Good morning,
I modified various parameters one by one, namely:
1)nozzle temperature increased from 255 to 258
nozzle temperature reduced from 255 to 252
dynamic flow calibration
flow calibration
hardened nozzle cleaner
slightly increased retraction
None of these changes have modified or improved the problem I am experiencing, and 20% of the purges remain attached to the nozzle and end up on the tray. The device in the discharge chute does not always work well and sometimes the drains accumulate and get blocked in the chute.
If any of you have an idea of ​​the cause, thank you.
I am thinking of trying to improve the cleaning of the nozzle when changing filament by adding a mini brush, but first I would like to understand the cause of this defect.
thanks again for your help
I had a few failed prints due to poop staying inside the machine. In order to stop poop from staying inside the machine, I had to do two things. One, I printed and installed a poop stopper cap. You can find many models on Makerworld. It makes the opening above the poop shoot smaller. This fixed the poop problem but caused additional blocking and backups in the poop shoot, so like others, I lubed the shoot and inside edge of the stopper. I used plain old vegetable oil on a paper towel. Worked like a charm, and I no longer have poop issues.
In my experience, poops tend to get flung because the filament needs to be dried. Without drying, the poop tends to be stringy and malformed, and then when the extruder stops extruding the filament oozes leaving a long string that is flexible enough it doesn’t break off the nozzle like it should.
PETG is particularly oozy. And it likes to string even when it’s good and dry. To avoid that blobbing buildup problem you need to tune flow extremely accurately…
The factory nozzle wipe is not a good design as you can see by the number of different or improved wipers on Printables, MakerWorld or Thingiverse.
There are models out there that work well but you have to really really really watch the clearance between the nozzle cleaner that is part of the build plate and the fixed wiper that mounts in the chute.
Some folks have mounted a wire cup brush back there like you would put in a drill.
hello, yes I use generic PETG. Between each print, I also have to brush the nozzle to make it clean, but it is not enough.
The nozzle temperature is at 252 ° C.
The last print failed because the purges agglomerated in the poop outlet, stuck together to form a plug.
I do not always have this type of problem, and the same print, the day before had worked correctly.
Probably doesn’t help if filament retract takes place away from the wiper vs retract occuring at same moment wipe occurs.
That takes care of the spiral blob as the nozzle drives to the nozzle cleaner slot where it gets a more detailed cleaning of the nozzle tip.
If that sequence is not right, nozzle tip is less than clean starting into the print.
Good morning,
Thks for your message; I will try to reduce the poops exit and use some oil as you did. Thats right, the original wiper is not so good and any improvement is good to be tried.
I have done several checks and experiments; if the nozzle is clean, the purges always come loose and fall into the purge box, behind the printer. Each time a purge ends up on the plate, a nozzle check confirms that the nozzle is dirty and that the filament is sticking to the nozzle.
By cleaning the nozzle with a soft wire brush, things return to normal.
This does not eliminate the comments of the various participants in this discussion, and the filament must be dry, the nozzle temperature well adjusted, a very good flow rate adjustment, etc…
I will start by improving the nozzle cleaning at the purge zone outlet by replacing the original cleaner with this one:
Absent the extruder drive pushing filament, the nozzle shouldn’t ooze, or should ooze extremely slowly (like, time on the order of a couple of mm after many minutes vs. seconds).
Retraction is most commonly needed because filament is often not completely dry. And people turn retraction up to address an oozing issue.
But think about the thing you can do with a drinking straw. Push it in to your drink of fruit juice and put your finger over the top, when you take the straw out the liquid stays inside, it doesn’t drip out no matter how long you wait. But do the same thing with soda, as CO2 comes out of solution it will drive fluid from the straw.
These fluid dynamics also apply to melted plastic in an extruder. More so, because the extruder opening is much smaller than a straw and the plastic is much more viscous than soda or fruit juice.
In my experience anyway, oozing is generally due to moisture and dry filament requires little if any retraction. So if you’re worried about not having enough, or are turning up retraction to address an oozing issue, consider re-drying your filament instead.
Thank you for your very clear analysis. I understand the issue of the nozzle leaking, but here, the phenomenon is very weak, and does not affect the nozzle. Of course, if the nozzle is dirty it is because of filament that sticks and can burn, blacken, etc…
But in fact, when the nozzle is in the purge zone, its temperature increases from 252° to 260° C and it happens that the end of the filament that comes out of the nozzle becomes brown and sticks to the nozzle.
It is a small section of filament, very fine, that browns and remains on the nozzle.
However, I do not think that the nozzle is too hot at 260° C, because this happens only rarely, and if the nozzle is not clean, there is an accumulation of this small part of burnt filament and it amplifies the problem.
If the nozzle is clean this phenomenon is avoided.
I’m not concerned about retraction. Comment more about nozzle WIPING v nozzle CLEANING
There is a lot going on with the nozzle, cleaning and wiping are two separate functions.
This is pared down but easy to see intent.
M104 S75 ;set extruder temp to turn on the HB fan and prevent filament oozing from nozzle
M412 S1 ; ===turn on filament runout detection===
M109 S{nozzle_temperature_initial_layer[initial_extruder]-20} ; drop nozzle temp, make filament shrink a bit
G1 X65 F15000; shake to put down garbage
G1 X165 F15000; wipe and shake
;===== wipe nozzle ===============================
G0 X135 Y253 F20000 ; move to exposed steel surface edge
G1 E-0.5 F300 ; retrack more
G1 X100 F5000; second wipe mouth
G0 X128 Y261 Z-1.5 F20000 ; move to exposed steel surface and stop the nozzle
;G28 ; home again after hard wipe mouth
I follow this nozzle cleaning/wiping principle and I will modify the wiper and add a mini brush at the purge outlet. Another, but related, problem is the purges sticking together in the purge funnel. This problem occurs with some filaments, which may lead me to believe that some spools are not dry enough. But I don’t have a spool dryer.
At this very moment I am trying to redesign my nozzle cleaner/wipe device.
Those little silicone nubs you can buy that are meant for the Series A printers do the job but there is very little free space in the right front corner of the purge chute.
I have taken a couple of my build plates and used heavy duty sheet metal cutters to remove a small notch on the nozzle cleaner to prevent getting an error.
If you are bumping your build plate against your preferred cleaning device you can get Z errors.
If you look at various aftermarket build plates you can see they have removed that angular piece entirely
Yes, just like me! Cut the build plate as shown in the diagram to fit a mini brush holder; but to replace the original wiper, no need to do that?
I come back to my project which consists of putting this device in place as a wiper Ultimate Nozzle Wiper V2 for X1C P1S P1 by TechNerd - MakerWorld
and this mini brush by cutting out the tray as in the image. that you publish. Nozzle wiper brush holder Remixed by franksj - MakerWorld
Of course, you must not hinder the movement of the board; the slightest obstacle or object in the path of the board will generate a Z error.
