INFLUENCE OF THE LASER PROCESS PARAMETERS ON THE EFFICIENCY OF AN EXCIMER LASER PRETREATMENT FOR ADHESIVE BONDING OF PEEK

Surface treatment with restricted thermal effects can be achieved using pulsed excimer lasers. Therefore these tools are appropriate to thermally sensitive materials such as polymer. The present work deals with the possibility of using the excimer laser to achieve a prebonding treatment on the PEEK and to study the influence of the wavelength on the efficiency of the treatment in terms of bonded joint strength. Regarding the mechanical test results, it appears that the adhesive properties of the polymer are mainly dependent on the laser wavelength. Without any pretreatment, the bonded joint strength does not exceed 5JIm2 and the failure occurs at the interface between the PEEK and the adhesive. After a 193 nm irradiation, below or above the ablation threshold, a cohesive failure in the adhesive at 700J/m2 is obtained whereas at 248 nm the laser treatment leads to an adhesive failure at the PEEK-adhesive interface at 330 JIm2. In order to understand why the wavelength have such a strong influence on the adhesive properties, the modifications induced on the surface after treatment are investigated