Real-time control of microstructure in laser additive manufacturing. Issue 5 (February 2016)

• Record Type: Journal Article
• Authors: Farshidianfar, Mohammad; Khajepour, Amir; Gerlich, Adrian
• Is Part Of: International journal of advanced manufacturing technology. Volume 82:Issue 5/8(2016)
• Page Start: 1173
• Page End: 1186
• Publication Date: 2016-02
• Subjects: Laser additive manufacturing -- Real-time control -- Infrared imaging -- Cooling rate -- Microstructure; Manufacturing processes -- Periodicals; Production engineering -- Periodicals; 670.427
• DOI: 10.1007/s00170-015-7423-5
• Languages: English
• ISSNs: 0268-3768

Abstract

Abstract A novel closed-loop process is demonstrated to control deposition microstructure during laser additive manufacturing (LAM) in real-time. An infrared imaging system is developed to monitor surface temperatures during the process as feedback signals. Cooling rates and melt pool temperatures are recorded in real-time to provide adequate information regarding thermal gradients, and thus control the deposition microstructure affected by cooling rates during LAM. Using correlations between the cooling rate, traveling speed, and the clad microstructure, a novel feedback PID controller is established to control the cooling rate. The controller is designed to maintain the cooling rate around a desired point by tuning the traveling speed. The performance of the controller is examined on several single-track and multi-track closed-loop claddings in order to achieve desired microstructures with specific properties. Results indicate that the closed-loop controller is capable of generating a consistent controlled microstructure during the LAM process in real-time.