Case 7: Cone Surface Mapping
In this example we examine the coating of the inner surface of a cone in the same planetary coater as in the previous case.
Here we compute for surface points in a polar-coordinate-system grid, instead of the Cartesian system. (In V-Grade 5 you have the complete freedom of choosing what surface points you want computed.) The center of the cone is located 14.3 cm from the fixture center. No correction mask is present.
First, we level the cone in the plane of the fixture, as shown in the left column below. The resultant thickness distribution is significantly uneven and asymmetric. We then pivot the cone by -3.25 degrees, resulting in a much more uniform and center-symmetric coating, as shown in the contour plot in the right column.
The overall peak-to-valley nonuniformity before and after pivoting is 3.6% and 0.87%, respectively.
