Inspecting for burrs in piston cooling channels

Connecting rod

Application

Engine oil is applied to the gap between the pistons and cylinder liners to ensure sliding performance and to prevent the pistons from overheating because of friction. Pistons are equipped with oil rings to remove used engine oil after each stroke. The oil rings are fitted into oil ring grooves along the piston. The grooves provide cooling channels to return the oil to the oil pan. Burrs formed within the channels prevent the proper attachment of oil rings into the grooves, potentially preventing sufficient removal of the used engine oil. Confirming the absence of any burrs is an important quality management concern. However, since the channels extend from the bottom to the top of the groove, it is difficult to obtain a clear focus on the entire image using a conventional microscope. 

Olympus’ solution

Inspection with an Olympus DSX series digital microscope
DSX series digital microscopes offer advanced focal functionality to enable automatic focus extending from the bottom to the top of the groove. This provides a clear view of the entire cooling channel.

DSX digital microscope features

1. With a single click, the extended focal image function automatically acquires fully focused images of the entire structure of samples that have significant differences in height.
2. Dedicated objective lenses achieve excellent image resolution and a high focal depth.
3. Zoom optics capable of seamlessly altering the magnification from 1x to 30x.
4. Annotation functionality enables the fault positions and descriptions to be indicated and saved directly on the acquired image, making it easy to share information.