To illustrate a typical application of the Model 50L, measurements were made on an electronic component.  The part is approximately a half inch on a side and has two contacts approximately 2 mm (80 thou) in diameter that are located 0.5 mm (20 thou) below the top surface of the part.  The inspection task was to determine the distance of the contacts to the part's upper housing.  The tolerance on each of the measurements was +/- 25 microns (+/- 1 thou).

When all four sides of the part are scanned, the 3D surface points are merged into a single composite called the datacloud.  The figure below shows an isometric view of the raw datacloud of the top surface of the part where the four views have been merged together.

             Figure 1.  Raw Datacloud

During the setup phase, the raw datacloud is grouped into surface primitives such as planes and cylinders.  The part has three surfaces from which dimensions are to be made: the tops of the two contacts and the housing to which the contact height is to be referenced.  Below, these three surfaces have been identified using CAItech's software.  The large red surface is the reference surface (i.e., the housing).  The small green surface is the upper contact and the small blue surface is the lower contact.

             Figure 2.  Surfaces Identified

Once the surfaces of interest are identified, the setup phase is completed by making relationships between the surfaces.  For this part, two dimensions are required: the distance from the reference surface to the top surface of each contact. Setup for this part took about 5 minutes.

The figure below shows the results of 10 measurements taken one after the other to determine the system's repeatability.  Shown in the upper right of this display screen is the summary data for the two dimensions measured using English units.  Distance 0, the distance between the reference surface and the upper contact, has a mean dimension of 20.54 thou, a minimum of 20.49 thou and a maximum of 20.59 thou.  It's 3-sigma repeatability is +/- 0.09 thou (+/- 2.5 microns).  For Distance 1, the corresponding parameters are a mean of 23.23 thou, a minimum distance of 23.13 thou and a maximum of 23.25 thou with a 3-sigma repeatability of 0.10 thou (+/- 2.5 microns).

Below the summary is a graph of the ten measurements using the mean as the zero value.  The scale goes from +.5 thou to -.5 thou (+12 microns to -12 microns).  The red dots are values for each Dimension 0 measurement.  Note that all points lie within 0.1 thou of the mean showing the repeatability graphically.  The left-hand side of the display screen shows the results that were obtained as digital values as well as the error of that value from the mean.

             Figure 3.  Inspection Repeatability

The display screen below results when the Dimension box (upper left-hand corner) is clicked to bring up the graph and data for Dimension 1.  The format is the same as in the figure above.  Dimension 1 represents the height of the lower contact below the reference surface.  Its graph and values show that it also varies by less than 0.1 thou from the mean value.

             Figure 4.  Results for One Dimension

The part's two dimensions were measured 10 times; the 3 sigma repeatability of the measurement was found to be less than +/- 0.1 thou (2.5 microns).  The inspection time was 14 seconds.