Offline Blank Machine Selection
For the Offline Blank process, aPriori selects the feasible machine with the lowest overhead rate, where overhead rate is the sum of the machine properties Direct Overhead Rate and Indirect Overhead Rate.
If there are multiple lowest-overhead, feasible machines, aPriori chooses the lowest-overhead, feasible machine with the smallest Shut Height.
aPriori selects only from preferred machines, if there is a feasible preferred machine and the cost model variable usePreferredMachines is set to true (the default in starting point VPEs). If there is no feasible preferred machine or if the cost model variable usePreferredMachines is set to false, aPriori selects from all machines. A machine is preferred if the machine property isPreferred (typically displayed as Is Preferred) is true.
A machine is feasible if it can accommodate all the following:
• Stock dimensions: stock length and width (see
Material Stock Selection for Offline Blanking Routings) must be less than the machine properties
Press Table Length and
Press Table Width, respectively.
• Required Press Force: the required press force must be less than the machine property
Press Force. The required press force depends on the material shear strength and on the blank perimeter and thickness. See
Required Press Force for Offline Blanking for more information.
Required Press Force for Offline Blanking
Required press force for a given part is calculated as follows:
Required Press Force = Required Shear Force + Required Shear Holding Force
Required press force is the sum of the following:
• Required shear force (see formula)
• Required Shear holding force (see formula)
Required Shear Force = Blank Perimeter * Blank Thickness *
Material Shear Strength
Required Shear force is the product of the following:
• Blank perimeter
• Blank thickness
• Material yield strength (the value of the material property Tensile Yield Strength)
Required Shear Holding Force = Required Shear Force * 0.5
Required shear holding force is assumed to be half the required shear force (see formula above).