gr5

I think it's a coincidence that it happened on both extruders. Note that it's very bad to leave PVA at printing temp for more than a few minutes. It gets gummed up/solid. Filament sensor is in the menu system. I recommend you leave it enabled. Try doing a few hot and cold pulls on the primary core. That is also in the menu system - it walks you through the process. I really doubt this is related to the feeder as the feeder on the S5 is so amazing but it's possible. To test it, use that lever on it to insert the filament only half way down the tube, then do "move material" to energize the stepper, then pull down hard on the filament. It should not slip with 5kg of force. So you say you "pushed" the speed a bit. What was the infill speed (or fasted of the 8 or so printing speeds) when you increased the speed? What was the temperature of the nozzle (hotter PLA is less viscous and can print a bit faster)?

So I have seen this exact pattern when printing too fast - like 200mm/sec on my fastest printer. Slower I suppose on my um2 with the black feeder. I'm not sure what causes it. But it goes away when I drop the speed by 50% (which you can do in the tune menu for your printer (looks like it's a um2,um3 or s5)). Please clarify a few things: 1) Please show this or a similar layer in layer view in cura. 2) Did you model a cube and set the top/bottom infill to 0 and use an infill pattern to make this? Or did you actually model all those thin walls? You will get *much* better results with the former method. And it will print much faster (only one pass on walls instead of 2 or more).

Well the issue is moderate to severe underextrusion. It has many causes. If you tell me your printer type I'll give you a list of 20 or so possibilities. The most common across all printers is printing too cold and/or too fast.

There are so many things that can go wrong it's hard to list them all. First and foremost seems to be temperature. If the printer has been off for an hour do both temp sensors read the same thing? If you heat up both at the same time do they both go roughly (very roughly) at the same speed? If the second nozzle suddenly jumps by more than 3 degrees in less than 1 second then you have a bad temp sensor or a loose temp sensor wire. If you heat both nozzles to 140C and put a drop of water on the nozzle does it boil at about the same ferocity? Next - test the feeder - put the filament half way down the bowden, do "move material" to energize your bondtech and then pull down hard on the filament. A bondtech can hold 15 to 20 pounds of force (10kg). Even 10 pounds (5kg) is good enough for decent prints. If temp passes and motor passes, next are extrusion issues...

All those red spots in xray view are problems. It means there is an extra infinitely thin plane or a hole. The way cura creates these colors is that it sends a line from your "eye" through the model and out the other side and counts how many triangles it passes through in the STL. If it's even it gets a shade of blue or light blue or white. If it's odd it colors it red or brown. So each red circle represents either a hole or extra infinitely thin wall (one can't make infinitely thin walls in real life) and they confuse cura as to what is "inside" and what is "outside" so it often prints nothing. You can zoom in on those spots in cura and then look at the same spots in cad and find the issues. Or you can just submit it to an STL repair service. netfabb free repair service is here (you have to create a free acocunt first): https://service.netfabb.com/login.php Did you create this model? If so did you use sketchup? If so here is a great guide: https://i.materialise.com/blog/3d-printing-with-sketchup/

I don't think you broke anything. Don't be afraid to take things apart.

I've certainly never heard of this. It seems to take only 4 minutes. maybe your "I" value in your PID is too low. Did you try autotuning the PID values? It doesn't seem to be oscillating too much. My first thought was your wall thickness wasn't a multiple of your wall thickness. For example if nozzle width is 0.4 and line width is .4 and it's printing a wall that is 0.6 it might print a 0.4 width trace followed by a 0.2 width trace. You need more heat for the 0.4 trace and less for the 0.2. But still, make sure your wall width is a multiple of your line widths and make sure the inner and outer line widths are the same and the "wall line count" makes sense. I like smartAvionics fan theory. Sometimes air from the fan bounces back. Sometimes it's not a problem when starting out because it's printing slower and the bed may also be heated.

By the way, the main reason I asked you to post a screen shot in layer view was because that shows support in a different color and I also suspect it might be support except... it just didn't look like a typical support pattern.

You can play with lots of support settings. For example XY distance will keep the support from touching the sides of your model. And you can play with the overhang angle. Or you can just create your own support in CAD (that's what I often do).

