Introduction: Simple Hack to 3D Print HUGE Parts

About: I make things, some of which work. Full Tutorials: Email:

☝️☝️**Watch demo video above first. It answers all questions.**☝️☝️

Check out the demo video!

In this tutorial, I will explain how to convert a regular 3D printer into a conveyor belt 3D printer! Why would you want to make this conversion? Because a conveyor belt 3D printer can print infinitely long parts. If you don't believe me then watch some of the demo above!

This project is completely opensource. Resultantly, I have have aptly named this 3D printer the "OpenBelt Printer". I have linked the CAD and firmware to this Instructable. I have also created detailed instructions so that you can easily build (and improve) this 3D printer. My goal is that this project serves as a platform to encourage/inspire other people to build conveyor belt 3D printers.


  • 1 × FDM 3D Printer
  • Instead of starting from scratch, we will be modifying an exiting 3D printer into a conveyor belt 3D printer. Almost any FDM 3D printer is suitable for this conversion. i am using an Artillery3D Hornet for my conversion.
  • 50 × M5x8mm Hex Bolts
  • Hex Socket Head
  • 4 × M5 Sliding T Nuts
  • 2 × 8mm Metal Axle
  • Each axle must be at least 200mm long. You can cheaply purchase such axles from vendors like Home Depot, Amazon, Canadian Tire, McMaster-Carr, etc.

Step 1: Project Introduction (You Can Skip This)

Conveyor belt 3D printers are arguably the most exciting development in 3D printing since RepRap. With its unique design, a conveyor belt 3D printer has two features which no other desktop 3D printer can offer: automatic part ejection and infinitely long printing. Resultantly, a conveyor belt 3D printer can both mass produce parts and print extremely large parts. If it works…

Over the past half decade, a number of desktop conveyor belt 3D printers have been released to the public. Unfortunately, these machines are buggy and finicky; their print quality does not meet our expectations of a 3D printer in 2022. Current conveyor belt printers are reminiscent of hobby 3D printers from 2007-2009: low quality, unreliable, prototype adjacent, but also lots of fun! The caveats and details of conveyor belt 3D printers still need to be ironed out. I believe that there is a missing ingredient that will rapidly move this design forwards: community. In its early stages, amateur 3D printer designs made rapid progress due to a large, committed, opensource community that was working together to make low cost 3D printers viable. Conveyor belt 3D printers need the same open source catalyst.

I have built many, many, many, many, many conveyor belt 3D printers. From the knowledge gained through these successes (and failures), I have designed a new conveyor belt 3D printer that is extremely simple for people to build. The 3D printer is completely free and opensource with the CAD and firmware available in this document. I have also provided detailed build instructions to make it straight forwards for others to replicate (and hopefully improve) the 3D printer. Due to the opensource nature of this project, I have aptly named this 3D printer design OpenBelt - The Opensource Conveyor Belt 3D Printer.

Step 2: Project Design Choices

My goal is that as many people as possible are able to replicate this 3D printer. Therefore, I tried to make the design accessible and easy to follow for people from all technical background. In pursuit of this goal, I made the following design choices while developing this project.

  1. All components for this project can be 3D printed
    In my previous conveyor belt 3D printer designs, I used a lathe and mill to machine some of the components. I am assuming most people attempting this project do not have access to such expensive machines. So I specifically designed all of the fixtures, jigs, and other components to be 3D printable. I hope this makes it easier for others to fabricate these components.
  2. Simple Design >>> Perfect Design
    I chose to make this conveyor belt 3D printer as simple as possible. There are many extra features that I would love to add to this machine. But I chose to only include the bare essentials for this tutorial.
  3. Starting with a 3D Printer
    In this tutorial, we start with an existing 3D printer and convert it into a conveyor belt 3D printer. If I were to instead build the 3D printer from scratch, I would have to include a lot of additional details that are irrelevant to the key conveyor belt aspect. There are already many tutorials online that document building a 3D printer from raw materials. I see no point reinventing the wheel. If you are looking for a good resource on building 3D printers from scratch, I recommend Dr. D Flo’s YouTube Channel!

