Page 32 - Plastics News November 2022

FEATURE

Point of Pivot: 3D Printing vs. Injection Molding

The good
Scale, speed, uniformity — injection
molding ticks the right boxes for high-
volume production. Able to reliably
handle a huge array of materials, in-
jection molding offers predictability
and quality.
Further, the more the process is used,
the more parts are produced, and the
more cost-effective the solution be-
comes.
While an IM setup can be a huge up-
front investment, the ROI is huge as its
use scales. Indeed, peer-reviewed re-
search indicates that “Injection mold-
ing is the best way to mass-produce
small, precise polymer components
D printing first made headlines as a As with any tool in a toolbox, nuance with complex shapes.”
3half-Star Trek, half-everyman tech- is vital to the appropriate application
nology that brought science fiction to of solution to challenge. When all you The bad
the kitchen table. Gassed-up media have is a hammer, after all, everything Injection molding is a well-understood
reports positioned the technology as looks like a nail. Today’s toolbox is and go-to manufacturing process, but
an “anyone can make anything” pro- substantially more robust, leaving us naturally isn’t without its limitations.
cess. Unsurprisingly, no such process with options and the wherewithal to The learning curve and expense of
exists with push-button precision. make informed decisions: When do setting up an IM installation are signifi-
Mainstream perceptions dimmed, dis- I need a hammer? When do I need cant, as is the ramp-up time to actu-
missing the technology. something else? ally producing a new design.
Today’s 3D printing is an indisputably More to the point: When do I need Well-known as it may be, the design
industrial suite, though, with attain- injection molding and when do I need for manufacturing process for IM is
able production-level efficiency. To- 3D printing? lengthy and often non-linear. As a
gether with the processes, the ways Injection molding: The devil you molding-based technology, IM relies
in which we refer to the technol- know on removable molds, which stifle the
ogy have matured. No longer is “3D ability to design for low part counts
printing” or the original “rapid proto- Tried and true, injection molding (IM) and complex internal geometries.
typing” the phrase bandied about in has made its stand for decades. Pat- Further, creating those molds can
most professional labs; now, “additive ented in the late 1800s, IM boomed add weeks to months to a production
manufacturing” or, more casually, AM, decades later as WWII demanded timeline.
is the go-to terminology, placing these low-cost, high-volume production. The ugly
layer-by-layer processes squarely in It can hardly be said to have slowed
the manufacturing realm. since. Nearly ubiquitous in modern Overall, IM can reliably produce parts
manufacturing environments, IM is with known quality at high quantity
What had been overblown promises perhaps best described as the devil — but it takes a while. When lower-
about a decade ago are now delivera- you know; it has its kinks and limita- volume end-use product runs are
bles: Production, scale, quality, vali- tions, but it’s familiar and generally re- required, injection molding may add
dation, and volume are now end-use liable. Could IM, though, be displaced time and molding costs that counter-
realities. by newcomer AM? balance desirable ROI.
In some cases.

32 PLASTICS NEWS November 2022