Extrusion Problems Number 2

So I am close to my wits end as to why I am having this issue and what can be done to solve it, I have already created a support ticket with Snapmaker but, I figured, I can ask the forums again and see if there is any other ideas.

The issue;


It appears to look like a delay in pushing out the filament after a move, this is on the same model and in two different places, one on the inner wall and one on the outer wall. I have something printing right now and I can see the support looks the same, barely there.

What I have tried;

*Cold Pull to confirm no clogs
*Changing the Nozzle
*Changing the Nozzle to a different diameter (0.4 to 0.8)
*Changing the hot end
*Calibrated the E-Steps to within 0.03mm
*Calibrated the Slicer (changed from 100% flow to 90.96), walls at 0.40 showing 0.40
*Changed the K-factor from 0.22 to 0.07
*Used both Cura and Luban
*Changed the speed of the print
*Turn off retraction and changed the settings around
*Updated to the latest firmware
*Used different filaments

I am also using a filament guide as well as a PETF tube to lessen resistance and the spool is on printed parts so it spins well.

I am starting to think that something might be wrong with the print head itself or I am missing something that is so simple that it has evaded me. I will say that the issue doesn’t appear if the model is something simple, like the calibration box used to tune a slicer. It is either that or I have something like the K factor not set right and I need to move it up or down (not sure which one would make the gears go faster) or something to do with the printer acceleration.

To be fair this is the only major problem I have had with the unit but, as this is my second time posting, it seems to be the most persistent.

Any help would be fantastic and, should snapmaker support let me know that there is something else going on, I will post it here so others that might have this issue will know.

Thanks

Hey! I guess this is underextrusion or a partial clog.

You have changed your whole hotend so,
i would suggest to recalibrate your e-steps.

One thing: If you calibrate your flow, did you print a wall greater than 0.4mm, like 0.48mm and calibrated to 0.48mm?

With a 0.4mm nozzle it is not possible to print a fine wall less than 0.4mm (i can’t describe in english what happens, its like the wall could be not straight out of the nozzle because of too less material extruded)

Try to calibrate your wall to 0.48mm.

Please post your M503 here for having a look.

Are you sure your printing temperarure is right for your kind of material?

I read somewhere (generic 3D printer site, not a forum thread) that wall width should be slightly smaller than nozzle diameter (no dimensions were given, but presumably 0.38 or 0.39 for a 0.40 nozzle), particularly for outer walls, in order to reduce layer ridging. This conflicts with “cannot print a wall less tn 0.4mm” but I have not been able to produce a reliable difference when switching the two (any difference in the print seems incidental). Curious what other people’s experience is with wall width setting.

I also think that it is something very simple like that, I will post my M503 as soon as the printer is done on this latest item.

I have done the E-steps quiet a few times, I am wondering if I am measuring it wrong, from the entrance of the printer tube up to, in my testing, 120mm then see if there is 20 left after sending out 100.

I will try the 0.48 calibration as well, I am sure a lower flow would cause issues as well.

Thanks!

@tracer300 is z hop on layer change disabled? I’ve seen it caused by having that on sometimes.

To me the sudden onset and resolution seems filament related, line a small piece is shaved off causing a clog that then resolves. Or maybe too low of temp is putting too much pressure on the extruder gear?

Separately:

The precision of the flow multiplier is less important than you’re making it seem. Because of the obround extrusion profile the correct flow setting will not give you exactly the desired width.

If you have an obround extrusion giving you the exact commanded wall thickness for a single wall then adjacent walls will have air inclusion as the two semicircular portions of the extrusion are just touching.

Try a flow multiplier of 95%, which is more typical for PLA, assuming the rest of your calibration is sufficiently good.

All of your other numbers look good to me.

General opinions below not necessarily related to this particular problem:

In my opinion while a .40 extrusion will have less of the semicircular portion of the obround, I think the shape of the extrusion is not well defined. Some test prints may be in order to ensure.

Additionally slicer settings can be a factor. Infill overlap and other settings may need to be tweaked.

Some settings could be part dependent, if you have bridging or other difficult to print geometries.

