Thermal conductivity measurements of polyamide 12

An important component in understanding the laser sintering process is knowledge of the thermal properties of the processed material. Thermal conductivity measurements of pure polyamide 12 were conducted based on transient plane source technology using a Hot Disk® TPS500 conductivity measurement device. Polyamide samples were packed to three different densities in nitrogen at steady state. Thermal diffusivity and conductivity were measured from 40°C to 170°C for both fresh powder and previously heated ("recycled") powder. The fresh powder tests revealed that thermal conductivity increased linearly with temperature while for previously heated powder, more constant and higher thermal conductivity was observed as it formed a powder cake. Tests were also performed on fully dense polyamide 12 to establish a baseline. Polyamide 12 powder had a room-temperature thermal conductivity of approximately 0.1 W/mK which increased with temperature, whereas the bulk laser sintered polyamide 12 room-temperature value was 0.26 W/mK and generally decreased with increasing temperature.