IRt/c’s are well suited for monitoring the temperature of plastic extrusions, either at the point of extrusion to monitor correct extrusion temperature, or after air cooling to monitor/control the cooling process prior to cutting to length. The model recommended depends on the monitoring geometry.
For extrusions of 1” (2.5 cm) width or more, the standard IRt/c may be used at a distance of 1/2” (1.3 cm), which is sufficient to keep the lens clean in a reasonably clean environment.
For smaller extrusions, or for up-reading; the IRt/c.3x is preferred due to its smaller 0.25” minimum spot size (6 mm), and built-in air purge, which will maintain cleanliness even when very close to the hot plastic and pointed up.
For larger extrusions, in which more convenient positioning at greater distance is desired, the IRt/c.5 is recommended, due to its narrow 5:1 field-of-view.
For the smallest extrusions, the “Slot Spot” models, with their tightly focused optical systems, can measure to 2 mm (see Tech Note No. 80).