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Sheet Metal

Geometry or Cost Engine Changes that Could Impact Configured Digital Factories

The following changes might impact costing, even for Digital Factories that use earlier cost model versions.

  • Complex Hole property Mec Diameter (in very rare cases, can affect feasibility of 2D cutting operations): In the previous release, aPriori overestimated the value of the Mec Diameter property for certain Complex Hole GCDs. Estimates were accurate for many hole shapes (including rectangle, oval, and key-hole shapes), but were too large for certain other hole shapes (including triangle, star, and crescent shapes).

    Info:

    The Mec Diameter of a hole is the diameter of the largest circle that can be inscribed in it.

    In this release, Mec Diameter is determined more accurately for these other hole shapes. As a result, aPriori now more accurately determines whether a given 2D cutting operation's kerf width can accommodate a given Complex Hole (the kerf cannot be wider than the hole).

    In very rare cases, a 2D cutting operation assigned in the previous release may be infeasible in this release. For such cases, costs may increase significantly when a machining operation is assigned in place of the 2D cutting operation. In a large test set, costs increased significantly for fewer than 1% of parts, and only for holes previously assigned OxyFuel Cut or Plasma Cut.

  • Other Complex Hole properties: aPriori now computes various Complex Hole properties more accurately, including Perimeter and Area. In a large test set, fewer than 1% of parts were affected. For affected parts, fully burdened cost changed by less than 1%.

  • Straight Bend properties Bend Flap Size and Min Bend Flap Size (can impact operation assignment, times, and costs): This release improves the accuracy of values for the Bend Flap Size and Min Bend Flap Size properties of Straight Bend GCDs. As a result, some previously feasible operations may now be infeasible, and some previously infeasible operations may now be feasible. For most bends the property values change by less than 10%, but larger changes can occur. Decreases are more common than increases.

    The change has no effect on cost for the vast majority of parts. Tube-like parts routed to Stage Tooling may see an increase in the number of Generic Press instances calculated by aPriori. In such cases, labor and tooling costs increase in proportion to the increase in the number of Generic Press instances.

    Note:

    To restore the behavior of the previous release, set the site variable flattenBendFlapSize to false.

  • Form properties Depth Up and Depth Down (can impact machine selection and overhead costs): This release improves the accuracy of the values of the properties Depth Up and Depth Down for curved bend Form GCDs. As a result, in rare cases, machine selection may change compared to the previous release (since a feasible machine's shut height must be sufficiently large to accommodate the part's deepest form). If a different machine is selected, overhead cost and (to a lesser extent) cycle time may change.

    In a set of test parts, decreases in form depth were more common than increases. For the majority of test parts, form depth values changed by less than 20%, but a significant minority had changes of greater than 20%. However, in the test set, there was only minor impact on machine selection. In some cases, a smaller, less-expensive machine was chosen than in the previous release.

  • Gussets: In very rare cases in the previous release, aPriori incorrectly classified some gussets as Straight Bend GCDs. In this release, such gussets are recognized as Form GCDs of Sub Type Gusset.

Bug Fixes or Small Improvements to Prior Cost Model Versions

The following changes might impact costing for Digital Factories that use earlier cost model versions.

  • NO IMPACT

Cost Model Changes that Do Not Affect Configured Digital Factories

The following changes do not affect costings with Digital Factories that use earlier cost model versions. The changes are available only in the latest cost model version.

  • Gusset Bends: In the previous release, bends with gusset features failed to cost. The Bending operation of the Bend Brake process previously was not considered feasible for Straight Bends with child Form GCDs of Sub Type Gusset. In this release, such bends are considered feasible for this operation. Bends with gussets that previously failed to cost or were not routed to Bend Brake may now be routed to Bend Brake and cost successfully. The gussets are assumed to be formed simultaneously with the bend feature, by default. Cycle times may be affected, but no additional tooling cost is assumed for gusset bends.
  • [CTL]/[Bend] Routing:In this release the [CTL]/[Bend] routing is never auto-selected; it now must be selected manually. Note that costs for this routing do not include material costs.
  • Complex Holes and Minimum Recommended Hole Diameter Setup Option: In the previous release, aPriori determined the feasibility of Waterjet Cutting for a Complex Hole by comparing the default value of the setup option Minimum Recommended Hole Diameter with the Complex Hole's Mec Diameter, even when the user supplied a setup option value. This release corrects the problem, so that aPriori takes user-specified values into account when it determines Waterjet Cutting feasibility for Complex Holes. Results may change compared to the previous release if you have overridden the setup option default.
  • Number of Parts per Sheet: This release corrects a problem that could occur when aPriori 22.1.0 was used with older cost models (that is, pre-22.1.0 cost models): when the user specified Override or Machine Default in the Material Utilization dialog, aPriori erroneously used the value 0 for the number of parts per stock sheet, resulting in very large, unrealistic values for labor and direct overhead costs. In this release, the number of parts is correctly derived from the specified override or machine default.
  • Progressive Die Drawing and Deep Drawing: In the previous release, in rare cases, a form covering more than half of the part that should have been assigned Drawing or Deep Drawing was assigned Forming instead. This release corrects the problem. The change had no impact on a test set of 120 progressive die parts.