I think if you find the right cfg file for your printer you can probably edit it there and restart cura. I found these in my local area - not in the cura installation folder. Your local folders will override the ones in the cura installed folder. Most printer profiles inherit from fdmprofile so it could be you can edit them there. To see what your current values are go to this profile dialog:

@ahoeben says you can access "heat up speed" and "cool down speed" but only if you do two things. You have to pick a gcode flavor different from "griffin" or "ultigcode". Also you need the "printer settings plugin". Regarding the tower - the whole point of the tower is to wipe off any little tiny strings/sausages coming out of the nozzle so you don't want it to hop over the tower. It's fine to set those temps the same but it won't help. You need to change the "standby" temperature. But again, if you can set the "heat up speed" and "cool down speed" properly then it will all work perfectly and be completely at temperature with no waiting when you switch nozzles. What is the risk if "stand by" temperature is too hot? It may leak and if the leak is long enough it may end up in the print. Your part is very small however so for this part in the video you could just set standby temp to the same temp as the printing temp and the tower will take care of any tiny strings/sausages.

Always look at your part in layer view before printing. You looked at it in solid view. Please show a screen shot of layer view and use the color scheme as "line type" so I can get a feel for the issue. I'm guessing there is something wrong with the model though - you could try sending it through the netfabb repair service. netfabb free repair service is here (you have to create a free acocunt first): https://service.netfabb.com/login.php

No. You just do it once in machine settings. Yes it does preheat before starting printing and it pre cools just before finishing printing. Search for "standby" to find and adjust the temperature of the inactive nozzle. These values are perfect for ultimaker cores on the UM3 or S5. I can't find the settings where you tell it when to start preheating. I'll keep looking... update: it's called "heat up speed" and "cool down speed". These are in degrees C per second. If cura knows the speed to heat and cool then it knows when to switch the heater back on so that it reaches printing temperature just at the moment when it needs to use the other nozzle. I don't know how to mess with those values because for a UM3 or S5 they aren't editable. Hopefully for your printer you can edit them directly. If not then they are probably set in one of the json files for your printer. You can view the current values in the profile dialog if you select the extruder1 tab.

The sensor is ignored on the first layer so if this is happening on the first layer the sensor is irrelevant. First of all don't loosen the feeder. That makes it more likely for the filament to slip and therefore grind flat. Only loosen it for delicate filaments. pla, abs, tough pla should all be fine at the midpoint of tension. So the most likely problems: 1) Printing too cold/too fast. If you have pushed the speeds over defaults (which is a good idea in general) you may have pushed too far. Or if you lowered the default temperature. At typical printing speeds the feeder is pushing at 3kg to 6kg force but if you go higher than 6kg then you get too much slipping. Or if you increased the flow rate (did you mess with the flow rate?). Flow rates over 110% are likely to cause problems like this. 2) too many retractions. Some prints have hundreds of retractions within just 1 or 2 minutes of printing. If the same spot of filament goes backwards and forwards through the feeder 10 times it's fine but 20 times is enough to sometimes cause this flattening. 40 times will almost guarantee this flattening. Look at the layer that failed in layer view in cura. There are 2 colors for non-printing moves: light blue and dark blue. I forget which one is retracting move but if you have more than other models that were fine then this may be the problem. You can tell cura to retract less. Do this by setting "maximum retration count" to 10 and "minimum extrusion distance" to your retraction distance (4.5mm for UM2 and 6.5 for UM3 and 8mm for S5). 3) Clogs/jams - extra material can get in the bowden and cause a jam but you already tested for this so I don't think this is the issue anymore but may have been the issue once. 4) Tangles

This is even a feature. You can add 0.01mm diameter cylinders (needles) of air in your print and cura will blindly print around them which can strengthen a portion of your print. You need to make them at least as tall as one layer though or the slice may miss the needle. Cura takes an STL file which is a randomly ordered set of triangles. When it slices it intersects a plane with EVERY triangle and gets a random list of line segments. Cura than has to figure out which go with which and puts them together in loops. Now most of the work starts - now that cura has a random set of loops. Cura doesn't think about voxels. There is some preprocessing to find overhangs and to note which areas are near a top or bottom surface. But mostly cura thinks in 2 dimensional slices.

If this happened on an ultimaker I would say it's probably the power supply. The Ultimaker power bricks will just suddenly cut power for a portion of a second and the printer reboots and if you aren't watching it the moment it happens it has already rebooted by the time you look. You can reduce power consumption by not using the heated bed at all for a print (use blue tape) or set the heated bed to a *higher* temp (it uses less power at higher power because it is warmer - overall it uses more power but on the second to second bases it uses less max power).

