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STRUdittle--A tiny/fast/precise/low-cost filament extruder!'s video poster

STRUdittle is the latest filament extrusion device -- it's fast (~1-2ft/minute), ultra-compact, reliable, low-cost and spools! Read more

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This project was successfully funded on October 11, 2013.

STRUdittle is the latest filament extrusion device -- it's fast (~1-2ft/minute), ultra-compact, reliable, low-cost and spools!

About this project

What it is:

The STRUdittle is a 3D filament creating machine. For those with 3D printing background, you know that you can rapidly use up a lot of the filament material. Each 1kg spool can run you from ~$35-$40 and up, plus shipping. The raw ABS pellets however run between ~$2-$5/lb, or ~1/5th-1/10th the cost. Why such a discrepancy? Because making high-quality filament is from pellet form is very challenging yet a necessity for your printer if you want accurate parts and not to clog your extrusion nozzle.

The STRUdittle is:

Compact: Measures approximately 9.5" wide x 6.4" deep 4.3" high (primary hopper/motor excluded). Note: Versions shipped will have much larger capacity hopper. In addition, the electronics enclosure unit (far right side) is detachable and can be placed in the most convenient spot)

See picture illustration:

The auto-spooler is also very compact:

Fast: Measured extrusion rates between 12-24"/minute -- operating at only 5V out of the rated 12V motor!

Precise: Can get up to +/- 0.05 mm tolerance on the extruded spool material when using the free-hanging floor coil method and +/-0.03 mm tolerance on the extruded spool material when using the auto-spooler!

See our measuring technique and resulting plots of data below:

Here's a plot of filament diameter width taken at 3" (every 1ft) and 6" (every 1 ft) intervals for the hanging (floor coiling) configuration.

Here's a plot of the test data for the auto-spooled configuration, taken at every 3":

Here's an image of our filament spool material (white) on top of highly regarded name-brand filament spool material (red)

Our filament (white) vs. major brand name filament (red)
Our filament (white) vs. major brand name filament (red)

Can't tell the difference? We can't either!

Still not convinced? Here's an example of a part made using our spool material. It was printed on a MakerGear M2 using Creator3D software, with the speed cranked up pretty high, random start point perimeter generation used, and 0.25 mm layer height. Notice that it is filled with the pellets used to create it:

Reliable: Fourth-iteration design has been tested for days at a time with no trouble.

We've designed, re-designed and then re-designed again. We weren't satisfied with the product until we felt it met the most stringent of requirements. The result? An awesome product for meeting your extrusion needs!

See the evolution of our product here:

More on product evolution:

Our v2 design CAD model:

And our v3 design CAD model:

Notice that our v4 design represents the latest and greatest:

Why did we decide to create our own filament extruder?

One day the freely available plans for the Lyman Filament Extruder came along, so we decided to try and construct it. Quickly found that you'd either have to be a skilled machinist and already own a lot of expensive tools or you'll find yourself with a lot of metal splinters, paying more than $250, and end up with a product with questionable reliability, mediocre quality filament that often gets tangled on the floor. However, we definitely applaud the Lyman Filament Extruder as a great starting point that inspired us to further advance the technology.

Other extruders on the market may pump out the material faster, but with far less precision and a much higher price. Products that extrude with a +/- 0.1mm tolerance have over an 11% variance when using a 1.75 mm spool, which make a clean print all but impossible. The precision on this extruder yields less than a 3.5% variance on filament diameter, making for excellent prints! In addition -- remember that this product is for the home hobbyist user -- you'll never be able to use up more than one spool a day anyway!

How does the main extruder unit work?

How does the constant speed and real-time feedback autospooler unit work?

More pictures of the main extruder and autospooler units:

So why do we need the funds?

Mass-scale savings. We've tried to purchase the parts ourselves, and we've tried to build one-off ourselves. Once shipping of parts, purchasing of precision tools (drill-press, metal drill bits, grinders, cut-off wheels, micro drills, electronics kits, etc) are factored in -- you'd end up spending hundreds more trying to build this unit yourself. We've been there and done that. Now that we've gone through the effort, let us make this easy for you.

We want to make this product available to the masses, and to do that we need to buy in bulk and save on unit costs and shipping In order to get the highest quality product, we need additional funds to buy even more specialty tools and R&D time to get the product the best it can be. To purchase these tools for one, two or even 10 units isn't cost-effective to deliver a unit at the prices we're offering.

How are we going to pull off mass-scale production?

We've already started contacting suppliers for various parts to set up bulk deals. In addition, we have spreadsheets outlining all of the parts involved, costs associated with each part, and location(s) to purchase those parts. 

We spend a large amount of the time going through iterations to design for manufacturability. Coming from a manufacturing engineering background, lets you know that having a proper design can make all the difference in quality and quantity of parts. Our first iterations were a major pain to assemble and had much room for error, so we learned from our mistakes and made the latest versions nearly mistake proof they're designed to be rapidly manufactured. 

We already have access to three 3D printers and are in the process of constructing an additional two units to assist in the generation of printed parts. 

