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Over the last 100 years, stainless steel has played a vital role in many industries ranging from nuclear energy and healthcare, to several domestic appliances that are commonly used each day. Currently, stainless steel manufacturers are looking to increase the potential of this metal by incorporating 3D printing technology during production. 3D printing is a method of manufacturing three-dimensional solid materials through the use of a digital model that prints the final product through the use of a printer that features this specialized digital technology.
Unlike conventional machining techniques that remove material by cutting and drilling procedures, 3D printing instead operates by additive processes that deposits successive layers of the desired material to create a final product.
Stainless Steel 3D Printing Technology
Stainless steel offers a low cost form of metal printing that is ideal for large objects as a result of its exceptional physical strength. Like titanium and aluminum, stainless steel can also be used as a metal 3D printing material for complex designs, which is not currently possible when traditional manufacturing methods are used. To produce stainless steel in the traditional sence, conventional steel material, which is a combination of both iron and carbon elements, is melted and eventually combined with chromium and molybdenum elements to prevent rust and corrosion to the final product. The melted material is then processed through a series of cooling, reheating and rolling steps that allow the final microscopic structure of stainless steel that accounts for its high strength properties through tightly packed alloy grains with thin boundaries
The main method used for stainless steel 3D printing requires binding the layers of stainless steel powder together with a bonding agent. During the process, a stainless steel powder layer is laid in a build box and a print head is allowed to move across the box to spray a binder solution. The layer deposited with binding agents is then dried using a heating lamp. Following this, a new powder layer is spread and the process is repeated. Once the final object is completed, it is then dried in an oven to cure the binder completely.
Unfortunately, the traditional method of 3D printing for stainless steel products has often left the final products to be highly porous and subsequently susceptible to fracture. To address this manufacturing issue, several altnerative methods for 3D printing stainless steel have been investigated.
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Alternative Methods
Selective Laser Sintering (SLS)
SLS involves the selective sintering, which is more simply understood as a heating and fusion, of a powdered material that allows layers of stainless steel powder to be laid down. The granules of stainless steel are then fused together through the use of a laser.
Selective Laser Melting (SLM)
SLM uses metallic powders to build functional 3D parts. Thin layers of metal powder are laid down and then fused together through the use of an ytterbium laser. Once the part is complete, it is removed from the bed and goes through any finishing processes that are required for the given object.
Direct Metal Laser Sintering (DMLS)
DMLS uses a laser source to bind a powdered material together used with metal powders.
Laser Powder-Bed Fusion
A recent study conducted by Lawrence Livermore National Laboratory in California utilized an approach known as laser powder-bed fusion to produce 3D printed stainless material that maintains a tightly packed microscopic structure upon completion. Through this method, the researchers use a series of lasers combined with a rapid cooling process that fuses metal alloy particles together. Furthermore, the researchers also designed a computer-controlled process that allows the user to create densely packed stainless steel layers by manipulating the structure of the material at the nano-level8. Through the use of both of these procedures, the researchers found that their final stainless steel product exhibited a much smaller quantity of fractures as compared to stainless steel that was produced through more commonly used 3D printing techniques.
Benefits of Stainless Steel 3D Printing Technology
3D-printed stainless steels have many benefits, including:
- Durability
- Resistant to heat at temperatures up to 831°C
- Light in weight
- Inexpensive
- Produced in shorter time
Applications of Stainless Steel 3D Printing Technology
As with traditional stainless steel, 3D-printed stainless steels find applications in a wide range of areas. These include:
- Jewellery
- Tools
- Construction applications
- Dental caps
- Metal implants
- Industrial applications – designing functional components
- Decorative models like statues, medals and keys
- Military applications
- Manufacturing automotive parts
Conclusion
The production of stainless steel through 3D ] printing offers manufacturers a reliable and rapid method of producing this material. Although the cost of functional 3D metal printers is relatively high, several inexpensive 3D printers are currently available on the market. Several manufacturing companies are now opting for 3D steel printing as it is precise, inexpensive and a more realistic technique as compared to other manufacturing technologies.
In general, continued innovation and development of 3D steel printing will likely produce more creative designs at lower costs.
References
- Stainless steel – i.materialise
- High detailed stainless steel available for 3D printing- 3ders.org
- Stainless steel - Shapeways
- Selective Laser Sintering
- Renishaw's laser melting (metal 3D printing)
- "3D printing doubles the strength of stainless steel" - Science Magazine
- 100 years of stainless steel
- Behind the rise of the 3D printing revolution
This article was updated on the 13th August 2018.