Part Geometry
The Investment Casting cost model supports parts that are no greater than around18 inches in width, length, and height.
Geometry extraction for Investment Casting is similar in many respects to geometry extraction for other casting process groups (see
Casting–Sand Process Group and
Casting–Die Process Group), although there are significant differences regarding Void extraction (for example, some features that are extracted as Voids in the other process groups are not extracted as Voids for Investment Casting). Investment Casting also provides some additional, special GCDs and properties:
• Is Shelled property for hole and void GCDs: a value of
true indicates that the feature has an aspect ratio that is large enough to allow refractory material to properly drain during shell making. A value of
false indicates that the aspect ratio is not large enough, requiring that the feature be handled by a ceramic core instead of a slide or soluble wax core. See
Core Molding.
• SlideBundle GCD: groups together features that are expected to be handled by the same slide during Wax Pattern Molding. These features are children of the SlideBundle GCD. A group of GCDs can form a bundle and be handled by a single slide only if they are all shell-able (that is, the value of the is Shelled property is true for each one), and there is a direction, D, (represented by a SetupAxis) such that all the following hold:
o They are all accessible from D
o D is sufficiently close to orthogonal to the draw direction.
o Any two adjacent GCDs are sufficiently close to each other (in the direction orthogonal to both D and the draw direction).
o Each GCD is sufficiently close to the part edge. That is, for each GCD, the distance from the GCD along D to the part edge is sufficiently small (where the part edge is the edge of the projection of the part along the draw direction).
o For any two adjacent GCDs that do not share the same volume, the distance between them along direction D is sufficiently small.
o All GCDs can be manufactured by a slide that does not obstruct any volume beneath the slide. The faces under a slide must not form any kind of hook; otherwise the slide would not be pullable.
o The slide is not too long (in the direction orthogonal to both D and the draw direction).
For more detailed information see
Slide Bundling Criteria.
• CoreBundle GCD: groups together features that are expected to be handled by the same core. These features are children of the CoreBundle GCD. They are near each other, and at least one of the features meets at least one of the following requirements:
o Feature is not accessible from any direction.
o Feature’s is not sufficiently near the part edge.
o Feature is not shell-able: that is, the value of the is Shelled property is false for the feature.