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Path Mate / Classic Zoom lens = rotating barrel w/slot + carriage with a pin

Question asked by Brian Catanzaro on Jul 25, 2013



A classic zoom lens design looks like this:

The barrel rotates, actuating the pins, causing them to slide along the axis of the barrel, precisely moving lenses inside the barrel.


I have these parts modeled and I want to check the location of the lenses in the assembly.  One way I conceived was to mate the pin to the slot and then specify the barrel rotation.  Then I would create a handful of configurations with the barrel at various rotations.  Finally, I would create a drawing of the assembly in a specific configuration.  Then I could copy the drawing a few times and change the configuration and all my distances would automatically update.  Then I would check the distances with the optical specifications.


Traditional mates failed to execute (could not select entities).  Cam mate would not select the features in the model.  One way I found was to use a path mate to mate the pin to the slot in the barrel.


Things ran awry with the path mate.  I had to use "Convert Entities" to convert my path into a 3D-Sketch to even get the path mate to even allow my selection of entities.  Once this was complete, I had to put a point at the center of the pin to connect with the path.  This is problematic because numeric precision could drive the point off of the curve.  In the real world, the circumference of the pin (104a) interfaces with the walls of the slot (104).  This type of mate does not seem possible in SolidWorks.  True?


I made some progress with path mate but as soon as it got interesting (three configurations), it suddenly stopped working - the mates could not be solved.  It seems sporadic.  I tried re-ordering the mates and that did not help.  Now about 10% of the time, just by supressing mates, slightly moving the positions manually and "randomly" selecting the order in which mates are unsuppressed, it will resolve the mate.


  • Am I using the right mating operation?
  • How do I get my model to consistently resolve the mate?
  • Is there a better way to achieve my goal?