Process Costing
Process costing proceeds in two passes: a right-to-left pass (the yield pass) and a left-to-right pass.
In the first pass, the yield pass, the cost engine visits each node in the process routing. For each node, the cost engine does the following:
• If the node’s
selectMachineAfterOpAssignment attribute is non-null (and so machine selection was not performed during Stage 1), the cost engine performs machine selection as described in step 2 of
Feasibility and Machine Selection.
• The cost engine evaluates only the following formulas (if present) in each node’s process taxonomy module:
o finishMass
o stripNestingPitch
o roughLength
o numPartsPerSheet
o utilizationWithAddendum
o scrapMass
o roughMass
o utilizationWithoutAddendum
o utilization
o materialYield
o goodPartYield
This pass proceeds right to left; that is, nodes later in the routing are visited first.
In the second pass, the cost engine again visits each node in the process routing, and evaluates the rest of the formulas in each node’s process taxonomy module. This pass proceeds left to right.
Once all processes taxonomy modules have been fully evaluated, the cost engine evaluates the Site Cost Model taxonomy module, which typically aggregates the results of the individual process taxonomy modules, producing the fully-burdened, per-part cost as well as the aggregate costs presented in aPriori’s Cost Summary tab.
For process groups that have templates with zero-or-more nodes, there is an additional step immediately before the yield pass. The cost engine evaluates special modules, if present, in order to expand these nodes into zero or more individual operations.