Reliable release analysis in the production of plastic granulate is important to ensure consistent colour quality of the end product. It is helpful to define the correlation between the colour of the granulate and the extruded colour sample platelets as precisely as possible so that the number of extrusions required can be reduced. A spectrophotometer that can be used to measure both pellets and platelets is therefore useful. Of course, the measuring process should be as simple as possible and not hold up the workflow.
The task
Since pellets have a non-uniform surface, the largest possible surface area must be examined during the colour measurement or a simple averaging of several measurements must be possible. The same device is also used to examine the extruded sample plates. It is therefore desirable to have an uncomplicated measurement of both granules and platelets, so that the colour values L*, a* and b* as well as the yellowness index YI, which is common for translucent granules, can be determined directly.
The solution
The Agera has a relatively large measuring aperture (51 mm) with the cuvette aperture, allowing a relatively large surface area of the granulate to be measured through the bottom of a glass cuvette. If this is not sufficient for repeatable measurements, you can easily set up an automated mean value calculation. The Colour measurement of the extruded sample plates can be carried out on the same instrument with the standard aperture. This makes it possible to define the relationship between the colour of the pellets and the platelets in the application and thus minimize the frequency of extrusions.
The measurement – very simple:
- Place the sample on the aperture or place it in a glass cuvette on the aperture
- Trigger measurement
- Read measured values on the screen
The accessories:
- 64 mm glass cuvette
- Cuvette aperture
