Multitool 3D Printer - Blackbox

Blackbox shifts 3D printing towards a multitool manufacturing robot.

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FDM printing is not just one of the slowest 3D printing processes; it also lacks accuracy and requires support structures. But in some aspects, they can still exceed High-end printing processes. While industrial processes can produce accurate parts consistently, they struggle when it comes to material diversity. And that's when FDM shines. You can print almost any thermoplastics like PLA, ABS, TPU, Nylon, PEEK and even Polyimide. But the best part about it, these Materials can be combined. Multitool printing enables entirely new ways to design and fabricate things previously rendered impossible.

The goal is to build a flexible platform for multitool fabrication, wether it be for printing soft robots, highly integrated assemblies or even living tissue.

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I believe that multi-material 3D printing will be the next big step. Not so much for 3D printing, but the fabrication of highly integrated mechanism. Robots still require a great deal of assembly, which makes them expensive. With multi-material manufacturing, it is possible to fabricate print in place mechanism with several materials which need little to no assembly. There are not many printers out there, which offers a platform robust enough for this task. The most common commercial multi-material printer Ultimaker, Sigmax, and E3D only provide Bowden fed extruder, which are barely capable of processing flexibles.

Soft robot proof of concept


With a tool changing platform trimmed for multi-material printing and material freedom. This is achieved by the unique passive water cooling and coupling system which provides up to six direct driven extruder. The motor is shared among all tools which is why standard electronics can be used. It also offers numerous possibilities to use the extruder motor for different tools with additional axes or various types of toolheads like Paste, Syringe, Fibre or Silicone.


Offering a convenient BOM and producing the custom parts to make this printer replicable. Custom parts are the X-Plate, tool cooler, and coupling lock. We are currently in talks with different supplier to deliver these parts at an attractive price point. From that point, we can add specialized tools and finally experiment and explore what's possible to fabricate with such a multi material beast.

Blackbox complete with 6 direct drive tools

Blackbox Multi Tool X-Axis, highly integrated and completely watercooled.

Direct drive tool coupled to the X-Axis

Toolbank with parking tools

X-Carriage and direct tool prototype

Soft robot gripper printed out of TPU and PLA in one process


  • Up to 6 direct driven tools
  • Passive Water cooling
  • High-Speed Z-Axis for 3D movement
  • True RepRap, most custom parts are printed
  • Built with Off-the-shelf Parts 
  • Readily accessible
  • Adaptable for specialization (especially medical applications)
  • Air cooling is possible as an affordable alternative

Technical Data

  • Prinsize: 300x300x275, fully usable with any tool
  • CoreXY Kinematics
  • T-Slot Frame
  • MGN 12 Linear Rails
  • Belted Z-Axis
  • 9mm GT2 Belts
  • Tailored for Duet3D Board

  • Renderings to fill in the waiting time

    Marc Schömann09/05/2019 at 14:49 0 comments

    The parts arrived Germany, but they did not arrive at my home yet, so I made some renderings to pass the time

    Toolbank with silicone wiper and leakblocker

    X-Axis with a docked tool

  • Ooze Blocker and Wipe Shield

    Marc Schömann09/04/2019 at 10:14 0 comments

    In the previous Iterations I faced some problems with oozing and leftover filament on the nozzles which often got dragged into the print. The solution was a combination of a silicone wiper and ooze blocker. The tool changing process was quite different before which is why I had to redesign this component.

    Old Oozeblocker and wipeshield in the previous iteration

    Silicone wiper (front) and the leak blocker at the back, closing the nozzle while the tool is parking.

    Toolbank with the parking tools 

  • Self Aligning Mating Gears

    Marc Schömann09/02/2019 at 17:27 0 comments

    The new tool changer uses the Bondtech Extruders 1:3 reduction to decouple the extruder from its motor. To make this work, the gears need to be aligned at any time (which sounds easy but it's complicated with open-loop stepper motors). 

    Another solution are rounded teeth which arrange themselves when they mate together. These gears are highly inspired by Lego gears (like Gear 12 & 24) which are beveled and often used for gear shifter models. I guess this method only works when one of the wheels is free, luckily that's the case when the extruder is heated up!

    These gears would be really expensive when they where made on a lathe. But Igus, a german specialist for non abrassive thermoplastics has a SLS process which produces accurate longliving gears similar priced like shapeways.

    I ordered them right away to test the tolerances and see if they are really self aligning, posting pictures as soon as they arrive!

  • Final Evaluation of the CNC Parts

    Marc Schömann08/30/2019 at 14:40 0 comments

    We are currently working on the latest modifications on the CNC parts to make them ready for Production.