Well the uprights shouldn't bend much - I mean they should just bounce back. when you have strong overhangs like as you approach the top of this arch, you get raised edges on the edge that overhangs. You can reduce this by cranking the fan to max but by default the fan should already be on max. If you can add more fans to your print head that will definitely help. Baring that you could add some kind of temporary support - maybe connect the two arches together when the arch hits about 45 degrees of overhang. To stiffen it up during printing. This should be unnecessary. You could also thicken those arms in the Y direction as shown in picture above. The strength/stiffness is proportional to the cube of the thickness so adding just 10% thicker will make it 30% stiffer. 50% thicker will be 3.3X stiffer. You could also consider printing this in 2 parts. The basket as one part and the handle as a second part (printed on it's side). Make sure there is lots of surface area of contact and strongly consider putting some kind of groove or something to help position the parts during gluing and also for mechanical strengthening later. cyanoacrylate (super glue) works well on pla.

For those too lazy to download the STL, here is his object.

I'm pretty sure it's the speed change. Set the infill/inner/outer shell speeds all to the same speed and I think it will mostly go away. When it starts the outer shell it typically drops the speed in half and so you get brief overextrusion as the pressure is equalized for faster printing and then it suddenly slows down.

Oh! Also there is I think an option for "concentric infill" that may fix this? I can't see your "percentage infill" in your screen shot but I assume it's less than 50% and this screen shot is "top" or "bottom" infill. So you can also make the top or bottom shell thinner but then your part will be weaker.

My first though is if you play around with wall thickness you can drastically reduce that gap and it will do two walls instead. Much faster. So try 0.7 wall thickness to see if that helps. Anyway, to answer your question, yeah there are a few options that if understood can eliminate this. I think. Or maybe that gap is too big? This "problem" you are talking about has annoyed me a little but not as much as you so I never really did anything about it but I found the discussion on this ticket extremely informative and may give you some ideas of a few things to try: https://github.com/Ultimaker/Cura/issues/3277 But again, maybe your gap is much too big to be affected by the suggestions in this github "issue".

I also find zhop to be bad for my ultimaker printers but I think it's really helpful on delta printers. Regarding knocking prints over - I find when I have overhangs, say at the bow of a boat, I also get raised edges that the print head can later bump into. The primary solution is to get your parts to stick like hell. My parts stick so well they don't get knocked over no matter what. The advice to do this super well is long and involved and takes 20 minutes to get all the important details. But if you are patient (feel free to watch it at 1.5X of course) I strongly recommend you sit through the entire video linked below. The other way to reduce raised edges is: "more fan". You want as much fan as possible. I've also found that higher print temperatures can help (210C was better for me than 195C). I don't know why. Maybe it's easier for the nozzle to push the edge back down? Maybe higher temp only works with slow print speeds (like 35mm/sec?). But what I *do* know is more fan helps a lot. So if you can add another fan to your printer that will help as well. Or use a blower instead of a fan. These fan's are a bad idea and Ultimaker finally figured that out with the UM3 - the um3 uses blowers, not fans.

Yes, changing the diameter is a way to cheat. You set the diameter smaller to get it to extrude more. The area is the square of the diameter so you have to adjust by the square root of what you what changed. For example if you want to increse by 10% you need to find the square root of 0.90 times the current diameter. However it's even easier to set the "flow". In cura you set the flow to 110% and it will extrude 110% more than nominal. For setting steps/mm you can follow these instructions here which should be identical for creality printers versus ultimaker printers:

If you are controlling the printer through repetier host then you can adjust steps/mm using gcodes. M92 is used to set steps/mm for example if the Y axis is currently 80 steps/mm but you want to increase that by 10% so it will move farther then you want 88 steps/mm: M92 Y88.000 After changing it and you are happy do a M500 to save settings. If you don't do M500 it will go back to the previous value when you power cycle the machine M500 To see what the steps/mm currently is for each axis (and all the other settings) do M503 and it will display all the current settings as gcodes. For example the steps/mm will look something like: M92 X80 Y80 Z200 E250 Which tells you the steps/mm for each of the 4 steppers. You can see what all the gcodes mean here: https://reprap.org/wiki/G-code#M503:_Print_settings

overextrusion is rare. The feeder is only commanded to extrude exactly what is necessary. Underextrusion is common because the filament can slip in the feeder if the pressure is too high.