Engineering Research Center for Reconfigurable Manufacturing Systems (ERC/RMS)

Cylinder Bore Surface Inspection: From Idea to Implementation

An engine cylinder bore with poor surface finish can cause premature engine failure, excessive oil consumption, and other warranty problems. Researchers at the University of Michigan ERC for Reconfigurable Manufacturing Systems (ERC/RMS) have developed an optical technique based on angle-dependent laser scattering for inspecting cylinder bores and have demonstrated that they can inspect the entire surface of every cylinder bore in every engine at production line speed.

Laser light striking a machined metal surface tends to scatter in a plane perpendicular to the direction of machining marks on the surface. This phenomenon can be used to detect residual boring marks on the surface of a cylinder, which must be removed by a process called "honing" to provide acceptable engine performance. Honing produces machining marks that scatter light in significantly different directions than the boring marks do. Researchers at the ERC/RMS exploited this difference to develop a laser scanning probe that differentiates between the light-scattering patterns produced by the two machining processes and rapidly inspects for the presence of residual boring marks. Results for acceptable and defective surface finishes are shown in the graphs.

After a successful proof-of-principle demonstration, RMS developed a second-generation probe and demonstrated that it could operate at the speed of a production line. Based on these results, DaimlerChrysler has decided to invest in building an inspection station using the probes in their Mack Engine Plant. This station will demonstrate the ability to inspect the entire surface of every cylinder of every engine block at the speed of the production line. This capability should greatly improve quality control and average engine performance and life.

To learn more about this topic:
Visit the Engineering Research Center for Reconfigurable Machining Systems industry page at http://erc.engin.umich.edu/industry.htm.

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Map of scattering from a cylinder with acceptable
surface finish.

Map of scattering from a cylinder with defective
surface finish.

Cylinder bore probe for inspection of surface finish.

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Last modified: February 18, 2005