Extrusion Enhancements (Bar and Tube Fabrication)

Improved Recognition of Complex Extruded Parts

aPriori 2023 R1 improvements to cross-section and feature recognition extends the types of extruded parts that aPriori can analyze and enables it to estimate extruded part manufacturing costs and material utilization more accurately.

aPriori now extracts geometry more accurately for extruded parts that:

• Are both bent, and heavily-machined such that large portions of the original extruded profile are removed.

• Include a CAD modeling error or imprecision. For example, parts that include a slight variation in the profile over the length of the part because the profile geometry was created as a blend of two profiles rather than as an extruded feature.

In previous releases, aPriori would frequently respond to parts with these characteristics by either:

• Failing to analyze the part and then displaying this message: aPriori cannot find the requested stock form.

• Extracting an erroneous cross section that neglected a significant portion of the actual profile or misinterpreted a hollow in the profile as material that was present in the extrusion but subsequently removed by machining.

Now aPriori is more likely to correctly extract GCDs and GCD properties, including the correct cross-section profile, part length, number of bends, and cutouts (material removed post-extrusion) for complex extruded parts.

This enhancement complements the extrusion-recognition improvements delivered in the aPriori2022 R1 SP1 service pack, which provided the ability to recognize extrusion profiles that contain spline entities. For more information, see the aPriori Professional Release Notes, 2022 R1 SP1. Due to the enhancements in releases 2023 R1 and 2022 R1 SP1, it is expected that a significant number of extrusion parts that could not be estimated in prior versions of aPriori will now be supported.

Limitations

• Geometry recognition might be incorrect for parts with embossed features that are formed after extrusion. In some cases aPriori may extract an incorrect extrusion profile.

  In other cases the extrusion profile will be recognized correctly but the formed features will not be recognized as a Form GCD and will instead be split into a Cutout GCD (concave side) and a NotSupported GCD (convex side). For the latter case, there is a workaround.

  Workaround

  If the extrusion profile is correctly recognized, but the formed feature is recognized as separate GCDs on opposite sides of a curved form, assign a No Cost Feature operation to the incorrect Cutout GCD that is located on the concave side of the form. If many of your parts have such features, consider either adding a custom process to the routing or configuring a manually-assigned Forming operation to account for forming costs.

• In some cases extrusion parts with bends of non-constant radius sometimes still may fail to be recognized correctly by aPriori, for example the cross section may be missing a hollow.

  Workaround

  Re-modelling the part in CAD may help for the recognition of extrusion parts with bends of non-constant radius. In particular, it might help to ensure that the extrusion profile is extruded or swept along straight portions of the extrusion trajectory and swept normal to the bend trajectory, rather than modeling it by using blend features.