Robot Army : From Tupperware to 3D Printing

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When I moved back home from art school in Chicago, one of the biggest drags was no longer having access to the beefy machine shop that was down the street from my apartment. I went from playing with a room-sized lathe and mill to having little more than a $20 soldering iron and dremel at my disposal. It seemed my metal-cutting days were going to end as soon as they started… well enough, this didn’t stop me from making the things I wanted to. I just had to use plastic now instead. Luckily for me, plastic was in abundance at my parent’s house. My mom hordes take-out containers and tupperware, so I had a bottomless stash to carve up.

Still pursuing my vision of creating the field of robotic flowers, I was trying to refine the design of my ‘steam’ into something a bit more controllable. At some point I ran across a video of a small delta robot someone had made on the internet. As I watched it bob up and down in that special twitchy, impatient way… I fell in love. From that moment on I became obsessed with building my own!

Long story short… Everything became a potential shape. I-beams. They’re everywhere :

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I used a lot of crappy plastic hangers. They made great paddles to connect onto the servo horn like you see below :

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In the beginning, mechanical joints mystified me. I didn’t quite understand what was going on with how a delta robot moved, so this prevented me from being particularly inventive with what I used to connect all the piece together. I read on a forum someplace that you could use 4-40 swivel ball links, which you can get from a hobby store… so I bought myself a set to try out. The thing is, they work great but they cost way more than any piece of plastic should (like… $18.00 for 12 of them. Just enough for one robot). ALSO, they require tiny spacers on either side of the ball. This helps give the rod a breadth of motion without smacking into the plastic piece its rotating in. The sucky part is that the pack of 12 joints form the hobby store only comes with half the number you’ll need (for a delta you need one on each side). The links are the pieces at the end of these 4-40 rods :

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In order to make a whole field worth like I was planning, I’d need to find a cheaper alternative that was less hardware dependent. For now though, these worked. I attached my paddles made of hanger bits to these arms :

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The next step was figuring out how to mount the delta robot. I realized that the servo motors would have to be elevated so that the paddles could swing below the angle of the table top. I didn’t have anything fancy to use at the time, so I took a pasta togo box from the cupboard and cut into it with my dremel to get some nice clearance slots :

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The next thing to figure out was how on earth I was going to mount the actual motors onto my base. A normal person would have used L-brackets of some sort, so I did precisely that… except again, mine were made from strips of plastic cut from togo boxes. >.<

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As you’ve guessed… the end effector was also eventually made from cut pieces of plastic. My first working prototype was practically a togo box with motors :

This was a great feat making my first functioning delta robot. I was proud of its frumpiness because though it wasn’t mechanically solid like a robot made of metal, it still worked. Of course, I wasn’t going to make a whole field of delta robots out of togo containers (although I probably could have because my mom surely had enough to do so). The next step was to shrink the design and refine the method so it could be repeated with ease.

My next prototype was still made of plastic, but I got classy and went to the Container Store and invested in some nice cylindrical boxes. These would become the new bases for my robots :

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I repeated the same steps, cutting the clearance slots for the paddles and making small L-brackets to mount the motors to the base. The base the motors were connects to was actually the lid of the container so you could remove it and use the bottom part as an enclosure for the board running it (clever!) :

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I had aspirations of building three of this particular prototype… to see if they could all be networked together and potentially all run at once :

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The two-dollar micro servos I bought from some nondescript hobby store (imported from China) were terrible quality. Though my second prototype worked, it moved like it had Parkinson’s disease. =/

I wasn’t really happy with this… but two dollars a motor was all I could afford at the time (I was still living at home with the folks). Eager to try again when I could invest in some more quality materials… I started rethinking the entire design.

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For the rest of the summer I meditated on what I had learned. The little blue servos from China stripped in a matter of days while I was testing out code… So I was left with nothing more than a delta shell.

