The Influence of Preheating on Laser Beam Melting

• Main Authors: Berger, Uwe, Merkel, Markus, Liebisch, Andreas
• Other Authors: Proceedings of the 2nd International Conference on Progress in Additive Manufacturing (Pro-AM 2016)
• Format: Conference or Workshop Item
• Language: English
• Published: 2016
• Subjects: Heated building chamber; Residual stresses
• Online Access: https://hdl.handle.net/10356/84417; http://hdl.handle.net/10220/41809
• Institution: Nanyang Technological University

Laser Beam Melting (LBM) represents an additive process where metallic components are generated layer-wise. A laser beam operates as heat source melting metal powder. The temperature level in the heat affected zone is considered as a critical issue and can be influenced by many parameters, e.g. the laser power and the scanning velocity. Temperature levels out of a reliable range cause residual stresses, which might lead to fracture of the component. Many activities are applied to the additive manufacturing process to analyse, control and forecast the temperature level in the critical process zone. In this paper the temperature level is influenced by a heated plate, which is included in the building chamber of a SLM system. Components can be fabricated at an ambient temperature level up to 800°C. Temperature gradients can be reduced resulting in less residual stresses. Results are presented for aluminum alloy and steel. Residual stresses are computed by numerical simulation and measured by X-ray diffraction (XRD). The surfaces of specimen are analysed by tactile measurement.