This is the result of a two-dimensional finite-element model of a doubly-wedged disk of aluminum spun at 30,000 rpm. This is 500 revolutions per second, which gives the desired scan rate of 1000 per second. The bending moments are balanced and the thinning can now be clearly seen. This 2D model indicates the thinning as 900 nm but it is actually twice that much because there is an equal tension in the orthogonal axis not treated by the 2D model. There are several reasonable approaches to maintaining the surface flat.