Step 3: Project History

The first time I used a 3D printer was in my freshman year of high school. After a few hours of working with the machine, I realized that a conveyor belt would be an excellent way to automate 3D printers and allow them to print a continuous stream of parts. After doing some online research, I came across the defunct Makerbot Replicator project. Seeing that a large company failed to successfully build such a conveyor belt for a 3D printer, I assumed that such a device was not technically feasible.

In December 2017, I saw the Kickstarter video for the Blackbelt 3D Printer. I was extremely impressed by the 3D printer; both its capacity for mass production and infinite printing capabilities. Since the machine cost several thousands dollars it was well out of my price range. Instead, I sought to build my own low cost conveyor belt 3D printer. I won several project grant competitions at my university and I was able to bootstrap my project. I tested my first conveyor belt 3D printer on January 30th 2018. I proceeded to build several more iterations of my conveyor belt 3D printer. Here is a demo of my most popular iteration which I also entered in the 2018 Hackaday Prize.

While developing my conveyor belt 3D printer, I relied on documentation from many other people online working on similar projects. For example, I routinely watched the YouTube channels of Zechy Coyte-King and Brook Drumm for advice / aha moments. Now it’s my turn to create documentation that will facilitate, assist, and inspire other people’s projects. Conveyor belt 3D printers have been around for half a decade. And in that time, the design of conveyor belt 3D printers has remained relatively stagnant. Compare the progress of FDM 3D printers between 2009-2014 and conveyor belt 3D printers between 2017-2022. The difference is staggeringly depressing. I believe the reason conveyor belt 3D printers have not taken off is because they do not have a community that supports them. Hobby 3D printers did not explode in popularity because of a single individual or company, but because there was a community working together to develop the machines. Conveyor belt 3D printers need a similar community to develop and improve the machine design. So that a large corporation can steal and profit off it :)

Step 4: Find a 3D Printer to Modify (Tutorial Starts Here!)

We could build our 3D printer entirely from scratch, but that would be a lot of work and a total PITA. Instead, it is much easy to take an old s****y 3D printer and reincarnate it as a s3xy conveyor belt 3D printer. I am assuming anyone who is interested in building a conveyor belt 3D on Hackaday already has some 3D printer parts lying around 💪.

You can turn almost desktop FDM 3D printer into a conveyor belt 3D printer. In this tutorial, I will be modifying an Artillery3D Hornet 3D Printer. I am modifying this 3D printer because Artillery3D gave me several of them for free. Thanks Arillery3D! I repeat, you can use pretty much any hobby FDM 3D printer for this project. However, all of 3D models I designed are specifically meant for the Artillery3D Hornet. The easiest way to following this tutorial is by using that exact 3D printer. However however, I have included the CAD for all of these 3D models as well. So you can modify the parts to match other 3D printers (i.e. TronyXY, Ender3, Prusa, etc). If you do modify the CAD, please let me know! I would love to add your models to the repo (with proper credit of course:)) so that more people can build conveyor belt 3D printers.

Step 5: Print Out the Parts

All custom parts in this project can be 3D printed. ALL CUSTOM PARTS IN THIS PROJECT CAN BE 3D PRINTED!

A major flaw in my previous conveyor belt 3D printer designs is that some of the parts had to be machined on a lathe, mill, or other expensive equipment. Obviously, this made the design less accessible to others. Duh!

I want people to be able to build this 3D printer even if they don't have access to their school's machine shop. I want people to be able to build this machine even if they do have access to their school's machine but their faculty is too crusty to let them use it. Therefore, I ensured that all of the mounts, jigs, etc. used in this project can be 3D printed. Once again, the CAD is available in addition to the STL models. So if you want, your more than welcome to machine high quality components out of metal (and if you do let me know!). But 3D printing works just fine.

You can access the CAD repo at this link:

I printed all components at 35% infill and .32 layer height.

Edit November 7th 2023:

GrabCAD is dead rip :(, It has been a few years since I did this project and I have lost a few things. I have posted the files I could find on github aswell.

Step 6: Remove Y-Axis

Finally, we can start assembling our 3D printer. And by assembling, I mean disassembling.

