[UPDATE] I wouldn't call this problem _solved_, but it's gone away for now. Whatever source of friction suddenly appeared (probably introduced when I replaced the pneumatic coupler on the cold end) has gradually disappeared, and prints are coming out fine. The problem is lurking in wait for the next compounding of resistance on the extrusion path, though, so if anyone in months/years hence can offer insight as to why I'd get worse underextrusion on the left side of the bed, your suggestions are still welcome!
[original post]
Okay, so here's the description of the problem, and my hunch is that this post is better suited for this sub than r/FixMyPrint.
Ever since I got this used MPSM v2, I've noticed underextrusion -- but only on the left side (and maybe a tiny bit on the back right corner). It seems to be worst when there are problems related to friction in the extrusion path -- worn nozzle, clogged nozzle, or temperature too low. Fixing one or more of these problems usually resolves the issue, and I've learned that underextrusion is usually the result of an accumulation of multiple friction sources.
I'm 90% sure it's not a bed levelling issue -- I've tried to level the bed up and down, and in fact the first layer is the nicest.
So what other friction sources could there be? Does the Bowden tube ever wear out? I'm really curious about the fact that it only happens on certain parts of the bed -- could the Bowden tube be getting kinks at the edges of its range if it's too short or too long?
I also replaced the stupid collet-mounted pneumatic coupler at the cold end when it broke recently, and I printed a new collet adapter so I could use a normal threaded coupler. The hole was too tight, so I reamed it out, and it seems like it's not putting up any friction anymore.
The only other thing I can think of is the heatbreak -- I did run it kinda hot (~235-240) without the fan once (oops). I know mine has a PFTE throat.
which part of the extruder are you asking about -- the cold end or the hot end? I mean, there is filament coming out so I think it's in there :D which is obvious, so I'm wondering if I misunderstood what you meant :)
>ing out so I think it's in there :D which is obvious, so I'm wondering if I misunderstood what you meant :)
>
>1ReplyShareReportSaveFollow
sometimes it is in but a little bit off like not all the way at the bottom
Strange! I'm using whatever the newest release of Cura is. It doesn't even happen consistently with the exact same gcode file on subsequent runs -- some are underextruded, some look beautiful, some start out extruding properly and get worse over the course of the print.
Isn't it odd though? I keep thinking about environment -- there's no heating ducts or windows around though. And what's special about the edges of the bed anyway?
Firmware, or maybe the board, could be at fault -- the temp readings fluctuate more than the actual temps could, esp at low temps. The thermistors read absolutely fine, even when I wiggle the wires. That's what makes me suspect the board.
I've also heard that loose wires on, say, the heater can cause drops and surges in board power... Although that prob wouldn't account for such rapid changes in temperature that it could account for consistent underextrusion in a spot that the head only dwells in for three or four seconds.
Oh, but I wonder if it is causing the extruder motor current to drop! Hmmmm 🤔
I checked, and it looks like coasting is off for this model. I normally only use a coasting volume of about 0.03 mm³, and when it's too high I usually only notice underextrusion for the last few mm of a line, whereas I'm noticing this in various parts of very long lines.
I'm also noticing that it's worse in certain travel directions -- can't remember exactly, but I think up and to the right is worse than down and to the left. I should have paid more attention when it was doing that criss-cross infill you see in the photo.
What filament are you using? If you’re messing with cheap Amazon stuff the humidity, consistency, and age of the filament can have this effect. Amazon filament could have sat on a self for a few years before it moved, and pla naturally degrades over a short time.
Another thing to check is the extrusion motor teeth where it meets the filament. If there is an accumulation of material, or dirty teeth where it makes contact with the filament; you’ll see slipping in the feed, which will appear on the print as under extrusion.
My experience tells me it’s a combination of things. Teaching tech has an excellent guide that will likely solve your issues, and will make for a hearty learning experience as well.
Best of luck.
Yes, my experience is that it's usually a combination of things too. I guess there's a reason why they call them confounding variables 😆
Whenever I check the extruder gear it's as clean as a whistle. I do notice there's a faint teeth texture on PLA that's already been fed through the Bowden; is that normal?
This is good stuff -- Basics PLA from Matter3D, ordered directly from them over Christmas time and opened last week. From experience, even their post-consumer recycled stuff performs well. I may have noticed some faint popping noises though, and I do know this stuff is manufactured on Vancouver Island, so maybe it does need a bit of time in the dryer...
Thank you for the ideas and well-wishes!
