Tube Laser

aPriori uses the formulas below to determine costs associated with tube laser processes.

Accounting Calculations

Labor Time = Cycle Time * Machine Labor Time Standard * Machine Labor Ratio

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.

  • Machine labor ratio (specified as a machine property)

Labor cost is a function of the following:

  • Labor time (see formula above)

  • 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 Cost = ((Labor Time / 3600) * Labor Rate) / Process Yield

  • Process yield (see formula below)

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)

Process Yield = 1 / (Machine Process Yield/100)

Process yield depend on the machine property Process Yield.

Programming Cost =  Programming Time * (Labor Rate + Direct Overhead Rate)

Programming cost depends on the following:

  • Programming time (see formula below)

  • 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)

Programming Time = Machine Base Programming Time +
(Machine Programming Factor * Number of Programmed Features)

Programming time depends on the following:

  • Machine base programming time

  • Machine programming factor

  • Number of programmed features (number of holes and ends to be handled by this process)

Cycle Time Calculation

Cycle Time = Cut Time + Pierce Time + Rapid Traverse Time + Handling Time

Cycle time is the sum of the following:

  • Cut time (depends on cross-section thickness, material type, machine wattage, feature perimeters and radii of curvature)

  • Pierce time (depends on number of holes, cross-section thickness, material type, machine wattage)

  • Rapid traverse time (depends on machine’s tube axial bar feed rate)

  • Handling time (see formula below)

Pierce time per hole and burn cutting rate are derived from the lookup table tubeLaserCutting. Lookups are keyed by cross-section thickness, material type, and machine wattage. The table provides two burn cutting rates: one for large features and one for small features. A hole is considered small if its radius of curvature is less than or equal to the larger of the following:

  • Machine property smallFeatureFeedRadius

  • Product of part thickness and machine property smallFeatureThicknessRatio

Handling Time = (Load Time / Number Parts Per Stock) + Unload Time

Handling time depends on the following:

  • Load time, which depends on min stock length and part mass (which depends on material density)

  • Number of parts per stock

  • Unload time, which depends on part mass (which depends on material density)

Load and unload times are determined with the help of the lookup table tubeLaserHandling. Load time lookup is keyed by stock mass. Unload time lookup is keyed by finish mass.