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Think of this machine as a very friendly sculpting spider.

For my last semester as an undergrad at IIT, I decided to give my education a twist and create my own research project. Fascinated by natures way to fabricate, I got inspired to create the Bug, a 3D printer-like robot that can create using composite fibers.

Step 1: Motivations and Inspirations

Fiber composites have been present for thousands of years now, they have evolved significantly into technologically advanced materials that today offer advantages like strength-to-weight ratio, flexibility or even insulating capabilities.

Today, we are living in a digital fabrication era where computers and prototyping machines are transforming our surroundings from mass-produced products into a world of endless customization. 3D printers have played a pivotal role in this desktop revolution, the speed of this additive process, as well as the low waste and relative low cost have made them a most-have machine for engineers, designers and researchers. 3D printers however are limited to layers and the strength of the bond between them, making parts significantly weaker than parts of the same materials made by injection molding, machining or casting. These days the market for 3D printers is getting crowded, and yet the market for fiber composites rapid prototyping has been barely explored.

Most of the inspiration was narrowed form nature, looking how animals and insects are able to create by mixing elements. My trip was also inspired by a trip to the Media Labs, where I saw a an amazing pavilion made by combining brilliant brains and hard working silk worms. If you don't know what I'm talking about you should.

Step 2: Research and Testing

With no time to lose I found myself spending hours trying to come up with ways to do this. Researching different resins I could use, different fibers I should start with, what sort of robot I would move all of these, how I would handle the extrusion of fibers and how they would bond and retain shape.

I decided to go for the UV cured type resins and tested a bunch of them until I found one that would cure fast enough and was able to retain shape. In the picture you can see my testing setup and an extruded thread holding horizontally once exposed to the process.

Step 3: IIT MMAE Department and IIT's IdeaShop

Realizing that I was not going to have enough time to design my own robotic CNC machine I decided I should try to get an existing one. I did some research into some repraps, the shapeoko and others, at the end Christmas came early with the donation by Ph.D Matt Spenko, a Fab at Home, an early 3D printer made by a group of students a couple years ago and left behind in the lab.

I would also like to take this opportunity to thank my advisor in this project, Ph.D. Matt Spenko and my unofficial advisor John Welin at the IdeaShop that not only provided me with tools, but more important, knowledge and challenges.

Thanks again!

Step 4: Design. Make. Test. Repeat...

Iterations. As you can see I did a couple until the time was up and I could no longer do more within the original time plan.

At one point I also changed my LEDs for 3W ones, huge improvement in curing time!

Step 5: Generating the Path

At the beginning, I didn't have an efficient way to generate the path, I had to select the points almost by hand. For this reason I came decided that the first print should be a simple 3 dimensional bell curve. I simplified the surface into a series of curves that intersected at the center and decided to give it a shot.

Step 6: First Prints!!!

The first couple of prints were very demanding and time consuming, a lot of monitoring was needed and problems with the Z-belt meant that I had pause the print to readjust the z-axis. The 3rd print however, was very rewarding as the object made looks somewhat to what I wanted to create!

Step 7: Code Generating the Path

Processing 2.0!

Using Processing I was able to grab any 3D model and extract a path for the machine to follow. In the images you can see some of the progress and how it went from a very chaotic randomness to a more smooth organized randomness, if that makes any sense. I also decided that it would work best if the machine would first make a supporting grid first and then it bonded the surfacing lines on top.

Here I would also like to thank John Mercouris for his help and trouble shooting while writing the code.

Step 8: Latest Print!

It has been a long way and I cannot yet see the finish, but the road looks amazing.

