Date of Award


Publication Type

Master Thesis

Degree Name



Mechanical, Automotive, and Materials Engineering

First Advisor

Ahmet Alias


Gear Inspection, Gear Metrology, Laser, Non Contact




Gear shape accuracy, surface quality and, as a consequence, a proper gear inspection needed to guarantee these features, are critical in order to improve drivetrain efficiency as well as to reduce noise in automotive power transmission systems. Contact stylus type measuring methods using contact probes are today’s dominant indus- trial solution for gear metrology. Due to the difficulties of further improving those methods, new non-contact measuring systems have been developed in the past few years. The most promising option that meets the requirements of accuracy, repeatability and high cycle time is the 3D non-contact measurement method based on triangulation laser sensors. These laser scanners have been improved over the last few years both in terms of resolu- tion, optical quality, image processing and data analysis to make them comparable, if not superior, to the traditional contact probe. This thesis provides an evaluation of the surface profilometer Urano HC-N400, using the contact technology currently employed by Omega gear metrology labs as a benchmark. The measurements obtained with the alternative inspection system indicate that the analyzed non-contact solution is not ready yet for in-line and high volume inspection applications, but is well-suited to research and development purposes. Omega is also looking for the possible causes of a particular noise problem which is difficult to detect using current technology. One gear that exhibited this phantom phenomenon, also know as the "ghost noise", has been analyzed and compared with another gear identified as the "best of best". During the analysis, undulations have been found in both gears. The combination of those waves through the use of the Ripple Analysis software represents the best solution to discover other gears with the same problem in the early stages of inspection.