# US 9,752,868 B2 · Optical measurement of lead angle of groove in manufactured part > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,752,868 B2 - Document ID: US9752868B2 - Status: Granted - Kind: B2 - Application number: 15/289,127 - Filed: 2016-10-08 - Published: 2017-01-26 - Granted: 2017-09-05 - Earliest claimed: 2010-10-29 - Assignees: Bruker Nano, Inc. - Applicants: Erik Novak; Florin Munteanu - Inventors: Erik Novak; Florin Munteanu - Web page: https://patentgrep.com/patent/US9752868B2 ## CPC - G01B 11/2441: {using interferometry} - G01B 11/26: for measuring angles or tapers; for testing the alignment of axes - G01N 21/952: Inspecting the exterior surface of cylindrical bodies or wires (G01N21/956 takes precedence) - G01N 21/95623: {using a spatial filtering method (per se G02B)} - G05B 19/41875: {characterised by quality surveillance of production} - Y02P 90/02: Total factory control, e.g. smart factories, flexible manufacturing systems [FMS] or integrated manufacturing systems [IMS] - G01B: MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) - G05B: CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS (systems for controlling or regulating non-electric variables G05D; systems for regulating electric or magnetic variables G05F; control devices or systems insofar as characterised by mechanical features only G05G) - Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS ## Abstract A portion of the surface of a cylindrical part with a machined groove is mapped with an optical profilometer during the manufacturing process and the height map is fitted to a virtual cylindrical configuration that best fits the data. Two-dimensional Fourier Transfer analysis of the map data is advantageously used to find the orientation of the groove on the part. The orientation of the groove is then compared to the longitudinal axis of such virtual cylinder to calculate the groove's lead angle. If the measured lead angle is outside a predetermined design tolerance deemed acceptable for manufacturing purposes, the part is removed from the fabrication line. ## Claims ### Claim 1 A method of detecting a defect for quality-control purposes in a lead angle of a groove in a surface of a part during a manufacturing process of the part, comprising the following steps: profiling a region of the surface with an optical profilometer to obtain a three-dimensional height map of said region of the surface; fitting said height map to a virtual three-dimensional geometric shape, thereby defining an orientation of a preferred axis thereof; determining said lead angle by comparing an orientation of said groove with said orientation of the preferred axis of the geometric shape; and removing said part from the manufacturing process when the lead angle falls outside a predetermined range of acceptable design values; wherein said profiling, fitting and determining steps are carried out with a processor. ### Claim 2 (depends on 1) The method of claim 1, wherein said part is a shaft. ### Claim 3 (depends on 1) The method of claim 1, wherein said part includes a frusto-conical structure. ### Claim 4 (depends on 1) The method of claim 1, wherein said groove is a product of machining the part. ### Claim 5 (depends on 1) The method of claim 1, wherein said determining step is carried out with a harmonic analysis of the height map. ### Claim 6 (depends on 5) The method of claim 5, wherein said harmonic analysis is a two-dimensional Fourier Transform analysis. ### Claim 7 (depends on 1) The method of claim 1, wherein said determining step is carried out with a correlation technique. ### Claim 8 (depends on 1) The method of claim 1, wherein said determining step is carried out with a 2-dimensional digital filtering technique. ### Claim 9 (depends on 1) The method of claim 1, wherein said lead angle is used to pass or fail the part based on a predetermined threshold value. ### Claim 10 (depends on 1) The method of claim 1, wherein said profiling, fitting and determining steps are repeated for multiple regions of the part's surface to calculate respective lead angles that are then averaged to obtain a final lead-angle value. ### Claim 11 (depends on 10) The method of claim 10, further including the steps of calculating a parameter of said multiple regions of the part's surface based on said profiling steps, and of disregarding a region when calculating said final lead-angle value if said parameter of the region exceeds a predetermined threshold value. ### Claim 12 (depends on 1) The method of claim 1, wherein said profiling step is repeated for multiple regions of the part's surface and the respective height maps thereof are stitched together for performing said fitting and determining steps. ### Claim 13 (depends on 1) The method of claim 1, wherein said geometric shape is a cylinder. ### Claim 14 A method detecting a defect for quality-control purposes in a lead angle of a groove in a surface of a part during a manufacturing process of the part determining the lead angle of a groove on a part's surface, comprising the following steps: profiling a region of the surface with an optical profilometer to obtain a three-dimensional height map of said region of the surface; defining an orientation of a preferred axis of the part based on an expected value of locally determined preferred axes; determining said lead angle by comparing an orientation of said groove with said orientation of the preferred axis of the part; and removing said part from the manufacturing process when the lead angle falls outside a predetermined range of acceptable design values; wherein said profiling, defining and determining steps are carried out with a processor. ### Claim 15 (depends on 14) The method of claim 14, wherein said part is a shaft. ### Claim 16 (depends on 14) The method of claim 14, wherein said groove is a product of machining the part. ### Claim 17 (depends on 14) The method of claim 14, wherein said determining step is carried out with a harmonic analysis of the height map. ### Claim 18 (depends on 17) The method of claim 17, wherein said harmonic analysis is a two-dimensional Fourier Transform analysis. ### Claim 19 (depends on 14) The method of claim 14, wherein said determining step is carried out with a correlation technique. ### Claim 20 (depends on 14) The method of claim 14, wherein said determining step is carried out with a 2-dimensional digital filtering technique. ### Claim 21 (depends on 14) The method of claim 14, wherein said lead angle is used to pass or fail the part based on a predetermined threshold value. ### Claim 22 (depends on 14) The method of claim 14, wherein said profiling, fitting and determining steps are repeated for multiple regions of the part's surface to calculate respective lead angles that are then averaged to obtain a final lead-angle value. ### Claim 23 (depends on 22) The method of claim 22, further including the steps of calculating a parameter of said multiple regions of the part's surface based on said profiling steps, and of disregarding a region when calculating said final lead-angle value if said parameter of the region exceeds a predetermined threshold value. ### Claim 24 (depends on 14) The method of claim 14, wherein said profiling step is repeated for multiple regions of the part's surface and the respective height maps thereof are stitched together for performing said fitting and determining steps. ### Claim 25 (depends on 14) The method of claim 14, wherein said geometric shape is a cylinder. ### Claim 26 Non-transitory computer readable medium containing computer instructions stored therein for causing a computer processor to perform the steps of detecting a defect for quality-control purposes in a lead angle of a groove in a surface of a part during a manufacturing process of the part by profiling a region of the surface with an optical profilometer to obtain a height map of said region of the surface, fitting said height map to a virtual three-dimensional geometric shape, thereby defining an orientation of a preferred axis thereof, determining said lead angle by comparing an orientation of said groove with said orientation of the preferred axis of the geometric shape; and automatically removing said part from said manufacturing process when said lead angle falls outside a predetermined range of acceptable design values. ### Claim 27 Non-transitory computer readable medium containing computer instructions stored therein for causing a computer processor to perform the steps of detecting a defect for quality-control purposes in a lead angle of a groove in a surface of a part during a manufacturing process of the part by profiling a region of the surface with an optical profilometer to obtain a height map of said region of the surface, defining an orientation of a preferred axis of the part based on an expected value of locally determined preferred axes, determining said lead angle by comparing an orientation of said groove with said orientation of the preferred axis of the part; and automatically removing said part from said manufacturing process when said lead angle falls outside a predetermined range of acceptable design values.