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A New Elbow

Arc-O-Matic

You may remember the Arc-O-Matic, an Arduino-powered drawing robot I built back in March for Gallery Night.

Well, things have been quiet on the Arc-O-Matic front for a while, and there are reasons for that. First, while shooting a video showing how it works, It started to fall apart. This was not unexpected. The whole thing was built in a few hours, and held together with hot glue and gaff tape. Failure was just a matter of time. Second, while it was in my workshop awaiting repair, one of the cats (ChaCha!) managed to knock it off a table onto the concrete floor, which made things worse.

But an important thing happened between the destruction of the Arc-O-Matic and now… I can easily 3D print things!

Elbow (old)

Here we see the old elbow mechanism, which consists of glue and tape. Pretty sad. It held up fine for Gallery Night, but it’s no permanent solution.

So my first idea for repair was to take some of the weight off the arm via the elbow joint. I thought about buying some ball casters but then realized I could just print my own! Here is one on Thingiverse, and here’s a photo of the one I printed. My initial idea was to just glue this on to the bottom of the micro-servo.

But when you’ve got a 3D printer, why stop there? I ended up designing a part that would hold the micro-servo, and allow the dowel to attach to it. See this photo.

Now, I know some of you still don’t get Google+, so here’s how it works. I posted my progress there, and someone who follows me mentioned a post about Florian Horsch printing a servo coupler on a Ultimaker. My first thought was, “crap, can I print that on my MakerGear Prusa?” And yes, I definitely can.

Elbow (new)

So here’s the result so far. A new elbow. The bottom piece holds the larger dowel and the micro-servo, while the top piece fits snugly onto the business end of the micro-servo and holds the smaller dowel. I’ve not yet attached the ball caster (which uses a marble) in this photo, but I tested attaching it to an earlier version using acetone to weld the plastic together. (I suppose a screw could be another option there.)

I’m hoping to get this thing rebuilt and working before the end of July (hint hint!) and once I’m pleased with all the pieces, I’ll write up some instructions, toss the files on Thingiverse, and hope someone else thinks it’s cool enough to play with.

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Spray Booth Reclaimed!

Spray Booth

Spray Booth

I picked up an Artograph 1520 Spray Booth from the Hack Rack at Milwaukee Makerspace. Well, just the base of one, but the rest of the parts are fairly easy to DIY, so I did.

This spray booth lists for about $250 from various places, and if you use the 3 stage filter system you’ve got to get replacements at some point, and those aren’t cheap either. I don’t quite have a carbon-impregnated polyester filter for the third stage, and I still haven’t figured out the first stage pre-filter, but I grabbed one of my favorites, the super-cheap Ace Hardware 30 day furnace filter. The 20x25x1 is about $1.29 so even if I replace them pretty often, it’ll still be pretty darn cheap.

Ace Filter

I use the larger Ace filters in my big spray painting booth, and with a lot of painting I can still go weeks before I replace one. Those are a bit larger, but they’re still under $2.00 each. I did need to cut the 20x25x1 down just a bit to fit in the 1520, but only in one dimension, so that’s not too bad. Scissors is all you need to cut it. And as for the cardboard hood (which you can see is recycled from a Pelican case) I ended up tracing the one we have at work. (Yup, same model, it’s a popular one. I didn’t even bother with the slots and tabs for the hood, I just used some gaff tape to secure the edges together.

I’ll probably use the booth as our spray glue booth, as the larger spray booth is already doing great for spray paint, and I’d prefer not to mix those two mediums if possible.

So yeah, a bit of cardboard, gaff tape, a furnace filter, and a little bit of time, and I’ve got an excellent reconditioned Artograph 1520 Spray Booth.

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3D Printing Camp

3DPCWI

For me, this story starts back in October 2011 at BarCampMilwaukee6. A few of us stayed up the entire night with a MakerBot CupCake printing things. I’d pretty much caught the 3D printing bug at that point.

So when Bob Waldron pitched the idea of “3DPrintingCamp” I was interested. I helped launch the web site, and have contributed (at little bit) to organizing and attempting to get sponsors (I’ve got none yet) there’s still a lot of work to do before July 21st, 2012.

Yes, the date is July 21st, 2012. The location is Sector67 in Madison, Wisconsin. All the other details are at 3dprintingcampwi.com.