    First step to finalize the design was an intereference analysis to see if everything is in place and nothing is blocking the tool from docking. It displayed some flawes which where easy to fix.

    Next step was prototyping the the Parts in PLA. It looks quite good but I can´t test a complete assembly yet because im still wating for parts...

    I even prototyped the Lock in PLA and surprisingly it works ok, good enough for prototyping. So I guess with a thicker bolt one could completely print the air cooled version without any special parts!

    In the final steps Max will perform a force calculation to display areas where material can be saved. I will continue adding other parts to the prototype making sure everything works.

  • How I designed the Blackbox

    Marc Schömann08/25/2019 at 21:12 0 comments

    As an Industrial designer, I probably got a different approach than other RepRap contributors, which are often mechanical or electrical engineers. With this log, I want to communicate how decisions are made from a designers perspective.

    Complexity and Material 

    3D Printer are visually complex machines, and in my opinion, there is no reason to increase the complexity by unnecessary ornaments. Many printers are taking the extra effort in hollowing and sparing areas, often in an ornamental fashion. Many times the origin does not stem from functional aspects but our visual habits. Mass-produced, injection-molded products look like this. Injection-molded parts need to maintain a specified wall thickness, and its weight is purely dependent on the outer shape. And CNC milled objects are carved out of solid material, which adds a lot of weight when it's not hollowed. But 3D printer work different, FDM printed parts are almost hollow, and it's the perimeter and solid layer which adds most weight. Just think about it, three perimeter weight the same as three lines of infill, which can be several centimeters depending on the density. Therefore a cutout or excessive contour is not worth the effort in most cases. Sometimes structure can add stability (like the groves on a can), but it needs to be purposefully deployed.


    Proximity is one of the gestalt principles, which are a fundament of design theory. The principle says that objects which are close together, share the same characteristics, and point in the same direction are forming visual groups. There is another design theory called "product language," which goes beyond that and imagines objects as subjects which speak a visual and tactile language. A group of buttons could say, "We control the same things, so we are close together." Braun did this masterfully in the 60s and 70s, the well-known calculators used the same buttons in a rectangular array, but four different colors are grouping the buttons in layers of interaction. I used this knowledge to create modules which appear as a unit inside the printer.

    Blocky Design

    When these thoughts are applied, the result is somewhat "blocky." It may look a bit plain, but it reduces visual complexity and makes adjustments and customizations very easy. The Fusion files are now open to everyone, and the hurdle for modifications should be low. The blocky design in combination with bevels is also a good indicator for the print orientation.

  • New Tool Changing System

    Marc Schömann08/24/2019 at 21:27 2 comments

    I'm very proud showing the new tool changing system. Mainly because many new ideas came directly from the community. The new system breaks with a lot from the previous version (which is why I have to redraw almost all outline representations), but this effort is well worth the trouble.


    The X-Carriage now carries only a motor and mainly consists of an aluminum plate. This plate is connecting the linear bearing with the motor and tool changer. The motor attached to the x-axis mates with the Bondtech style tool. That way, only one stepper is necessary for all the tools, which is a massive advantage over other tool changers. It´s similar to the Makerbot smart extruder system, where the tools can be removed from the motor. Bondtech is the perfect platform for this because it already decoupled the drive gear from the motor with it's 1:3 reduction. The motor gear might need some small changes in its geometry to make sure it docks smoothly.

    Docking System

    Besides the X-Carriage, Blackbox is now using a different docking system for accounting the additional tool weight and ensuring a trouble-free usage. I was using a magnetic system along with a bent wiper, which works well for small tools. But it always was a compromise to gain fast results. The next version will use a system first introduced by Joshua Vasquez. It utilizes a cable-driven mechanic, which I adopted almost wholly. This mechanism is a remote locking system, which allows using a big servo or stepper motor away from the moving axes. The only changes are the bearing arrangement (double-flanged bearing), and I will use shifter cable housing, which is self-lubricating and bendable. 

    Direct driven tools

    The tools are essentially a shrunk-down Bondtech BMG extruder with additional kinematic coupling. A passive cooler cools the tool, but it can also be air-cooled! Yes, that's right, air cooling will significantly lower the entry hurdle to build this printer. But the best about it is that Blackbox can now utilize up to 6 direct driven tools, which means flexibles can be printed in any tool! The external motor also opens up a vast scope for other power tools, whether it be a syringe tool, a rotation axis, or additional z-axis.

