The Evolution of Metal Additive Manufacturing

Jan 31, 2022 | 3D printing, CNC Machining | 0 comments

Additive manufacturing is well-known for its use of plastics, but metal additive manufacturing is a key, up-and-coming part of the field. Working with metal as a medium with additive manufacturing has its own challenges that some top-notch engineering has started to overcome so the advantages of additive manufacturing can be used in even more industries


Brief History of Metal Additive Manufacturing


Metal additive manufacturing traces back to the 1980s, the early days of any kind of additive manufacturing. In 1987, plastic 3D printing known as stereolithography came into the commercial world. With stereolithography, a UV light was used to solidify UV-sensitive liquid polymers layer by layer. From this process came Selective Laser Sintering (SLS) in 1992, which uses a laser to fuse powdered materials into solids one layer at a time. It was at this point that metal additive manufacturing, or metal 3D printing, became possible.


Why did it require the introduction of Selective Laser Sintering? With plastic additive manufacturing techniques, plastics are melted into a molten state in order to be malleable enough to work with. With metals, the molten state requires much higher temperatures that are dangerous to work with. Molten metal also does not go into the same kind of workable, vaguely coherent state as plastics due to their respective chemical structures. On top of that, cooling newly created objects made from molten metal needs to be done carefully to ensure structural integrity. It’s simply not a viable option for working with in the same way as plastics. 


In a powdered form, however, metal is far easier to deal with. The powder is especially prepared to react to the sintering laser, which works quickly. The end results do not resemble alloys as much as composites as durable materials are combined with materials with low melting points. The range of materials that can be used in metal additive manufacturing has grown by leaps and bounds.


Today, metal additive manufacturing can produce objects in stainless steel of various grades, titanium, cobalt-chrome, nickel, and aluminum. This wide range (and cost) allows for greater creativity and availability for metal additive manufacturing.


How Metal Additive Manufacturing Evolved


When first introduced in the 1990s, metal additive manufacturing was primarily only used for prototypes. This was due to the newness of the technology, which did not work fast or well enough for large-scale industrial use. However, this early version of additive manufacturing allowed for relatively cheap and much faster than usual prototyping, giving rise to a form of rapid prototyping that had never been seen before.


Metal additive manufacturing continued to develop and can work with a wider range of materials, much faster than before, and can produce objects of higher quality. Not only is Selective Laser Sintering used, but also metal binder jetting, directed energy deposition, and sheet lamination. 


All three depend on the same principle as Selective Laser Sintering: binding metal together layer by layer. Metal binder jetting functions similarly to an inkjet printer, using a liquid binder layer to bind layers of metal powder together, which does require a great deal of post-processing for structural integrity, though the stresses of heated materials are avoided. 

Directed energy deposition combines the laser used in Selective Laser Sintering with the layer-by-layer deposition used in plastic 3D printing techniques. A laser melts metal material, usually titanium or cobalt-chrome, and a nozzle deposits it in the desired layer. This technique is usually used for repairs or add-ons to existing structures. Sheet lamination binds layers together through bonding, ultrasonic welding, or brazing; the end result is not highly durable and works better as a cost-sensitive aesthetic method of metal additive manufacturing.


Modern metal additive manufacturing has unique advantages that have helped drive it to improve. As with other forms of 3D printing, metal 3D printing is based on computer models and printers will follow the model exactly. This means that more creativity is possible with designs, as well as more ability to create designs among more people; you don’t need the ability to draft things with additive manufacturing, you just need a computer, the correct programs, and some practice at creating 3D printing models. 


It’s also possible with metal additive manufacturing to create products with unusual angles, gaps, and internal spaces that would be difficult or even impossible to create with more traditional manufacturing methods. It also allows for optimization of design in a way not truly possible before. How little material is really needed to make a usable product? With 3D printing, it is possible to calculate this in a computer model and produce it, which is not often viable with subtractive manufacturing. You can optimize strength, flexibility, and other key properties in ways never possible before without expensive engineering work and large numbers of prototypes.


Metal additive manufacturing also has more material advantages. It is a very rapid method of production, often taking only a few hours to create small products- or, with smart model design, several products in the same print run. Complex parts can take only days to build rather than weeks. It’s also one of the most cost-effective choices for smaller runs of products. Whether you are printing one product or one hundred, you are only paying for the run of the printer and the exact amount of materials you need to use. Set-up costs are not an issue as it is with molding, machining, and other more traditional manufacturing methods. This also makes metal additive manufacturing highly sustainable, as powdered material that is not used to build the product is reusable for another project.


At Jawstec, we offer metal additive manufacturing services on our EOS M280. This top-of-the-line metal 3D printer uses Selective Laser Sintering to fuse layers of metallic powder together into the desired shape as directed by a prepared computer model. Jawstec offers industry leading turnaround time and is looking to become one of the leaders in the growing real of metal additive manufacturing. Our team has experience with everything from small custom projects to rapid prototyping to small production part runs. Give our 3D print quote tool a try to see if our services are right for you, or contact us today for more details. 


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