INDUSTRY
Medical
CHALLENGE
Bringing Laser Powder Bed Fusion (LBPF) to Total Hip Replacements to reduce production costs using a multi laser system and a larger build plate
KEY BENEFITS
- Maximum throughput with 78% OEE
- No supports = reduced post processing = lower part cost
- Reduced lead time
- Fine feature resolution and optimal osseointegration for better patient outcomes!
Integrated Features
Reduced Lead Time
No Support
Performance
History
Acetabular cups are used during the total hip replacements to sit against the native bone of the illum and articulates with the femur through the hip stem. Inside of the hip cup there sits a liner that connects with the head of the stem for articulation of the hip.
Acetabular hip cups are traditionally manufactured by casting and forging. This method has a long turnaround time from order to final product. This is primarily because of the lost wax method. This method creates a sacrificial wax mold in which a shell is formed around. Then the wax is melted out of the shell and the metal of choice is poured into the shell. The shell is then broken to reveal the final part in the metal of choice. Then these acetabular hip cups must have some sort of porous structure applied to them, which is either expensive to manufacture or difficult to validate.
When additively manufactured, the part is originally printed using Electronic Beam Technology (EBM). This manufacturing process uses a stream of electrons guided by a magnetic field to melt layers of powder on top of each other. The EBM technology is subject to unpredictable failures. This is particularly unsatisfactory when multiple hip cups are being stacked onto one another in a single build. This creates a cascading effect where one failed part can create a large amount of scrap at once. Additionally, it complicates the validation process as each layer must be mechanically validated independently. Although EBM can be faster than Direct Laser Metal Sintering, DMLS produces smoother and more accurate parts with no supports.
Challenges
Casting and forging parts require a large amount of time to manufacture. This method requires foundries that are only justified with large part volumes. The long primary process along with the additional steps creates a bottleneck in the supply chain. This leads to increased prices, inventory, and lead times.
Parts manufactured by EBM technology are less precise and have a higher surface roughness. This results in increased post-processing costs. More material that is melted must be traditionally machined away and the medical device industry is specifically sensitive to roughness that can lead to an increase in risk of build failure as the build time is longer. This does not coincide well with a technology that has a lower Overall Equipment Effectiveness (OEE).
SOLUTIONS
Laser Powder Bed Fusion (LPBF) technology provides a closer net shape part compared to EBM technology. There are also no supports needed in LPBF technology. All of which significantly reduces less post processing, reducing lead times. The FormUp 350 also has a larger build plate with more lasers compared to EBM printers leading to potentially more than double the throughput. AddUp’s FormUp 350 also has a fine feature resolution and a roller recoater which allows for a lattice structure printed with the implant. Lattice structures improve osseointegration which allows for longer lasting implants and better patient outcomes.
Results
The FormUp 350 from AddUp delivers throughput capabilities currently unchallenged on the market. This can be seen in the below Hip Cup Productivity Study. Parts shown were printed with a compression roller technology in 30µm layers of Ti6Al4V ELI. Compared to EBM technology, the FormUp 350 has a shorter run time of 12:41 compared to 15:23 (EBM) which leads to an improved annual throughput of 9,309 (16,403 LPBF, 7,094 EBM).
| 2 Lasers Competitor 250 | 4 Lasers AddUp 350 |
|
|---|---|---|
| Parts per Laser | 10 | 8-9 |
| Runtime 30μm | 15:23 | 12:41 |
| Annual Throughput 30μm* | 7,094 | 16,403 |
