System, method, and device for designing a die to stamp metal parts to an exact final dimension
View Patent ↗A system and method for designing stamping tools that produce parts of desired dimensions. The system and method compensate for post stamping deviations from the desired dimensions in the shape of the tools used to produce the parts. The compensated tools result in nearly ideal parts.
1. A computer implemented method of designing a tool used to form a part, the method comprising:
receiving final desired dimensions of the part;
simulating the tool used to form the part with a finite element model of the tool;
simulating the part, the simulation including residual internal forces at an intermediate stage of the formation of the part;
identifying one or more mesh node locations on the simulated part that correspond to one or more mesh node locations on the simulated tool respectively, and thereafter
modifying the finite element model of the tool to account for the residual internal forces at the intermediate stage of the part such that the residual internal forces deform the part to the final desired dimensions, thereby compensating for springback deviation resulting from any of the residual internal forces; wherein the compensation is initially applied in a normal direction to each element of one or more of the finite element models, and wherein the compensation is subsequently applied only in a stroke direction if the initial compensation is unsatisfactory.
2. The method of claim 1 wherein modifying the tool comprises projecting the one or more mesh node locations from the mesh of the simulated part to the mesh of the simulated tool.
3. The method of claim 1 wherein a scale factor is applied when modifying the tool.
4. The method of claim 1 wherein there are two or more iterations of the formation of the part.
5. The method of claim 1 wherein the method of designing the tool further comprises automatically detecting undercutting as part of the computer simulation of the tool and the part, and eliminating any detected undercutting from the tool.
6. The method of claim 1 , further comprising computing a vector dot product of an element normal vector of each element with the stroke direction.
7. The method of claim 6 , wherein the initial compensation is deemed unsatisfactory if any of the vector dot products evaluates to a negative sign, and wherein the initial compensation is discarded if deemed unsatisfactory.
8. A computer implemented method of designing a tool used to form a part, the method comprising:
(a) receiving, from a user, dimensions of the part after any potential springback;
(b) creating a finite element model of the tool;
(c) creating a finite element model of a part made with the tool and saving the finite element model of the part as a first reference geometry finite element model file;
(d) simulating the springback that occurs when the part is made with the tool;
(e) automatically compensating for the springback by directly modifying the finite element model of the tool;
(f) simulating the part with the compensated tool;
(g) detecting undercutting as part of the simulation by computing a vector dot product of an element normal vector of each element of the finite element model of the tool and/or part with the stroke direction of the finite element mode of the took; and
(h) saving the finite element model of the compensated part as a second reference geometry finite element model file.
9. The method of claim 8 , further comprising:
(i) repeating steps (e)-(h) one or more times in order to refine the compensation and
minimize or eliminate the springback deviation of the part, and for each repetition updating the second reference geometry finite element model file to reflect accumulated modifications resulting from each repetition performed.