B_Y Thanks Jane!

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B_Y: Update 23.7.19: Nearly there! Good enough for testing I guess Wow! For a simple little mod getting the details right has been a bit of an adventure. I'm in the process of fully updating this thing with a full of instructions and files... What is it? B_Y Thanks Jane is a homage to a Black Adder character, never seen but much talked over. It's intention is to enable two colour printing through a single hot end. At it's a Y-joiner to allow two Bowden-type to take turns with a shared hot end. The devil is in the detail and the detail has not been easy to sort; this thing can be 'split' in to a number of sub-parts: i) Why? Two colour printing opens up all sorts of possibilities. The traditional way is to have a head with two hot ends. This doesn't require much thought and has the added advantage that you can use dissimilar plastics in each hot end. The downsides are the extra weight will limit accuracy with speed while getting the two heads properly aligned and functioning together is an exercise in extreme frustration. The Y-joiner approach does away with nearly all these disadvantages from the user's point of view while requiring far fewer modifications to your printer. It's primary downside for the user is remembering to set up for two colour prints properly and printing with dissimilar plastics probably won't go well. From a design point of view getting this method of printing to work is really not easy. ii) How? The concept is easy enough but getting it to work requires careful juggling of hardware, printer firmware, and slicer mods. -Hardware: The Y-joiner needs to have as strait a path in to the hot end for both filaments as possible while being as short as possible and preferably be lined with Bowden tube for as much of it's length as possible. The included BY_72.stl file contains the parts to be printed: A layer height up to 0.2 will be fine but it doesn't print well with a nozzle larger than 0.4mm. Construction is a follows: 1) Print out the .stl file as oriented.. Three surface layers would also be sensible. 2) The smaller part is a guide to cutting some Bowden tube to line the joiner - Press some tube in to the hole until the end bottoms out in the guide. Then take a VERY sharp knife and closely following face of the guide slice off the side of your Bowden tube. You should end up with a nice, neat cut end that will fit the joiner perfectly. - Next cut off your sliced end, closely following the end of the guide where the Bowden tube enters it. - Carefully remove your cut end and repeat the process. You should now have two pieces that will form a Y-join and perfectly fit the joiner when dropped in place. Note: You will need two Bowden couplers to screw in to the top of the joiner later on. Some are intended for Bowden tube to stop at the coupler and others for the tube to pass right through. It doesn't matter which you use but if it's the latter type don't cut off your end! The complete tube will want feeding through the coupler and then in to the Y-joiner. 3) Drop your two cut pieces of Bowden tube in to the Y-joiner such that the cut faces face each other and gently press home. You then want to screw your two Bowden couplers in to the top of the Y-joiner. Note: It's a darn tight fit, pliers may be required. They should screw down to the 'hilt', and be very careful to macke sure they go in strait. 4) Take a look down the other end. You'll likely see the two previously cut ends mostly blocking the hole - these need to be eased in to their seats. - Take a length of filament and pass it down one of the connector ends, wiggling it as you go, until it comes out of the bottom hole. Then remove it. -Having made a sufficient hole carefully push an Allen key up the output so that it goes past the ends and up in to the joining area. With care you then want to twist and wiggle the Allen key while using it to to press the cut Bowden tube ends left and right. -All being well, when you look up the hole the cut ends will be barely visible. They should be nicely held in place by a couple of small tabs that you'll only see by examining the files. 5) This is the point I would suggest pressing both lengths of Bowden tube you intend to run from your extruders in to the top of the Y-joiner. Using somewhat transparent Bowden tube will be useful later on. 6) If not already done unscrew the Bowden coupler from the the top of your hot end. Next take a length of Bowden tube and push it down in to your hot end as far as it will go. Note: there is a seat the end of the tube fits in to. A common issue is to think the tube is all the way in when it's actually snagged on the edge of said seat - a very common cause for a repeatedly blocking hot end. You then want to cut the tube properly seated in the hot end so as near to 1.5mm is proud of the top. Extreme accuracy is not needed, you can fiddle later, but it's vital you make as flat and horizontal cut as possible. Having done that take out your newly cut tube and twirl the end of a sharp knife in the end that's going to fit in to the Y-splitter. The idea is to create an internal chamfer in the tube. This helps the tube properly seat in the Y-splitter and reduce filament snags. Press your piece of tube in to the Y-splitter and then screw the whole lot in to the top of your hot end. Again it's a pretty tight fit and take care to be sure it's going in strait. The Y-splitter should screw in all the way to the flange, if not you either didn't screw hard enough or your Bowden tube was cut too long. Note: Too long is easy enough to fit, too short will make for very unreliable prints. 