Degrease Formulas

Degrease 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 = Load Time + Unload Time + (Conveyor Time / Number of Parts per Conveyor)

Process time depends on the following:

• Load time (looked up by part mass in the lookup table degreaseHandling)

• Unload time per part (same as load time)

• Conveyor time (see formula below)

• Number of parts per conveyor (see formula below)

Conveyor Time = Window Length/Conveyor Speed

Conveyor time is depends on the following:

• Window length (specified by the machine property Conveyor Window Length)

• Conveyor speed. By default this is the product of the following:

o Machine property Conveyor Speed Limit

o Cost model variable conveyorSpeedRateRatio--0.1 I aPriori starting point VPEs

Users can override the default with the PSO Speed of conveyor.

Number of Parts per Conveyor = Number of Parts in Entrance * Number of Parts in Row

Number of parts per conveyor depends on the following:

• Number of parts in entrance (see Number of parts that can fit across conveyor entrance)

• Number of parts in row (machine property Conveyor Window Length divided by the part’s longest dimension)

Degrease Additional Direct Costs

Additional Direct Costs = (Solvent Price * Solvent Quantity) / Final Yield

Additional direct costs depend on the following:

• Solvent price. By default, this is looked up by solvent brand in the lookup table degreaseSolvent. The brand is, by default, the one with the lowest price per gallon. Users can override the default brand with the PSO Brand of degreaser. Users can override the looked up price with the PSO Price of solvent. aPriori converts any looked up price from cost per gallon to cost per liter.

• Solvent quantity (see formula below)

• Final yield (see Surface Treatment Yield Calculations)

Solvent Quantity =

(Dilution Ratio * Water Loss per Unit Time * Conveyor Time) /Number of Parts per Conveyor

Solvent quantity is a function of the following:

• Dilution ratio. This is the fraction of water volume consisting of solvent, specified by the cost model variable degreaseSolventRatio (0.15 in aPriori starting point VPEs) or by the PSO Solvent Dilution Ratio.

• Water loss per unit time (see formula below)

• Conveyor time (see formula above)

• Number of parts per conveyor (see formula above)

Water Loss per Unit Time = Tank Change Loss + Evaporative Loss

Water loss in liters per second depends on the following:

• Tank change loss. This is specified in liters per year by the formula below. aPriori converts this value to liters per second of working time (based on the cost model variable workingHoursPerYear).

• Evaporative loss (specified in liters per second by the cost model variable dragEvaporativeLoss, 0.000525 in aPriori starting point VPEs)

Tank Change Loss = Number of Annual Tank Changes * Tank Capacity

Tank change loss in liters per year is the product of the following:

• Number of annual tank changes (specified by the cost model variable annualTankChange, 2 in aPriori starting point VPEs)

• Tank capacity in liters (specified by the machine property Tank Capacity)