Rotary Draw Bending
aPriori uses the formulas below to determine costs associated with this bending process.
Accounting Calculations
Labor Time = Cycle Time * Machine Labor Time Standard * Machine Labor Ratio
Labor time is the product of the following
• 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 = ((Labor Time / 3600) * Machine Labor Rate) / Process Yield
Labor cost is a function of the following:
• Labor time (see formula above)
• Machine labor rate (specified as a machine property)
• Process yield (see formula below)
Amortized Batch Setup =
(Machine Setup Time * (Machine Labor Rate + Direct Overhead Rate)) / Batch Size
Amortized batch setup is a function of the following:
• Machine setup time (specified as a machine property)
• Machine labor rate (specified as a machine property)
• Direct overhead rate (see
Direct and Indirect Overhead)
Process Yield = 1 / (Machine Process Yield/100)
Process yield depends on the machine property Process Yield.
Cycle Time Calculation
Cycle Time = Load and Unload Time + Number of Bends * (Bending Time + Rotate Time + Axial Traverse Time)
Cycle time depends on the following:
• Load and unload time (obtained from lookup table—see below; increases with part mass, which increases with material density).
• Number of bends (obtained from GCD extraction)
• Bending time (specified as a machine property, Mandrel Bend Time or Non Mandrel Bend Time)
• Rotate time, which depends on the following:
o Number of changes in bend angles
o Machine property Clock Angle Rotate Time
• Axial traverse time, which depends on the following:
o Distance between bends
o Machine property Axial Feed Rate
Load and unload times and manipulation times by part mass are contained in the lookup table rotaryDrawBendingHandling.
See
User Inputs for information on mandrel bending.