APPLICATION NOTE: Laser Triangulation Sensors - MTI Instruments ...

Figure 12: Vacuum Seal Integrity for Canning Industry
Figure 13: Surface Profile of a Wide Variety of Materials
iii.) Thickness and Dimensional Measurements
On-line production thickness measurements have conventionally been made using direct
contact type measurement systems. Sensors, such as LVDT’s, are positioned above and
below the material being measured to track surface position. The sensor outputs are
combined through software or a summing device and thickness is determined.
Unfortunately, contact type methods cause measurement problems. Not only can the
material being measured be damaged but sensor wear also occurs. In addition, contact
sensors are slow and may not properly track targets that may move or vibrate, making
these applications ideal for MTII’s laser systems.
Single sided thickness measurements are possible if one side of the material can be held
constant against a fixed reference plane, however, for best results, two sided
measurements are preferred. This is because a two sided approach eliminates any errors
that might be introduced from the material moving or vibrating. MTII’s two sensor
approach synchronizes the data sampling for both sensors which ensures a correct