The good news is that a technology by any other name might perform as sweet, to riff off of Juliet’s centuries-old question — but we still have to ask: what’s in a name?

This question comes up all the time when
talking about manufacturing processes used today, especially those newer to
shop floors like 3D printing. (Or is that additive manufacturing…or rapid

Let’s start at the beginning. This technology suite traces its current roots back to the 1980s when processes like stereolithography (SLA) and fused deposition modeling (FDM) were being developed. These technologies found their initial usage in prototyping applications, achieving faster results than traditional processes. As these and other layer-by-layer approaches developed and matured over the last few decades, applications evolved as well, including into end-use production.

Throughout this briefly laid out history, we
see several stages of evolution in both process and usage. At each stage, a
different name has been appropriate, growing along with the fledgling industry
surrounding these technologies. Now that we’re in 2020, though, and have four
decades of experience in this maturing manufacturing area, we’re able to take a
step back and look at what the best terminology is to use today.

Printing or Additive Manufacturing?

A question that comes up a lot is simple:
“What’s the difference between 3D printing and additive manufacturing?”

At the simplest level of response, these terms
are often used interchangeably. Use either phrasing and anyone in the industry
will understand what you mean. But of course, there are ways to be more
accurate in discussing these processes, and more precise in nomenclature.

3D printing is the process of actually
building up a part, as a step in the overall additive manufacturing workflow.
Additive manufacturing itself can be seen to encompass the total process: CAD
design to slicing to 3D printing to post-processing to finished product. Rapid
prototyping would then be an application, rather than referring to the process

That’s one way of looking at it, and
understanding what is meant when any of these terms are bandied about.

Another way is in terms of the user. Additive
manufacturing is recognized as a more industrial term, and tends to encompass
expensive professional machinery being used in applications from prototyping to
end-use product production. 3D printing can refer to the process of
layer-by-layer building of an object, or more generally to refer to any usage
of this technology, from hobbyists using inexpensive desktop systems to
professionals using industrial equipment. Rapid prototyping was one of the
first terms used for these technologies, which in the 1980s were geared toward
the rapid production of prototypes and for a few decades so dominated usage
that this application was synonymous with the tech itself.

These conversations are ongoing, and opinions among experts are still fairly varied. When, for example, in working to understand viewpoints on the terminology of technology, I turned to industry professionals, responses extended from ease of understanding to familiarity of phrasing.

That conversation was perhaps best summed up by industry veteran Rachel Park, long-time journalist and currently a principal at PYL Associates, who said of 3D printing (3DP) and additive manufacturing (AM):

“3DP versus AM will not be resolved any time
soon, and like many others here, I often use them interchangeably depending on
application, audience and process being used. On that – I have noticed that
process names (re the 7 categories identified by ASTM) are being used more
frequently, to differentiate capabilities and applications for manufacturing /

Printing Technologies

That leads into an important conversation in
its own right, as the different 3D printing processes each have their own
terminology to take into account.

Industry expert Terry Wohlers, Founder of independent consulting firm Wohlers Associates, which puts out the annual Wohlers Report, recently discussed the importance of terminology through the lens of industry standard phrasing. He brings up several key points in this Wohlers Talk piece, chief among them the very availability of industry standards.

ASTM International, which defines standards in
a number of industries including additive manufacturing, has been publishing
terms for AM to serve as recognized standards. The first version, as Wohlers
points out, was published in 2009 as the ASTM F2792 Standard Terminology for
Additive Manufacturing Technologies defined 26 terms. That work was
foundational for the current ISO/ASTM 52900 Standard Terminology for Additive

As laid out from that standard in Wohlers
Talk, the presently recognized seven AM processes include:

  • Material extrusion—an additive manufacturing process in which material is selectively dispensed through a nozzle or orifice
  • Material jetting—an additive manufacturing process in which droplets of build material are selectively deposited
  • Binder jetting—an additive manufacturing process in which a liquid bonding agent is selectively deposited to join powder materials
  • Sheet lamination—an additive manufacturing process in which sheets of material are bonded to form a part
  • Vat photopolymerization—an additive manufacturing process in which liquid photopolymer in a vat is selectively cured by light-activated polymerization
  • Powder bed fusion—an additive manufacturing process in which thermal energy selectively fuses regions of a powder bed
  • Directed energy deposition—an additive manufacturing process in which focused thermal energy is used to fuse materials by melting as they are being deposited

Different companies, of course, refer to
technologies that fall under these umbrellas by proprietary names. Think of the
ongoing conversation regarding FFF v. FDM (that is, the common term Fused
Filament Fabrication versus the trademarked Fused Deposition Modeling), both of
which effectively refer to the same process and are in fact classified as
material extrusion.

Seeking to differentiate may lead many a
company to brand copiously; why say the standard “material extrusion” when they
could tout FFF, which as an acronym may sound more intriguing — or, if that
branding is from Stratasys, why not further herald FDM, which is trademarked
and is one of the original 3D printing technologies invented decades ago.
There’s certainly something to be said for standing apart from the crowd by
owning a process name.

Still, it absolutely comes across clearly to
everyone what sort of process is up for discussion when the term is universal;
material extrusion will convey just what’s meant quite neatly, and without any
potential confusion.

Naturally we must include a disclaimer that
while these seven ISO/ASTM recognized processes cover most of what we see in 3D
printing, they do not cover every technology. Significant R&D is ongoing
around the world, with efforts to create wholly new 3D printing technologies
abounding. Most of even these new processes will still fall generally under one
of these categories, but some will be new unto themselves. This is why
standards creation is so important, as these experts regularly discuss and
evaluate new processes that may need to be added.

In A Name?

So ultimately, what is in a name?

Everything, when it comes to clarity,
legality, and precision. Certainly it never hurts to be precise when sharing
information about industrial technologies.

At the same time, if you say “additive manufacturing” to someone unfamiliar with today’s advanced production processes, it’s perfectly fine to clarify that you mean “3D printing”, which may be more easily understood. There’s a time and place for full accuracy, but as always the most important part of communication is establishing understanding.

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