Study on the Main Influencing Factors in the Removal Process of Non-Stick Fluoropolymer Coatings Using Nd:YAG Laser

Óscar Rodríguez-Alabanda; Pablo E Romero; Carlos Soriano; Lorenzo Sevilla; Guillermo Guerrero-Vaca

doi:10.3390/polym11010123

Study on the Main Influencing Factors in the Removal Process of Non-Stick Fluoropolymer Coatings Using Nd:YAG Laser

Polymers (Basel). 2019 Jan 12;11(1):123. doi: 10.3390/polym11010123.

Authors

Óscar Rodríguez-Alabanda¹, Pablo E Romero², Carlos Soriano³, Lorenzo Sevilla⁴, Guillermo Guerrero-Vaca⁵

Affiliations

¹ Department of Mechanical Engineering, University of Cordoba, Medina Azahara Avenue, 5, 14071 Cordoba, Spain. orodriguez@uco.es.
² Department of Mechanical Engineering, University of Cordoba, Medina Azahara Avenue, 5, 14071 Cordoba, Spain. p62rocap@uco.es.
³ IK4-Tekniker, Advanced Manufacturing Technologies Unit, Iñaki Goenaga Street, 5, 20600 Eibar, Spain. carlos.soriano@tekniker.es.
⁴ Department of Civil, Materials and Manufacturing Engineering, University of Malaga, Doctor Ortiz Ramos Street, 29071 Málaga, Spain. lsevilla@uma.es.
⁵ Department of Mechanical Engineering, University of Cordoba, Medina Azahara Avenue, 5, 14071 Cordoba, Spain. guillermo.guerrero@uco.es.

Abstract

The coatings with fluoropolymer resins rich in fluorinated ethylene propylene (FEP) and polytetrafluoroethylene (PTFE) are applied as anti-adherent coatings on aluminum⁻magnesium substrates for use in food containers. In many cases, due to wear, they must be stripped for the application of a new coating on the same substrate. There are several processes for this: blasting, plasma, pyrolysis, chemical processes, laser, high pressure water, and combinations of these. This work focuses on the characterization of the main factors that condition the FEP coating removal process by a continuous wave (CW) Nd:YAG laser, and on the determination of the efficiency of this type of technology used for this purpose. Stripping surface per unit of time and energy consumption per unit area has been determined among other efficiency indicators. Regarding the characterization of the coating object of study, its thickness, surface roughness, contact angle, microhardness and absorbance-reflectance responses have been determined, and the results have been compared with those obtained in the case of PTFE. In addition, to evaluate the mechanical damage caused in the substrate after coating removal by (CW) Nd:YAG laser, the tensile strength, Vickers hardness, R_a and R_z roughness, and the substrate thickness have been measured and analyzed.

Keywords: FPE coatings; Nd:YAG laser; PTFE coatings; laser coating removal; laser stripping.