Experts in my country studying EBM: Professor Lin Feng from the Department of Mechanical Engineering of Tsinghua University
Electron beam melting is a 3D printing technology that uses electron beams to fuse metal powders together to make parts. The editor of "3D Printing Business Information" will briefly explain how this technology works in this article, point out its advantages and disadvantages, and demonstrate its uses, hoping to help you understand this technology in a preliminary way.
01. What is electron beam melting?
Electron beam melting (EBM) is a 3D printing technology that is very similar to SLS, but EBM has two differences - energy comes from electron beams rather than CO2, and the material used is a conductive metal, not a thermoplastic polymer.
Specifically, EBM usually uses titanium alloys and cannot print plastic or ceramic parts. This is determined by the charge on which the entire process is based.
The reason why EBM needs conductive metals is because the technology itself is based on charge. In other words, charge is responsible for reacting the powder with the electron beam, thereby curing the powder.
Below we will introduce EBM in more depth, including its working principles, advantages and disadvantages, and some ideal application areas.
02, electron beam melting process
EBM 3D printing parts post-processing
All EBM 3D printers include an energy source that can emit electron beams, a powder container, a powder feeder, a powder recoater and a heating construction platform. The printing process is carried out in a vacuum so that production can be carried out under strictly controlled conditions. More precisely, the vacuum is mainly intended to prevent the powder from oxidizing at high temperatures.
EBM The 3D printing process begins with filling the powder chamber with the required metal powder. After completion, the powder box is placed on the 3D printing machine, where the heating phase begins. Before printing, the powder needs to be heated just below its melting point.
3D printing itself starts with a powder recoater, which deposits a layer of preheated powder onto the build platform. Once the powder solidifies, the electron beam melts. The electron beam is controlled by a set of electromagnetic coils that precisely point the electron beam to the desired point of building the platform. The electron beams selectively move as the powder is melted, allowing the powder particles to merge together.
After completing a layer, the build platform moves the height of one layer downward. The recoater enters again with a new layer of powder, and the electron beam begins to induce the fusion of powder particles, resulting in the formation of a new layer... This process is repeated until the entire component is completed.
03, electron beam melting post-processing
Remove powder from EBM printed parts
When finished, the parts will not be visible immediately because they are covered with non-sintered powder in the powder bucket, and the non-sintered powder must be removed first.
1, Distortion
Because the EBM 3D printing process is surrounded by high temperatures, the parts themselves are exposed to stress, which may lead to deformation. Although the surrounding non-sintered powder provides support for the parts during printing, it is not effective enough.
Due to the risk of distortion, EBM needs to support the structure. The support is made of the same material as the part itself.
When the part is finally completed, remove the powder bin from the 3D printer. Although the part has been manufactured, you cannot use the part for the time being.
2, heat treatment
Because there are molecular stresses in the parts, the powder bins containing these parts are printed and heat treatment ensure the elimination of stress, thereby reducing the risk of deformation. Heat treatment also helps improve the mechanical properties of parts.
After heat treatment, compressed air is used to expose the parts from the powder. If the component has a support structure, it is removed after the compressed air removes the powder.
3, support
Since the brackets are made of metal, they are quite strong. Because of this, removing support is a common problem for metal 3D printing. Like other metal 3D printing techniques, support structures are usually away from parts processing.
After the support is finally removed, the EBM parts can be polished, coated or even further processed using conventional techniques if needed.
04, EBM Advantages and Disadvantages of Electron Beam Melting
EBM 3D Printing Racing Components
Like other 3D Printing technologies, EBM also has its advantages and disadvantages.
1. Advantages
·Full melting of powder on a high density basis—the electron beam achieves complete melting of powder, ensuring high component density and thus ensuring strength.
·Because of high density, high intensity. Compared with other metal 3D printing technologies, it is considered to have the best strength.
·Faster printing process.
·Non-sintered powder can be recycled.
·The risk of warping is low due to being in a vacuum state.
2. Disadvantages
·Small print volume (maximum diameter 350 mm, height 380 mm);
·Not very accurate because the laser spotlight is slightly wider;
·Limited material selection (titanium or chromium cobalt alloy only);
·Technology and time-consuming post-processing;
·Expensive machines and materials ($300 +/kg)
05, electron beam melting industry and applications
EBM 3D printing skull implant
An interesting fact about EBM 3D printer is that only one company produces this kind of printer—Arcam EBM, this is a GE Additive company, and of course, it is naturally a leader in the EBM field.
EBM 3D printers are very expensive. We don't know the exact price because it is not public.
Since EBM 3D printers and powders are expensive, it is no surprise that this technology has not been used for mass production yet, it is mainly used to make small series of parts that usually have complex structures.
As you would expect from the technology used to make high-strength metal parts, it has been used in many fields. EBM has been used in industries such as medicine, aviation and automobiles.
It is worth mentioning that EBM applications were born in the medical industry. With EBM, it is possible to produce a fully functional custom skull implant. Since EBM parts are usually strong, this part is certainly as strong as a skull or even stronger.
Source: 3D printing business
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