# Extrude Cut Along Guide Curves

Question asked by Matt Schott on Oct 9, 2015
Latest reply on Oct 16, 2015 by Matt Schott

Edit: I have included a simplified model with curves included if It can help anyone.

I'll start off by describing how the parts will act in the real world. The part that needs to be cut rotates the Y axis between 86*1"15" and 92*12'45" off of the Top Plane, and one face of it is attached to the Right plane. A 0.200" diameter roll pin will rotate around a point (0.400,1.625,0.185) from a positive 32* to a negative 42* (total of 74*) based on the rotation of the part that needs to be cut. The last picture shows the initial and final positions that the roll pin would be in with respect to the part.

Here is my problem: I have points that dictate the center of the roll pin, the relevant edge of the roll pin, and a calculated midpoint. I am unable to make a smooth cut in the part to mimic a 0.200" diameter roll pin moving along this path with no interferences. I have tried Lofts, Sweeps, 3D Sketches, Boundary Surfaces, and nothing seems to retain both a proper cross section of the roll pin and follows that guide curves correctly (curves generated through Curve Through XYZ). I even tried a pattern along a curve with the midpoint as my curve, but the ends of the roll pin do not rotate along the XZ properly.

With there no being a static plane I can reference, I am lost on how to do this. Is there a way to do this in an assembly where I would have a static frame of reference and I could limit angles and cut the interference? I could mimic the rotation of the pin by making a part that is solid through the entire 74*, but I am not certain how to make an interference cut to follow the dual rotation. I have also though of just creating a surface and CAM toolpath to follow that which would ignore the actual model, but I would prefer to have it done correctly. Any help would be greatly appreciated. If you need any other explanation or pictures please let me know. I could make up a quick partial model as well if it would help.

I am unable to attach the model unfortunately, but here are pictures describing what is happening and all of the curve points I am using:

Picture 1: Shows an Offset of the surface generated and the errors it creates.

Picture 2: Shows the surface generated and the calculated midpoints that it should follow (I can use the midpoint line to make it follow better, but it is concerning and leads me to to Picture 1)

Picture 3: Shows the curves through the calculated points

Picture 4: Shows the start and finish positions of the roll pin in relation to the part