My tutorial assumes you are starting this project with a functional fully assembled FDM 3D printer which you want to turn into a conveyor belt 3D printer. I am also assuming your 3D printer has a standard cartesian kinematics system and not some other weird s*** (i.e. CoreXY).

The first step we must take is removing the y-axis of the 3D printer. This is the axis that moves the heat bed forwards and backwards. We will be replacing this axis later on with the motion of the conveyor belt.

Unbolt the extrusion that connects the y-axis to the printer and disconnect all of the electronics (heat bed, stepper motor, limit switch) from the main board. Carefully remove the y-axis components and store them in a safe place. Because we are recyclers, we will be reusing all of these components later on in the project.

Step 7: Assemble Base Extrusion Pieces

Extrusion is awesome. With t-nuts and an allen key, we can easily mount anything to extrusion; including almost all of the 3D printed components in this project.

The front of the Artillery3D Hornet is a plastic injection molded part. It is not easy to mount things on this part. Therefore, I removed the plastic injection molded piece and replaced it with aluminum extrusion (I reused the extrusion we took out of the y-axis). I connected the aluminum extrusion pieces with the 3D printed "CORNER_BRACE" components.

Step 8: Mount Heat Bed

In a conveyor belt 3D printer, the heat bed does not move back and forth along the y-axis. Instead, the heat bed remains fixed in place with the conveyor belt running over it.

Use the "STANDOFF_MOUNT" and "HEATBED_STRUT" pieces to secure the heat bed in place. Your 3D printer likely came with springs to raise and lower the heat bed. Install these springs between the heat bed struts and heat bed for a similar purpose.

Step 9: Rotate Z-Axis by 45 Degrees

With traditional 3D printers, the z-axis is perpendicular to the heat bed. But a conveyor belt 3D printer has the z-axis at a 45 degree angle to the heat bed. This allows the conveyor belt 3D printer to produce infinitely long prints (also the prints have some interesting structural properties).

Unscrew the z-axis from the base of the 3D printer. Use the "ANGLE_BLOCK" and "ANGLE_BRACE" pieces to remount the z-axis at a 45 degree angle to the base.

Step 10: Rotate Extruder by 90 Degrees

The extruder needs to be rotated as well. Use the "EXTRUDER_BRACE" piece to mount the extruder in a perpendicular position to the z-axis.

Step 11: Press Bearing Into Bearing Holders

The drums of our conveyor belt must roll on frictionless smooth bearings to function properly. You can salvage such bearings from the y-axis you dismantled earlier on.

Carefully press one of these bearings into each of the bearing blocks. I recommend using a vise or clamp to press the bearings in place.

Step 12:

I lied. Earlier on, I said that all components used in this project could be 3D printed. One component you do need purchase is an 8mm metal axle. Fortunately, it is extremely easy to find this item. Here are a few vendors I found after a 30 second google search: Amazon, Home Depot, Metal Supermarket.

Technically, you can 3D print this component. But I would be afraid of the axle breaking from the shear stress of the conveyor belt.

Once you have obtained a suitable metal axle, cut it into two pieces and hammer each halve into one of the drums. If it is difficult to hammer the metal axle into the drum, I recommend running an 8mm drill bit through the hole of the drum. This ensures there are no 3D printing defects that reduce the hole size.

Step 13: Mounting Drums

Bolt the y-axis stepper motor to the "MOTOR_BLOCK" components. Than use the respective bearing and motor blocks to mount both drums in place. Use the "MOTOR_COUPLER" component to connect the stepper motor to the drum.

Step 14: Mount LCD

The "SHEAR" component contains the mounting holes for the LCD. Use the "SHEAR" component to attach the LCD to the front of the 3D printer.

Step 15: The Conveyor Belt!

What conveyor belt should I use for my 3D printer? This is a straight forwards question without a straight forwards answer.

There are several materials that you can use for your conveyor belt. In order for your conveyor belt to function correctly, it must have the following three properties.

