Mold Design Using Solid Modeling Techniques

Take advantage of solid modeling to simplify the complexity and reduce the time needed to design molds.

FaceWorks from Capvidia combines the power of standard SolidWorks® software with functions designed to simplify tooling and manufacturing applications on 3D CAD models. FaceWorks uses the latest SolidWorks user interface concepts (Property Manager) providing smooth integration into the SolidWorks environment. Users benefit from standard SolidWorks functions complemented with specialized, easy to use tools that d ramatically simplify the tool-making process to minimize costs and manufacturing times.
 
SolidWorks and FaceWorks - Unmatched Functionality for the Midrange Sector

Traditional mold design is accomplished using surface modeling techniques.  This approach is still feasible, but can be very time consuming when creating complex molds. With FaceWorks, users can create complex parts 10 to 20x faster than with traditional techniques.  This is primarily due to the fact that many of the operations are automated:

• Draft Angle Analysis – Quickly calculates draft and automatically arranges the information.
• Parting Line Generation - The parting line is automatically generated in such a way that it always forms a closed loop. Problematic segments that are difficult to manufacture can be easily changed with a simple manual operation.
• Parting Surface Generation - The parting surface is automatically generated using a sophisticated approximation algorithm from Capvidia. The user defines the surface propagation direction and the surface type as either 2.5D or 3D.
• Surface assignment - Surfaces are automatically grouped into logical layers such as core, cavity, inserts, and sliders.A Drag & Drop feature is also provided for manual assignment.
• Solid Core and Cavity Generation - Splitting a solid block automatically generates the core and cavity objects as solids.
• Associative - Changes made to the model automatically update the core and cavity solids.A tracking mechanism is used to automatically update the information to provide immediate feedback. 

FaceWorks combines the best of solid and surface modeling techniques in one integrated environment.  It works on both open and closed (solid) 3D models and uses standard SolidWorks commands with special FaceWorks extensions.  Using SolidWorks’ intuitive user interface, the learning curve is very short, even for novice mold designers.  FaceWorks is SolidWorks exclusive and the combination of the two products provides unmatched functionality in the midrange 3D CAD market.

Simplify the Design

Figure 1a. Original Part

 Figure 1b. Problem Features

The original part (shown in Figure 1a) has an area with zero draft and a hook-like feature (shown in Figure 1b).  Constructing parting line and parting surface in this area can be quite difficult. Upon further inspection, we determine that the hook-like feature should belong to the core and the area with the zero draft should belong to the cavity.  

With a traditional surface modeling approach, one would spend a considerable amount of time generating the parting line around the hook-feature.  Using solid modeling software (SolidWorks), this feature can easily be removed by introducing a temporary modification to the original part. Figure 1c  shows the simplified model.  Simplification of the model reduces model complexity and the amount of time required to generate the parting line and parting surface.

FaceWorks Automatic Parting Line and Surface Generation

Now that the part is simplified, we can generate the parting line and parting surface using FaceWorks.The parting line is automatically generated in such a way that it always forms a closed loop.Problematic segments such as undercuts are automatically split and assigned to their respective core or cavity. Holes are filled in using the SolidWorks Surface Fill command. Additional changes can easily be introduced using standard SolidWorks commands. The parting surface is automatically generated using a sophisticated approximation algorithm provided by Capvidia. Notice that the parting surface around the modified area is much simpler and contains material that can be removed later.The result is shown in Figure2.
  

Automatic Generation of Core/Cavity Blocks

The parting surface and surfaces belonging to the original model need to form a “skin.” This skin is used to generate the core and cavity blocks. FaceWorks conveniently organizes all of the surface information into folders representing the parting surfaces, core surfaces, and cavity surfaces.  To complete the core and cavity objects, we select from menu option ‘Create assembly’ and both core and cavity parts are generated as solid blocks.  The result is shown in Figure 3.
 
 

Putting the Features Back

Now, we need to incorporate the original simplified feature into the simplified core and cavity objects. The hook-like feature belongs to the core. To do this, we create an assembly in SolidWorks with the simplified core object and the original part (shown in Figure 4).
 
 
 

 Figure  4.  Assembly of Simplified Core and Original Part

The final step is to perform a Boolean operation, subtracting the original part from the simplified core object.  This operation removes the material from the simplified core block where the hook-like feature exists.  The result is a core object that matches the exact geometry of the original part (Figure 5).  We then repeat the same operation on the cavity object to recapture the area with zero draft.

Associativity between Model and Core and Cavity

Another example will show the associativity between the model and core and cavity elements. We add some modification to the base geometry like a rib, and all the geometry and related drawings automatically update.

Benefits

By simplifying the geometry of the part, we avoided the complexity and time involved in generating the parting line and parting surface.  Using SolidWorks capabilities, we easily generated the core and cavity blocks.  The combination of SolidWorks and FaceWorks provides a powerful, feature-based solid modeler that allows users to make modifications to parts for mold design.

For more information, contact Lyle Fischer, Technical Marketing Director for Capvidia.