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Machining

Changes that Could Impact Configured Digital Factories

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

  • NO IMPACT

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 don't 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 (CMV370).

  • Improved Face-Milling Tool Size Selection (impacts tool selection): This release corrects some issues in which aPriori selected a flat end mill or face mill tool that was larger than is generally available in practice or larger than was appropriate for the part size:

    • In this release, aPirori selects a face mill tool where previously it selected an end mill whose diameter exceeded the largest diameter in the lookup table tblOperationSize (38.1 mm by default).

    • In this release, facing tool diameters are constrained based on part size and length-to-width aspect ratio (calculated based on the largest two part dimensions), according to the following heuristic:

      Length / Width Maximum Facing Tool Diameter
      <= 4 12% of (Part Width + Part Height)
      > 10 40% of (Part Width + Part Height)
      > 4 and <= 10 Interpolate between 12% and 40% of (Part Width + Part Height)

      (Note that "Width" and "Height" refer here to the smallest two part dimensions.)

      Previously, aPriori sometimes selected a facing tool diameter that was very large compared to the overall part size (for example, almost 80% of the part width).

    As a result of these changes, smaller facing tools now are chosen for some part surfaces, compared to previous releases, and facing operation cycle times may increase. More rarely, a larger tool may be selected, due to the fact that aPriori limits the total number of distinct tool diameters used for all the part's face-milled surfaces. In some cases, the selected process routing may change, because the previous routing may no longer have the lowest cost (due to increased cycle time caused by decreased tool diameter).

  • Improved Side-Milling Tool Size Selections for Slot GCDs: This release corrects an occasional issue in which the side-milling tool selected to finish-mill the walls of a slot was larger than some internal corner radii of the slot.

    As a result of this change, smaller side-milling tools are chosen for some Slot GCDs, compared to previous releases, and side-milling operation cycle times increase. However, the impact is modest overall—in a large test set, only about `10% of parts were impacted by this change, and the largest observed increase in total part cycle time was 3.4%.

  • Improved Cut Depth and Cycle Time Estimates for Rough Milling of Holes: Previously, aPriori erroneously used a radial cut depth of 1 (equal to the tool radius) when rough milling large-diameter SimpleHole GCDs.

    In this release, lower cut depths are selected from our standard milling cutting data tables, considering factors such as the tool diameter, tool type, tool series, and material cut code. In most cases, a cut depth of 50% of tool radius now is selected.

    As a result of this change, cycle time estimates will increase for SimpleHole Rough Milling operations by close to 100%..

  • Improved Estimates and Cut Depths for Enlarged Pocket GCDs in 2-Model Machining: This release improves the estimates for rough-milling pocket features that are present in a cast or forged part but then enlarged by machining in the finished part. Previously, for enlarged pockets with angled (tapered) walls , aPriori sometimes selected overly large rough-milling tools and/or overly large cut depths that didn’t properly reflect that the pocket is simply being enlarged not fully machined and that only a relatively small depth of material along the pocket walls and floor needs to be removed

    As a result of this change, compared to a previous release, aPriori now may select smaller tools and smaller axial and radial cut depths to enlarge pocket GCDs in the 2-Model Machining process group, resulting in larger cycle time and cost estimates.