The Laser Engineered Net Shaping (LENS®) system at Sandia National Laboratories, a laser-based direct metal deposition process, was recently used for the fabrication of a complex prototype. The LENS process involved the challenges of adjacent areas of thick and thin cross section, overhanging unsupported features, high aspect ratios, and a hemispherical substrate. These challenges were overcome through the use of closed-loop weld pool control, height monitoring, a strong understanding of build parameters, and unique process planning strategies. The near-net shape LENS part was completed with annealing and conventional machining to produce the complex components in a reduced timeframe.

Femtosecond laser processing is a promising new technology for the fabrication of micro-scale components from engineering materials, such as metals. In the femtosecond time regime, the ablation process is nearly a solid to vapor transition, thereby providing access to cut smaller features. Sandia National Laboratories has constructed a femtosecond laser microfabrication system to study the ability to produce microscale components in metals and glasses. In this paper, we will report on our initial studies to understand the metal ablation process with respect to manufacturing process parameters. With this understanding, we will show that femtosecond laser processing can fabricate complex components with fine feature detail and clean surfaces. A key finding in this work is the substantial effect of layer decrement on resulting recast material deposition when processing in air.

The primary purpose of this LDRD project was to characterize the laser deposition process and determine the feasibility of fabricating complex near-net shapes directly from a CAD solid model. Process characterization provided direction in developing a system to fabricate complex shapes directly from a CAD solid model. Our goal for this LDRD was to develop a system that is robust and provides a significant advancement to existing technologies (e.g., polymeric-based rapid prototyping, laser welding). Development of the process will allow design engineers to produce functional models of their designs directly from CAD files. The turnaround time for complex geometrical shaped parts will be hours instead of days and days instead of months. With reduced turnaround time, more time can be spent on the product-design phase to ensure that the best component design is achieved. Maturation of this technology will revolutionize the way the world produces structural components.

Direct metal deposition technologies produce complex, near net shape components from CAD solid models. Most of these techniques fabricate a component by melting powder in a laser weld pool, rastering this weld bead to form a layer, and additively constructing subsequent layers. This talk describes a new direct metal deposition process, known as WireFeed, whereby a small diameter wire is used instead of powder as the feed material to fabricate components. Currently, parts are being fabricated from stainless steel. Microscopy studies show the WireFeed parts to be fully dense with fine microstructural features. Initial mechanical tests show stainless steel parts to have good strength values with retained ductility.