initiated by initial difference in elastic bending of layers and developed by plastic deformation of the first layer.
