Rockwell Automation 5370-CBPK Color CVIM BLISTER-PAK Option - Manual (Page 9)

Chapter 2
Functional Overview
2–2
Most tablets are a single color (A, Figure 2.1), but some applications require
that two or more different types of tablet (each a different color) appear in
different pockets on the blister. As many as eight different color tablets
sometimes occupy a single blister.
Other applications involve multi-colored tablets, which may be inverted or
“flipped,” and thereby appear from above to be either of two colors (example
B in Figure 2.1). Two-color capsules (example C in Figure 2.1) may or may
not be placed in a known orientation.
Figure 2.1
Variations in Tablet and Capsule Configuration
A B C
PVC blister materials vary, too. Often they are clear, but in many cases they
are white or colored. Clear PVC is the easiest to manage in a vision
inspection setting because background color can be controlled by changing
the type of material below the web. White PVC cannot be used with white
tablets, so it is often replaced with a colored PVC web.
Aluminum blisters present special challenges because aluminum’s reflective
properties and the gradual slope of the pocket walls make it hard to light.
Side lighting gives a black background, but the sloping walls of the pockets
appear gray, and can even change color as they reflect the color of their
contents. The BLISTER–PAK option, however, provides a feature that can
accommodate the apparent difference between the general background color
and the pocket color in aluminum blisters (or non–aluminum blisters that
present a similar problem).