Analysis of time dependent thermal properties for high rates in selective laser sintering

Abstract

Purpose

The thermal history during laser exposure determines part properties in selective laser sintering (SLS). The purpose of this study is to introduce a new measurement technique based on a CO₂ laser unit combined with a high-speed DCS. A first comparison of the thermal history during laser exposure measured with Laser-high-speed-(HS)-differential scanning calorimetry-(DSC) and in SLS process is shown.

Design/methodology/approach

This Laser-HS-DSC allows an imitation of the SLS-process in a very small scale, as the sample is directly heated by a CO₂ laser. For this study, the laser power and the impact time is varied for determining temperature and achieved heating rates. Consequently, the temperature levels measured by the Laser-HS-DSC are compared with measurements in SLS-process.

Findings

The influence of laser power and impact time on resulting maximum temperatures und heating rates during laser exposure are investigated. With increasing laser power and impact time the maximum temperature rises up to approximately 450°C without material degradation. The heating rate increases up to an impact time of 3 ms and stays almost equal for higher durations.

Research limitations/implications

The Laser-HS-DSC experiments are based on few particles limiting a complete comparison with SLS process. In SLS, one volume element is exposed several times. In this study the PA12 material was exposed only once.

Originality/value

For the first time, laser sintering experiments can be transferred to a laboratory scale to analyze the influence of laser exposure on resulting temperature field during laser exposure without superimposing effects.

Citation

Wudy, K., Drexler, M., Lanzl, L. and Drummer, D. (2018), "Analysis of time dependent thermal properties for high rates in selective laser sintering", Rapid Prototyping Journal, Vol. 24 No. 5, pp. 894-900. https://doi.org/10.1108/RPJ-01-2017-0013