<p>Sebastian, this is great work. I am trying something similar, with a thick paste. I have two questions,<br>1. How do you manage to keep your thread stiff and how do you cut the thread once the process is done.<br>2. how do you store the photopolymer ?<br><br>Please upload detailed design of the extrusion head if possible<br>Thanks in Advance</p>
<p>As the thread was extruded it was coated in a uv cured resin, immediately after extruded it was radiated with uv light hardening the resin at the chosen position.</p><p>The code was design to have a single path to cover the entire surface, once done you could simply cut it with scissors. The point being that you would only have to cut once per print (simplicity).</p><p>The resin was contained in a lightproof reservoir (a photo film canister) and pumped to the mixer at the extruder. </p>
<p>Sounds interesting. This brings up a couple more questions. <br>1. how do you load the fiber at the start and after every print ? wont the photopolymer cure or jam the nozzle ? <br><br>2. Also I was wondering if the thread doesn't fold or bend inside the extruder when it comes in contact with the polymer, how is the force applied to the thread to push it our through the nozzle?</p>
<p>Wouldn't a deltabot give you better range and agility, for what you're doing? I get that you're using the robot at hand, but if you're going to build v2 I'd consider going delta. Less parts, easier to scale up (i think), and the code needed probably won't scare you. Mobilizing it would involve pretty much the same arachnoid mechanisms and parts, plus the deltabot resembles that vectored orifice that spider web comes out of.</p><p>Now that I think of it, if you're going to mount it under a hexapod/octopod, the legs can do what the deltabot would be doing. So mobilizing it that way solves the entire deposition-coordination issue. That gecko &quot;velcro&quot; stuff would be great on the leg tips for stability, even if the small surface area of the spider's sticky &quot;feet&quot; won't accomodate wall-climbing (but it might, cue ground-breaking battery tech :).</p><p>The machine could print it's own support structures to climb on, like some type of specialized disposable scaffolding. The object being built could itself have small holes on its surface for the robot's legs to lock into. In the finalizing stage those holes could even be filled as the robot climbs down. Support structure placement could be realized procedurally of course.</p><p>Nice work on the Processing side btw! Can't wait to see where this is going, other than up :)</p><p>A nice isolated hut would be cool, or an ultra light bird wing made of movable segments, or a drone skeleton, or how about a lamp with varying degrees of translucency. Seal a hollow structure with foil, and you can pour concrete in it. Should I go on? :)</p><p>Several spiders could be cooperating to build one big structure, like a bridge that needs to be built overnight, or emergency housing. AI swarm tech is booming right now, so the timing is perfect.</p>
<p>tl;dr - way to bury the compliment dude.</p><p>Also possible upgrades: multiple strands of stronger/lighter materials like glass, aramide, kevlar or carbon fibre for filament. You could combine it with a suitable polymer like epoxy with some type of accelerant, or a monomer with quick-working activator introduced in extrusion chamber resulting in a high density polymer on the spot. Sci fi stuff. But if the end product only needs the tensile strength of the filament (like when you're going to fill up the empty spaces with something else, for example: concrete, bacterial excretions or acrylate) UV resin works just fine.</p><p>Prices for UV resin have gone down so what you're doing now will probably remain the most sensible method for prototyping this way for years to come.</p><p>To conclude, sorry for my ramblings (your amazing project got my gears spinning, and I still think a deltabot makes sense with all your Z-axial activity).</p><p>Keep up the great work. And thanks for sharing it!</p>
<p>Hi Netgrazer,</p><p>First of all, thank you for taking the time to write this comment. Regarding the Deltabot, I think it is a good idea, I still think the next iteration should be a robotic arm that gave the extruder some extra degrees of freedom, that way the thread could always extrude tangent (or close to tangent) to the surface. </p><p>I love your idea of having this be able to move around, specially how if many of these could work together, then they could really start weaving, reinforcing the structure some more (and build a lot faster!). Then you could even have different materials giving selected volumes distinct properties.</p><p>Stronger materials are coming next, I started with cotton due to is low price, availability and ability to absorbe the resin but I recently got a carbon fiber spool.</p><p>Thanks again,</p>
