Finishing Formulas for Die Casting

The Finishing process relies on the formulas below.

Cycle Time = Process Time * Cycle Time Adjustment Factor

Cycle time is the product of the following:

• Process time (see formula below)

• Cycle time adjustment factor: specified by the cost model variable cycleTimeAdjustmentFactor; 1 in aPriori starting point VPEs.

Process Time = Grinding Time * Design Complexity Factor

Process time is the product of the following:

• Machine load and unload time (specified as a machine property)

• Grinding time (see formula below)

• Design complexity factor (see Design Complexity Factor)

Grinding Time = (Parting Line Grind Volume / Grinding Speed Material Parting Line) +

((Ingate Grind Volume + Riser Grind Volume) / Grinding Speed Material Gating)

Grinding time is the quotient of the following:

• Parting line grind volume (see formula)

• Grinding speed material parting line: this is the product of the machine property Grinding Speed Parting Line and an adjustment factor looked up by material cut code in the lookup table tblGrindingSpeedMaterialFactor.

• Ingate grind volume (see formula)

• Riser grind volume (see formula)

• Grinding speed material gating: this is the product of the machine property Grinding Speed Gating and an adjustment factor looked up by material cut code in the lookup table tblGrindingSpeedMaterialFactor.

Parting Line Grind Volume = Parting Line Length to Grind * Parting Line Height * Parting Line Thickness

Parting line length to grind is the product of the following:

• Parting line length to grind: this is the product of the Projected Perimeter property of the Parting Line GCD and the fraction of the parting line to grind, specified by the setup option Percent Parting Line to Grind—1 by default.

• Parting line height: interpolated based on values looked up by Mass Before Machining (see Material Cost and Utilization for Die Casting) in the lookup table tblGrindingDimensions.

• Parting line thickness: interpolated based on values looked up by Mass Before Machining (see Material Cost and Utilization for Die Casting) in the lookup table tblGrindingDimensions.

Ingate Grind Volume = Total Ingate Area To Grind * Ingate Height

Ingate grind volume is the product of the following:

• Total ingate area to grind (see formula)

• Ingate height: interpolated based on values looked up by Mass Before Machining (see Material Cost and Utilization for Die Casting) in the lookup table tblGrindingDimensions.

Total Ingate Area to Grind = Total Ingate Area * Percent Ingate Area to Grind

Total ingate area to grind is the product of the following:

• Total ingate area: this is the product of Ingate Area (see Gating System Formulas for Gravity Die Casting) and the number of ingates. Numberof ingates is specified by the setup option Number of Ingates for Gravity Die Casting.

• Percent ingate area to grind: fraction of the ingate area to grind, specified by the setup option Percent Ingate Area to Grind—1 by default.

Riser Grind Volume = Riser Base Area To Grind * Riser Height

Ingate grind volume is the product of the following:

• Riser base area to grind (see formula)

• Riser height: interpolated based on values looked up by Mass Before Machining (see Material Cost and Utilization for Die Casting) in the lookup table tblGrindingDimensions.

Riser Base Area to Grind = Riser Base Area * Percent Riser Area to Grind

Total ingate area to grind is the product of the following:

• Riser base area (see formula)

• Percent riser area to grind: fraction of the ingate area to grind, specified by the setup option Percent Riser Area to Grind—1 by default.

Riser Base Area = Pi * Riser Radius2

Riser base area depends on riser radius, which is half the riser diameter. The formula for riser diameter is below.

Riser Diameter = ( 8 * Riser Volume) / Pi )1/3

Because the riser is assumed to be cylindrical with height equal to half the diameter, riser diameter can be determined from riser volume alone. The formula for Riser Volume is below.

Riser Volume = 1.9 * Shape Factor-0.7 * Part Volume * Contraction Ratio

This formula is based on the NRL (Naval Research Laboratory) method for determination of riser volume. Riser volume depends on the following:

• Shape factor. This is the ratio of the sum of part length and part width to the maximum thickness of the part (determined by geometry extraction).

• Part volume (determined by geometry extraction)

• Contraction ratio. This is the ratio of the contraction volume percentage for the current material to the contraction volume percentage for steel (looked by material type in the lookup table tblSolidifcationShrinkage).