Metal Additive Manufacturing for Aerospace and Defense | Manufacturing Industries | advancedmanufacturing.org

Evan Butler-Jones, Vice President, Product & Strategy, Equispheres Inc.

The evolution of laser-powder-bed fusion (L-PBF) is headed in a direction that will be familiar to most manufacturing engineers. At the intersection of multi mode lasers, engineered metal powders and sophisticated control software is a process that looks a lot like CNC machining.

L-PBF can now produce larger sections at high build rates (~400 cm3/hr) and then switch to lower speeds and finer resolution for thinner features and better surface finish, similar to the roughing and finishing cycles in CNC machining. This requires advanced metal powders that can operate at both low– and high-energy inputs while producing reliable and consistent results.

As the metal additive manufacturing (AM) ecosystem develops, it’s getting closer to the model the manufacturing industry is familiar with from CNC machining. This is not hybrid manufacturing, where a part undergoes both AM and subtractive machining.

A recent innovation in L-PBF is the capability to combine high-powered multi-mode lasers with beam shaping and dynamic process control. Akin to wielding lasers as end mills, the technique employs broad, fast passes for rough shapes and fine beam paths for detailed features and smoother finishes. One challenge is the feedstock’s ability to withstand such drastic energy input changes.

Previously, with the lower-powered lasers and limited flexibility in laser focus and speed, the process of metal AM could be painfully slow, like machining the whole part with the finishing end mill.

The industry now achieves unprecedented productivity levels, combining speed with precision to meet diverse part requirements. This synergy enhances cost efficiency and productivity.

I first heard of beam shaping being similar to the tools used in milling at a DMG Mori presentation. It’s a relevant and accurate descriptor of what’s coming in metal AM. I began to notice parallels between the two processes immediately, and my conviction that this is the direction of the future grew as Equispheres worked with Aconity3D and high-powered, multi-mode lasers.

Today, metal AM can deliver both design freedom and high speed, making it cost competitive without compromising material properties and performance. This progress results from collaborative efforts, integrating complementary technologies to elevate performance across the board. Significant strides in machine technology, process control software and material development for the past 7–8 years have enabled faster build rates.

The essential elements for this roughing/finishing concept for high-speed AM processing are:

One of the key barriers to the evolution of beam shaping was the lack of versatility of the powder. This advanced AM process requires a feedstock with very specific capabilities. The material must produce a stable, consistent melt pool at both the slower build rates with finer beam profiles as well as the high-energy, high-speed rates to achieve reliable results.

Various partners have now validated that beam shaping and high-powered lasers can deliver industrial parts with suitable quality and amazing print speeds. But only a few companies possess the necessary components and systems for this advanced L-PBF process. A small number of suppliers of multi-mode/tunable lasers, coupled with a handful of machinery companies and even fewer powder suppliers, are pioneering this technology.

The powerful combination of multi-mode lasers, advanced process control and engineered AM powders make AM equal to a CNC machine with a well-stocked tool changer. Roughing can be done at higher speeds with thicker layers; when fine surface work is needed, simply switch tools/modes.

A step change in productivity is imminent for L-PBF, and this new level of productivity for metal AM has ignited the industry’s imagination. We have moved the bar and people are thinking differently about what is possible.

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