Manufacturing has been a way of life since the first industrial revolution. By the 1980s, advanced factories created products in ways never before imaginable. That same decade, a new form of manufacturing with the promise to revolutionize the way we make things was born—additive manufacturing (AM).
Unlike traditional manufacturing processes that stamp, extrude, inject, or subtract material to create, additive builds up an item layer by layer. The first additive systems utilized stereolithography, where a laser cures a thin layer of photo curable resin to create a part.
At first, users were restricted to a few materials and early machines offered limited possibilities. Like early computer systems, the first additive machines were prohibitively expensive, bulky and turned out pieces not suitable for final use. Initially, manufacturers utilized the technology for rapid prototyping, eliminating time-intensive and expensive moldmaking and other traditional manufacturing processes used in prototyping at the time. The new technology also allowed for iterative designs to optimize for final production.
However, engineers sought to unlock the potential of AM to be used with any material —especially metal. While polymers, the first materials available for AM, are widely used in products, additive’s true potential could not be fully realized without the strength, versatility, and heat and wear resistance of metal.
Over the years, new processes have been developed for metal AM, including binder jetting, direct energy deposition, and electron beam melting. As these methods evolved, the range of materials, part precision, speed and machine size have all improved. Today’s metal additive machines are more accessible to manufacturers than their predecessors but remain a more significant investment than many polymer systems.
Differences in price, accessibility, ease of use, knowledge, and final part quality have limited the investment in metal AM by smaller manufacturers. Improvements enabled by additive have been limited to using polymers or having metal parts produced through a service bureau or contract manufacturer. For small and medium-sized operations, this provides a way to test the technology before investing in larger scale operations.
Over the past five years, several companies have announced or released machines that put metal within the reach of nearly every manufacturer. Smaller, cheaper and easier to use, these new systems allow manufacturers to gain experience with metal additive methods before investing in larger, more production-level machines. No longer are engineers limited to prototyping and additive manufacturing with polymers.
These new machines, while differing in their exact process, tend to follow a similar path to the final product. While many industrial metal AM machines produce final parts in one or two steps, often sintering the metal on a layer-by-layer basis, many of the more affordable machines use a method first developed at MIT.
First, a green part in which the metal is not fully fused into the final product is built. This part then may go through a process to remove the primary binding material before being placed into a furnace to finish the final sintering of the metal and/or infuse metal into the open spaces left by the binder.
As metal additive technologies continue to improve and new techniques, materials and machines are created, manufacturers will continue to see more affordable and accessible metal additive solutions. With this, additive manufacturing will further fulfill the disruptive potential first envisioned when the technology was invented in the 1980s.
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