A. We all like to save money, but usually you really do get what you pay for. The designers of your 3D printer have put a lot of time and effort into the
design of an effective print head. They carefully selected
their materials to match with the heater, extruder, and
motion of their device. This is an easy question to answer.
You use what the manufacturer of your way-cool toy
suggests that you use. No one else will know better what
works. You could compare specifications and material
composition of alternative plastic to find a cheaper
alternative, but I suggest that you answer two questions
to yourself first:
1. How much more expensive is it to have someone
else make the parts that you are fabricating yourself?
2. How much are you willing to spend to fix the
possible damage done to your 3D printer?
Once you have established those boundaries to your
experimentation, you are ready to try and find your lower
cost solution. Now, I’m not totally hating on your idea,
mind you, it’s just that I have not always had stellar
success with eBay cost-reduction solutions. I figure that I
am about 50/50 on that path costing me less, but when I
add up the extra costs of correcting mistakes and making
repairs, my ratio drops. Of course, your mileage may vary!
That’s all the time I have for questions this month.
Now, to wander off in another direction, I want to
mention Li-Po batteries. I love Li-Po cells. Their power-to-weight ratios are fantastic, and they are quick and easy to
You Tube videos of spectacular Li-Po use failures; I roll my
eyes now whenever I see another one because the topic is
pretty stale. You can catch any battery on fire if you
abuse it! My list includes common D cells and NiCd cells
that have failed incredibly enough to make my own
That said, I’ve never caught a Li-Po on fire myself. I
have experienced “puffing,” however, caused by too much
current draw. Figure 1 shows you the most extreme case
of Li-Po “puffing” that I have ever seen, and it came from
a cell phone (whose name will remain undisclosed until I
have chastised the responsible party!). As you know, a
single Li-Po cell is typically thin and compact. Check this
Usually, a Li-Po that goes down this path is also
issuing smoke. I feel pretty lucky this one didn’t!
Okay then. Here’s to another busy month! Have fun
building robots and moving our hobby forward! As usual,
if you have a question, please send me an email at
email@example.com. Keep building robots, keep
learning new things, and above all, keep smiling! SV
10 SERVO 08.2014