And what is 3DPrintingCamp? Well, it’s a participant-driven unconference focused on the emerging technology of 3D printing. You may be interested in 3D printing for personal fabrication of functional parts, or maybe you want to create beautiful objects that would fit in the “art” category. Perhaps you want to produce organs to save lives. The people involved in this event believe that 3D printing will change the world.

If this is all a bit above your head, that’s OK. Join us and learn about 3D printing technology. Find out what a spool of plastic and an open source bot can do for you.

Oh, this event is FREE, but you do need to register. As of my writing this we’ve got 41 people registered and we’re limited to 125 people max, so sign up now.

And if you’re interested in sponsoring, we could really use the help to make this event even more awesome… thanks!

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The Magic Whistle

Whistle #1

One of the first things I printed on the RepRaster 5000 was a whistle, you know, in case there was an emergency soccer game or something. To my amazement I took it off the bed and blew into it and it worked! I had just printed a fully functional whistle, and thusly declared The Future™ to be here.

Whistle #1 was a little rough. It worked, but it didn’t look very beautiful. (Well, beautiful by 3D printing with plastic filament standards.) After some tweaking and calibrating I printed Whistle #2 and it sounded just like Whistle #1 but looked a little better. An improvement!

Whistle #2

That brings us to Whistle #3. As any good RepRapper knows, you can’t just leave well enough alone, and if you’re happy with your slicing settings, you’re doing something wrong. With this in mind I set about changing all the numbers in Slic3r and then attempted to print another whistle.

When I popped Whistle #3 off the bed and blew into it… nothing. Well, not nothing, just the sound of air, minus the sweet whistling sound. I recently told my kids that failure is just a part of the learning process, so I wasn’t ready to quit.

I got a knife and made sure to cut out any stray filament from the bridging during printing. Still no go. I decided to rinse the whistle out thinking maybe there were bits of plastic inside. (Yeah, at this point I was just grasping.) Lo and behold, with the water inside my whistle totally worked! There’s a fine line between science and magic, and I’ll get to that in a minute.

Whistle #3

I’m no Whistlologist, but my first guess was that the volume of air inside the whistle was too much and preventing it from operating properly, perhaps due to the lower infill I used when printing. I ended up being totally wrong about this. It had nothing to do with the volume of air (duh!) but everything to do with where the air was going!

It seems that the crappy print actually left some gaps in the top of the object, which happened to be the left side of the whistle. By putting water inside it was temporarily filling the holes. I could get the same effect by just giving a slight squeeze on the left side of the whistle with my thumb to block the airflow. Zing! Magic whistle. (Magic is just science you don’t understand, right?)

I then hatched a plan to trick the kids by having them try to blow into it, and then telling them they were doing it wrong, and then showing them how it’s done. I wonder if they’d see me squeezing the side or not.

Now I’m left thinking I need to design a new whistle with intentional holes. Anyway, that’s the sort of crazy stuff I do. You’re welcome!

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Scrabble Coasters

Laser-etched coasters

I finally finished these Scrabble coasters I’ve been working on forever. There were so many issues with this project, I’m calling these beta and plan to completely redo them. This is all fine though, as I spent some time this weekend explaining to the kids that screwing up and doing things wrong is all part of learning. Fail faster and all that. I’m pretty sure that the next version of these coasters will not have all the problems that this version had.

Laser-cut coasters

So what were the problems? Well, for one thing, I’ve really got to remember to sand the wood first! Yeah, like, before I etch it. Not a huge deal, but I think they’d look better if I had sanded first. As for the backing, I first thought about using cork, but decided against it but then I had to use cork to cover up the mistake on the back of using the wrong wood stain. The cork was not easy to cut, and there are some rough edges. I used a lot of X-ACTO blades in the process, but I think this cork may have been aged a bit too long. As for the wood stain, the wrong stain nearly torpedoed this project. Lesson learned? Test the stain on scrap wood. Besides all that, I think they turned out pretty good.

Oh, while I was using the laser cutter at Milwaukee Makerspace Shane commented that the letters looked a little rough. I had to explain that I didn’t just type up the letters in CorelDraw, I actually scanned real Scrabble tiles, as I wanted these to be authentic replicas, only much larger. I probably didn’t get the color quite right, but again, I’d like to redo the whole project. A deeper/darker etch may be in order next time, and I’ve got another idea for the backing/feet.

Glass on coaster

But do they work? Yes! Surprisingly enough, the glass did not tip over or go flying off the coaster, though honestly I think gravity had a lot more to do with it than my skills at making things. Still, I’ll count it as a success. :)