by Bryan Bergeron, Editor by Bryan Bergeron, Editor
When Additive and
Don't Add Up
When I made the move to 3D printing a few years ago, I imagined that by now I would have sold my milling
machine, drill press, and other 'subtractive' technologies.
The reality is that 3D printing is simply another tool in my
prototyping toolbox. This additive technology isn't really
clean or waste free — I’m constantly vacuuming starter
strands of PLA and ABS from my shop floor. Plus, the
technology isn't completely safe. There's the hot extruder,
hot bed, and — as I recently discovered — danger in
machining a 3D printout.
I like to prototype in PLA and then use ABS for a final
print. Printing with PLA has a number of advantages over
printing with ABS: It's relatively odorless; the nozzle
temperature is relatively low; there's no need to heat the
printing platform (a 10 minute process); and there's no
fumbling with the plastic film tape that always traps a few
bubbles. I just put down a layer of blue painter's tape on
the platform and hit the print button. Within a minute, I'm
I typically take the PLA printout and rework it with a
Dremel or other tool to reshape or add mounting holes to
the prototype. That is, until now. For some time, I've
noticed prickly feelings in my fingertips, akin to what I've
experienced after working with fiberglass insulation. I
didn't connect the 3D printing with the pain until I
switched from natural to black PLA.
Under my workstation microscope, I found dozens of
short black PLA shards embedded in my fingertips. After
spending an hour with tweezers extracting the splinters, I
decided that — as far as PLA is concerned — additive and
subtractive technologies don't add up.
I haven't given up on PLA altogether because of the
advantages noted above, but when there's a modification
called for I do it in software and make a new print. I still
rely on my drill press, Dremel, and other subtractive tools
to get a prototype into shape, but now only with an ABS
My latest experiment in 3D printing is thermoplastic
elastomer (TPE) — basically printable rubber. It's expensive
at about double the price of PLA or ABS ($50/500 gm
from AdaFruit, not including shipping). However, the
ability to print flexible structures is intriguing, and — like
ABS — there aren't any fragile shards flying about when I
shave an edge or drill a few holes in the printout.
Clearly, 3D printer technology is evolving, and the
spools of PLA, ABS, TPE, and other materials will
eventually give way to the powders and liquids used in
So, should you wait for those next-generation
materials to reach the consumer 3D market? No way. 3D
printing is a fantastic prototyping tool that should be part
of every electronics experimenter's arsenal. Just take the
proper precautions when you work with printouts, such as
gloves and eye protection when you're reworking
something printed in PLA. NV
6 May 2014
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