So much purge - tower, infill, support, poop, why does it do them all?

I’m new to multicolor printing and thought I could mitigate the waste by purging to infill and support. I have that selected the flush to infill and support options, but my prints are flushing to infill/support, printing a purge tower, AND still pooping between colors. I thought the tower would be instead of the poop chute. For example I’m printing in gray and green. It’s printing green and wants to switch (using an AMS). It’ll print a layer of green infill, go to the rear chute and purge the rest of the green until gray is running cleanly, then goes to the tower and prints a full layer of gray, then prints the gray layers in the model. The chute and tower don’t make sense together - am I missing something in settings?

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I’m with you - it is a big waste of filament. I’m thinking I would have been better off getting a dual-nozzle printer. The AMS does work, but since it has to send each filament to the single extruder/nozzle, it has to “clean out” the old filament first. Note that you can reduce the amount of waste changing the settings in the slicer. On the “Prepare” tab, see “Prime volume” → “Prime tower” section. Mine defaults to 45mm³. I changed it to 25mm³, and it seems to still come out pretty clean. I would imagine if you were changing from black filament to white filament, you may need a larger number.

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Also tweak the flushing volume quantities here…

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I’m surprised the moderators didn’t shut you down for that complaint. Investigating very low filament purge for some 3D printing materials - YouTube

I was a bit worried about that…

Is there a setting to not use a tower, so I can just adjust the poop purge?

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Here…

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Thank you! Not sure how I missed that.

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I am there too. Poop is bad. :wink:

I never had any poop with my Prusa and it works fine. So I just modified my machine start G code.
Every so often I use the standard bambu profile, but most of the time I use my “fast” profile. It gets rid of all the nozzle wipes and pooping. It just does the machine safety (don’t hurt me) parts, heats up the bed and nozzle and used a short nozzle purge at the front of the plate.

I never understood why Prusa both filled the nozzle with a line across the front and then defaulted to printing a skirt, the purpose of is to make sure the nozzle is flowing well before starting the print.

I do not want this, unless I need it.
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This is so much nicer.
image

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Thanks for sharing this! Would you be willing to share your starting G code? I’ve worked with editing the G code on my Creality printer but I don’t get it as well as I would like :slight_smile:

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FWIW, in an attempt to reduce the poop waste, I made this model to test the flushing volumes: Printables

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Thank you, before my next print I’m going to turn off the tower and optimize the flushing volume.

I also need to vent for a moment. I’m doing my second AMS multicolor print now which is supposed to use black and green filaments (spools 2&3). In coloring the model I missed one thin line of gray (spool 1), and it’s used a quarter kilo of gray already in flushing, plus has stopped printing 3x so far due to a clogged poop chute.

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Let me start by saying there is a great deal of improvement that can be made. Even the engineers at Bambu made the wire from the back of the ams to the inside of the ams barely long enough. The best of humanity could not spare an extra couple of inches of wire. This is how most things people do end up. If you try to discuss you get slammed instead of helped and then called a trouble maker.

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In my experience, the prime tower helps with reducing stringing after a filament change tho… It’s not so much useful when it comes to flushing out the old color so it doesn’t wash into the new one, but with the models I printed without prime tower, it seems that I had more stringing directly after the filament changes. Feels like the tower pulls out those strings before they end up in the print :smiley: Not sure if it’s just a subjective feeling though…

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I don’t use the prime tower at all, and I set the purge multiplier to .55 or .6 and do the auto calculate. A lot less, but certainly not no waste.

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To be fair, biggest waste are the billions of Benchies that people keep printing! I really can’t imagine who needs a benchy with Rock’s head on it.

Remember that even BL X1C is a stupid machine, it does not know how to do things, you need to tell it how to do stuff. Some models have lots of infill in all layers, some models don’t have any infill in higher levels but the machine does not know that, so you need to set slicing parameters by hand for every print you make. Or you can just leave the basic settings and not care about few extra grams that the printer poops out. You can also use just one color and paint your model yourself!
There are no plug and play 3D printers!

“Remember that even BL X1C is a stupid machine, it does not know how to do things, you need to tell it how to do stuff.”

Ahh yes compared to the smart machines that nobody or anything ever had to give instructions to in order to function. Those darn sentient non-biological contraptions they are!

That attitude blocks improvements. Why add Lidar? We can just manually determine the flow rate. It is programmed to work as it does until they improve how it is programmed.

Ahh yes compared to the smart machines that nobody or anything ever had to give instructions to in order to function. Those darn sentient non-biological contraptions they are!

I’m not comparing it to anything, just saying that many people seem to be totally lost of the fact that user is controlling the printer through slicer settings.
Like mike.yearwood here saying lidar would calibrate the flow rate. Which it does not do and Bambu Labs has clearly stated that lidar only helps probing nozzle height and pressure advance. But even that has nothing to do with optimizing purge amounts. You really need AI for that and without AI we only have a stupid machine that only does what it has been programmed into.

Hi Jules,

How do I mod the prep to be as quick as yours in the photo above you posted?

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Not an answer or any solace for your issue, however the CEO of Bambu Labs addressed this issue in a recent Interview. He too is concerned about poop. They are working on the issue he said. How l9ng it will take to resolve or make better, he did not say.