3D Metal Printing: Does It Add Up?

Prolific Renaissance artist Michelangelo said, “The sculpture is already complete within the marble block before I start my work. … I just have to chisel away the superfluous material.” I wonder what the great visionary would think of exchanging his chisel for an additive-manufacturing tool such as today’s 3D printers.

3D printing has been around since the 1980s, when it was first known as rapid prototyping. For several decades, the technology was applied in a variety of ways – from forming the external cartilage structure of an ear to creating functioning, transplantable human organs. Then about 15 years ago, selective laser sintering (SLS) became commercially viable and opened the door to fabricate objects made from metal, ceramics, glass and other substances. This began the age of on-demand industrial parts.

More recent advances have enabled 3D printing of parts made with aluminum, titanium, platinum, gold, brass, copper, steel and other metals. This range of capabilities allows 3D metal printing to be used in making prototypes, working components, miniatures, jewelry, medical and dental implants, automotive and aerospace parts, and much more. Fabricating some of these items using traditional manufacturing methods can involve a large amount of waste. For example, the tight machining tolerances for precision aircraft components can lead to a high percentage of rejected parts and, even when production is successful, more than 90% of the starting material may need to be cut away. 3D printing is much less wasteful and more energy efficient. Objects derived by 3D printing can be as much as 60% lighter than more traditionally produced parts, which can present advantages ranging from fuel economy to facilitating the delivery of goods by drone.

There are several means of 3D metal printing. For example, direct metal laser sintering (DMLS), also known as selective laser melting (SLM), is a powder-bed process. It uses a laser to “melt” a 2D design onto a thin bed of powder. This step is repeated multiple times and each subsequent layer is bonded to the previous one. Although slow, this widely used process yields stout and durable results.

Another approach is powder-fed printing, which uses directed energy deposition (DED) or laser metal deposition (LMD) to send a concentrated stream of metal powder through an extruder and then exposes the powder to laser energy upon reaching its target. It’s a highly accurate printing process that can create complete objects or even patch faulty parts.

Then there is metal binder jetting, in which a binding resin is applied on a powdered metal material. This approach is fast, cost effective and lends itself to printing large objects, but there is a trade-off in structural strength and density.

With the growing use of 3D printing, the cost of owning and operating an in-house manufacturing capability is now within budget for many small companies. What once was available only in large, expensive industrial equipment is now becoming accessible through desktop systems, making 3D metal printing much more widespread.

Perhaps due to the processing time involved, it appears that there are no 3D metal-printing foundries in operation yet. However, traditional foundries do apply 3D printing indirectly as a way to create the casting molds that they use. And with the cost of printers trending downward while new technologies and methodologies continue to make strides, it may only be a matter of a few years before 3D metal printing reaches the production volumes needed to make it a practical alternative to serial-casting foundries.

The parallels between 3D metal printing and semiconductor fabrication are interesting. Both processes are capable of creating highly precise metal structures; both offer ways to  improve efficiency, whether it’s reducing the weight of finished parts or reducing operating voltages; and both are critically concerned with throughput, reliability and production costs. Who knows? Although 3D metal printing is still a long way off from challenging the manufacturing might of wafer fabs and foundries, tomorrow’s Michelangelos of IC design may be able to realize their visions using the additive-manufacturing capabilities of 3D metal printing.