Color measurement is a widely used technology for ensuring the quality of color values during the manufacturing process. Typically, these measurements happen offline. The time it takes between sampling and receiving results from the laboratory can be lengthy. A significant disadvantage is that only one measurement occurs during this period, and the color quality during, before, and after the sampling point is unknown. A complete analysis is possible because inline color measurements are performed directly in the melt, but when color variations occur, immediate intervention is possible.
Inline color measurement will provide product-quality indicators for immediate and automatic adjustment of process parameters. The outcome is to maintain the highest possible product quality without waiting for sample analysis from the plant's laboratory.
Equitech International Corp. has been in business since 1995, supplying fiber-optic spectroscopic instruments for process analysis to pharmaceutical, chemical, and food manufacturers. In 2005 they entered the plastics market and began extending their technology into inline color monitoring and real-time closed-loop process control. They published a helpful Technical Paper titled In-Line Color Measurement in the Molten Polymer. You can download that paper here.