Frequently Asked Questions
1. What is Additive Manufacturing?
Additive manufacturing (AM), also known as 3D printing, is an innovative technology that allows a new approach to design and production by creating complex parts layer by layer until the full parts are produced. This technology bypasses many multiple manufacturing steps that would be required with traditional manufacturing and can produce parts that can be used in certain applications right after printing. By harnessing the design freedoms and efficiency of the AM digital workflow, highly engineered parts that exceed the strength of traditionally manufactured part can be printed with higher productivity, which has the capacity to change the manufacturing landscape in the medical, aerospace, and automotive industries among others.
2. Can you tell me about the additive manufacturing process?
Additive manufacturing is performed using a 3D metal printer, which is about the size of two large refrigerators put together and a Build File which is a 3D model of the desired part(s), sliced in small cross-sections (or slices). The 3D printer coats a thin layer of metal powder over a plate that sits on a build table, melts a thin cross-section (or slice) of the desired part according to the Build File. The printer then moves the plate down repeats this process layer by layer until the part(s) are fully printed.
3. What is EBM? (Electron Beam Melting)
Electron beam melting is a type of additive manufacturing in which a high-power electron beam melts metal powder on a powder bed layer by layer to create a production part. It can be a time and cost-effective way of producing complex geometries of high density with minimal post processing operations. The process also allows you to produce parts with little to no residual stress in a clean and controlled vacuum environment.
4. What is the difference between laser and EBM?
While both technologies are powder bed-based, the main difference between Direct metal laser melting and EBM is the energy source each uses to melt layer by layer. EBM technology melts 50-90 micron powder layers with a single electron beam which has a power of 3000W and penetrates multiple layers of the powder bed for optimal melting sub-surface. The electron beam position is controlled with magnetic coils which allow the beam to move up to 8000m/s.
5. What are the advantages of the ebm process?
- High Power Electron Beam (3000W)
- Extremely fast beam movement and control (up to 8000m/s)
- Thick powder layers allow for shorter layer melting times
- Stacking of parts on sintered powder bed for utilization of entire build envelope
- Low level of internal porosity and defects of as built components
- Excellent microstructure and material properties from as built material compared to wrought and cast material
- Vacuum chamber allows for a clean and controlled environment during EBM Process
- Minimal residual stresses due to high process temperature
- Little waste material: virtually all excess powder can be recycled
- Lesser need for support material for certain negative surfaces compared to Laser technology
- Futureproof technology: Further advances will allow EBM machines to have the same functionality as Scanning Electron Microscopes
6. What's better? Laser or EBM?
The real question should be:
“What level of resolution for orthopedic implants will produce the greatest clinical benefit, for both the patient and the surgeon, and will the design stand up to the verification and validation testing required to obtain the product clearance?”
What’s important to understand: In the world of orthopedics, we are concerned with fusion and bone ingrowth. Clinical studies have consistently demonstrated that the microstructure at the strut level is better for fusion on EBM than laser. That is why you will see more laser companies detuning their systems to increase their implant surface roughness to accommodate and promote that required osseointegration for fusion.
7. What is the time to market and cost of EBM vs other manufacturing technologies?
EBM has many distinct advantages over DMLM and traditional manufacturing. Let’s use a Titanium cervical implant with unique lattice features as an example, 48 hours from hitting the print button, assuming the part design has already been finalized and all AM Build Files/Traditional Machining Tooling Paths have been created.
The EBM machine preparation is standard no matter the part
DMLM machine preparation is standard no matter the part
Tooling Design and Manufacturing needed before Part can begin manufacturing process
|Output||1,225 units (178 X 7 layers high) Cervical cages coming out of the EBM machine ready for the secondary process. EBM allows you to stack parts. The ArcamEBM machine can run 24/7 without an operator present from when the print starts all the way until the print finishes||178 units. Constrained to single layer build||Units are variable, assuming all machining operations are available with a 3 shift operation|
|Raw Material||Powder used in the EBM Process is a larger powder fraction size (45-105um), and therefore is cheaper for powder cost||Powder used in the DMLM process is a smaller powder fraction size (25-45um), and therefore tends to be more costly||Casting needed from an outside supplier, which results in a high initial cost for the mold. Considerable scrap material is generated during machining operations|
EBM needs very few post-processing operations compared to other manufacturing technologies
Many processes must be performed after printing which adds time and cost for production
Remaining processes and cost. Additional 2 weeks to start of secondary processes
In summary, EBM is not only much more productive than DMLM or Traditional Manufacturing over a 48 hour period, but it also saves quite a bit of cost right from the beginning. DMLM has considerable Post Process Operations and expensive powder which both add cost. Traditional Manufacturing has extensive setup time and costs before even beginning production.
8. Is additive manufacturing more expensive than traditional manufacturing?
No. If you understand the clinical importance of osseointegration & fusion, then you should have the freedom to design a solution that will optimize overall patient outcomes. That means evaluating and applying lattice structures, internal features, and complex geometries where needed, without having the constraints of traditional manufacturing in the back of your mind. Additionally, the manufacturing cycle of a part is significantly lessened when implementing AM vs traditional manufacturing. While AM only requires the AM process and 2-3 post processing steps, traditional manufacturing requires a part to move through a considerable number of machining steps along with heat treatments and post processing on top of that. The longer manufacturing cycle only adds additional cost and processing time to each part and increases the chance for scrap and non-conforming product.
9. What materials are you capable of printing?
The primary material we use for implants is Titanium, Grades 5 and 23. For other applications, the EBM process can print in CoCr, Nickel alloy 718, Copper, and Tool Steel.
10. We want to update a cage design from PEEK (Polyether ether ketone) 3D printed titanium, is that possible?
That is always a possibility. However, this is by no means an optimal way to leverage AM.
PEEK is traditionally machined; therefore, you will inherit all the same design and manufacturing limitations that reside with traditional machining. Secondly, and most importantly, PEEK is a form of plastic, with material characteristics that do not support bone-in, on or through-growth. Perhaps, you can achieve this by coating PEEK with either TPS (Titanium Plasma Spray) or HA(hydroxyapatite) treatment. From a process and cost perspective, you’re adding additional steps impacting both. Also, the TPS process is a clear concession to the value of using Titanium. Advancements in technology & materials are paving the way for better patient and clinical outcomes, and AM is the next step to ensure these outcomes
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