Method and device for generating sheet metal model from solid model

A sheet metal model generation device constituting a three-dimensional sheet metal CAD/CAM system, comprising:

• a solid model generation portion for generating a solid model by modeling an outer shape of a sheet metal product;
• an attribution information assigning portion for assigning entered attribution information including material and thickness of a sheet metal to the solid model;
• an open plane and bending portion designation portion for assigning entered designation information for designating an open plane and a bending portion to the solid model;
• a minimum radius of curvature obtaining portion for obtaining a minimum radius of curvature at the bending portion from the entered material and thickness of the sheet metal;
• a downsized model generation portion for generating a downsized model defined by the designated open plane and a plurality of planes that are generated by moving a plurality of planes of the solid model except the open plane inward in parallel by a distance that is a sum of the thickness of the sheet metal and the minimum radius of curvature;
• a plate portion generation portion for generating inner wall surfaces by moving a plurality of surfaces of the downsized model except for the open plane outward in parallel by a distance that is equal to the minimum radius of curvature and for generating plate portions by a projection process in which the inner wall surfaces are further moved outward in parallel by a distance that is equal to the thickness of the sheet metal;
• and
• a bending portion form generation portion for generating a bending portion form that is a fillet connecting neighboring plate portions at the bending portion designated in the solid model.

A computer program product that is installed in a computer that constitutes a three-dimensional sheet metal CAD/CAM system for making the computer execute the process for generating a sheet metal model including the steps of:

• assigning entered attribution information including material and thickness of a sheet metal to a specified solid model;
• assigning entered designation information for designating an open plane and a bending portion to the solid model;
• obtaining a minimum radius of curvature at the bending portion from the material and the thickness of the sheet metal;
• generating a downsized model defined by the designated open plane and a plurality of planes that are generated by moving a plurality of planes of the solid model except the open plane inward in parallel by a distance that is a sum of the thickness of the sheet metal and the minimum radius of curvature;
• generating inner wall surfaces by moving a plurality of surfaces of the downsized model except for the open plane outward in parallel by a distance that is equal to the minimum radius of curvature;
• generating plate portions by a projection process in which the inner wall surfaces are further moved outward in parallel by a distance that is equal to the thickness of the sheet metal;
• and
• generating a bending portion form that is a fillet connecting neighboring plate portions at the bending portion designated in the solid model.

A computer-readable storage medium storing a computer program that is installed in a computer that constitutes a three-dimensional sheet metal CAD/CAM system for making the computer execute the process for generating a sheet metal model including the steps of:

• assigning entered attribution information including material and thickness of a sheet metal to a specified solid model;
• assigning entered designation information for designating an open plane and a bending portion to the solid model;
• obtaining a minimum radius of curvature at the bending portion from the material and the thickness of the sheet metal;
• generating a downsized model defined by the designated open plane and a plurality of planes that are generated by moving a plurality of planes of the solid model except the open plane inward in parallel by a distance that is a sum of the thickness of the sheet metal and the minimum radius of curvature;
• generating inner wall surfaces by moving a plurality of surfaces of the downsized model except for the open plane outward in parallel by a distance that is equal to the minimum radius of curvature;
• generating plate portions by a projection process in which the inner wall surfaces are further moved outward in parallel by a distance that is equal to the thickness of the sheet metal;
• and
• generating a bending portion form that is a fillet connecting neighboring plate portions at the bending portion designated in the solid model.