7) Of course the free ends of your Bowden tubes need to be attached to your extruders and filament run through. Firmware: The changes to be made are detailed in Printer_Firmware_Changes.txt I'm basing this guide on my printer running Marlin 2.0. It should be fully applicable to any printer and version of Marlin while being adaptable to other firmwares. This mod isn't going to work if your firmware doesn't know about the extra extruder, and realities you still only have one hot end! I've included a modded version of Marlin 2.0 for the Anycubic Kossel Linear Plus. Feel free to mod it further. Flash that to your printer using the ArduinoIDE and don't forget to do a calibration after. This version is based on the excellent work of: https://www.thingiverse.com/thing:3661097 I would strongly recommend a look at his page for further info and set up. I've added the dual extruder support and also modded Marlin to recognise a second extruder when using a Trigorilla board - as it happens while this board has an E1 header Marlin doesn't know about it, probably because there doesn't seem to be any useful documentation! The information is contained in pins_TRIGORILLA_13.h for the curious, or those running a Trigorilla board that isn't my model of printer. Don't use this mod with _TRIGORILLA_14.h, it won't work! Slicer Set up: Nearly there, sort-of. You have the hardware, you have the firmware, you now need your slicer to play nice with your new set up. I would suggest not changing your current settings as they can be used for 'single filament mode', but to set up a new profile for dual filament use. These settings are based on my printer and Cura 3.6 but should be transferable for other systems: So... 1) Run Cura, go to Preferences -> Configure Cura... -> Printers -> Add 2) Add a CustomFFF printer, give it a sensible name, and make darn sure you change the Number of Extruders tab to two. Then save "But Cura has a ready made prfile for my printer!" Yes, but you will likely fine you can't change the number of extruders in a pre-made profile. 3) The tedious bit is you now need to transfer ALL the settings from your normal printer profile to your new one. I'd suggest methodically doing this one page at a time. Transfer your single extruder settings to BOTH the extruders in your new settings. Then save. 4) Time for the changes: Open the Cura Setup.txt file, open your new profile's settings and copy / replace all the labelled sections of gcode over any default versions, then save. This new code is heavily based on the excellent work of: https://www.thingiverse.com/thing:2328933 Certainly well worth a visit if only to say thank you and check out the detailed set up instructions. Note: Do take a good look at the default Start G - Code and End G - Code before you copy / replace. Is there any printer-specific stuff there that should be part of the replacements? If so I'd suggest adding that to the beginning of the new gcode. 5) One little nuisance with Cura is it doesn't use different colours for the filament from each extruder. The work-around I use for this is to set one extruder for the default filament and the other for a specific manufacturer's filament that's been assigned a different colour... then go through BOTH extruder's settings to be sure they are using the parameters you want! sigh. Time to test? Um, not quite. There are two things to be aware of when using this dual filament set up: 1) Usually you start a print with the filament all the way through to the nozzle. You can still do this for single filament mode. BUT when in dual filament mode the ends of BOTH filaments want to start in their 'park' positions: ie: the end of the filament should be at the level of the input of the Y-joiner - hence the reason for using Bowden tube you can see through! 2) This method of printing is HIGHLY dependent on getting the filament being introduced and retracted by the correct amounts. For my set up using an E3D_J6 with a Volcano: My 'storage' length is 130mm so replace: 130 with your value in printer start gcode. -130 with -value in printer end gcode. 127 with your value minus 3 in Extruder start gcode. -127 with -(value - 3) in Extruder end gcode. ...I would expect an E3D_J6 with a standard hot end would be 8mm shorter, but don't take this as gospel! Go take a simple dual-colour model, slice the gcode, and test. Some tuning WILL be required. Assuming you are running the printer via some kind of host (I'm using Octoprint) the following gcode should be added to perform a final retract if a print gets cancelled. G1 E-5 F10000 ; stage 1 of 3 stage retraction G1 E2 F10000 ; stage 2 G1 E-127 F10000 ; stage 3, this keeps from producing "hair" Again, replace that E-127 with the appropriate number for your printer. Have fun! PS The try2.123dx and tr3.123dx files contain the filament path for my take on this device. They should help if you want to make a custom version of your own. Also included is a three filament path for the adventurous - actually if going for a three filament set up I'd suggest something like a Diamond hot end (see my other things) as having a fully mixing hot end will allow for full colour printing when using C, M, Y, filaments.

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