Research on the Process of Paint Removal from Thermoplastic Materials by Laser

Thelaser cleaning technology offers many advantages compared to the traditional paint removal technologies such as cleaning by chemical solvents or using media blasting. Yet, the effects of this technology depend on the carrier material onto which the paint has been applied. Sensitive carriers with a low melting point such as thermoplastic materials can be thermally damaged or destroyed. This paper analyses the paint removal from standard thermoplastic materials such as polypropylene (PP) by laser and aims at identifying the influence of the laser parameters on the carrier surface. The research includes experiments of paint removal from plastic substrates by a pulsed fibre laser at 1064 nm with various parameter settings and the characterisation of the treated surfaces. The results show that the paint layers can be removed completely while keeping the sensitive thermoplastic substrate unimpaired. The laser energy density, speed and spot size have impact on the paint removal effect and substrate surface quality. After the paint removal it is possible to use again or to recover thus cleaned thermoplastic parts without reducing the quality of the recyclate.