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Parametric Spur Gear

Question asked by Thomas Piaget on Apr 18, 2014
Latest reply on Sep 12, 2018 by Dennis Dohogne

I am playing around with redesigning the extruder feeding mechanisim of my 3D printer.  As part of my redesign I am looking at creating a different gear ratio between the stepper motor and the drive bolt so I am creating a spur gear model.  I would like to print my new gears using my 3D printer so I would like the models to be accurate.  Just for extra fun I am trying to make the model parametric, however I am having a few issues with features that are not updating properly with new parameters.


The model is defined by 3 parameters:

1.) Pitch Diameter

2.) Pitch (teeth per inch)

3.) Pressure Angle

All other features are defined by equations (except face width - I haven't parameterized that one yet).


I have attached the model for reference.  Here are the issues I am having:


1.)  In the sketch titled "Involute Curve", the right side of the gear tooth is defined by an equation driven curve and the left side of the tooth is defined by a mirror of the equation driven curve.  When I update the input parameters to the gear file the equation driven curve is updated but the mirror isn't.  Is there a way to update the sketch mirror when the model parameters are changed?  I know that a work around is to define a second equation driven curve, but I like the efficiency of using the mirror function.


2.) In the circular pattern, the number of pattern itterations and the angular offset of the pattern are both defined by equations (which I used to create named variables).  In the feature dialoge box I can type in the name of the variable and the correct value will be calculated and replace the name of the variable that I typed.  When I update the model parameters the circular pattern features won't update.  Is there a way to link those feature parameters to equation driven variables?