Super Racer auto ejection belt conversion

I wanted to have a 3D printer capable of ejecting completed parts and work through a print queue automatically, but without compromising the kinematics or build volume. My solution is to add a conveyor belt over the heated bed of a delta 3D printer, so that X/Y/Z movement is unchanged.

This project is covered in this video:

Source printer

The donor printer is a FLsun Super Racer, as reviewed here: 

Source CAD

This project is freely available and open source. I use Onshape as my CAD, which is browser based. Without making an account, you can load the 3D model in your browser by clicking the link below. This will allow you to hide and show components, check the position of parts in the assembly, measure distances and export parts in STL or other formats.

https://cad.onshape.com/documents/be498707ae61cf549f8029b6/w/db76ed076578f71ffe54f733/e/668bf1cc03de78c81b36cb6a?renderMode=0&uiState=6260a10125c34204db3441e4

Bill of Materials

A full bill of materials is available in spreadsheet form. The parts are organised in sections that match the assembly video below. Links are provided where possible for parts from Amazon, as well as links for purchase of items from suppliers in Australia. Where necessary, substitute parts are discussed such as the PVC pipe used for the rollers.

https://docs.google.com/spreadsheets/d/1RrBCPvUssZloxM7NJm7T5pGYOEVWMCtSiClOSP3Q8Vw/edit?usp=sharing

3D printed parts

All printed parts are included here. They are already oriented correctly for printing. The BOM details quantities and what section each part is used for. No parts require support apart from the ‘Loom guide’, which requires support from the build plate only.

I used black X3D PLA for all of my parts. Unless you are planning to enclose the printer, PLA will be strong and rigid enough. Most of the parts require thick walls and/or high percentage infill for strength.

Some parts have a false wall to avoid needing support. This is covered in the assembly video and simply requires drilling to open up the bore(s).

Bed plate part

This will be the hardest part to source for most people. I milled mine from a 3mm sheet of aluminium. This part could potentially be laser cut from acrylic, or another sufficiently rigid 3mm material that can withstand the nearby heat of the (insulated) heated bed plate.

Assembly steps

Disassembly of the Super Racer and assembly of the new frame, conveyor belt system and wiring is covered in a dedicated video here:

As stated in the video, some aspects of the design and individual parts were changed during and after filming, so you may notice visual inconsistencies.

Firmware

This printer has been converted to Klipper firmware, as covered in this video: 

Firmware changes for the belt modification are covered in the video at the top, and the configuration file is available here: https://github.com/teachingtechYT/klipper-configs/tree/main/FLsun%20super%20racer

Other firmwares could potentially be used but I have not investigated how to manually control an extra stepper motor in anything besides Klipper.

Software

I am using Octoprint for my webUI, simply so I can use the Continuous Print plugin: https://smartin015.github.io/continuousprint/

Although it is not mandatory for this project, it allows the user to queue up multiple print jobs and have the plugin excecute them in order with the eject macro inbetween to rotate the belt and remove the old parts.

In terms of your slicer settings, The only thing to watch for are thin priming lines and skirts that will remain stuck to the belt. Either remove these or make them thick and rigid enough to peel off the belt.

Belt fitment, tensioning and print settings

All of this is covered by Powerbelt3D on the custom belt page: https://powerbelt3d.com/product/formula32-custom-size-conveyor-belt/

Thanks to Adam from from Powerbelt3D for providing some tips during my design process.