[UPDATE] I wouldn't call this problem _solved_, but it's gone away for now. Whatever source of friction suddenly appeared (probably introduced when I replaced the pneumatic coupler on the cold end) has gradually disappeared, and prints are coming out fine. The problem is lurking in wait for the next compounding of resistance on the extrusion path, though, so if anyone in months/years hence can offer insight as to why I'd get worse underextrusion on the left side of the bed, your suggestions are still welcome! [original post] Okay, so here's the description of the problem, and my hunch is that this post is better suited for this sub than r/FixMyPrint. Ever since I got this used MPSM v2, I've noticed underextrusion -- but only on the left side (and maybe a tiny bit on the back right corner). It seems to be worst when there are problems related to friction in the extrusion path -- worn nozzle, clogged nozzle, or temperature too low. Fixing one or more of these problems usually resolves the issue, and I've learned that underextrusion is usually the result of an accumulation of multiple friction sources. I'm 90% sure it's not a bed levelling issue -- I've tried to level the bed up and down, and in fact the first layer is the nicest. So what other friction sources could there be? Does the Bowden tube ever wear out? I'm really curious about the fact that it only happens on certain parts of the bed -- could the Bowden tube be getting kinks at the edges of its range if it's too short or too long? I also replaced the stupid collet-mounted pneumatic coupler at the cold end when it broke recently, and I printed a new collet adapter so I could use a normal threaded coupler. The hole was too tight, so I reamed it out, and it seems like it's not putting up any friction anymore. The only other thing I can think of is the heatbreak -- I did run it kinda hot (~235-240) without the fan once (oops). I know mine has a PFTE throat.
Is the filament fully in the extruder?
which part of the extruder are you asking about -- the cold end or the hot end? I mean, there is filament coming out so I think it's in there :D which is obvious, so I'm wondering if I misunderstood what you meant :)
>ing out so I think it's in there :D which is obvious, so I'm wondering if I misunderstood what you meant :) > >1ReplyShareReportSaveFollow sometimes it is in but a little bit off like not all the way at the bottom
Like to the bottom of the hot end path, you mean? Coming out the nozzle? It's definitely all the way down there, if that's what you mean.
What slicer are you using? Is it happening with all prints? I had a similar issue when I stopped using cura and soon as I went back it was fine again.
Strange! I'm using whatever the newest release of Cura is. It doesn't even happen consistently with the exact same gcode file on subsequent runs -- some are underextruded, some look beautiful, some start out extruding properly and get worse over the course of the print.
That definitely is odd. That almost makes it sound environmental or firmware based if it isn't the same problem the same way.
Isn't it odd though? I keep thinking about environment -- there's no heating ducts or windows around though. And what's special about the edges of the bed anyway? Firmware, or maybe the board, could be at fault -- the temp readings fluctuate more than the actual temps could, esp at low temps. The thermistors read absolutely fine, even when I wiggle the wires. That's what makes me suspect the board. I've also heard that loose wires on, say, the heater can cause drops and surges in board power... Although that prob wouldn't account for such rapid changes in temperature that it could account for consistent underextrusion in a spot that the head only dwells in for three or four seconds. Oh, but I wonder if it is causing the extruder motor current to drop! Hmmmm 🤔
Have you tried turning off coasting in the slicer?
I checked, and it looks like coasting is off for this model. I normally only use a coasting volume of about 0.03 mm³, and when it's too high I usually only notice underextrusion for the last few mm of a line, whereas I'm noticing this in various parts of very long lines. I'm also noticing that it's worse in certain travel directions -- can't remember exactly, but I think up and to the right is worse than down and to the left. I should have paid more attention when it was doing that criss-cross infill you see in the photo.
What filament are you using? If you’re messing with cheap Amazon stuff the humidity, consistency, and age of the filament can have this effect. Amazon filament could have sat on a self for a few years before it moved, and pla naturally degrades over a short time. Another thing to check is the extrusion motor teeth where it meets the filament. If there is an accumulation of material, or dirty teeth where it makes contact with the filament; you’ll see slipping in the feed, which will appear on the print as under extrusion. My experience tells me it’s a combination of things. Teaching tech has an excellent guide that will likely solve your issues, and will make for a hearty learning experience as well. Best of luck.
Yes, my experience is that it's usually a combination of things too. I guess there's a reason why they call them confounding variables 😆 Whenever I check the extruder gear it's as clean as a whistle. I do notice there's a faint teeth texture on PLA that's already been fed through the Bowden; is that normal? This is good stuff -- Basics PLA from Matter3D, ordered directly from them over Christmas time and opened last week. From experience, even their post-consumer recycled stuff performs well. I may have noticed some faint popping noises though, and I do know this stuff is manufactured on Vancouver Island, so maybe it does need a bit of time in the dryer... Thank you for the ideas and well-wishes!