Machine Selection
aPriori selects the default machine if it is feasible; otherwise, aPriori selects the feasible machine with the lowest overhead (specified by the sum of the machine properties Direct Overhead Rate and Indirect Overhead Rate).
The machine feasibility rules require that the machine can accommodate the following:
Die Length and Width
Die must fit on the press table with a margin specified by the cost model variables pressTableWidthMargin and pressTableLengthMargin. Table dimensions are specified by the machine properties Press Table Width and Press Table Length. Die width is the sum of the following:
• Coil width * station count (see
Material Cost and Utilization)
• Coil width (additional coil width to allow for stamping area)
• Die block width allowance (specified in the lookup table toolingComponentAttributes, 609.6mm in aPriori starting point VPEs)
Similarly, die length is the sum of the following:
• Coil pitch * station count (see
Material Cost and Utilization)
• Coil pitch (additional coil pitch to allow for stamping area)
• Die block length allowance (specified in the lookup table toolingComponentAttributes, 254mm in aPriori starting point VPEs)
Die Height
Die height must fit within the machine Shut Height with a margin (on both top and bottom) specified in the lookup table toolingComponentAttributes for minParallelHeight (76.2mm in aPriori starting point VPEs). Die height is the sum of the following:
• 2 * die shoe thickness. Die show thickness depends on coil width (see
Tooling Calculation), and is specified in the lookup table
toolingComponentAttributes as one of the following:
o dieShoeThicknessLarge (101.6mm in aPriori starting point VPEs) if coil width is greater than cost model variable upperCoilWidthThreshold
o dieShoeThicknessMedium (88.9mm in aPriori starting point VPEs) if coil width is between the cost model variables upperCoilWidthThreshold and lowerCoilWidthThreshold)
o dieShoeThicknessSmall (76.2mm in aPriori starting point VPEs) if coil width is less than or equal to lowerCoilWidthThreshold.
• Cost model variable
defaultPartSpacing (25.4mm in aPriori starting point VPEs) plus 75% of part height (specified by the PSO
Height of the finished part’s Bounding Box)
• Cost model variable defaultDieSpacing (101.6mm in aPriori starting point VPEs)
Required Press Force
Required press force must not exceed the machine property Press Force (which is specified in kilonewtons). Required press force in newtons is the sum of the following:
• Required shear force, which is the product of the following:
o Blank perimeter (specified by the PSO
Perimeter of flat pattern blank) plus total hole perimeter (specified by the PSO
Total Perimeter of Holes)
o Blank thickness (specified by the PSO
Thickness of Part)
o Material shear strength (specified by the material property Shear Strength).
• Required bending force, which is the product of the following:
o Total bend length (specified by the PSO
Total Length of Bends)
o Blank thickness (specified by the PSO
Thickness of Part)
o Material property Ultimate Tensile Strength
• Required drawing force, which is the product of the following:
o Total form perimeter (specified by the PSO
Total Perimeter of Forms)
o Blank thickness (specified by the PSO
Thickness of Part)
o Material property Tensile Yield Strength
• Required total holding force, which is the sum of the following:
o 5% of required shear force
o 10% of Required bending force
o 30% of Required drawing force