One extremely fateful day I met the people of SYN Shop at an art faire downtown. The hackerspace was just a glimmer in someone’s eye at the time and was run out of the garage of the man who is now my collaborator (Mark Koch). They invited me to stop by some time and show off whatever I was working on. Eesh. Even though I was embarrassed and apprehensive, I brought the mangled corpse of my second delta prototype to show to people. In spite of its appearance, my gimpy child got a lot of attention for the mere fact that I managed to pull off making a delta robot from garbage. Mark had always wanted to build his own pick and place machine, so seeing my creation urged him to get off his butt and make one of his own.

This is when the discovery of 3D printing changed my life. Mark suggested that I design my delta’s parts in CAD and of all things…print them. I was familiar with 3D printers, however the one my art school had was huge and they charged an insulting amount just to produce tiny things with it. Up until then, I had no clue that desktop 3D printers even existed, so my mind was blown when I saw his Replicator for the first time. The usefulness of this tool was revolutionary. I could continue building my robots in plastic like I had been, but I wouldn’t have to machine my parts as if they were metal. How easy!

I spent the rest of the year learning Sketchup. This is a free piece of software that I highly recommend to beginners. It isn’t as powerful as Maya or Solidworks, but its intuitive so you can start making things with it immediately. You basically draw 2D shapes like you would in Illustrator and then extrude them upward to make basic geometrical objects. You can edit things from there of course. If you’re looking to design mechanical parts, this tool is a wet dream, but be patient because it has it’s irritating quirks and limitations.

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One day during CES in 2013, Mark came onto something rather brilliant while we were discussing our designs over margaritas. The solution for those expensive and convoluted swivel ball links (that I had been stuck using) was to use some sort of U-joint that could compress onto ball bearings and twist freely in all directions. The idea was simple and genius :

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This was an important quality because now we could completely divorced ourselves from having to source out any hobby parts. This means aside from some hardware, we no longer had to buy link joints, or cut rod in order to make the robot work. Everything was designed in CAD. Everything was 3D printed. My cost went down significantly, and at last I had the perfect model which I could realistically expect to afford building in mass… and all I had to do was hit ‘print’.

Once we mastered this technicality, it was a matter of implementing it throughout our designs. My personal delta robot went through many…….. many revisions before it became the thing it is now :

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It was at some point last spring that our robots reached their pinnacle. My first complete and polished delta made from 3D printed parts was named Jeden (after the Polish word for one), and Mark’s hanging delta robot was named Amber (after an inside joke Mark and I had at the time). This was the revision of Jeden right before I got my neon yellow filament in the mail :

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We had been working so hard that our collaboration was getting noticed by the others in our community and our friends from SYN Shop decided to interview us about our ‘rivalry’ for their first podcast :

We hadn’t really thought of one another as collaborators (or rivals for that matter) until that point in time. Once it was brought to our attention however we took off like rockets loaded with beer and nitrous. We’ve been working together ever since and within a year brought a delta robot kit to market… which is the thing I’m promoting so heavily right now on Kickstarter.

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This campaign is not only getting us our funding to build that elusive art installation I’ve been wanting to create, it’s also the introduction of our new company to the maker community. Mark and I don’t expect this will be our last kit. We’re sort of hooked on this process now and already have plans for what’s next. We are Robot Army LLC and it looks like we’re here to stay =]

It’s been a fantastic journey. I’m getting to strike a couple of goals off my bucket list. I started this blog two years ago to prove to the world (and myself) that anyone with a little bit of drive and passion can bring something from their dreams into reality… even coming from a position where you lack experience or expertise. There is a wealth of open knowledge and support out there to be drawn upon. If you choose to use it, anything is possible.

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3 responses to “Robot Army : From Tupperware to 3D Printing

  1. Pingback: Robot Army Starter Kit: From Tupperware to 3D Printing - Sense 3D Printer

  2. Pingback: Robot Army: From Tupperware to 3D Printing #3DxRobotics #3DThursday #3DPrinting « adafruit industries blog

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