Material Cost and Utilization

Final Yield = Final Output Volume / Input Volume

Final yield affects material, labor, and overhead costs per part. It is the fraction of parts created by this process in the current production scenario that will survive as good parts once any secondary processes are completed. That is, final yield is the fraction of parts created by this process that are not discarded as scrap parts, either by this process or by a downstream process. Final yield depends on the following:

• Final Output Volume (product of the annual volume and number of production years, specified in the Production Scenario screen of the Cost Guide)

• Input volume (see the formula below). This is the total number of parts produced by this process, including all parts discarded as scrap from this process or downstream processes.

Input Volume = Local Output Volume + Number of Scrap Parts for This Process

Input volume is the total number of parts produced by this process in the current scenario, including all parts discarded as scrap from this process or downstream processes. It is the sum of the following:

• Local output volume (see the formula below). This is the number of parts produced by this process, excluding parts discarded as scrap by this process, but including parts that are discarded as scrap by downstream processes.

• Number of scrap parts for this process (see the formula below)

Local Output Volume = Final Output Volume + Number of Scrap Parts Downstream

Local output volume is the number of parts produced by this process in the current scenario, excluding parts discarded as scrap by this process, but including parts that are discarded as scrap by downstream processes. It is the sum of the following:

• Final output volume (product of volume and number of production years, specified in the Production Scenario screen of the Cost Guide)

• Number of Scrap Parts Downstream. This is the number of parts discarded as scrap by downstream processes.

Number of Scrap Parts for This Process =

(Local Output Volume / Good Part Yield) – Local Output Volume

Number of scrap parts for this process is the number of parts produced by this process in the current scenario that are discarded as scrap by this process, before any downstream process is performed on them. It is a function of the following:

• Local output volume (see the formula above)

• Good part yield (specified by the machine property Good Part Yield). This is the fraction of parts produced by this process that are not discarded as scrap by this process but may be discarded as scrap by downstream processes.

Material Cost = ((Material Cost Per Mass * Custom Cut Multiplier * Part Mass) / Utilization) / Final Yield

aPriori calculates the cost for material based on the following factors:

• Material cost per mass (determined from Material Stock if stock is selected; otherwise, from Material Composition in the Material Selection dialog)

• Part mass (product of part volume and material density)

• Custom cost multiplier (specified by the cost model variable customCutMultiplier)

• Utilization (see formula below)

• Final Yield (see formula above)

Utilization = Part Mass / (Blank Mass / Number of Concurrent Patrs)

Utilization depends on the following:

• Part mass (product of part volume and material density—see the Part Volume PSO and the Density property in the Materials table)

• Blank mass (see formula below)

• Number of concurrent parts (1 by default in aPriori starting point VPEs, but see Number of Parts Stamped Concurrently)

Blank Mass = Coil Pitch * Coil Width * Blank Thickness * Material Density

Blank mass is the product of the following:

• Coil pitch (calculated using the formula below or specified by a PSO—see Coil Pitch)

• Coil Width (calculated using the formula below or specified by a PSO—see Coil Width)

• Blank thickness (specified by the PSO Thickness of Part)

• Material density (specified by the Density property in the Materials table)

Coil Pitch = Blank SER Dimension + (2 * Addendum) + (2 * Edge Margin) + Center Carrier Strip Margin

Coil pitch depends on the following:

• Blank SER dimension (specified by the PSO Width of the flat pattern’s Smallest Enclosing Rectangle if the blank XY orientation is widthwise--the default in aPriori starting point VPEs; specified by the PSO Length if the blank XY orientation is lengthwise. The XY orientation is specified by the cost model variable defaultXyOrientation or the PSO Blank XY Orientation within Part Strip)

• Addendum (0 by default or specified by the PSO Width of Addendum Added to Blank Size [per side])

• Edge margin (specified by the cost model variable defaultEdgeMargin or the PSO Trim Strip Applied to Length and Width of Part)

• Center carrier strip margin (0 if carrier strip type is not center—see the PSO Press Carrier Strip Type; otherwise specified by the cost model variable defaultPartStripSpacing or the PSO Pitch Margin Adder for Center Carrier Strip Type)

Coil Width =

Number of Concurrent Parts * (Blank SER Dimension + (2 * Addendum) + (2 * Edge Margin)) +

Carrier Strip Margin + French Stop Margin

Coil width depends on the following:

• Number of concurrent parts (1 by default or specified by the PSO Number of Parts Stamped Concurrently)

• Blank SER dimension (specified by the PSO Length if the blank XY orientation is widthwise--the default in aPriori starting point VPEs; specified by the PSO Width of the flat pattern’s Smallest Enclosing Rectangle if the blank XY orientation is lengthwise. The XY orientation is specified by the cost model variable defaultXyOrientation or the PSO Thickness.)

• Addendum (0 by default or specified by the PSO Width of Addendum Added to Blank Size [per side])

• Edge margin (specified by the cost model variable defaultEdgeMargin or the PSO Trim Strip Applied to Length and Width of Part)

• Carrier strip margin (0 if carrier strip type is center—see the PSO Press Carrier Strip Type. If the carrier strip type is singleEdge, this is specified by the cost model variable singleEdgeCarierStripWidth or the PSO Single Edge Carrier Strip Width. If the carrier strip type is doubleEdge, this is double or—for two concurrent parts--triple the value specified by the cost model variable doubleEdgeCarierStripWidth or the PSO Double Edge Carrier Strip Width.)

• French stop margin (0 by default, or specified by the PSO Press French Stop)

Note that this value is constrained by the minimum and maximum coil widths specified by the cost model variable maximumStripWidth and the PSOs Maximum Strip Width and Minimum Strip Width. If the formula violates these constraints, the maximum or minimum coil width is used instead of the formula.