11. Thickness gauges

Whereas thickness checks are carried out by taking samples from the production process, thickness gauges are designed to monitor and adjust the process, enabling any deviations to be checked before they are noticed at the end of each reel.

An in-line thickness measurement system is now a standard feature of flat die extrusion.

In its simplified version, it reacts in a closed loop to the speed of either the extruder or the calender rolls, so that the calculated average thickness tends towards the target value, and informs the operator of the thickness profiles so that he can correct the distribution.

In its full version, in addition to the above functions, it assumes the role of a setter, reacting in a closed loop to the heating bolts on the die lips to optimize the thickness profile (cross direction standard deviation...