Journal march10
The Biggest Technical Problem Yet.
Ahead of me is a solid 2 weeks of prototyping with no presentation
and no class. So now is the time to solve the major construction issues
and do large bulks of work. Let me first give a detailed branching explanation
of my prototyping process. Here is the progression so far:
1. abstract sketches
2. object sketch
3. rough handbuilt first stab
4. rough handbuilt correct sizing
5. laser cut
6. laser cut with gears
For both laser cuts, the machinery is already in place but the program
has not been fully coded. I am deliberately stalling on the programming
until I am sure about the sizing of the bands, and until an actual keyboard
is connected to my breadboard. Right now, my priority is getting this
machine to roll in a reliable way.
Prototype 5 (the first laser cut before the midterm) was the first time
a full character was realized. The problem I encountered was that the
servo motors (by only having a 180 degree range) were not rolling the
paper far enough to give me ample drawing space! That is why I moved
on to the second version that featured gears. The gears were not a problem
to design, cut, and position because of the magic of computers, however
the actual acryllic material was too brittle for such abusive collision.
Many gears in this prototype crumbled. They crumbled from interacting
with other gears, and they crumbled when I was forcing them onto their
wooden axels. Unfortunately, our laser cutter cannot do a softer material
that is as thick. So the negative outcome for laser cut 2 is that the
rollers are rolling very unreliably. However, they give a very desirable
rotation range! I was very happy that I at least solved the original
problems while I created these new ones.
I am now presented with a series of options. I can go back and redesign
the gears, then cut another full object. This would require waiting
around for the laser cutting services (7 days). However, I do not like
to waste this much time. I can also go back to this latest prototype,
and try and reposition the holes and do slight hand-tweaks to the parts
in order to make them run better. I realize that doing gears takes people
years to learn, and I stumbled upon a pandora's box by introducing those
gears in the first place. And that leads me to the third option. I can
scrap this dead-end prototype, and go back to the last one and see if
I can't make use of the range that I am given.
( 3 days later . . . )
Okay, I am returning to this file instead of making a new entry. I just
spent 3 hardcore building days in the lab, and I tried 2 of my options.
I hand-tweaked the gear prototype to see if I could not adjust it a
bit. It took a lot of custom solution for each of the 12 modules to
make them spin in unison without jamming up. I found myself gluing weird
things in place, shortening and lengthening rods, re-cutting the wood
components to see if I can "get them more precise this time",
and similar tasks that do not promise to be useful for next time. Basically,
my hand-carpentry is no match for the scale of this computer-generated
machine. I think the biggest bug is my clumbsy fingers. So I tried redesigning
the whole machine from scratch on the CAD level. While I was sitting
there trying to figure out clever ways to avoid all the problems I encountered,
I realized that trying to get things this precise was no use unless
I could get the ENTIRE machine cut by a computer. The length of these
wooden rods make a rather big difference in this machine, and I can't
find a way to get them cut as precise as the rest of the model. Is there
a way that I can possibly redesign this machine so that building the
mechanism does not rely on the work of my clumbsy fingers?
It's apparent how much of a curve ball I've thrown myself.
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