Laser Cut, Oxy Fuel Cut, Plasma Cut

aPriori uses the formulas below to determine costs associated with these cutting processes (used for plate rolling).

Accounting Calculations

Labor Time = Cycle Time *
Machine Labor Time Standard

Labor time is the product of the following

  • Cycle time (see Cycle Time Calculation)

  • Machine labor time standard (specified as a machine property). This value reflects the amount of time spent by machine operators in between machine cycles, including time performing maintenance and cleaning tasks as well as time pausing between tasks. The amount is expressed as a cycle time multiplier.

Labor Cost = (Labor Time / 3600) * Labor Rate

Labor cost is a function of the following:

  • Labor rate: this is the product of the following:

    • Machine property Labor Rate
    • Cost model variable laborRateAdjustmentFactor (1 in starting point Digital Factories)
    • Machine property Work Center Labor Rate Factor (1 in starting point Digital Factories)

  • Labor time (see formula)

Direct Overhead Cost = (Cycle Time / 3600) *
Machine Overhead Rate

Direct overhead cost depends on the following:

  • Cycle time (see formula below)

  • Machine overhead rate (specified as a machine property)

Amortized Batch Setup = (Machine Setup Time *
(Labor Rate + Direct Overhead Rate)) /
Batch Size

Amortized batch setup is a function of the following:

  • Machine setup time (specified as a machine property)

  • Labor rate: this is the product of the following:

    • Machine property Labor Rate
    • Cost model variable laborRateAdjustmentFactor (1 in starting point Digital Factories)
    • Machine property Work Center Labor Rate Factor (1 in starting point Digital Factories)

  • Direct overhead rate (see Direct and Indirect Overhead)

Cycle Time Calculation

Cycle Time = (Cut Time + Pierce Time +
Rapid Traverse Time + Scrap Cutting Time + Shuttle Time) /
Machine Number of Heads

Cycle depends on the following:

  • Cut time, which depends on the following:

    • Cross-section thickness

    • Material type—aluminum, for example, cuts faster than steel

    • Machine wattage

    • Blank size

    • Feature perimeters—cut time increases with hole size.

    • Feature radii of curvature—tighter cuts are slower.

  • Pierce time, which depends on the following:

    • Number of holes

    • Cross-section thickness

    • Material type

    • Machine wattage

  • Rapid traverse time, which depends on the following:

    • Blank size

    • Machine’s rapid traverse feed rate

  • Scrap cutting time

  • Shuttle time (increases with blank size)

  • Machine number of heads (specified as a machine property)

Pierce and burn cutting rates by machine watts and material type and thickness are contained in the following lookup tables:

  • Laser smNestingCutRate

  • Plasma smNestingCutRate

  • OxyFuel smNestingCutRate