Minus Coplanarity is simply the distance between the lowest fiber and the “best-fit plane” through the array of fibers (also called the “fiber line”). It is a measure of fiber height variation within an array of fibers. A lower number is better, with a value of “0” indicating the theoretical ideal – all fibers are EXACTLY the same height.

The best-fit plane is a line through the array of fiber protrusions calculated by using the mathematical “least square method.” Think of it as a straight line through the array which is the best representation of all heights. The least square method is high-school math and not extremely complicated, but it is exactly the same formula used in Excel graphs when you add a linear trendline through data points.


READ THE BLOG: MT Ferrule Geometry Specifications: Minus-Side Coplanarity in IEC 61755-3-31:2015