Northwestern University Robert R. McCormick School of Engineering and Applied Science

Advanced Manufacturing Processes Laboratory

LENS - Laser Engineered Net Shaping

Motivation

Most current 3D printing technologies allow us to use plastics to create three-dimensional objects, but there is a high demand in many different industries for printed metal objects with good surface finish and properties. In this project, we will establish a well-instrumented LENS station, a type of direct metal deposition process that stands for 'Laser Engineered Net Shaping', and a comprehensive numerical model of the process to better understand the physics of LENS, and therefore, further improve the process for engineering applications.

Description

LENS, or laser engineered net shaping, is a type of additive manufacturing process. It is essentially 3D printing with metal directly from a CAD design. In the process, a small amount of metal powder is delivered to the process zone through a nozzle, and a laser is focused in the area to melt the powders as they collect onto the substrate. The process was developed from laser cladding, which is basically a type of laser welding. The current issue with this process is mainly that there is a lack of dependable multi-physics process models capable of predicting material characteristics as built.

Approach

For this project, our lab is collaborating with three other groups at Northwestern, along with Northern Illinois University and Quad City Manufacturing Laboratory in order to evaluate several different aspects of this process, from powder design, the solidification process, in-situ sensing, and finite element modeling for LENS, to characterization of as-built properties. All of the above aspects will be integrated and validated by a new lab-scale LENS setup with well-instrumented sensing for temperature, position and in-situ porosity detection.

Photos

LENS

Fig. 1 - Machine Design Assembly

Sponsor

National Institute of Standards and Technology (70NANB13H194)

Results