Effect of processing parameters in manufacturing of 3D parts through laser direct metal deposition

摘要

Laser cladding is a flexible technique which allows to deposit a wide variety of alloy protective coatings on metal substrates. By means of multilayer processing 3D objects can be created, a technique which is commonly known as 3D cladding or laser direct metal deposition (LDMD) This fabrication approach is a promising technique in the field of design and manufacturing technology, as it permits the direct one-step creation of parts with the desired shape and engineered composition for a particular application. In this work a study is presented on the fabrication of thin metal parts of Inconel 718 by means of laser direct metal deposition. It is shown that the deposition efficiency and the geometrical uniformity of the fabricated element are basically determined by the suitable combination of input laser specific energy (J/mm~2) and the laser step height set on consecutive laser scans. In order to guarantee the industrial reliability of the technique, on-line processing control and monitoring procedures are of major importance. A closed loop control method based on a photodiode IR sensing device has been tested which resulted in a substantial improvement of the finishing quality of the fabricated samples.