3D Printing Machine Training

Share

Electron beam melting (EBM) has become a reliable production choice for end-use components ranging from jet engine parts to medical implants. The metal 3D printing method often fills the niche where a laser powder bed fusion (PBF) process might build too much residual stress into a part or require inordinate amounts of support structures. But EBM also has its limits, some of which are tied to the very mechanism by which it works.

The electron beam inside the 3D printer functions like a particle accelerator, attracting electrons from a filament and firing them onto the powder surface to fuse the particles together. But these electrons can also create problematic charged powder particles, something Wayland Additive sees as the Achilles’ heel of the process. The UK-based company has recently introduced an electron beam melting variant to the market that circumvents this shortcoming. Its NeuBeam process still relies on an electron beam as its energy source, but steps taken to prevent charged powder particles have led to process efficiencies over conventional EBM metal 3D printing.

Electron Beam Melting without Layer Pre-Sintering

A conventional electron beam melting process happens under vacuum at a high operating temperature. Each layer of powder is “pre-sintered” before the electron beam selectively fuses the geometry of the part; completed builds emerge from the printer packed into a cake of semi-sintered powder. This “hot-bed” metal 3D printing approach provides support for parts during printing, helps avoid the creation of stresses, and allows EBM parts to resist microcracking and other defects better than laser-based powder bed fusion prints.

The pre-sintering step has not been a choice, however, but a necessity for EBM. If the electrons were to hit a loose powder bed, a surface charge could build up causing the particles to repel each other, disperse and perhaps even create a smoke event that forces the build to terminate. Many metal powders also form an oxidation layer on the exterior of the particles, which is conductive; pre-sintering is necessary to hold the powder in place and ground this conductive layer.

Wayland Additive’s NeuBeam (for “neutral beam”) process avoids these challenges by neutralizing the surface charge that accumulates in the powder bed. When the risks associated with this charging are removed, electron beam melting can look much more like laser sintering. (In fact, Wayland describes the process as a “third way” of metal 3D printing, one that sits between EBM and laser sintering.)

Wayland Additive NeuBeam 3D printing process

As a “hot part” rather than “hot bed” process, NeuBeam 3D printing requires pre-sintering only of the part’s cross-section, shortening build times. Unused powder stays loose which also simplifies postprocessing. Photos: Wayland Additive

NeuBeam 3D printing takes place at temperatures above annealing but below sintering for the material used — meaning that the unused powder stays loose. The lack of a powder “cake” widens EBM’s geometric capabilities and dramatically simplifies part unpacking, powder removal and postprocessing. And because the process still takes place under vacuum, oxidation of the unused powder is minimized, making it possible to recycle all or nearly all of the leftover material for future prints.

But although NeuBeam is not a “hot bed” process, users still benefit from its “hot part” 3D printing strategy. Each layer cross-section is pre-sintered before melting, rather than the entire bed; this technique allows for time savings and productivity improvements while retaining EBM’s resistance to distortion and residual stresses. Parts cannot be entirely free-floating in the bed as with conventional electron beam melting, and supports may still be necessary for heat extraction from overhangs, but anchor points do not need to be substantial and can be designed for easy removal, the company says. Users also have the option to pre-sinter regions of the powder bed if desired. Like conventional EBM, NeuBeam parts typically do not require heat treat following printing, simplifying the additive manufacturing workflow.

Calibur3 metal 3d printer from Wayland Additive

The Calibur3 includes three methods of in-process monitoring for quality assurance, and offers an open architecture to enable the verification of new materials for the process. 

Neutralized Process Supports New Materials

The NeuBeam process will be available through the Calibur3 3D printer, which Wayland Additive expects to begin shipping in the fall of 2021. The initial machine launch will accommodate a maximum component size of 300 by 300 by 450 mm. The Calibur4 planned for later release will have a maximum size of 450 mm in all dimensions; existing Calibur3 machines will be upgradable in the field. In-process monitoring through structured light scanning, electron imaging and infrared cameras makes it possible to detect defects and track quality assurance data across the entire build. Open parameters support process control tailored to the material at hand.

Wayland Additive Calibur3 3D printer

The Calibur3 is expected to beginning shipping from the UK in September or October 2021.

It’s this materials openness that Wayland Additive believes will help drive additive manufacturing forward. Thus far titanium alloys and CM 247 have been verified for the NeuBeam process, but validation is ongoing. The neutralized printing environment can support finer powders than have previously been used in electron beam melting (likely improving surface finish for these parts), and could also open the door to new metal 3D printing materials. The company anticipates that refractory metals, highly reflective alloys, and materials not currently compatible with other EBM or laser powder bed fusion processes could all be compatible with this platform.

World According To
Airtech
SolidCAM Additive - Upgrade Your Manufacturing
Acquire
AM Radio
The Cool Parts Show
North America’s Premier Molding and Moldmaking Event

Related Content

Ceramic

AM 101: What Is Binder Jetting? (Includes Video)

Binder jetting requires no support structures, is accurate and repeatable, and is said to eliminate dimensional distortion problems common in some high-heat 3D technologies. Here is a look at how binder jetting works and its benefits for additive manufacturing.

Read More
Tooling

3D Printing Molds With Metal Paste: The Mantle Process Explained (Video)

Metal paste is the starting point for a process using 3D printing, CNC shaping and sintering to deliver precise H13 or P20 steel tooling for plastics injection molding. Peter Zelinski talks through the steps of the process in this video filmed with Mantle equipment.

Read More
Production

VulcanForms Is Forging a New Model for Large-Scale Production (and It's More Than 3D Printing)

The MIT spinout leverages proprietary high-power laser powder bed fusion alongside machining in the context of digitized, cost-effective and “maniacally focused” production.

Read More
Postprocessing

Postprocessing Steps and Costs for Metal 3D Printing

When your metal part is done 3D printing, you just pull it out of the machine and start using it, right? Not exactly. 

Read More

Read Next

Metal

3D Printed Parts on the Mars Perseverance Rover: The Cool Parts Show #23

The Perseverance parts made through additive manufacturing are extreme examples of lightweighting. We have replicas of the 3D printed parts that were sent to Mars.

Read More
EBM

Freemelt Offers an Open-Source Toolbox for Material Development

Swedish startup Freemelt believes collaboration will be a way forward for metal additive manufacturing. Its Freemelt One electron beam melting system for R&D supports this open-source philosophy.

Read More
LPBF

Wayland Additive's NeuBeam PBF Process Creates Parts Free of Residual Stresses

Wayland Additive has been working on the development of an entirely new powder bed fusion (PBF) process for metal AM called NeuBeam.

Read More
3D printing machine trainings