Orbiter Filament Sensor/Clockwork 2 Mod

cults3d

Summary This is an adaptation of Robert Lorincz's Orbiter Filament sensor that has been modified for use with a Voron Stealthburner/Clockwork 2 extruder setup. Background While preparing to build my new Voron 2.4 I stumbled upon Teaching Tech's video review of the Orbiter Filament Sensor (https://youtu.be/GbFhhh3tSEU) and thought it looked like a fun bit of kit. Knowing that I wanted a filament sensor for my new Voron, I wondered if I could figure out a way to use this filament sensor with a Clockwork 2 extruder and thus this project was born. I researched the original project (https://orbiterprojects.com/orbiter-filament-sensor/), and ordered my kit from one of the many on-line providers. It wasn't long before I realized that the geometry of the board as designed didn't really work with the Clockwork 2 geometry. Obviously the housing wouldn't work, since it's designed to mount to an Orbiter, but the parts on the PCB are mounted in such a way that no matter how you try to orient the PCB, any housing you design will probably interfere with the Clockwork's latching mechanism. After experimenting in CAD and trying out different configurations, I realized that by reversing the orientation of the unload button and the JST connector, I could compact the whole assembly by quite a bit and, along with a minor modification to the Clockwork 2 main housing, get it to fit nicely. Assembly The difficult part of this assembly is relocating the button and the JST connector to the opposite side of the PCB. If, like me, you purchase a pre-assembled kit, you're going to have to carefully desolder the connector and the button so that they can be mounted on the opposite side of the PCB. This will be much easier if you purchase the PCB and parts unassembled and assemble them yourself. Either way, some soldering will be required. This is all a bit fiddly but, unfortunately, this is necessary to get everything to fit properly and have the wiring attach to the PCB from the rear where it can be kept nice and tidy. Once the board has been modified as described, the rest is simple. Print out the new sensor housing (using the exact same settings you used to print your extruder parts) and the alternate main_body for the Clockwork 2. Assemble the PCB in the sensor housing following the exact same instructions you would have used on the original kit. Cut an approximately 14mm length of PTFE tube to insert between the top of the extruder and the bottom of the filament sensor. Replace the main_body in the Clockwork 2 extruder and use 2 M3x6 BHS to mount the sensor housing to the top of the extruder, using the PTFE tubing section to align them tightly together and keep the filament path constrained. Be careful not to over tighten the screws! The screws are screwing directly into plastic. Unfortunately there isn't enough space to use heat inserts but, for this application, they really aren't necessary anyway, especially since the screws are going in at opposing angles. As long as you don't deliberately try to yank off the filament sensor you shouldn't encounter any problems with it staying firmly mounted. Software Configuration and Wiring You'll want to wire up your sensor exactly as described in the original sensor's instructions. Just remember that your wiring harness is leaving the PCB from the opposite side so the wire orders will be reversed. I'll assume that you're going to be using Klipper, since this is a Voron extruder. I've provided my modified copy of the OrbiterSensor.cfg file. (Remove the .txt extension first. Cults won't let us upload .cfg files but it will allow .txt files.) It contains a few minor bug fixes and (more importantly) updates to extrusion commands that take into account the geometry of the Stealthburner/Clockwork 2 combination. You can choose to use mine or you can provide your own. If you choose to use mine, upload this file to your configuration directory and include it in your printer.cfg. You'll want to make sure that the pins in the file match how you've installed your sensor and update them accordingly if necessary. Usage Using the filament sensor works exactly as you would expect. loading When you insert filament into the top of the sensor, press it firmly until it reaches the gears. After a brief pause, the sensor will detect the filament and the gears will engage, pulling the filament into the extruder. When that happens, you can push the reverse bowden tube on to the sensor and walk away. The extruder will begin to heat up (if it isn't already at temp) and once the extrusion temp has been reached (235c) it will finish loading the filament and purge any old filament in the extruder. Messages will be sent to the console to let you know what's happening and when the operation is complete. If the extruder was heated to load filament then it will begin cooling again after the operation is complete. unloading To unload filament, press the "unload" button and wait. The extruder will be brought up to temp (235c) and filament will be unloaded from the extruder. Once the operation is complete you'll see a message on the console and the extruder will begin cooling again (assuming it wasn't already at temperature when the operation began). filament runout Should filament runout be detected, the printer's pause operation will be triggered and the system will wait for you to unload what remains of the old filament and reload. Just press the button, pull out the old filament once it's been ejected, and load more filament as described above. Standby/Idle Behavior If, like me, you often aren't around when your print runs out of filament, you may wish to make sure that your printer doesn't time out while it's waiting for you to reload. I've included an "idle.cfg" file which includes some code that will alter the printer's standby behavior so that it won't time out if the printer is in "paused" mode. You may wish to include this in you "printer.cfg" file. If you do, make sure you get rid of any [idle_timeout] section in your "printer.cfg" file because this replaces it. Pros & Cons This sensor may not be for everybody but it's a fun project and it's kind of neat to have your extruder automatically do some of the work for you. It adds a few centimeters to your extruder height which reduces your build volume by a similar amount. It correctly detects filament runout (provided your housing prints cleanly like mine did). Loading and unloading filament is automated and works as expected. That said, many people will find it just as easy (if not easier) to have their printer extract filament out of the extruder in their print end macro and push it back into the extruder on print start so that between prints, changing filament is as easy as opening the Clockwork latch and pulling it out. There's no need to heat the hot end that way. Indeed, I've modified my start and end macros that way and that's how I prefer to swap filaments even with this filament sensor installed, most of the time. Note that I usually swap by hand this way when the printer is turned off because pulling the filament out when the printer is on will trigger a filament runout event and putting new filament in will trigger a filament load event. Those are just a few of the pros and cons. I'm sure there are many more and, like I said, this mod won't be for everyone. I enjoyed building it and if you think it's for you then here you are! Be my guest! Have fun and good luck!