<p>The degrees of freedom needed to print tangential to your printable surface could be provided by mounting the whole thing under a hexapod (yes, I'm still at it). They can tilt their bodies in pretty much any direction. Your printable area (action radius) would instantly be sized up towards power cable length :)</p><p>Coding the thing to maintain awareness of its position could be a bitch, though. IR beacons defining the print bed (your entire room) might help, but the necessary computing power will be increased even more.</p><p>Nice to see your work pop up on blogs, you're making everyone giddy with anticipation!</p>
<p>Ha! Talking about robotic friendly spiders... I think there might be still some developing before I can reach that point...</p><p>Yeah! the blogs covering my work have been really cool surprises. Some of them do a great job on setting high expectations :)</p>
<p>No pressure... no pressure at all :) Just make sure you're having fun.</p>
<p>I'm a sophomore working towards a ME degree as well. Amazing stuff, and you have given me some amazing ideas about this project. Wish I was knowledgable enough to help you work on this!</p>
<p>This is a great project. If something seems a little 'hair brained' that probably means it is still doable given a bit more thinking and experimentation (It has been 40 years since I was in college, but it was still on of the best times of life to learn and experiment! I am sure you are seeing great posibilities, so keep going!)</p>
<p>Hey Otto(clav), </p><p>Are you also at IIT? It is an amazing school, even more so if you dare to go a little outside of the curricula. Don't worry about being knowledgable, knowledge comes with interest and drive. </p>
<p>Great work. I hope you get a chance to develop it more.</p><p>In the fiberglass industry (and possibly carbon fiber) they have a device called a 'chopper'. It cuts the fiber into short pieces as it is being sprayed with resin onto a mold. This might be a good addition after the initial structure is layed up to help complete the process. The shorter pieces help the fibers conform to curves more readily.</p>
Excellent approach... I like it. I own a conventional 3D printer.. which I don't mind to tune to work with your system and help on testing. Some troubles you got was more for path finding and hardware failure... taking you out of the aim.. composites and other materials for 3D printing...<br>
<p>i like your invention</p>
This is so very interesting. Like you I was bitten by this bug some time ago and about 3 years ago built and ran a Fab@Home. I still have it and recently added a Sanguinololu board to run it. However the belt system leaves a lot to be desired and I am converting to leadscrews. I had looked at turning it into a large format printer with dual heads and even a light duty CNC machine (I originally had it running with a dremel head) but this is most intriguing. I would love to see how this evolves if it does any further.
<p>The belts! ahhh! what this project really needs is an arm. I am sure you have seen the shapeoko, but I think it could be ideal for what you are trying to do. </p>
At one point I debated that the entire printer actually be an arm and in fact I saw Lockheed Martin's industrial sized printer in action that does exactly that. It's a robotic arm with an extruder at the end. What can't be simpler! No rails, no gantries, no rods, no belts, no leadscrews. Just 3 steppers with arms and the extruder. Hmmmmmm.....
I actually have a ShapeOKO and I used the left over acrylic from the Fab@Home to build a small desktop CNC machine. I am going to use a Rasberry Pi as the computer and a GrblPi as the motor controller. It makes the system completely independent. I have a small monitor that I can use and that makes the unit completely self contained. But for the Fab@Home, I have 12&quot; in X and Y and only 6&quot; in Z because of the shape of the table. Putting in leadscrews turns the Z motor 90 degrees which consumes some Z travel. What I like about the Fab@Home chassis is the ability to interchange the head. So I bought a spindle for it AND a dual head extruder. With leadscrews I have zero slop and very accurate and high resolution. Using Teacup I then can do 2D and 3D work by simply swapping out the head. If I take this project to its logical conclusion, I would replace all the acrylic parts with aluminum and tap all the holes eliminating the large number of thermoplastic inserts. It really is a solid chassis and it's terrible that it was abandoned as a structure -- it has a lot of potential. The gantry (what you refer to as an arm) enables you to do CNC operations as well as printing because the structure is so rigid.
<p>I wasn't refering to the gantry, more like the KUKA robotic arms.</p>
<p>I know this is not exactly your end goal, but have you attempted to print a continuous sliced print much like the existing 3d printers achieve. I am curious if your finished product of hardened resin and threat would have unique properties which may make it a viable 3d printing technology on its own, further having it 'print everywhere' and scaling back to a looser more random print may be easier to achieve in code then starting from scratch.</p><p>Second thought- ditch the LEDs and get a laser on the activation frequency instead, single point of exposure, much greater power available.</p>
