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Plastic Molding

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.

  • Draw Direction: This release improves the determination of draw direction by changing the default value of the site variable drawDirPinHoleFactor from 1.0 to 0.25. This can affect the draw direction for parts with ejector pin bosses that are not aligned with the natural draw direction.

    Note:

    To restore the behavior of the previous release, set the value of the site variable drawDirPinHoleFactor to 1.0.

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.

  • Required Clamping Force (can impact machine selection and overhead costs): This release corrects a problem that sometimes caused aPriori to select a larger, higher-overhead machine than was necessary. The change affects Injection Molding, Reaction Injection Molding, and Structural Foam Molding.

    In the previous release, aPriori assumed that flow length was part length, which caused overestimation of both the flow ratio and the required clamping force. In this release, aPriori makes a more accurate determination of flow length that better accounts for the number and location of gates.

    Info:

    Flow length is the maximum distance the melt must travel from a gate to the extremities of the mold cavity. Flow ratio is flow length divided by nominal wall thickness, and is crucial in the determination of required clamping force.

    As a result of this change, required clamping force generally decreases somewhat, compared to the previous release, but increases may occur for parts that have a nearly square bounding rectangle (in the parting plane) or have a short-side gate. In a set of test parts, required clamp force, machine overhead, and fully-burdened cost all decreased by an average 5%-10%.

  • Material Cost and Regrind: This release improves the calculation of material cost for Injection Molding and Structural Foam Molding by better accounting for the inclusion of regrind material. As a result, material cost decreases compared to the previous release. The amount of decrease depends on part geometry, number and layout of cavities, and regrind percentage. In a set of test parts with varying regrind percentages (between 5% and 25%), material cost decreased by an average of 7.5%.

  • Injection Molding Material Properties: Values for the material properties Injection Pressure Max and Injection Pressure Min have been updated using industry sources.