New materials for Laser Sintering (LS) are usually developed using a trial and-error approach that consists of a series of builds within LS systems. This strategy is time consuming, costly and focuses only on the optimisation of the processing parameters, ignoring the powder properties of the materials under examination. Being able to predict processing parameters on the basis of the powder material properties would enable a faster development of new materials and new applications, while acknowledging a more in-depth understanding of the mechanisms involved in LS. This paper provides new results into the prediction of processing conditions from the material properties. It is here shown that high temperature polymers such as Poly Ether Ether Ketone (PEEK) and Poly Aryl Ether Ketone (PEK) can be successfully used in LS despite the lack of a super-cooling window. The evaluation of the stable sintering region of PEEK 450PF and the application the energy melt ratio parameter in relation to the mechanical performance of laser sintered PEEK samples are also provided. Lastly, a new method for estimating the powder bed temperature is proposed.