How to build an auger with an arbitrary (step, path) helical blade in Inventor

Sometimes in the practice of an engineer there is a need to design a screw-type product whose helical surface has an arbitrary step. Consider the construction of this product. Create a sketch describing the trajectory of the future helical surface, this can be a spline given by the coordinates of points or a graph of any function.

Next we create a second sketch tangent to the first, in which we set the base of the auger in our case it is a pipe with an internal diameter of 30 mm.

Extrude the second sketch, we get the foundation of the future auger. Next, create a 3D sketch. In the 3D sketch editing environment, select the CURVE CURVE PROJECTION command, select the SURFACE PATTERN in the Output option, then select the surface itself, this is the pipe and the curve, this is the first sketch created.

The result of this command is the projection of the curve on the outer surface of the pipe. Create a 2D sketch that will determine the cross section of the screw auger blade. With the help of the SHIFT command, we squeeze out the section along the trajectory of the projected curve and the guide surface of the pipe. Preliminary it is necessary to choose the type of shift «Trajectory and guide surface». We get the result.