I am trying to test the stepper motor and switch mechanism before installation. I think the board may be programmed wrong or is acting up. The first extruder does go to the proper one after 1 second. The quarter second holding does switch between them. When doing the five and a half second holding, it reverses itself on any of the extruders on the next switch hold. When doing the three and a half second holding, the motors just make a jamming sound and don't do anything (it's the one on the right where there are no tubes). I suspect something could be reversed or stuck. I have got it to feed correctly randomly twice the correct direction, only in the first extruder, I have been unable to repeat it,
To see this working, head to your live site.
37 Comments
The button location is calculated based on the position you enter into the gcode generator. It always subtracts 3mm from it... so if you enter 212, it will put in 209. But if you put in 215, it'll put in 212.
Bill
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.
For large moves, don't edit the tool change gcode directly, edit the parameter in the gcode generator, that way it will flow through the entire system. By only editing that line (especially down to 0) you're only editing the very last move, but not the entire sum of all the moves. (This parameter is really a fine tuning element, for that last mm of accuracy.) Course adjustment should always be done with the gcode generator parameter so that it both loads and unloads the correct distance.
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
Blobs at the start of each layer indicate that you're loading the filament too far... reduce the distance between the extruder drive gears and the hotend so it doesn't push it in so far.
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.
I've added these images to the 3D Chameleon Switch Mount page on Thingiverse: https://www.thingiverse.com/thing:4663605
These should help clear it up.
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.
Yes, the flag is on the back "X brace" of the Y axis, not the front one and the switch is about 4" from the front of the printer.
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?
Here's a picture of it.
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?
Are you sure it's not just going back to the first extruder (the grinding noise indicate that it's trying to rehome.) It sounds like your 3.5 seconds is a littler short. Try for 4 seconds and then try for 6 seconds. You should see it rotate one way or the other depending on the time.