Process for producing a packaging weld

A process for continuous welding of a sheet of plastic material for manufacturing flexible packages, comprising the steps of:

• positioning the sheet relative to the welding device;
• putting ends of the sheet into contact;
• forming a weld by heating, pressing and cooling the ends of the sheet that are in contact;
• acquiring a primary temporal signal with a sensor, the primary temporal signal proportional to a thickness of the weld;
• transforming the primary temporal signal into a primary frequency signal and defining a low-frequency spectrum, a medium-frequency spectrum, and a high-frequency spectrum from the primary frequency signal;
• reconstructing a secondary low-frequency signal from the low-frequency spectrum;
• and
• determining the thickness of the weld based on the secondary low-frequency signal, the secondary low-frequency signal providing for an accuracy of a measurement of the thickness below 10 μm, such that the accuracy of the measurement is approximately ten times below than an amplitude of an interference noise.