Question

What is undulation?

(a) Departure of the actual tooth surface from design surface

(b) Departure of the virtual tooth surface from design surface

(c) Departure of the design surface from actual tooth surface

(d) Departure of the design surface from virtual tooth surface

The question was asked by my school teacher while I was bunking the class.

My doubt stems from Sources of Errors in Manufacturing Gears in chapter Measurement and Testing of Gears of Engineering Metrology

Answer 1

The correct answer is (a) Departure of the actual tooth surface from design surface

To explain: Undulation is a departure of the actual tooth surface from the design surface and undulation height is the normal distance between 2 surfaces that contain the crests and the troughs of the tooth undulation.