The Oregon Manufacturing Innovation Center Research and Development (OMIC R&D) recently welcomed Capture 3D, a Zeiss company, as a member of the collaboration, now at 41 members. Headquartered in Santa Ana, California, Capture 3D is a leader in innovative optical 3D metrology solutions, including accurate blue light 3D scanners, precision photogrammetry systems, comprehensive inspection software, and high-tech automated inspection systems.
In this article, equations for finding profile and base pitch errors with a micrometer are derived. Limitations of micrometers with disc anvils are described. The design of a micrometer with suitable anvils is outlined.
Base helix error - the resultant of lead and profile errors is the measured deviation from the theoretical line of contact (Fig. 1). It can be measured in the same way that lead error on a spur gear is measured, namely, by setting a height gage to height H based on the radial distance r to a specified line of contact (Fig. 2), rotating the gear so as to bring a tooth into contact with the indicator on the height gage, and then moving the height gage along two or more normals to the plane of action. The theoretical line of contact on helical gear must be parallel to the surface plate, which is attained by mounting the gear on a sine bar (Fig. 3).
