Concept Laser M3 Linear

Germany’s Concept Laser has been a leader in the field of laser metal melting since the debut of its M3 Linear system in 2004.

Complete with a 350 × 350 × 300 mm (just over one cubic foot) build volume, the M3 Linear can process a wide variety of metals, including stainless steel and other chromium alloys.

To melt its atomized metal powder stock, the M3 uses either a 200W or 400W fiber laser.

Given its relatively large build volume, the M3 uses galvo scanning optics, beam deflectors, mirrors and linear direct drives to maintain laser accuracy across its vast powder bed.

Aside from printing, the M3 is also capable of performing laser erosion jobs and laser marking jobs. With these added features, the M3 can be employed in a number of operations, increasing the machine’s productivity.

How the M3 Linear Works

Concept Laser’s proprietary LaserCUSING technology builds metal components layer by layer in a fashion similar to other metal sintering machines. The major difference between Concept Laser and other metal additive manufacturing (AM) manufacturers’ melting process is that Concept Laser’s engineers have designed a machine that doesn’t require a heated build chamber. For this reason, the only energy that is applied to the machine’s atomized metal material is direct laser energy. According to Oliver Edelmann of Concept Laser, “This is a prerequisite to get very high density and almost identical mechanical properties [similar] to a normal part milled out of a solid steel block.”

At the outset of a print, a layer of atomized metal powder is spread across the print bed and swept to form a completely flat surface. With an even metal surface established, a 200W-400W laser rapidly traces the profile of whatever model is being built before a new layer of metal is laid down on the print bed and the melting process begins again. As each successive layer builds upon the next, M3’s laser binds the previous layer to the current layer, forging a solid final product.

Once a print job has been completed, leftover material can be re-sieved and returned to the material hopper to be used in another build.

Although many metal AM machine manufacturers offer a wide variety of materials, to my knowledge Concept Laser is the only firm that offers an in-house material customization service that will develop atomized custom alloys tailored to a client’s needs.

The M3 Linear in Action

While metal 3D printing has been forecast as the “future of additive manufacturing,” the truth of the matter is that metal AM has already found its way into the industry. In fact, the likes of Lockheed Martin, GE, NASA and others are already exploiting the technology’s abilities and achieving incredible results.

NASA’s Marshall Space Flight Center is home to the most cutting edge developments in rocketry. For the past few years, engineers at the center have been developing the Space Launch System (SLS), a rocket that will take astronauts into orbit and eventually to Mars. While tried and true methods for rocket manufacturing have existed for decades, Marshall’s engineers wanted to know if they could build rocket components using additive manufacturing. Armed with a LaserCUSING machine, NASA’s engineers decided to build a rocket injector.

After modeling and designing a scaled-down version of the SLS’s injectors, NASA’s engineers printed two copies of their new rocket components. From the beginning of their project to the time the injectors were removed from the Concept Laser machine, just over a month had elapsed. Then it was time for live fire testing.

Mounted to a fuel setup, each injector was subject to 11 main-stage, hot-fire tests. For a grand total of 46 seconds, the AM injectors were subjected to temperatures nearing 3,315°C (6,000°F).

In the end, NASA’s AM injectors compared favorably to their traditionally-manufactured counterparts. “We saw no difference in performance of the 3D-printed injectors compared to the traditionally-manufactured injectors," said Sandra Elam Greene, the propulsion engineer who oversaw the tests and inspected the components afterward. “Two separate 3D-printed injectors operated beautifully during all hot-fire tests.”

Moreover, NASA’s engineers also found that by using metal AM they were able to reduce the cost of building an injector by 60 percent. In an age where funding for the world’s premiere space agency is drying up, AM might be one of the technologies that keeps NASA efficient and relevant.