Appliance Design - September 2008 - (Page 60) SOFTWARE Different stakeholders throughout the extended product development team perceive design intent differently according to their discipline. Although it is possible for detailed designers to agree on design intent in the production CAD system, other contributors may need to make edits that contradict those rules. For example, this casting design receives many edits as it’s brought to production: A. The model created by the original design team has a regular pattern of ribs. The original designers expect CAE analysts and manufacturing engineers to make edits, but they cannot anticipate those changes. B. To optimize the structural properties of the design while minimizing resonance and material consumption, CAE analysts rotate the rib structure and vary the thickness of individual ribs. In a history-based system, the rib features would need to be deleted and replaced with individual features of varying thickness. In SpaceClaim, each rib can be individually edited without any rework. Also, the analysts use SpaceClaim’s fill tool to delete rounds and fillets to prepare the model for meshing. C. Where the designers and analysts perceive a network of ribs, the manufacturing engineers see a set of pockets. To make a prototype, the manufacturing engineer offsets the pockets to isolate geometry for rough milling and fills in other pockets to better visualize the in-process model. SpaceClaim allows machinists to de-feature a design in the reverse order of machining operations, helping them optimize the manufacturing process. Derived uses: Reusing the CAD data in ways that the original CAD designers did not intend. Common examples include creating in-process models for manufacturing, adjusting tolerances to accommodate different manufacturing processes, editing data created in a different CAD system in the supply chain, simplifying models for technical publication and marketing, and removing intellectual property from data to be supplied to customers. A new type of complementary design tool from SpaceClaim makes these 3D design workflows possible without CAD. Design tool traits When considering complementary 3D design tools, companies engaged in product development should consider the following qualities and capabilities: Complementary 3D is not CAD: Although some vendors are starting to add features to let their CAD systems work with foreign data, these features increase the complexity of already complicated CAD systems. Casual users need a streamlined 3D design solution that lets them work with 3D designs without learning production CAD. Low total cost of ownership: Consider all components of cost of ownership. In addition to software price, be aware of the cost of training, ongoing support, IT implementation and hardware requirements. Although CAD training can take weeks, complementary design tools are designed to be learned in hours using quick, self-paced tutorials. The software should use simple concepts that make it easy to learn. Interoperability: Complementary solutions should have the ability to open and save diverse CAD data. Additionally, the solution should open assemblies with the correct assembly structure and instancing, and provide the option to only open the assembly structure or lightweight graphics representations without translating entire large assemblies. Also, look for a 3D mockup environment that can graphically highlight changes and track edited dimension values. Simple model editing: Look for conceptually simple modeling tools that seem intuitive. Geometry creation should use straightforward concepts such as pull and move, not historybased features that can cause “regeneration” or “rebuild” failures. Fill and combine tools should be available for model simplification, merging, and tooling creation. All modeling tools should work in 3D and in any arbitrary 2D section. Also look for model cleanup tools, like cylinder and sphere tools and the ability to directly sketch 3D shapes. Model creation: Look for the ability to make unplanned changes to assembly structure, the ability to turn a part into an assembly and vice-versa, and a data model that can store components internally and externally to the documents containing assemblies. Check for the ability to organize data on conceptually simple layers that are compatible with layers from imported 2D and industrial design data. Also, look for strong 2D drafting tools, the ability to turn 2D drawings into 3D, and the ability to make simple annotated drawings of your 3D designs. SpaceClaim has been designed from the ground up to provide these capabilities without the burden of history-based modeling. It does not depend on an underlying historybased paradigm, which makes solid modeling in SpaceClaim more conceptually simple than in any CAD system. www.applianceDESIGN.com 60 applianceDESIGN September 2008 http://www.appliancedesign.com
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