    Toolbank & Parking System

    The tool bank is now cooled with a single 15x3mm aluminum strip which cools all tools together. The parkin system mostly stays the same; it's just arranged a little different because the extruder gets now picked up by the Y, not the X-axis as it was before. Apart from that the nozzle still gets wiped with a silicone sheet when it's picked up or off. When it's parking a small height adjustable silicone cube blocks any leakage.

    Waiting for Parts

    While I'm pretty confident that the rebuild will go well due to the great detail in the Fusion Files down to the screw, I'm currently waiting for crucial parts (Chrome steel balls and shafts, Fans, Linear Rails, Bondtech gears). But I already started prototyping the tools and x-axis with PLA.



    More Custom Parts

    The new coupling mechanism uses more parts which need to be gathered and assembled. The lock bolt is an additional custom part.


    All direct driven tools

    The previews system with one direct and x Bowden driven tools was a compromise. Bowden can work, but they are annoying, especially in a tool changing scenario due to the additional leaking. Bowden extruder also limits the maximum speed when used with pressure advance systems.

    Easier Electronics

    It was necessary to use one of the few boards which support multiple extruder and lots of stepper driver to power several tools. Now only 5 Steppers are required to drive the whole system: one for XYZ each + one extruder...

    Read more »

  • Custom PCB for easier wiring

    Marc Schömann08/24/2019 at 16:17 0 comments

    Extruder PCB

    These little PCBs originate from the Cobot Project. At that time, we were planning to ease wiring by using some small adapter PCBs. They are based on the red micro match connector and the well known JST connectors. The idea is to connect all the different electronic parts on an extruder (Fan, Heater, Heatsensor, Endstops, Motor) to a board which adapts it to a ribbon cable. Ribbon cables do not require special crimping tools. They can be assembled using just a vice. These things are so practical that I'm still using them for the Blackbox project. Willy Blum created the PCBs, a talented electrical engineer and I'm currently planning to sell these together via known RepRap shops.

    The Heater in this PCB is also connected via a JST connector. This is not ideal ofc and will be one of the minor changes regarding the PCBs. I thought about a screw terminal, but it seems like a bad idea on a vibrating moving device. 

    Hall Effect Sensor

    The other PCB is a two-channel hall effect endstop. It is reliable and can be daisy-chained to use two endstop with one four-wire ribbon cable (this two-channel). But the best about this sensor is it´s size, compared with other hall effect sensors used in the RepRap community this one is around half the size. While it´s designed to be used with a ribbon cable and the micro match connectors, there are three soldering pads for JST connectors to remain compatible.

    As always any input is appreciated!

  • Soft Robot Gripper

    Marc Schömann08/22/2019 at 10:58 2 comments

    Tri Gripper

    The next version of the soft robot actuators can grab things, and the tri gripper is even powerful enough to crawl! While the dual gripper is printed the same way as the waving hand, with a sliding rack and pinion, the tri gripper works a bit different. The cables are directly attached to the servo rolls the wires up. This rotating movement causes a lot of stress for the wires. Some adjustments to the roll-up attachment helped to reduce the stress, but the lifespan is still quite low.

    Tri gripper close up: cables are already damaged

    Dual Gripper

    The dual gripper works like a charm and is quite powerful. Thanks to the linear actuator, it´s a lot more durable than the tri gripper. But there could some enhancements made regarding the release angle and grip profile, especially regarding small round parts.

    What's next?

    Next challenge will be something that walks/crawls, I want to use as few motors as possible to achieve that, but im unsure how will work in the ende, so any inspiration or tip is very welcome! But for the next two weeks priority will be on the printer again, there are some great updates which i can´t wait to share!

  • Quick Release Housing

    Marc Schömann08/19/2019 at 15:35 0 comments


    The housing may seem like a small insignificant detail, but I'm using this printer daily. And I don't want to struggle with inadequate housing or long-lasting disassemblies before I can reach essential areas.

    How not to mount

    The housing of a 3D Printer is an crucial factor to achive temperature stability, protection and is the fundament for a heated built chamber. But mounting thin sheets on a vibrating machine is not as easy as it seems. Fluctuating temperatures add another problem. Acryl, for example, expands quite a bit, causing stress and nasty sounds. I experienced how bad this problem is when I worked for a german 3D printer company which bolted the acryl sheets directly to the frame. 


    This one might be more important to people like me who continuously change stuff, but it has paid off for me. I can detach all housing parts in seconds, which makes maintenance a bliss.


