Blackbox - 3D Printer

Blackbox is a highend CoreXY 3D Printer. Aiming for multi material extrusion, reasonable build volume, fast printspeeds and high resolution.

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Blackbox is a high-end open-source printer which is highly reliable, precise fast and feature rich. I designed the printer for daily model building, but also for further experiments. Since I have to rework many models, which costs a lot of time and work, it is particularly important for me to be able to produce high-quality prints. My vision for the future is a 3D printer that can operate autonomously and rarely needs human support. More a production robot than a 3D printer in the traditional sense.

The source files can be downloaded on

All files are released according to the following license unless specified differently in the file or directory:

Short Description

40x40 t-slot profiles form the 470x500x550mm (HxWxD) sized frame. The large build volume of 300x300mm can be used with up to five Materials. This is achieved by water-cooled exchangeable tool heads. The tools do not have their own cooling, instead they are cooled passively by the tool bank or the x-axis. While the tools are bowden driven the X-Axis carries one direct driven Extruder for flexible materials. The Z-Axis is based on belts with a 1:10 pulley reduction, compared to ball screws a fast, precise and cheap alternative. To keep the print area warm and chill im using 3mm laser cut acrylic sheets. All Axis are based on linear rails, the Y-Rail is supported by the T-Slot frame while the X-Axis is supported by a lightweight carbon square rod.


Watercooled Toolchanger

At first I build the Blackbox around a water cooled Kraken hot end with four extruders from E3D. But the results where a bit disappointing. My goal was and still is to be able to print complex composite parts with multiple materials. But the leakage of the inactive extruder made it really messy. I was aware of dual x-carriages and tool changing printer but i had no idea how to combine that with a water cooled hot end. Just to think about connecting several tools with their own cooling circle gave me nightmares. But one day it hit me, the tool can be cooled passive by a cooling cycle hooked to the extruder and the tool bank just by touching the cooled surface. The idea is that the tools are cooled on the tool bank while they are inactive and on the X-axis after they are picked up by it. As a result, the tools require neither cooling hoses nor fans and are therefore extremely compact and lightweight (<40g).

Belted zero backlash Z-Axis

I started the Blackbox with a ball screw driven Z-Axis. It worked really precise with zero wobble, but it wasn´t able to accelerate fast because it was overconstrained. So I redesigned the Z-Axis completely based on belts. To achieve the necessary precision and to prevent the heating bed from falling down I use a 1:10 belt reduction. The Pulley configuration for the reduction is 16 teeth on 40 teeth, 16 teeth on 64 teeth. This results in a full step resolution of 0.01mm with 0.9° Stepper and almost no backlash, great for fast z-hop moves.

Carbon X-Axis

The X-axis is based on a small and lightweight MR9 (like MGN9) linear rail supported by a cheap carbon square tube. Im using printed brackets to guide the belts. Therefore the total x-axis including direct drive extruder and Y bearing weighs just about 750g-900g. This should reduce jittering and vibrations resulting in higher acceleration.


The black box was designed from the ground up with the idea of easy maintainability and assembling in mind. One example is the housing which can be completely removed within a few seconds. Another example is the X-Axis/Extruder which consists of very few parts and can be accessed easily. I also integrated cable channels which should clean up the wiring. All bearings are clamped in a way they can´t pop out. This is the result of extended iteration and prototyping. Im working almost two years...

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  • 1 × MK10 Heaterblock It´s a real pain to get quality MK10 Heatblocks, if you fid some tell me. Im using Wanhao ones currently.
  • 2 × 20x60 T-Slot profile Aluminium Profiles 20x60 size
  • 1 × GT3 Belt 9mm wide, 2mm tooth offset. You can also use GT2 Belts.
  • 2 × GT2 Smooth Idler Toothed Idler for 9mm wide Belts
  • 3 × Nema 17 Stepper Motor 0,9° Im using the 44Ncm version from omc-stepperonline but any Steppermotor with more than 25Ncm will do

View all 25 components

  • Wiring done!

    Marc Schömann2 days ago 0 comments

    I got the XY-Axis assembly done after some seriously annoying problems. One major problem were tolerance issues which I have already mentioned. I found the cause by accident, i was switching to a .25 nozzle for some really problematic parts (flexible fan encoupling) and noticed the extreme wear of the nozzle. I was printing around three roles of carbon ABS until then. Although i was aware of the abrassive characteristics of carbon filament, i didn´t expected it to be THAT abrassive. I think we need to be careful to use claims like "wear resistance" like micro swiss does when you see something like this after just 3 roles.

