Suppose you want to assemble a spring, rivet or mechanism to an assembly. Often, developers will model different flexed, formed and/or kinematic states of the component in a family table—for example, they might model instances for the different ways a rivet can be formed when assembling sheets of different thicknesses together. The trouble is, if you also work with PTC Windchill and use WTParts, you now have to manually associate each of those formed instances of the component to the WTPart.
There’s a simpler way, says Darcy Parker, PTC product manager. Parker is teaching the course “Advanced PTC Creo Parametric Data Management Processes and Techniques Using PTC Windchill PDMLink 10.2,” at PTC Live Global, June 7-10. In this course, aimed at users who already know the basics of CAD data management, Parker will dive into WTParts and how CAD documents can be associated to WTParts in order to drive their structure.
For springs, rivets or mechanisms, Parker suggests that instead of modeling an instance for each assembled state and associating these instance’s CAD Documents to their WTPart, create a flexible component in PTC Creo Parametric. Dimensions, parameters, and features in a flexible component can vary when assembled so you don’t need separate components for each assembled state. So you only have to associate the CAD Document to the WTPart once. And you won’t have to model new assembled states for future assemblies that may use the component.
A component’s flexibility is defined in the Flexibility dialog and there are different ways to get to this. A common way is to select File > Prepare > Model Properties. In the Model Properties, find the Flexible item under Tools, select Change. This takes you to the Flexibility dialog where you can define items you want to vary: dimensions, parameters, features, geometric tolerances and/or surface finishes.
Flexible components then appear in the model tree with a special icon, such as and their geometry will vary according to the assembly constraints and the variable items defined in the component’s Flexibility property.
For more about working with CAD Documents and WTParts, attend Darcy’s class at PTC Live Global this June in Nashville, Tennessee.
Darcy Parker began his career at PTC 15 years ago as a technical support engineer. Since then, he has filled roles as a consultant, developmentmanager, process master architect, and product manager. Parker is best known today for his work with the Expert Modeling Analysis (XMA), a tool for assessing PTC Creo Parametric and Pro/ENGINEER models. Darcy says you can find out more by attending sessions about XMA at PTC Live Global, or just look for him on the convention floor and start a conversation!
How does PDMLINK handle this? We have used flexibility for a spring in an assembly and it would want to regenerate every time the assembly was opened. We have PDMLINK set to automatically lock objects added to workspace, so a dialogue box would open stating the spring was READ ONLY and would not be regenerated. If the spring was unlocked, it would regenerate and show as being modified. We have now removed the flexibility from the spring and have none of the above problems.