When a CAD import is done in DFM Concurrent Costing, what data is imported from SolidView?

The following data is transferred into DFM Concurrent Costing during a CAD Import:

• Part name
• Part envelope X, Y, Z dimensions
• Part volume
• Part surface area
• Part area projected in each of the directions X, Y, and Z
• Number of surface patches on the part

Information on Transferred Data

The overall dimensions of the part, its volume, and its surface area are accurately obtained from the CAD model.  However, the projected area and the number of surface patches are estimates.  An estimate of the average wall thickness is based on the volume of the part and its surface area.  For thin walled parts this estimate is quite accurate and is equal to the volume of the part divided by half of the total surface area.  For parts that are not thin walled we have developed expressions which estimate the average wall thickness which, in some processes, such as injection molding and die casting, is used to estimate the cooling time.  The average wall thickness is also used to check against the limits for wall thickness included in the material and process database.

For parts with no undercuts and no features that require sidepulls in an injection molding or die casting, the projected area in the direction of molding will be accurate, for other parts you should check the value.   For example, if the part was similar to a tube being molded perpendicular to its axis, the projected area estimate will include both the external and internal surfaces divided by two.  In other words, the estimate will be almost twice the real value.

The surface patch count depends on the CAD software employed.  The estimate of surface patches can be overestimated or underestimated and for large complicated parts the overestimate can be as high as 200%.

Even though the part volume will be transferred accurately, it is still necessary to check and perhaps edit the value.  This is because for a casting, for example, the CAD model will probably represent the finished machined casting which will have a lower volume than the shape produced by the basic casting process.

It is important to check the transferred values under the following circumstances:

1. Check the projected area in the mold direction if the part is molded and has undercuts or holes requiring sidepulls, etc.
2. If the part approaches the shape of a solid block or solid cylinder, check the average thickness.
3. If the surface patch count seems low, manually count the number of surface patches. See Part Complexity in the DFM Concurrent Cost help for a description of surface patch counting.

Additional documentation on counting surface patches is available by downloading this PDF file! injpatches.zip