We also have the machining center consisting of a drill press, rotorary (dremel-like) tools, cut-off grinder wheel, power saws, hand drills, and an assortment of drill bits and a welder in addition and electronics lab in-house, but are looking to further expand our capabilities

The more backers we get, the better an end product we can make. If we're going to make lots of these units, we'll be sure to pay attention to every detail to make it the best product available to the home hobbyist.

Long story short -- we love to print:

And we know you love to print, so let us help you make it a more cost-effective hobby!

About the creator of the project:

Ben Fishler: Born and raised in Silicon Valley, CA, I'm currently employed as an aerospace engineer in San Diego. I've held my current position as an aerodynamics engineer for over three years, and came from a background of two years as a manufacturing engineer. I have an undergraduate degree in Mechanical Engineering, and a Master's degree in Aerospace Engineering -- both from the University of California, San Diego, California (UCSD).

My duties at work include using computational fluid dynamics to assist in designing the internal gas-path parts of compressors -- namely the impeller, diffuser, and deswirl components. I also have experience in heat transfer, aero-acoustics, turbine and inlet design, and have six patents currently pending -- three of which I am the primary author.

In my spare time I tinker with electronics (embedded programming), fly airplanes (licensed private pilot), play with the 3D printer (currently building two more), and of course visit the wonderful beaches of sunny San Diego, California.

About the assisting members:

Angelina Altshuler, Ph.D: Project title: Product assembly coordinator. Daytime job and achievements: Siebel scholar, currently process engineer at biotech firm as well as consultant at biotech startup.

Joel Perez: Project title: Technical consultant, printer resource and unit tester. Daytime jobs: Aerospace engineer, owner of high altitude start-up InterSpace Systems []

Project Timeline:

Risks and challenges

As stated, we've worked very hard to minimize risks and mitigate any potential problems that may arise. That being said, there's always the chance for things out of our control. Suppliers could suddenly raise prices or run out of stock of a key component. We could receive a shipment of poor quality parts. A hurricane could also roll through San Diego and sweep up all of our stuff (kidding...)

To circumvent these problems, we've already worked on designing the bulk of the components so they can either be purchased through widely available sources or made in-house. However, there are still a few to go and we'll be working on completing this for all the components as the project progresses.

You'll notice that we have limited the supply of every single physical product offered in the rewards section, and spaced them out in batches with increasing estimated delivery times. This is to allow for quality product with very realistic manufacturing goals.

Future design work: In addition, we still have some minor design work to do and finishing aesthetic touches to add. While the main extruder unit is pretty much completed except for the aesthetics and wire-routing side, the AutoSpooler beta v1 is just that -- in beta version. We've successfully tested a constant-speed spooler for ~1/2 lb of material with great results, and have a working circuit for the real-time feedback autospooler (spool speed based off filament slack). We still have to integrate this into a production-ready package, which will take time. This is why we delayed the release date of this version a few months further back.
In addition, the auto-spooler current spools with a decently tight wind. We'd like to even further improve our product to make store-bought quality wind, which will take some additional design efforts. We're also looking into alternate smaller package motor suppliers. All of these efforts will take time and funds.

The What -- Goal #1: Meet and exceed advertised specifications; delight backers.

The how -- Meeting and Exceeding Goal #1:

-We’ve already build four separate variations of our unit.

-We’ve thoroughly tested each one, and made improvements to meet the shortcomings of the prior units.

-We’ve taken measurements of our spooled abs filament in a controlled fashion and published the resulting graphs.

-We’ve given our material to third party testers to test in their 3D printers, as well as printed numerous test parts on our own printers.

The What -- Goal #2: Deliver all units on-time

The how -- Meeting and Exceeding Goal #2:

-We’ve thoroughly documented the assembly process via pictures and typed instructions
using Google Presentation slides (freeware on Google Drive).

-We’ve designed the units to be assembled in an hour of time.

-We’ve minimized hard-to-obtain parts. The most complex part to create is the printed base unit, and we’ve designed it to be entirely 3D printable. We worked hard to design printed components to be rugged and reliable. We also made it such that the necessary printed components can be printed on our in-house 3D printers within one day per unit.

-For the remaining components that can’t printed or purchased through widely available suppliers (such as nuts, bolts, pipes, wires, etc) -- such as the PID controller, the auger bit, the high-quality flanges, the solid-state relay, the bearings, the nozzle, and the heated band clamps -- we’ve contacted individual suppliers and have already negotiated out unit ranges and prices. All we have to do is provide them a number of units, send the payment and they start shipping us the parts.

-We’ve created a complete timeline of the project which details what steps will be taken to follow through with the complete manufacturing of all ordered units

-We’ve limited the number of units to be well within our manufacturing capabilities per month

The what -- Goal #3: Keep current backers and future buyers happy.

The how -- Meeting and Exceeding Goal #3: Throughout the Kickstarter campaign, we will be answering any FAQ’s on a regular basis. After units start being shipped, we’ll set up a forum on our B3DPrintJobs website which will act both as a product feedback/tips-and-tricks for users. We’ll have technical support ready to respond to any emails on troubles encountered while getting started (which should be very minimal as we’ll test each unit before you receive it!) Furthermore, Kickstarter profit funds and customer feedback will result in new and refreshing products coming out via our soon-to-be-published website. Note that new products and orders for existing products will only be taken after 100% of the Kickstarter orders are fulfilled. We want to take care of you!