    It may sound superficial and unnecessary for an open-source project, but "looks" matter. Open Source 3D Printer are in fierce competition with cheap and sleek but mostly closed source Chinese printer. If we want to keep the community committing to open source, we need to compete on every level with the commercial alternatives. It is no coincident that Ultimaker and Prusa are working so hard on making their machines look like they do. We judge objects just as we do with humans, superficial and very fast. A capable 3D Printer should radiate precision and reliability to built trust in the user. This can also be understood as a promise. It promises to look like it's capable so it should better deliver!

    The Solution

    Adding four sliding cylinders to each corner on the Acryl sheet. The idea is that the sheet slides into the shaft pressing the sealing against the frame by its weight. That way, each sheet can be detached by pushing it up and out, no tools required.

    While this is an excellent solution for side and back walls, it´s no solution for the door or the cover. The door could be split and opened by a printed double hinge like this:

    Finalizing the doors is high on the bucket list, if you want to speed things up and construct something like this please contact me!

  • Passive Water Cooling

    Marc Schömann08/18/2019 at 13:53 0 comments

    Passive water cooling was one of the innovations I brought in with the Blackbox. 

    There are three reasons why I prefer water cooling:

    • I had only good experiences with water cooling before, the Kraken Hotend which I used for a while never failed me (unlike air cooled v5 or v6 hotends)
    • Blackbox was designed with a closed built chamber in mind, and water cooling performs way better in that scenario. Another plus is that it's more resistant to general ambient temperature. I witnessed a few summers (in Germany!!) in which the air cooling of an e3d v5 came to its limits.
    • It shortens the distance between drive gear and nozzle. A short distance is especially crucial for soft materials, the smaller the gap between gearwheel and nozzle, the more direct the control. And you can truly feel and see it in practice.

    Watercooling a tool changing printer the "classic" way would require many hoses to every single tool, which produces just as many possible leaks. Water cooling in a device which has countless high voltage parts can be very dangerous, so you naturally want to avoid too much unnecessary fittings. With the Blackbox setup, you only need two hoses: one goes to the X-Axis and another one to the tool bank. That way, the tool is cooled when active and inactive without beeing cooled actively by itself. 

    How it works

    The system works like any other water block with the only difference that there is no thermal grease and it is not screwed and therefore removable. The lack of heat conductive paste substantially impairs efficiency, but a hotend produces significantly less waste heat than we are used to from CPU or GPU. And while the conductivity between the two cooling blocks is rather low, the water cooling itself is extremely efficient. Maximilian Arnold was so nice to calculate how much waste heat dissipates at the cooler of an e3d hotend. These are his results:

    Original E3D Hotend
    Sunon fan 3010 Maglev 12V
    Fan flow rate 0.154 m3/min
    Air density 1,2041 kg/m3
    cp Air 1.005 kJ/(kg*K)
    Ambient temperature 26 °C
    Hotend temperature 250°C
    Air temperature upper end of the heatsink 30.5 °C
    Air temperature lower end of the heatsink 40.5 °C
    Average value 35.5 °C
    delta T is thus 9.5 K

    Thus 29.5 W should be delivered under perfect conditions. 
    The lamellas got a higher air resistance, therefore one gets counterairflow from the fans. I think that the heat dissipation lies rather in the range of 20-25 W

    Instead of the 100-500 watts we are used to cool our computer chips, only about 20w have to be dissipated. And appearantly pure touch is enough to do that, if paired with a titanium heatbreak there should be plenty of room even for high temp materials.


    I tried to do a simulation in Fusion 360, but the results do not represent reality. As you could see in the video, the tool cooler reaches around 35°C (250°C), in the simulation the tool cooler stays at 25°C. I guess the reason is that fusion calculates with perfect contact surfaces. If anyone knows how to improve the simulation, you can download the Fusion file. I would love to have a better representation. 

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Andrew Overby wrote 6 hours ago point

I've been following your first iteration of this project for a while now and I couldn't help but create an account so I could comment on a job well done! The single motor idea is amazing and I'm very impressed by the kinematic coupling setup (saw the article explaining it on your website). I also like the water-cooled system to help with higher-temperature materials. Can this system account for different tools and offsets if a different hotend is desired? 

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Joe Pomodoro wrote 09/05/2019 at 01:35 point

@--marc  Very nice, clever use of the single extruder motor on the tool-changer carriage. What control board are you using? It seems most are using Duet or Klipper for tool changing machines. Also, you mentioned a fast-moving z-axis. Is the Z-axis leadscrew driven, belt driven?

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Marc Schömann wrote 09/05/2019 at 10:16 point

Thanks Joe! Im using a ultratronics board with klipper currently but the next iterations will be tailored towards duet. The Z-Axis is belt driven with a 1:25 belt reduction!

