Billet Preheat
Process Time = Heating Time / Parts Per Billet
Process time depends on the following:
• Heating time: see formula. This value is converted from hours to seconds for use in this formula.
Heating Time = Required Heat / Oven Power
Heating time in hours depends on the following:
• Required heat: see formula.
• Oven power: specified in kilowatts by the machine property Machine Power. This value is converted to watts for use in this formula.
Required Heat = (Billet Mass * Material Specific Heat at Room Temp * Delta Temp)
Required heat depends on the following:
• Billet mass: this is the product of billet volume and material density. See
Billet Size and Parts per Billet.
• Material specific heat at room temp: specified by the material property Specific Heat RT. This is the amount of heat energy per unit mass that is required to increase the material temperature one degree C.
• Delta temp: this is the magnitude of the temperature change effected by heating. See formula.
This value is converted from joules to watt-hours for use in the Heating Time formula.
Delta Temp = Solidus Temp – Room Temp
Delta temp is the magnitude of the temperature change effected by heating. It is the difference between the following:
• Solidus temp: specified by the material property Solidus Temp. This is the highest temperature at which the material remains in a solid state.
• Room temp: this is the ambient temperature, specified by the cost model variable defaultRoomTemp (23°C in starting point VPEs).