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Hey all,
Just got my pix back from the Rapid Prototyping conference and thought I’d
share..
Folder Pending Mod
Full credit has to go to:
Tom Burger (for designing the parts in the first place and making the DAT
files freely available)
Greg Overkamp (for designing the original MOCs - though I must admit I had to
do some creative substitution to make up for my small parts collection)
The great folks at the RP Technologies conference for making the parts, and of
course..
The staff and students of Orange Coast College and DRAFT 159, who put up with
all my LEGO foolishness!
The DAT files had to be tweaked a little - some of the part features were
un-buildable. For example, there was no way to make the impossibly thin low
profile tyre part and expect it to survive, so we just made it part of the
wheel.
The machines I used were a 3DSystems InVision (this uses a photopolymer resin
build material, encased in a wax support) and a Stratasys Dimension (ABS build,
water-soluable support). I didn’t use a ZCorp machine even though one was
available at the conference. The consensus of the Techs was it wouldn’t be able
to hold the fine detail in the wheels, etc.
It was great fun to make these parts, and I learned a lot!
1- The conversion factor of 1 LDU = .4mm isn’t exactly applicable to RP LEGO.
Some of my parts are loose, some are tight. We built in a little fudge factor in
the STL files, but obviously it wasn’t enough for some machines/part features
and too much for others. I knew LDraw was extremely simplified compared to real
LEGO, but nothing like experiencing it!
I only got to make a few parts on each machine. There were lots of people at the
conference, so I didn’t have time to tweak dimensions and run more.. I could
probably get much better fits the second batch.
2- The 3DSystems machine could hold extremely fine detail - the spokes on part
46000 are tiny! I even modeled a little groove on the front face of that part,
trying to represent the joint between the wheel and the tyre. It’s fractions of
a mm in the CAD file, but it showed up nicely in the raw part. Of course
painting to that groove was a challenge - one that I didn’t take up, LOL..
3- Don’t leave your photopolymer parts in the support cleaning bath for more
than a few seconds at a time - they’ll melt! When I found out some of my parts
were heat damaged, I was really bummed. The parts as they came out of the
machine looked great. One in particular, a wing (part 42461), looked fantastic -
until we broke it trying to get the wax supports off. It was repaired and broken
several more times before I even got a chance to photograph it, but I managed to
cobble it back together with superglue. Of course the wing angle got screwed up
in the process, but what are you gonna do? I broke one of the wheels trying to
get it onto an axle too..Grrr.
4-The Stratasys Dimension rocks! The ABS is very durable and LEGO-like. I’d
really like to try some of the wheels in that machine. The machine we have at
OCC uses solid “breakaway” support material - in other words you have to get in
there with tools and chip your part out of it. Not fun. The Dimension cleans up
in a little whirlpool bath. Much nicer.
5- I didn’t really have time to finish the parts properly - you can still see a
lot of “step-over” (the edges of the layers of material are apparent). That
could’ve easily been sanded smooth. I didn’t do any sanding or finishing on the
bodykit parts at all, though actually I think they look more realistic in white!
I did decide to paint the broken wing since it was so hideously ugly from the
repairs. I painted the wheels just because they looked funny in translucent
resin, but they probably deserved to be sanded and clearcoated.. In the pic in
the folder that shows the four wheels you see: two painted very basically (front
and rear views), the broken one (subsequently painted black), and a completely
raw part.
Hope you enjoy the parts and mocs - I know my students will really get a kick
out of them. I brought the parts to SIGGRAPH and they seemed to go over well,
though Tim Courtney trumped me with about 30 beautiful Stratasys and ZCorp parts
on display... Punk! :)
I wish I could go to BrickFest, but I’m seriously conferenced-out. Plus school
is starting up soon! I might be able to make NWBrick Con - I should have more
stuff printed by then too.
PLMKWYT
Darrell
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Message has 4 Replies:
 | | Re: My Big Phat RP Parts
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| (...) Those are really cool! Thanks for sharing them. If I, as a small hobbyist, wanted to make a batch of parts in this way, what would my options be? Is there any company that will take a CAD file, print a small batch of parts, and mail them to (...) (20 years ago, 13-Aug-04, to lugnet.cad, lugnet.parts.custom)
| | | Re: My Big Phat RP Parts
|
| "Darrell Urbien" <durbien@mail.occ.cccd.edu> wrote in message news:I2DzA0.120q@lugnet.com... (...) (URL) (...) DAT (...) had to (...) and of (...) with (...) low (...) resin (...) build, (...) able (...) LEGO. (...) factor in (...) features (...) (...) (20 years ago, 13-Aug-04, to lugnet.cad, lugnet.parts.custom)
| | | Re: My Big Phat RP Parts
|
| In lugnet.cad, Darrell Urbien wrote: <snip> Well, consider me blown away. I never imagined I would see actual pictures of those models but there they were. I love the extra speakers in the scion too! (btw, when i made that model scion wasnt sold in (...) (20 years ago, 15-Aug-04, to lugnet.cad, lugnet.parts.custom, FTX)
| | | Re: My Big Phat RP Parts
|
| <snip> (...) Way cool! Thanks for sharing. On the topic of scale. What I've determined is the following: the LDU to mm conversion is an exact conversion However: A 1x1 brick is only 7.8mm x 7.8mm and the studs are located 8.0mm for one another (...) (20 years ago, 26-Aug-04, to lugnet.cad, lugnet.parts.custom, FTX)
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Message is in Reply To:
| | Re: ldraw based import parts
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| (...) First, the rear hatch is part 4858 on peeron (see (URL) just in transparent blue. Of course lego doesnt make the wedge in transparent colors, but thats the beauty of ldraw. Yes, I actually made a few custom parts, some of them modified or (...) (20 years ago, 7-Aug-04, to lugnet.cad, FTX)
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