Wet Coat Line Formulas

Wet Coat Line Cycle Time Calculation

Cycle Time = Process Time * Adjustment Factor

Cycle time includes setup time per part. It is the product of the following:

• Process time (see formula below)

• Adjustment factor (specified by the cost model variable cycleTimeAdjustmentFactor). This factor is 1 in aPriori starting point VPEs. VPE administrators can modify cycleTimeAdjustmentFactor in order to adjust cycle times across processes within the current VPE.

Process Time = Paint Cycle Time + Mask Time

Process time is the sum of the following:

• Paint cycle time (see formula below)

• Mask time (see formula below)

Paint Cycle Time = Load Window Time/Number of Parts per Load Window

Part cycle time depends on the following:

• Load window time (specified in hours by the machine property Load Window Time; aPriori converts this to seconds). This the time it takes for the load window to complete a paint cycle, that is, progress through the entire paint line or complete a cart-based cycle (usually gated by oven/diptank time).

• Number of parts per load window (see below)

Number of Parts per Load Window

This is specified by the PSO Number of Components per Paint Cart or calculated as the maximum number of parts that satisfies both size and weight constraints. The size constraints are determined by the following factors:

• Part height

• Part width

• Machine property Cart Window Height

• Machine property Cart Window Length

• Machine property Cart Spacing Factor (the fraction of tightly packed parts that can fit when parts are spaced appropriately)

The weight constraints are determined by the following factors:

• Part mass (part volume times material density)

• Machine property Cart Weight Limit

Mask Time = Number of Masked Features * Mask Time per Feature

Mask time is the product of the following:

• Number of masked features (number of threaded holes, by default, or specified by the PSO Number of Masked Features)

• Mask time per feature (specified by the cost model variable maskTimePerFeature—5 seconds in aPriori starting point VPEs)

Amortized Batch Setup = Setup Time / Batch Size

This is the cost per part for batch setup. It is 0 in starting point VPEs, since any required setup is assumed to be accounted for in direct overhead rates. VPE administrators can establish a nonzero value for this output by setting the machine property Setup Time to a nonzero value.

Amortized batch setup depends on the following:

• Setup time: specified by the machine property Setup Time (0 in starting point VPEs).

• Batch size: the size of a production batch. By default this is the batch size specified in the Production Scenario tab of the Cost Guide. Users can override the default with the setup option Painted Batch Size.

Wet Coat Line Additional Direct Costs

Additional Direct Costs = Paint Unit Cost * Volume Used + Primer Unit Cost * Volume Used

Additional direct costs consist of paint cost, which depends on the following:

• Paint unit cost (specified by the machine property Paint Unit Cost)

• Volume used (see formula below)

• Primer unit cost (specified by the machine property Primer Unit Cost)

• Volume used (see formula below)

Volume Used = Painted Surface Area / Paint Coverage Area per Unit Volume

Volume used, in liters, is a function of the following:

• Painted surface area, in mm2 (see formula below)

• Paint coverage area per unit volume (specified in m2 per liter by the machine property Paint Coverage; aPriori converts this to mm2 per liter).

Painted Surface Area = Fraction Painted * External Surface Area

Painted surface area is the product of the following:

• Fraction painted (1 by default, or specified by the PSO What Fraction of Component is Painted?)

• External surface area (see below)

External Surface Area

External surface area is estimated as follows:

• 65% of part surface area, for tube stock

• Assembly bounding box surface area, for assemblies whose bounding box surface area is less than assembly surface area divided by the value of the cost model variable asmBoundingBoxAreaRatio.

• Part (or assembly) surface area, otherwise.