The Edge Break Sensor

The edge break sensor is a compact handheld optical sensor prototype used by operators in the workshop environment to identify micron sized defects without the time consuming processing of taking a wax mold and measuring that mold on a profilemeter. The system was designed and built in partnership with a large industrial manufacturer and is undergoing field testing.

System Description

The handheld sensor captures surface profile information: it works by projecting a pattern of lines onto the region of interest and then capturing images of that pattern for evaluation with software. Using LED optics, this pattern in created by projecting a LED through a grating (shown in green). The grating sits on a piezo stage which moves to three positions.

A second optical channel includes a camera with a zoom and focusing lens (shown in red). This optical channel collects three images of the grating pattern. These three images are used by a software application to extract profile information.

Software

Images

Specifications

RequirementNumerical valueUnits
Measure radii max0.050Inch
Measure radii min0.005Inch
Resolution0.0001Inch
Absolute calibration0.001Inch
Measure straightness of facets0.0005Inch
Working DistanceHandheld, contact 
Field of View at part0.125Inch
Exposure Times1-100msec
Supply Voltage100 – 240 Volts AC/50-60 Hz 
Sensor Tips ProvidedStraight, right angle, fast change 
Battery BackupUPS with x hr capability 
Sensor Size8 x7 x 3  w/handle 
Sensor FocusManual 
Image and profile analysis platformWindows XP PC 
Sensor ControllerWindows XP PC 
Sensor InterfaceFirewire 
Light sourceLED