Powder flowability depends on many variables. Not only intrinsic powder characteristics, such as particle size and shape distribution, contribute to the quality of the powder flow, also external parameters such as temperature and humidity play a large role[1-2]. Therefore, it is advisable to check the extent of their influence on powder flowability in the intended application. The application of interest is Laser Sintering (LS), a form of Additive Manufacturing (AM) that uses polymer powder as a base material. Particles, with an average particle size of around 50 µm, are spread into thin layers of around 100 µm[3]. Temperature effects are relevant in this application, as the powder bed in a sintering machine is heated between the crystallisation and melting temperature to minimise part warpage[4]. This heating influences powder flow in two ways. Firstly, the elevated temperature may soften the polymer, thereby changing the contact between particles and thus altering flow. Secondly, the long exposure to elevated temperatures, combined with the load of the powder bed above it, can lead to caking of the powder. Depending on the caking strength, this affects the recycling of the unsintered powder for the subsequent builds. To evaluate the influence of temperature, two independent techniques are used. The first technique, the powder spreader, an in-house built device, mimics the LS application as close as possible on a lab scale. It evaluates the density and surface quality of deposited layers at elevated temperatures. The second technique, powder rheometry, measures the force needed to move through a powder bed. Both tests indicate a decrease in the flowability of the standard LS polyamide of EOS above the glass transition temperature. 1 A. Amado et al, RapidTech 2013 Messe Erfurt, Germany (2013) 2 R. Bhadra et al, Int. J. of Food Prop. 16, 1071-1079 (2013) 3 R.D. Goodride et al, Prog. in Mater. Sci. 57, 229-267 (2012) 4 D. Drummer et al, Phys. Proc 5, 533-542 (2010)