For our purposes, the full curve-fitting abilities of fityk are a distinct overkill. Attenuated total reflectance Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy confirmed that there is no remarkable degradation. An open source program called fityk does a great job of curve-fitting equations to arbitrary data and can handle the same range of equation types as Excel. A general kinetic equation that describes the degradation of the material with temperature has been proposed and validated. Thermogravimetric analysis under linear heating and constant rate conditions show that thermal degradation is a complex process with a number of overlapping steps. Rheological measurements showed that there is negligible degradation in PEEK for the temperatures reached during the process. This study is devoted to analysing the possible effects of thermal degradation produced by this manufacturing technique. If you are interested, please ndthe source code at GitHub7. To see its formula, type: info Gaussian(or i Gaussian) or look for it in the section Built-In Functions. Automatic lay-up and in-situ consolidation with thermoplastic composite materials is a technology under research for its expected use in the profitable manufacturing of structural aeronautical parts. Fityk manual, Release 1.3.1 1.1Open Source Fityk is open-source (GPL2+6). Fityk manual, Release 1.3.1 As our example data has no background to worry about, our next step is to dene a peak with reasonable initial values and t it to the data.