    But if you see these tolerances you may understand why i used carbon ABS. The tolerances i build with are very tight and the slightest warping would turn out to be a big problem. The X-Axis/Extruder assembly is the only part where this is REALLY crucial, the rest is fairly easy to Print.

    The fans were surprisingly troubling too, in order to get them as compact as possible i decided to ditch the original aluminium housing for a custom sls printed housing/fanduct combination. The backside of the fan is held by flexible printed coupling. This results in a really slim and lighweight partcooling solution.

    Total weight is around 930-950g, my goal was to stay below 1kg for the complete XY assembly and it looks like I'm gonna achieve that goal.

  • So close!

    Marc Schömann05/08/2018 at 19:06 0 comments

    After several tolerance issues with my printer i was finally able to print the last iteration before the rebuild. The toolsystem looks good at first glance and i think i picked appropriate sized magnets. The new 8mm Z-Axis including heatbed is also ready for the big rebuild at the weekend. There is still an issue with the printed pulley, I still haven't managed to print a pulley that doesn't wobble.

    Here is a small demo of the extruder toolchange mechanism

    I used regular 2k epoxy glue for the Magnets. I had to buy way more magnets than necessary because they got big variance in tolerance.

    X-Axis weight: ca. 400g

    Tool weight:  ca. 36g

    Belt tensioner on the Z-Axis, hopefully strong enough to hold this massive aluminium bed.

  • Team expansion

    Marc Schömann04/29/2018 at 13:35 0 comments

    Im proud to announce that the Blackbox team has a new and ambitious supporter!

    Let's welcome Prashanth Ray, experienced in 3D printing and currently researching on the topic of 3D Bioplotting at the Johns Hopkins University, USA.

    Rays goals will be as follows:

    "My goals in contributing to the project are

    • Design and fabrication of a Multi-channel 3D bioprinting system containing

    • Pneumatic extruder (Pneumatic control)

    • Piston extruder (Mechanical Extrusion i.e Motor driving),

    • Microneedle jet (Microdot i.e Pulse generation control)

    • The 3D bioprinting system should be able to accept a variety of bio-materials to build composite hybrid scaffolds.

    • Create an environment to maintain biocompatibility, mechanical properties etc.

    I have few more ideas to work/modify and yes, keeping everything open-sourced."

    Im thrilled to see Rays vision cumming true in the future!

  • collecting the last bits

    Marc Schömann04/28/2018 at 14:27 0 comments


    I have finished the Z-axis and tested its functionality. The reduction works great but the 5mm rod seems to be undersized. On top of that i bought the wrong pulleys (6mm instead of 9mm) so i guess it´s a good excuse to size this axis up. While i think that 6.35mm is plenty the rods in this size are really hard to source so i guess i will use 8mm rod instead. That might be oversized but weight isn´t that important here.

    Above you can see the bearing pedestal, next to it the printed 64t pulley (unfortunately difficult to get in the EU) and below the pulley gearbox with belt tensioner.

    Apart from that I am collecting all necessary parts together, as I only have one 3D Printer, all parts have to be together before the conversion can start.

  • Alu parts are back!

    Marc Schömann04/27/2018 at 16:52 0 comments

    The CNC milled coolers are back from anodising, and they look... wow

  • Illustratrion time

    Marc Schömann04/25/2018 at 21:39 0 comments

    In order to enhance the communication of my concept i decided to use the waiting time for the anodised parts for some drawings which should help to explain the concept behind the Blackbox.

    X-Axis, direct drive extruder and toolchanger. 

    Toolchange process, the X-Axis has a watercooler as well as the toolbank. So no matter where the tool is hooked to it gets cooled by it. 

    A single tool close to the X-Axis. The CNC machined alumium parts touch the Mastercooler and are constantly pulled by neodym magnets. The tools can be very compact and lightweight that way. Lightweight tools are making the coupling process much easier.

    The X-Axis side of the toolchanger. You can see the blue Mastercooler which features two neodym magnets. Dividing the tools and the coupling into two Parts (Aluminium parts for cooling and printed parts for coupling) makes this solution way more accessible. 

    Here you see the belted Z-Axis. The reduction happens next to the stepper motor which transmit the force to a 5mm rotation axis. 