Here is my M503 output;

M503
others < G21 ; (mm)
others < M200 D3.00
others < M200 D0
others < M92 X400.00 Y400.00 Z400.00 E238.80
others < M203 X120.00 Y120.00 Z40.00 E25.00
others < M201 X3000.00 Y3000.00 Z100.00 E10000.00
others < M204 P1000.00 R1000.00 T1000.00
others < M205 B20000.00 S0.00 T0.00 J0.02
others < M206 X-15.50 Y-7.00 Z0.00
others < M420 S1 Z0.00
others < G29 W I0 J0 Z1.98500
others < G29 W I1 J0 Z1.94000
others < G29 W I2 J0 Z1.88875
others < G29 W I3 J0 Z1.83625
others < G29 W I4 J0 Z1.87000
others < G29 W I0 J1 Z2.00250
others < G29 W I1 J1 Z1.93125
others < G29 W I2 J1 Z1.91875
others < G29 W I3 J1 Z1.89125
others < G29 W I4 J1 Z1.99375
others < G29 W I0 J2 Z1.97250
others < G29 W I1 J2 Z1.92500
others < G29 W I2 J2 Z1.89500
others < G29 W I3 J2 Z1.96875
others < G29 W I4 J2 Z2.05750
others < G29 W I0 J3 Z1.95625
others < G29 W I1 J3 Z1.87375
others < G29 W I2 J3 Z1.91250
others < G29 W I3 J3 Z1.95750
others < G29 W I4 J3 Z2.06375
others < G29 W I0 J4 Z1.86125
others < G29 W I1 J4 Z1.88125
others < G29 W I2 J4 Z1.91125
others < G29 W I3 J4 Z1.95375
others < G29 W I4 J4 Z2.03375
others < M301 P13.00 I0.10 D17.00
others < M851 Z1.00
others < M900 K0.07

I have had it both off and on, so far that has made no change sadly.

@brent113 I agree that the flow shouldn’t really be the issue, it helps but it shouldn’t be causing this issue. The PLA I am using is showing a temp rage from 180 to 200, I normally print around 190 but have changed to 200 without a change. I have changed out my flow to 93.46% as I used my latest print to check and I see that it is off by a bit (4.40mm printing at 4.28).

I have more troubleshooting to do for sure, but I like the idea that there is something to do with the gear in the print head, maybe I will need to take and check how the gear is pushing. However I have used three different types of PLA and they all show the same issues.

Will report back.

So, quick update, @xchrisd I have done a calabration cube at 0.48 and it came out bigger than expected, this would mean tuning down the flow rate which does seem like going in the wrong direction;

@brent113 Currently printing with 95% and I am seeing what appears to be the same problem, will not know for sure until it is done.

I am wondering if this all has to do with changing out the hotend, is there something that I missed? place into unit, screw in, seems simple but did I put it in too far or not far enough and maybe that is causing the clog? To be fair this seems to have started after I removed the hot in and put in a 0.8 nozzle, now back to the 0.4 but with a different hot end, makes me think something I have done is causing the issue…

As I said I am kind of grasping at straws, I love the machine and I want it to work for me. However while looking on the facebook page for Snapmaker support it did seem like another user is having the same problem as me, I am keeping an eye on it to see what they say but if we can fix it here I will gladly pass it along to them.

Yea that’s makes sense. Permanently increasing the flow shouldn’t really affect a transient issue. Good luck Hope you’re able to find a solution. Have you tried using a different filament? It looks like the black part printed didn’t experience that, is it possible there’s some diameter variation in that orangeish filament

I have used at least 3, a local PLA that is made here, and two types of Sun PLA, the PLA+ and the eSlik, all of them appear to show the same thing.

The black piece has the same markings but on a different sides, the issue tends to move around on a printed part. I am thinking, once the printer is finished with this one, I will take the hot end out and see what I can see, I almost want to think that I have shoved the hot end in to far or not far enough and that is the true cause of the issue.

There is a part of me that worries the head has become damaged in some way and I will need to look at getting a replacement, a pain for sure but at least I might get some answers…

Here’s an off the wall idea: if you remove the hotend entirely and just have the machine extrude 100mm and then retract 100mm and then do that for like 5 minutes how far from the origin does it drift?