  1. Flexible: The conveyor belt must be flexible. If it is too stiff, it will not lay on the heat bed and this will warp your prints.
  2. Heat Resistant: Your extruder will touch the conveyor belt at some point during a print job. The extruder will be running at temperatures of ~250 degrees celsius. If your conveyor belt cannot withstand this heat, it will deform and quickly become unusable.
  3. Filament Adherent: 3D printer filament must stick to your conveyor belt. If the filament does not adhere to the belt material, all you will be able to print is abstract art.

There are several materials that I have tested as conveyor belts. I have made a convenient table that summarizes the pros and cons of each material. By far, the best material is the Formula32 made by Powerbelt3D. This is a belt material that is fabricated specifically for the conveyor belt 3D prints. Unsurprisingly, it produces the highest quality prints. The conveyor belts are a bit pricy at $40 USD per unit, however you can use my promo code to get a 20% discount.

Get a formula32 belt here: (affiliate link)

MaterialProsConsSourceBrass / Stainless Steel Shim Stock-Can withstand high temperatures -Not Flexible Tape-Flexible-Cannot withstand high temperatures Belt-Can withstand high temperatures
-Flexible-Expensive (But not with my promo code!)

Once you have selected a conveyor belt, cut it to size appropriately. Use the belt tensioners to move the front drum as far inwards as possible. Then, tape the belt ends together over the drums.

Step 16: Tension the Belt

Use the belt tensioner to move the front drum outwards until the conveyor belt is taut. Test drive the belt motor to ensure it can move the belt at the set tension.

Next, mount the four "BELT_FLATTENERS" on the heat bed. These components should keep the belt flat against the heat bed.

Step 17: Update Firmware

Download firmware from the GitHub repo below.

I have included both the compiled HEX file and the uncompiled marlin files. The firmware is stock marlin besides three minor changes in the configuration.h file.

Firmware Modifications

/*Ln 625: Comment out the USE_ZMIN_PLUG property as the conveyor belt has not endstop*/
/*#define USE_ZMIN_PLUG*/

/*Ln 743: Update the STEPS_PER_UNIT properties accordinly. Verify that easy axis is moving the correct distance afterwards.*/
#define DEFAULT_AXIS_STEPS_PER_UNIT { 80.121, 400, 16.9, 445 }

/*Ln 1133: Put in a large value for the max conveyor belt position*/
#define Z_MAX_POS 99999

Step 18: Run Test Print!

I made a cool Print Infinitely sign and I think it is the perfect first print for your 3D printer. Try running it to ensure your 3D printer operators correctly. I have included both the STL file and gcode for your use.

Link to test prints:

Edit November 7th 2023:

GrabCAD is dead rip :(, It has been a few years since I did this project and I have lost a few things. I have posted the files I could find on github aswell.

Step 19: Optional - Tailstock Holder

As you print increasingly longer parts, eventually they will need to be propped us as they are printed. You can use the "EXTENSION_TOP" and "EXTENSION_BOTTOM" components to build a small tailstock holder at the front of your 3D printer. I also used successfully used a saw horse stand to support long print jobs, as shown in the demo videos.

Step 20: Future - Moving to Rwanda

In the middle of writing the documentation for this project, I moved from Toronto, Canada to Kigali, Rwanda. I made the move to install one of my conveyor belt 3d printers at E-Commerce Rwanda: a local makerspace in Kigali which is funded by the Rwandese and German governments. Local Rwandese entrepreneurs, students, and youth will get to use the 3D printer for their technical projects. And I think that is friggin awesome! I hope to see more conveyor belt 3D printers pop up around the world in the future.

Step 21: Credit

I have no intention to sell this 3D printer. This is purely an open source project that I hope will inspire other more innovative designs. Currently my life goal is to be a famous engineering YouTuber ala the next StuffMadeHere. In order to achieve this goal, I need clout and a lot of it. So if you don’t mind please subscribe to my YouTube channel. I promise, the illest engineering projects of 2022 will be on there. To my knowledge, I have created the most viral videos on conveyor belt 3D printers. But I do not receive much credit in the media when conveyor belt 3D printers are discussed. I understand this lack of recognition is part of creating open source projects, but I feel like I need to promote myself more for my YouTube channel to be successful. So if you can help me out, I would appreciate it!

Anything Goes Contest 2021

Runner Up in the
Anything Goes Contest 2021