HIGH ACCURACY AND EFFICIENCY MODELING SYSTEM USING DIRECT ENERGY DEPOSITION BASED ON REAL-TIME CONTROL OF DISTANCE BETWEEN NOZZLE AND MELT-POOL

Abstract

Directed energy deposition (DED) is a type of additive manufacturing (AM) that uses a metal powder as the material and a laser as the heat source. A laser beam is irradiated on a metal surface to create a melt pool, and metal powder is sprayed into the pool for modeling. For high-accuracy, high-efficiency, and high-quality molding in DED, the stand-off distance (SOD) between the head nozzle and melt pool must be maintained at an optimal value. However, owing to the many complex parameters of DED, the height of the modeled object is unstable, and the SOD cannot be maintained at an optimal level.

Three systems were developed in this study. The first system measures the SOD of the Nth layer in-process using a CMOS camera and calculates the build height of the N+1th layer. The second generates the modeling paths according to the calculated N+1th build height. In addition, it optimizes the modeling direction and pattern of path according to the shape. The third generates NC programs in real time based on the generated modeling paths, and models the object. The effectiveness of the overall system was confirmed through verification experiments.