<p>One of the reasons I made this printer is because I wanted to avoid the traditional methods of layering slices. Making a part by layers reduces the strength of the part since at the end it will only be as strong as the bonds between layers. Fiber reinforced composites have the advantages that the fibers are multidirectional and overlapping (this is what I was trying to achieve with the random patterns) giving the part a higher strength-to-weight ratio.</p><p>Using lasers would be nice, and it would definitely make it more controllable. The reason I didn't did it yet is because in this iterations the extruder is not very sturdy and if the fiber were to move just slightly out of range it would not cure at all. In the future however, I do see it as a viable option. </p>
Looks good, when do you start on the wrist mounted web slingers?
<p>Yeah, does your 3D printer come with wrist straps?</p>
<p>Imagine that!!! wow that would be amazing!</p>
<p>Composite fiber in a single layer or as close to it as possible could make some very cool things. If you are looking for ideas of what to make I have a few ideas for you that could be something someday. Not sure if you want to try suggestions or not. You can let me know and we'll go from there.</p>
<p>Brilliant work, Sebastian! Keep on hackintg!</p>
<p>You seem to really be on a great start already. A couple of thoughts that I had when looking at this were.</p><p>Enclose the UV exposure into a single spot just after extrusion. This way you could selectively expose or underexpose sections, this could allow you to make a intersection that could be exposed at the same time together adding rigidity.</p><p>Add a 2nd or 3 axis on the head to prevent the fiber from needing to bend constantly this would help get the vectors tighter also it would allow some tension on the line at points.</p><p>This reminds me of how racing sails are made but they don't expose while laying down the fiber.</p><p>Great job keep going. This would be a great way to make a shell for further fiber-glassing, removing the need to sculpt a form on a low volume production. </p>
Awesome. Thank you for sharing your inspiration from nature. That totally resonates with me. Using textiles is a great idea.
<p>You've done an awesome job with this! Keep up the good work. I've oftentimes talked about spiders when describing 3D printers to laypeople. And here you are, not only talking about it, but demonstrating just how cool / amazing that overlap can be. The light curing process you've developed is amazing. Thanks for including us in the fun process of discovery!</p>
<p>Fantastic !</p>
<p>This is amazing with incredible potential. It is really cool that you chose to put this on instructibles too.</p>
<p>Looking very cool so far, I understand the potential here, go go go!</p>
<p>Hi Just wanted to say what a great idea does the resin harden any faster when at a higher temperature? or is it just the UV light that sets it off?</p><p>I wish you luck with the future progress do not get put off due to setbacks everyone gets them.</p><p>regards Poppy Ann.</p>
Wow. So this is how it's done. Almost like digital hunches. Completing incomplete topography.
<p>&quot;Digital hunches&quot; I like that... thanks</p>
<p>Really good Idea, lots of potential. From the images of your printing test I would say that having a consistent coat of resin as you deposit the string is one of the big challenges. Having an irregular resin coat affects curing time and pliancy of the string. Getting the string stiff enough to hold its shape and not over do it must require a lot of tweaking. Have you considered a peristaltic pump to control the flow of the resin? They can be really precise and since they use the tubing instead of a chamber you don't have to worry about clogs or messes. Another idea is that viscosity can be an issue. If it is too fluid the resin can run down and bead. Maybe if you apply a little UV light before you coat the string you can change its viscosity and that could help get a more consisting coat. </p><p>Best of luck and keep us posted!</p>
<p>You are totally right, the feeding of the resin is one of the biggest challenges. At the beginning I was was feeding it through a syringe but I quickly got a peristaltic pump. I didn't quite got into that detail in the instructable but you can see it in the picture below (on the left). It made things better but the speed isn't perfect and sometimes I had too much resin leaking and clogging the nuzzle. </p><p>Some of the huge blobs you see in the picture was me with the syringe artificially reinforcing the bonds between intersecting threads. In the future this would be integrated into the code and idealy it work cleanly. </p>
<p>Wow that a really awesome project. Thanks so much for sharing it! Good luck on the rest of your journey.</p>
<p>Thanks! I'm glad people like it, it has been a lot of work but hopefully I'll get some more progress soon. </p>
You're one of the hardcore Makers! Well done!
<p>Thanks! hopefully many better to come... </p>

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Bio: Mechanical Engineer who loves merging science and art.
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