3D Printer problems - Monoprice/Wanhao D6

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awake

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Hah - my home-built 3d printer is still running on a cheapo E3d clone, all-metal hot end. I've been amazed that it has continued to work.

That "popping" sound might be the stepper motor losing steps - or at least, that's what I hear. IOW, if the filament won't feed, there are two options - either the extruder grinds the filament, or (if the extruder has too good a grip on the filament to start grinding) the stepper reaches a point where it "pops" back into a previous rotational setting.
 

ddmckee54

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The MP10 doesn't make that popping sound, and the D6 hasn't made it since I got rid of THAT particular spool of fillament.

I was discussing the issue of the MP10 grinding chunks off the filament with one of the engineers at work and he was wondering if somehow the spool was getting bound up and not feeding the filament properly.

I do remember that when I was threading the filament back into the printer after cleaning the drive gear, that I thought there was a lot of drag on the spool. I'll check on that tonight. Redesign of the filament holder was already one of the things on my "To Do" list for the MP10 anyway. There aren't many other tools that can make the parts to fix themselves.

Don
 

awake

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Spool bound up - that's another good idea that somehow did not occur to me. Apparently it is not hard to get the filament tucked under itself to where it binds coming off the spool. I have only had it happen once ... I found the spool pulled right up to the extruder!
 

skyline1

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Spool bound up - that's another good idea that somehow did not occur to me. Apparently it is not hard to get the filament tucked under itself to where it binds coming off the spool. I have only had it happen once ... I found the spool pulled right up to the extruder!

I have had this many times especially with cheaper filaments. Those "El Cheapo" 800 Gram spools you can get on ebay are notorious for it.

The filament is wound on such tiny spools with no side wall to guide it that they can turn into a knotty mess in no time. The stuff seems to print O.K. but you have to keep a very careful eye on the spool. If it shows the slightest signs of tangling, lift it off the carrier and twist it to take any twists out of the filament.

With a little care this can be done whilst still printing but it can be tiresome on long prints having to check it regularly.

On my Chiron I have a ball bearing spool holder which helps. Anycubic Chiron Filler Spool Holder Adapter by RichterScaleStudios and parts of Filler - The Customizable Filament Holder that fills your printer! by HugoHuge

Popping noises are often due to damp filament

I've been trying 3 times to add an edit saying that I got a food dehydrator and tried it on the brittle roll of filament. Each time the site kicked me out of the edit mode when I tried to add the degrees symbol. (I just realized that I didn't have the Num-Lock on - makes a BIG difference.) I put the filament in the dehydrator over-night at about 110-120°F but it made no diffference on the filament, so it wasn't a moisture problem. (The dehydrator does make some quite tasty Granny Smith Apple chips though - just not at the same time.)

I use a modified dehydrator myself, I have found that this along with a domestic vacuum sealer keeps filaments in good condition both cheaply and easily available domestic items

Degrees symbol - Start - Windows accesories - Character Map - select copy and paste on windows not sure about Mac or Linux ° ° °
Banana chips too I love 'Em

extruder drives often click when they do a filament retract perfectly normal and nothing to worry about

Best Regards Mark
 

awake

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Mark, what type of extruder do you have? I've never heard mine click on retract. Yes, there can be a popping, crackling sound from wet filament. The sound of a stepper losing steps is quite a distinctive sound, and of course can be verified by observing the extruder.
 

skyline1

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Standard Chiron Geared Bowden type (E3D clone I think)

Bowden type ones tend to click more than direct drive ones. I think it's partially caused by the filament hitting the side of the tube when it retracts fast.

My other printer is direct drive and that does it much less. It depends on your retract setting of course.

Yes the sound of a stepper struggling is quite different and pretty distinctive, more of a grinding or whining noise depending on how fast the motor is going

It certainly indicates a problem and it can be difficult to diagnose sometimes.

My usual first step is to heat up the extruder manually to your normal print temperature then try to push some filament through by hand. You should be able to create a steady stream from the hot end with fairly little pressure. It is a good idea to do this before printing to check things anyway or when changing filaments

If you can do this then the problem is more likely to be either the extruder grip pressure is wrong or the filament is tangled on the spool somehow or possibly the drive rollers are worn. (they have a pretty long life but they do eventually wear out)

If, however you cannot feed filament then the fault is at the heater end. It could be a) blocked nozzle, a set of gas welding nozzle cleaners are useful for checking and fixing this. b) temperature too low. try temporarily increasing the extruder temp. c) a problem or wear in the hotend, the PTFE liner (if it has one) may have worn or the hotend itself may have fractured (I have actually had one break up !)

There are of course other possible causes some which are very obscure but these are the ones I tend to look for first.

One final and sometimes overlooked cause of print failures is ambient temperature, 3D printers (FDM ones) get very temperamental, and sometimes won't work at all below about 15°C so make sure your room is reasonably warm.

I hope this may help with some of the common problems.

Best Regards Mark
 

awake

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Good words on the process to unblock a hot end. Do you ever use the "freeze plug" (my name for it - not sure it has a name) method, where you squish some filament into the hot end, let it cool to around 180°, and then pull it out? That has been helpful for me a few times.

Not sure why my extruder doesn't click on retraction, but I've never heard it. Of course, my extruder is a custom design that I worked up to enable printing with TPU (yes - even on a Bowden setup!), so maybe that is the difference.
 

skyline1

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Yes I have done it now and then, it's a handy trick to know if the blockage is up towards the heatbreak, using a nozzle cleaner tends to just push a hole through the blockage without completely clearing it.

With the big Chiron If I start getting problems with persistent nozzle blockages or things like that I usually just change the whole hot end. They take about 10 minutes to change and they are so cheap it's easier to change the whole shebang. They are only about £12 direct from Anycubic for the whole assembly so I keep a couple of spare ones just in case.

Doing It with my little printer (Geeetech I3 clone) is a right pain though so I usually try to clear it in situ if possible.

If your extruder is a custom job for TPU then it probably does retract silently.

I've heard that printing TPU with a Bowden setup is quite tricky because it's so flexible it tries to go everywhere but where you want it, I once heard it described as pushing cooked spaghetti up a drinking straw. It would be interesting to hear your approach to this.

I've tried it quite successfully with a direct drive extruder but never with a bowden one.

Best Regards Mark
 

awake

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It does feel a bit like spaghetti up a straw ... but surprisingly, it does work. The key is to leave no gaps where the filament can veer off course. In the extruder, there is typically a bit of room between the drive gear / roller / whatever and the start of the Bowden tube. My design uses a V-shaped block that comes right up to the gear and roller, so that the filament cannot squeeze out of line.

TPU does require rather slow printing speeds, at least with my setup - not sure if that is true for TPU in general, even on a direct drive. I generally print PLA at 60-80mm / sec, but TPU at 15-20.
 

ddmckee54

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Jeeesshhh, I feel like such a knuckle-dragger.

Whenever I get a nozzle plug I throw in a fresh nozzle, then burn out the plug. I picked up that trick from a video I saw years ago when I started printing.

After removing the plugged nozzle, I heat it with a torch, the plug will melt and fall out. Then I continue heating the nozzle for another minute or so. I only bring it up to a dull red since you aren't trying to melt the brass. Then I quench it in a dish/glass of water. The steam from the quenching will blow any remaining crap out of the nozzle leaving it nice and clean. It takes longer to get things set up, and cleaned up afterward, than it does to actually clean the nozzle.

If you're worried about the burning plastic starting something on fire, then heat the nozzle over the water. The burning blob will fall in the water and the problem's solved.
 

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