I keep having the same issues as well, I had it working very briefly for the first two or three changes a few months ago and then quit fighting with it since I ran out of time and was waiting till I got a revo installed on my MKS3+. I had even adjusted gcode to get the temperatures exactly right for a certain brand of filament. I got the tips pretty decent (matching what it looks like we should have), but in general my issue seems to be the same problem that could be resolved with just a slightly better grip on the filament. If I just push a tiny bit on my spool when it pulls, it can get things right. I'm willing to pay for an upgrade cost if it makes this thing work better since I know its kind of a labor of love backed kit.

I could try that. I had started experimenting with doing the temp changes in part of this shaping , with random success.

The ptfe in the hot end is the stock one, it has not been removed or messed with at all.

So you are saying put both those commands back to back or just at some point in the gcode when it looks like it's pulling or pushing the filament? I haven't touched the original ptfe tube that is in the hot end at all. It seems like it sits way too long, but I haven't timed it. I'm assuming that's causing the jamming with the filament staying at a temp too long when it is finally pulled.

I got it the way I think it is supposed to be (lowers temp before doing the code and increases temp before feeding), but I think maybe the timing may have to be adjusted as well. It seems like it sits too long at the certain temperature and gets jammed. I've tried 210, 215 (becomes flat on both of these), 220 (too stringy and blocks). When I just print at straight 215, the cone is fine when it pulls out and no jams. Using this code for the first part (putting previous gcode for context) {if previous_extruder>-1} M109 R{(first_layer_temperature[previous_extruder]) - (10)} Then using this to change it back ; load extruder #{next_extruder} M117 Loading Tool T{next_extruder} M109 R{first_layer_temperature[next_extruder]} ;Set back to normal temperature

So finally had my test two filament print succeed. Reducing length of both the feeding ptfe tubes to the adapter and the tube from adapter to extruder. You had mentioned about changing the change temperature, how does one do that exactly? I printed at 215 successfully but it looks better at 225, but extreme stringing when it pulls at 225. So I think 215 would be ideal to set it to before pulling filament.

So are you talking about the length of the PTFE tube between the green mechanism and where it hooks into the top of the carriage? If you are talking about the extrusion length in the gcode generator, its already set to zero. I am still getting the notches after adjusting length to better match your picture setup. It actually seems to be failing at the first change now.

Just incase it's the angle causing it, this is how I have it setup right now.

I might try 230, I usually have good success at 225, but it makes such a long string that it blocks the other filament when it retracts. It's kind of a notch in part of the filament, I think it gets caught just before it can go to the hot end on that notch.

I have gotten pretty far with just two color changes as tests. On my third filament change, I have been getting a notch around 195 mm or so without fail. If I don't pull the filament out and cut and put it in before the next change, it wont pull it due to the friction. If I cut that piece off and reput it in the tube, it will complete. I have loosened a lot of the tension on the extruder gear, so not sure if that would be causing this, seems to be at about the same point each time. Not sure if the angle of the green switching mechanism and the tubes could be doing it too. It's a fairly glossy filament, using jessie pla at 215 C.

Thanks for your help, I have gotten further along. I'm struggling with jamming, but it seems like it may be a matter of temps impacting too long of strings when it retracts. It either drops pieces in the extrusion or still has bits out when another color comes out and gets stuck. I had to set the extruder offset to zero to remove blobs. For now I ran out of time to mess with it further. I don't know when I'll have time to try again. Seems I'm close though.

Any reason why it removes 3 from it? The prusa location has it as 212 when I dial to it and the gcode works when it is set to 212.

Looking in the gcode, I see, makes since, will give it another shot. Might just be my end, but the button location appears to be hard coded to Y209 in the generator. I have just been modifying it manually myself.

I even set the E part to zero and still getting blobs, though a lot less (first extruder almost none, but I get blobs of the previous filament after it switches out and loads the new filament). This is the line I'm assuming I am supposed to use to set this: G0 E0 F2000 ; <<<<<----------- EDIT THIS DISTANCE TO FINE TUNE THE FILAMENT LOADING TO STOP BLOBBING OR UNDEREXTRUSION

I'm still working on this, got it mounted and looking like its doing the switching okay. I have had to reduce my tension on the extruder, was scarring the filament too much to be fed back and forth. I have now had a couple layer changes between two filaments, just doing a simple test for now. Main thing I'm noticing is the start of extruding has a blob with the first extruder filament in the middle and the other in a bigger blob circle. The second layer change just has another blob. I haven't seen a ton or almost no blob volume in subsequent filament changes. I am assuming the filament has to be up to the little black spot just past the coupler, otherwise the filament kind of pulls back out. Is this correct? Just trying to see if there is something I need to modify or change. Also to note, I was initially running into problems in PrusaSlicer 2.4 as well, which slowed down my progress a lot yesterday until I found your post with the python script. It does fix the issue you detailed.

That makes a whole lot more sense now that I think about it, especially why the trigger mechanism is in place as well. I'm hoping once I am done with setting this up that I can document it and do some lessons learned/tips.

Assuming there is a lot of variables here, possibly how the bottom of the bed frame is, but looks like mine is activating at 182 with the mount flush with the edge of the printer. I did notice that the youtube video on limit switch mounting had a number more in the 200s. Is there something that I may have missed?

I was able to get it to work on a few of them with increased counting. I am assuming I'm just counting off. So going to just try to get it going since the gcode will be better than my counting abilities. Now I am trying to figure out the Prusa mounting setup, there is really no documentation on what the trigger is supposed to mount to on the board to make the limit switch work. It kind of looks like there is a spot for maybe a tie wrap, but kind of at a loss. Does anyone have a picture of what their Prusa MK3S+ look like under the printer to see how this goes?