Somebody had a print head or controller issue that resulted in occasionally steps were being missed.

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I blobbed the printing head something fierce back in April. Melted a lot of the plastic around the air duct and proximity-sensor housing.

Been worried about its reliability ever since.

After hunkering down and actually working on the thing, I have gotten it to print reliably albeit not perfectly (is there such a thing?)

A new print head is like 150 with shipping. Not great, not horrible. I ordered one so I can yank the internals out of the original and make a new enclosure.

I am thinking that is my last resort but one I will have to keep open, I am more than willing to spend the money if I need to, really I am just really wondering what happened, my only thought is a bad install or something got broken during hot end insert.

Yeah for me it was more of a “license to tinker” purchase.

I had extrusion problems; tried swapping nozzles and hot-ends (with-or-without default nozzles).

When things started working, it was with a recent hot end (received 2-3 weeks ago), with a smear of thermal paste added. The thermal paste was because I was desperate, but probably did no harm. I suspect that SM shipped some flaky hot-ends for awhile: the thermistor on the recent one was well and tight in there, while on all previous ones (those that shipped with the machine, and those ordered in April) the thermistor would pop out as soon as you looked at it wrong.

Before the new hot ends arrived, I actually picked up a tube of 500f silicon adhesive to attempt to fix them in place. Did not give it a go (YET - might use it on the flaky ones).

@tracer300 I have observed the same behavior in some of my prints… some time ago. See pictures below…
If I remember correctly, I concluded that it had something to do with the starting point of the affected layers, the short movement and how delicate the part was at that spot. I used luban with no fancy settings and it occurred with different materials but similar parts!

As the behavior occurred in places which were not visible later on and I was in a hurry to print many parts, I did not investigate it further.

Maybe now it’s time to catch up.
I will check all settings and try to reproduce it and see if it still occurs. (Next week, as I will not be around for the next few days.)

If it’s always near the start and end point of a layer check your K value in M900, if it’s the default 0.22 you could try changing it to 0.07 and see if that affects this.

@m2001s That is pretty close, my only issues it that is tended to appear in areas where it was either seen or at a point where it wold weaken the whole side, worse one is on box lids on the outside edge.

@brent113 It always is near the start, normally after a travel move, my K Factor was at 0.22 but it is now 0.07, however there is an update and it makes…well some sense I guess, I changed the flow to 95% and it did seem to get better on the whole as you can see by the pictures below





There only appears to be a slight bit on the top model, which is the one at 95%.

However I did notice this when I was looking at the supports;

The same odd extrusion pattern, and it so happens that this part of the support was done after a move from the length of the model which may have been what saved the rest of the model from looking bad.

Still working away at this, and awaiting a return message from support as they said that they would print the parts and see if they could reproduce the issue.

Will pass along any updates I get.

That wall looks like a bit like sieve. The 95% might not be helping (I seem to recall the general advice is to only change this by a % or two), but are you sure the wall settings are ok?

Also might want to tweak the e-steps slightly (less than 1% increments, down to decrease flow and up to increase it) using code from Luban before starting a print. I found a few iterations of that vase-model wall-thickness print, stopping the print when extrusion looks less than ideal and applying a new e-step value, worked very well for fine-tuning. The e-steps calibration procedure gets you in the ballpark, but you’re still looking at +/- 0.5mm due to measurement error (unless you’ve built a jig especially for marking and measuring the filament coming out of the print head - something I am seriously considering at this point).

EDIT: sorry, forgot the earlier half of this thread, where this was all covered :slight_smile:

Based on my experiences with swapping out hot-ends, it might be worth popping yours out to take a look. I got a few bad ones, the wiring on the thermistor was too short and it kept creeping out while printing, slowly getting worse until the nozzle did not hold a temp reliably. Bought some high-temp silicn adhesive to fix that but have not cracked the tube yet.

At this point I am willing to try anything, the issue seemed to start after a nozzle change out but, to be fair, it could have been happening the whole time and my models were just not showing it.

I am still waiting to hear back from snapmaker support to see if they can re-create it, if they can then we are on to something.

If not then there is something for sure wrong with the print head.

I will keep playing around to see what I can see.