Insert Pick and Place Process Formulas
Labor Cost = Labor Time * Labor Rate / Final Yield
Labor cost depends on the following:
• Labor time (see formula)
• Labor rate (specified by the machine property Labor Rate)
• Final yield (see Yields for Assembly Molding)
Labor Time = Cycle Time * Number of Operators * Labor Time Standard
Labor time is the product of the following:
• Cycle time: see formula.
• Number of operators: by default, this is specified by the machine property Number of Operators. Users can override the default with the setup option Number of Operators.
• Labor time standard: specified as the machine property Labor Time Standard. This multiplier is used to account for otherwise unaccounted for factors that affect labor time, such as operator fatigue or time spent by the operator for cleaning or maintenance.
Cycle Time = Process Time * Cycle Time Adjustment Factor
Cycle time is the product of the following:
• Process time: see Process Time, below.
• Cycle time adjustment factor: specified by the cost model variable cycleTimeAdjustmentFactor (1 in starting point VPEs). Administrators can customize this value in order to globally adjust cycle times for Assembly Molding.
Process Time
The method of process-time calculation depends in the Table Configuration of the current Insert Injection Molding machine.
Process Time No Table =
(Pick and Place Non-idle Time + Insert Injection Molding Non-idle Time) /
Number of Cavities
If the machine selected for Insert Injection Molding has no table (as specified by the machine property Table Configuration), Insert Pick and Place operators are idle during Insert Injection Molding tasks. In this case, Insert Pick and Place process time depends on the following:
• Pick and Place non-idle time (see formula)
• Insert Injection Molding non-idle time (see formula)
• Number of mold cavities (see Number and Layout of Mold Cavities in the Plastic Molding chapter)
Process Time Shuttle or Rotary =
max (Pick and Place Non-idle Time, Insert Injection Molding Non-idle Time) /
Number of Cavities
If the machine selected for Insert Injection Molding has a rotary or shuttle table (as specified by the machine property Table Configuration), Insert Pick and Place operators can work with one or more lower tools (removing parts and then placing inserts) while Insert Injection Molding operators use another lower tool together with the upper tool (for injection and cooling). Pick and Place Operators are idle during a cycle only if injection and cooling takes longer than removing parts and placing inserts. In this case, the two parallel streams of activity might be represented as follows:
On the other hand, if removing parts and placing inserts takes longer than injection and cooling, Insert Injection Molding operators are idle during each cycle. In this case, the two parallel streams of activity might be represented as follows:
For manual loading (see Manual or Robotic Loading), increasing the number of Insert Pick and Place operators is assumed to decrease the total time required to place inserts.
Insert Pick and Place process time depends on the following:
• Pick and Place non-idle time (see formula)
• Insert Injection Molding non-idle time (see formula)
• Number of mold cavities (see Number and Layout of Mold Cavities in the Plastic Molding chapter)
Pick and Place Non-idle Time =
Part Removal Time +
((Child Operation Times * Number of Cavities) / Number of Operators)
Pick and Place non-idle time is the time required to remove parts from one mold and then place all inserts into it. It depends on the following:
• Part removal time: depends on how the setup option Part Eject Method is set:
o Robotic: part removal time is the value of the cost model variable robotGrabTime (6 seconds in starting point VPEs).
o Manual: part removal time is the value of the cost model variable manualGrabTime (8 seconds in starting point VPEs).
o Gravity: part removal time is the value of the cost model variable gravityDropTime (1.25 seconds in starting point VPEs).
The default in starting point VPEs is Manual. Administrators can customize the default with the cost model variable ejectMethod.
Note that, with multiple cavities, it is assumed that all parts are removed at once, regardless of eject method.
• Child operation cycle times for Insert Pick and Place (see Insert Pick and Place Operation Formulas)
• Number of Mold Cavities (see Number and Layout of Mold Cavities in the Plastic Molding chapter)
• Number of operators for Pick and Place: For manual loading (when Manual or Robotic Loading is set to Manual), this is specified by the machine property Number of Operators, by default. Users can override the default with the setup option Number of Operators. For robotic loading (when Manual or Robotic Loading is set to 3-axis or 6-axis.), this is assumed to be 1, regardless of how Number of Operators is set.
Insert Injection Molding Non-idle Time =
Mold Close Time +
Injection Time +
Cool Time +
Hydraulic Slide Time +
Mold Open Time +
Ejector Plate Time
Insert Injection Molding non-idle time is the sum of the following:
• Mold close time (see Insert Injection Molding Formulas)
• Injection time (see Insert Injection Molding Formulas)
• Cool time (see Insert Injection Molding Formulas)
• Hydraulic slide time (see Insert Injection Molding Formulas)
• Mold open time (see Insert Injection Molding Formulas)
• Ejector plate time (see Insert Injection Molding Formulas)
Amortized Batch Setup =
(Setup Time * (Labor Rate + Direct Overhead Rate)) / Batch Size
Amortized batch setup is the cost per part for setting up one production batch for the current process. Starting point VPEs assume that there is no batch setup associated with the Pick and Place process, but VPE administrators can configure the cost model to include setup cost (by setting the machine property Setup Time to a nonzero value). Setup cost depends on the following:
• Setup time (specified as the machine property Setup Time)
• Labor rate (specified by the machine property Labor Rate)
• Direct overhead rate (see Direct and Indirect Overhead)
• Batch size (specified in the Production Scenario screen of the Cost Guide)
Note that indirect overhead depends on cycle time, while direct overhead depends on labor time.