All being said and done, we'll do what we have to do to make this happen.

We hope we've convinced you to back our project!

Learn about accountability on Kickstarter


  • Due to the demand, we will be offering the option of picking a 1.75mm or 3mm nozzle size at checkout. We will also be offering to drill a pilot hole and let you drill out a size of your choice. Note that the graphed tolerance data available is from the 1.75 mm, and we will be posting results from the 3mm size shortly.

    Last updated:
  • We've successfully output usable PLA filament, but it's a lot more sensitive to settings. It hasn't gone through the rigorous testing of ABS. For now, think of ABS output as "production-ready" and PLA as "experimental". More to come soon.

    Last updated:
  • The center core unit encompasses all of the main mechanical components which are responsible for extrusion, minus the motor and the PID temperature controller/relay box. Each time you switch between plastics (if you want to experiment with multiple types or do multiple nozzles sizes), there is inherently the material left in the barrel which has to be flushed out before the new material starts extruding out.

    In addition, if you want to switch between nozzle hole sizes the current procedure is to heat up the unit, unplug it once at temperature, remove the thermocouple unit from the nozzle, unscrew the nozzle/clean off extra plastic, and insert the new nozzle in. This all has to be done while the unit is hot (as parts are fused together with plastic when the unit is cold). Likewise the nozzles have to be scraped clean around the threads so they can thread back in.

    To circumvent this difficulty, the iteration 2 designs will utilize technology in where the entire core of the part can be pulled from the base once the four main bolts holding it down are removed. The procedure can be done while the unit is cold, and all you have to do is swap in the new core, replace the bolts and you're good to keep on extruding!

    For a CAD exploded view, see our website (newly listed/can be found under my picture).

    Last updated:


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    Pledge $5 or more

    3 backers

    Be listed on our website with a thank you for your support!

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    2 backers Limited (48 left of 50)

    Get a bottle cap opener printed with spool material extruded from a STRUdittle.

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    Only ships to: United States
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    3 backers Limited (97 left of 100)

    Auto-spooler unit batch 1 [CONSTANT-SPEED set by user], for those who already have an extrusion device but want auto-spooling capability.

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    Ships anywhere in the world
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    10 backers Limited (90 left of 100)

    Auto-spooler unit batch 2, with real time feedback control algorithm. Unit will sense spool material as it begins to droop and correspondingly turn the wheel to tighten. Allows for more trouble-free spooling!

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    Ships anywhere in the world
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    Pledge $285 or more

    5 backers All gone!

    Early-bird special -- get a FULLY ASSEMBLED STRUdittle extrusion device with a SureCoil attachment (makes the filament fall into perfect coil on floor for easy hand spooling).

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    Ships anywhere in the world
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    Pledge $300 or more

    5 backers Limited (95 left of 100)

    A fully-assembled second-generation STRUdittle (swap-able cores for ease of switching between plastic colors and types) with a SureCoil attachment for easy floor spooling. Note that you will need to purchase a core unit package to utilize the swap-able core feature.

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    Ships anywhere in the world
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    6 backers Limited (4 left of 10)

    A fully assembled STRUdittle extrusion device [batch 2] with a SureCoil attachment for easy floor spooling that will double as a bottle opener.

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    2 backers Limited (23 left of 25)

    A fully assembled STRUdittle extrusion device with an constant-speed auto-spooling mechanism included.

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    Pledge $385 or more

    18 backers Limited (12 left of 30)

    A fully assembled second-generation STRUdittle extrusion device (swap-able cores for easy switching between plastic colors) with a real-time feedback auto-spooling mechanism included.

    Note that you will need to purchase a core unit package to utilize the swap-able core feature.

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    Ships anywhere in the world
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    Pledge $385 or more

    5 backers Limited (45 left of 50)

    A fully assembled second-generation STRUdittle extrusion device with a real-time feedback auto-spooling mechanism included, available in a choice of constant color.

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    Pledge $450 or more

    1 backer Limited (24 left of 25)

    Get a fully assembled second generation STRUdittle (can use swappable core feature).

    *Includes a spare swappable assembled center core unit:
    Center piece; Four flanges (three high-quality brass); Machined stainless-steel center pipe unit; Stainless steel coupler; Heated band clamp; Solid brass nozzle; Machined auger bit (drill into shaft for setscrew); Bearing; Clamp.

    -Comes with SureCoil attachment

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    The gold package: A fully assembled second-generation STRUdittle extrusion device with a real-time feedback auto-spooling mechanism included, a choice of color schemes (color of individual gears, main base), your choice of a custom hopper (think Mayan Urn or other sculptures!), and a short paper detailing all the engineering challenges and solutions, lessons-learned during the making of the STRUdittle (for those who may want to move on to further improve the design).

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    Ships anywhere in the world

Funding period

- (31 days)