  • Watercooling is (almost) ready

    Marc Schömann04/14/2018 at 13:31 0 comments

    The CNC Parts are back from the shop, and they are awesome!

    I had to wait two weeks for them, but it was worth it. Next step will be sanding and anodising the parts. I think this is necessary to prevent corrosion, but also to achieve a harder Surface for the tool changer.

    X-Axis/Extruder and the mastercooler which will cool the direct drive extruder directly and the tools indirectly

    i wanted to use compression fittings known from PC watercool systems. They turned out to be way too heavy so i swapped them with PE fittings used in the chemical industry.

    While i waited for the tools to be machined i worked on how the hoses are guided along the energy chain.

    Z-Axis is also on a good way, the tension mechanism is ready, just a few brackets left to do.

  • Quick Update

    Marc Schömann03/24/2018 at 16:50 0 comments

    Just a quick update: Im currently way behind my time shedule, i was a bit distracted setting up my new workstation and the Extruder turned out to be really tricky in detail. Anyway im close to finish with the 4. Iteration and will upload the new source files soon. What you see here is a modificated Bondtech BMG with a custom Waterblock/Tool changer and Belt fixtures (basically 90% of the X-Axis)

    Custom Waterblock, its a very waterblock with two fron holes and one cross hole which get sealed with two grubscrews.

    The magnet side of the Waterblock, tools will be attached to the block and hopefully cooled enough just by contact. Magnets are inset .1 so they are permanently pulling.

    Hose adapter and water block for the Extruder in one Part.

  • Introducing the BOM

    Marc Schömann02/26/2018 at 21:41 0 comments

    I started the Blackbox BOM, i don´t know whats the best way to keep track of all the Items but until now im using a google docs excel sheet:

    The Price (Without Acryl Housing, Screws Nuts and Watercooling) should be around 1400€. 

    Yes, this is not a cheap Printer but it could be dropped way down with cheaper retailers. If you want to collaborate on this BOM just contact me.

  • Blackbox V0.3 - STEP Files

    Marc Schömann02/25/2018 at 18:59 0 comments

    These are the current CAD Files for the Blackbox Printer. I don´t recommend replicating it yet!!! I didn´t planed to release the files so early but due to request i decided to change my plans. Most Parts are untested. The Frame howeever is final and will not be changed.

    It would be really nice if you would share Feedback, Ideas and toughts!

    T-Slot Frame

    Blackbox with Acryl Housing

    Direct drive Extruder / Custom Bondtech

    Watercooled toolchanger

    Watercooled tool Rack

    1/2 of the Extruder Bracket

    Belted Z-Axis and Belt gear 1:10 (Draft)

View all 11 project logs

Enjoy this project?



neeek wrote 05/02/2018 at 09:30 point

Any chance you could upload a rhino file that is saved for an older version ? (I'm still on version 5)  :)

  Are you sure? yes | no

Marc Schömann wrote 05/02/2018 at 23:45 point

sure! added a rhino 5 version to github 

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neeek wrote 05/03/2018 at 11:41 point

Thank you :) much appreciated.. keeping up with CAD software releases these days is crazy.. Especially given the price of a single user license ($16k a year ??)

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Marc Schömann wrote 05/03/2018 at 15:58 point

That's true, I'm lucky to have a education license.

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Mynasru wrote 02/24/2018 at 23:35 point

What is the name of your desk lamp? It looks nice

  Are you sure? yes | no

Marc Schömann wrote 02/25/2018 at 19:21 point

The lamp was a project during my sixth semester years ago. Every segment can be controlled individially via DMX. Here are more Informations:

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art wrote 02/24/2018 at 01:00 point

i think id like to make this as well.  thanks for sharing!!!

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Marc Schömann wrote 02/25/2018 at 19:11 point

Great! Looking forward to it!

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John M. Owen wrote 02/19/2018 at 20:44 point

did you publish some plans? I would like to build something similar...

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Marc Schömann wrote 02/19/2018 at 23:51 point

i will after the third iteration, im currently doing final adjustments. By the end of the week i should be able to publish something.

  Are you sure? yes | no

John M. Owen wrote 02/24/2018 at 15:06 point

hope so! I get the impression your design is somewhere in the space I was converging on. I showed it to some other folks with similar interests and the consensus was if you open source it we’ll attempt a build. 

  Are you sure? yes | no

Marc Schömann wrote 02/25/2018 at 19:16 point

That would be so awesome! I uploaded the current version.

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