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Andrey V wrote 09/02/2019 at 17:50 point

I can't understand the idea. Yes, pics looks good, but what benefits this device has IRL?

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Marc Schömann wrote 09/02/2019 at 18:37 point

Six direct drive extruder which can be used in a single print process. Have a look at the youtube video to see the potential!

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Andrey V wrote 09/03/2019 at 02:54 point

If you are talking about multi-material printing, I think this idea was already realized around 10 years ago for industrial printers and more than a year ago for Prusa very clever way and with only one extruder.

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Marc Schömann wrote 09/03/2019 at 11:04 point

Im sure the Prusa engineers put a lot ofthoughts into this, but the system clearly has it´s flaws. It consists of many fragile components which need to be aligned perfectly to work and many user are facing problems. A tool changer on the other hand is almost self aligning and therefore more reliable.

The temperature is adjusted while printing the purge tower, but depending on the material combination that can cause problems. PVA, for example, undergoes pyrolysis at around 200°C, if you purge it with a material which requires higher temps it will certainly jam the extruder. Just look up the prints done with this approach, multi-material examples are very seldom, but you see tons of multicolor prints. 

The Blackbox concept also allows using other tools than filament extruder like silicone, syringe, fiber, paste extruder or CNC tool head. The possiblities of a tool changing 3D printer are not limited to extruding filament and thats what I like about it!

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Marc Schömann wrote 09/03/2019 at 08:17 point

Industrial FDM Printer where only able to print two materials, mostly used for support structures. The Prusa ist not really multi material but multicolor like the palette. 

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Andrey V wrote 09/03/2019 at 09:26 point

If I understand correctly, it is possible to use completely different materials(with the same printing technology) with Prusa multi-material addon.

ProJet MJP 5600 is able to print with 6 different materials.

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Marc Schömann wrote 09/03/2019 at 09:56 point

Shared nozzles limit temperature differences between the materials; also, such systems are prone to jam, the crazier the material combination the more likely it is to do so. This approach also requires a very big purge tower making the process even slower than tool changing. 

Now the ProJet MJP 5600 utilizes an entirely different print process. They call the process "MultiJet Printing" but it's essentially what Stratasys does with their polyjet technology (which they bought from Polyjet). Instead of using filament it prints photocurable resins very different to thermoplastics we use. The flexible resins, for example, feel sticky, attract dust like a magnet and disintegrate after a few years. It's a true prototyping platform and despite that these printer cost 50k+.

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Andrey V wrote 09/03/2019 at 10:12 point

I think the temperature changing for each material is not a problem. I think Prusa engineers already done this. The problem with the materials mixing also solvable with the software and/or small mechanical upgrade (additional place for old material).

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Victor Dedios wrote 09/01/2019 at 19:28 point

Really cool project! It's great to see smart mechanical designs like this around here. In this DIY community, there are lots of good electronic projects but there is a need of more designers that can bring concepts to reality. There is a lot of creative work that can be done in mechanics!

I love the coupling system, I have a project about a PCB manufacturing platform and multi-tool changer is what is giving me more headaches, still a concept.

Keep up with the good work @Marc Schömann !

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Marc Schömann wrote 09/02/2019 at 10:13 point

Thanks a lot for your kind words! Yes especially industrial designer neglect the open source movement almost entirely. Even tough it makes design comprehensible (maybe it´s because of that). I like your PCB platform concept, would love to have something like this here!

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RandyKC wrote 08/01/2019 at 20:13 point

So glad to see this project entered!

Beautiful work. I’ve got to explore your choice of Fusion, but as considered as your design is I’m sure it was the right choice as well.

I’m going to see how your ideas could be adapted to work on a FABtotum I backed way back when. It has a horizontal carriage instead of a vertical. I hate to lose working area by putting it on either side of the carriage.

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Marc Schömann wrote 08/02/2019 at 19:27 point

Thanks a lot for your support! Fusion has two crucial advantages over all other CAD programs: It is accessible to everyone and allows cooperative working. I am very excited about how it will be to work with the community.

Pls update me if you plan to retrofit your FABtotum, would love to see it!

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Carlos Echenique wrote 08/22/2019 at 19:10 point

Is there a Linux version of Fusion 360?

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izak.oliver wrote 07/31/2019 at 15:12 point

Exceptional design! This printer will put the industry on its head! Great work Marc! It deserves top spot

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Marc Schömann wrote 08/01/2019 at 18:23 point

It´s so nice you are on board with this! Thanks a lot!

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