Temperature Dependent Optical Properties of Polymers as a Basis for Laser Process Modeling

Abstract

The knowledge of laser absorption is essential to describe the behavior of polymers in different laser processes, i.e. SLS, LOM, etc. By means of transmission IR-spectroscopy a method for measuring temperature dependent penetration depths (absorption length) of polymers, especially at a wavelength of 10.6Jlm (C02-Laser), is developed. Results for the laser sintering materials polystyrene (PS), nylon 11 (PA 11), nylon copolymer (CoPA) and polyethylene terephtalate (PET) are presented. It is detected that the absorption length of polymers will increase or decrease significantly dependent on temperature. This paper will point out simplified methods based on the one dimensional heat transfer equation with volume heat source to set the processing parameters i. e. for the SLS process. The calculations correspond with the measured data.