Cycle Time for the Hydroform Process
The formulas below are used for each occurrence of Hydroform Deep Draw or Hydroform Fluid Cell.
Cycle Time = Process Time * Cycle Time Adjustment Factor
Cycle time is the product of the following:
• Process time: unadjusted cycle time for the current process. See the formula below.
• Cycle Time Adjustment Factor: value of the cost model variable cycleTimeAdjustmentFactor. This is set to 1 in aPriori starting point VPEs. VPE administrators can change the cost model variable to globally adjust cycle times.
Process Time = Tool Cleaning Time + Loading Time + Forming Time +
Unloading Time + Visual Inspection Time + Hand Adjusting Time
Process time is the sum of the following:
• Tool cleaning time: cleaning time is the quotient of the following:
o Tool surface area (half the part surface area)
o Cleaning rate (looked up by tool surface area in the lookup table tblCleanRate)
This value is bounded below by the cost model variable minimmToolCleanTime (5 seconds in starting point VPEs)
• Loading time: loading time is looked up by stock mass in the lookup table tblMaterialHandling.
For fluid cell routings, if a throw pad is in use, this time is supplemented by throw pad application (see formula). A throw pad is used by default for fluid cell routings, but users can override the default with the setup option Use a Throw Pad.
• Forming time (see formula)
• Unloading time: unloading time is looked up by stock mass in the lookup table tblMaterialHandling. For fluid cell routings, if a throw pad is in use, this time is supplemented by throw pad removal time (see formula). A throw pad is used by default for fluid cell routings, but users can override the default with the setup option Use a Throw Pad.
• Visual inspection time: this is specified by the cost model variable defaultInspectionTime (45 seconds in starting point VPEs).
• Hand adjusting time: this is the sum of the manual forming times for all GCDs to which the Manual Forming operation is assigned. The manual forming time for a given GCD is the quotient of the following:
o GCD perimeter
o Cost model variable defaultManualFormingRate (50mm/minute in starting point VPEs)
The Manual Forming operation must be manually assigned to individual GCDs for each desired occurrence of Hydroform Deep Draw or Hydroform Fluid Cell.
Forming Time = Machine Forming Cycle Time / Number of Parts per Tray
Forming time depends on the following:
• Machine forming cycle time (specified by a machine property)
• Number of parts per tray: for deep draw routings, this is 1. For fluid cell routings, this is specified by the cost model variable defaultNumPartPerFluidCellTray (1 in starting point VPEs) or by the setup option Number of Formed Parts per Tray.
Throw Pad Application Time = Throw Pad Surface Area / Throw Pad Application Rate
Throw pad application (which supplements loading time for fluid cell routings if a throw pad is in use) time depends on the following:
• Throw pad surface area: a rectangular throw pad is assumed, where each throw pad dimension (length or width) is the corresponding blank dimension extended by the cost model variable throwPadAddendum (75mm in starting point VPEs).
• Throw pad application rate: specified by cost model variable throwPadApplicationRate (3000mm2/sec in starting point VPEs).
Throw Pad Removal Time = Throw Pad Surface Area / Throw Pad Removal Rate
Throw pad removal (which supplements unloading time for fluid cell routings if a throw pad is in use) time depends on the following:
• Throw pad surface area: a rectangular throw pad is assumed, where each throw pad dimension (length or width) is the corresponding blank dimension extended by the cost model variable throwPadAddendum (75mm in starting point VPEs).
• Throw pad removal rate: specified by cost model variable throwPadRemovalRate (3000mm2/sec in starting point VPEs).