GregValiant

I know there are some oddities with Hole Horizontal Expansion but I hadn't run into this before. I drew a test box 50mm square with 5mm walls and two 8mm cross holes. I exaggerated Hole Horizontal Expansion to 3.0mm. This is a slice through the center of a cross hole. In this area the walls are still 5mm thick. Here is the model at the last layer below a cross hole. The wall is 2mm thick as the 3mm HHE is applied to the square vertical hole. (This happens to be layer 380.) Here is the very next layer (381) and Cura has reached the 8mm cross hole. Now the walls have reverted to 5mm thick and even required support for the step that occurs there. From the build plate up to the first layer that cuts through a horizontal hole - Cura sees the square hole as a hole and so applies your (0.3) Hole Horizontal Expansion. When the slicing gets to the horizontal round holes then the square hole disappears and becomes a "U" shaped section and is no longer defined as a hole by Cura The Square vertical hole will have steps HHE wide every time a cross hole occurs. (That is my theory which may not actually be right, but sounds good so far). Is it wrong? I dunno. Mr. Spock would say that logically Cura is correct that there is no vertical hole feature in the area of the cross holes. In the real world you would think that the HHE would be applied uniformly all the way up the chimney. The only way I can think of to fix this is for Cura to make a decision based on what the user "expects" or maybe "hopes for". Some tough coding to get that done I betcha. So that's my take on it. Maybe @ahoeben or one of the other main contributors can provide a better description or maybe even a fix or workaround.

Each nozzle has a file in "resources\variants". You can copy one of the Ender 3 nozzle files, rename it to match the naming format, and change a couple of lines in the file using Notepad. Next time you start Cura it should be present in the dropdown list. Be careful when altering the file as Python is fussy about punctuation and spacing. If you get a " corrupt file" warning, c!ose that warning, get out of Cura, and try again.

@eightbitghost, if you could Use "File | Save Project" and post the 3mf file here then someone can take a look. Taking a SWAG I'd guess the bottom isn't quite flat. Have you tried the rotation tool "lay flat" option?

@Torgeir is a U2 guy. He may have some ideas. Torgeir, take a look at the square print. I think the problem is carrying over to everything.

PLA+ would be around 225. Regular PLA I would think to be 200-215. For a non Ultimaker printer - you have calibrated your E-steps? The filament diameter in Cura is correct? (1.72 is not the same as 1.75). Typically when I use Spiralize I push my line width to 0.6 for a .4 nozzle. I would want to fix the under-extrusion first. It may be easier to troubleshoot and the flowrate through the nozzle effects the temperature. A line width of .35 is what Cura typically defaults to for an "engineering" profile.

You need advice from one of the heavy hitters here. @nallath or @ghostkeeper may be able to point you in the right direction (if there is one).

I agree with @Cuq a post processing script is required OR two gcode files that you hand copy-and-paste together. Changing the way Cura handles building a gcode file would seem to be much more work than building a single file from two files with proper handling of tool-switch retractions and extrusion resumption. Even a macro in Excel could handle merging the files. Cura was not built with IDEX printers in mind. If the printer requires u and v axis then the difficulty would go up.

If it isn't part of a group it will be available in the object list on the lower left. There may be a way to cycle through the objects of a group but I am unaware of how to do that.

Can you right-click and Ungroup? CNTRL+left-click any object? Select from the object list in the lower left of the screen?

So the laser is extruder 3? Or is it extruder 2? I will assume it is extruder 2. If extruder 1 deposits material and then extruder 2 (laser) is to come in to fuse material then I think the layers need to be "interleaved". Layer:1 extrude with T1 Layer:1 fuse with T2 Layer:2 extrude with T1 Layer:2 fuse with T2 Etc. Something like that? Cura would preview that as it would a gcode file created with objects printed "one at a time" which is correct but seems wrong because of multiple instances of each layer number. The preview is layer-by-layer though the gcode is really line-by-line.

What printer? The Creality printers have known problems as they no longer support M0 or M25. There is a workaround using G4.

Did you have combing turned on?

Not when I got done.

Nice. Now that it's a proper 3D model it slices correctly. I started with U-Control planes and eventually progressed to Radio Control. They were balsa models that unfortunately never lost their "tree" instincts. (Or just possibly I had progressed to my level of incompetence? Nah!) At any rate, at the end of a day of flying I could get 5 U-controls, or 2 RC planes, into a 5 gallon bucket. It was big fun.

The printer is not a "printer". It is a USB Serial device so it is handled differently by the operating system. There are a couple of things you can try. You need an actual USB data cable. A lot of the cables used by phones are for charging only and don't have the transmit/receive lines in them. With Cura running go to the MarketPlace and "Installed" (can take a minute to load) and scroll down to USB Printing and make sure it is checked. Try different USB ports. If the USB-SERIAL (CH340) driver was installed on a particular USB port then it might not be available to other USB ports (my Win7 computer will only talk to the printer on a particular USB port but my Win10 laptop doesn't care which port I plug it into). If you are on a Windows system bring up the Device Manager and then plug in the printer USB cable. The screen should flash and refresh and under "Ports (COM and LPT)" should be a line describing the printer connection as "USB-SERIAL CH340 (COM4) where the COM number is particular to your connection. The Cura USB Printing plugin will search for a printer every 5 seconds (thanks @ghostkeeper) so you can have the printer plugged in via USB before Cura starts, or you can plug it in after Cura starts. It can take a minute or two for Cura to notice a COM port (as acknowledged in Device Manager) and then cycle through the baud rates until it finds what works. Greg's SD Print Tool.zip

That model won't print the way you want because it is not a solid in any way, shape, or form. I tried different repair utilities but the "60 unsealed edges" around the hole always seal together and eliminate the hole and the model ends up solid. It isn't so much that Cura is attempting to repair it as much as it is just an illegal model in it's original form and Cura is making a guess as to what it should be given the geometry Cura sees. If the Shell function doesn't work (that can also happen with Solidworks, Inventor, Fusion, etc.) then you might have to break your design down into simpler pieces that can be modeled. Those simpler pieces can then be assembled (union) in the design software into the finished skin of a part and then you can merge your interior rib structure. Sometimes when a model refuses to "shell" it's possible to make a copy of the model, scale the copy to give you an approximate .45 wall, and then locate the copy within the original and subtract it from the original. That would leave an outer portion that would be similar to a shell but probably wouldn't have the exact .45 wall thickness that a Shell operation would give you.

"It’s not a software problem either apparently. It’s just physics." Just to be clear - you've changed your opinion and it is not a Cura problem? I am attaching a version of your original file that I post-processed to alter all Z-Hops from a height of 0.6 to 0. It is not a re-slice, but rather your file with no Z-Hops. If you are right and it's "just physics" then the problem will still occur. This is the relevant area of the gcode as read into AutoCad. It showed that there are no missing layers. NoHop.gcode

With Cura running, select "Market Place" at the upper right of the screen. When the dialog comes up (it can take a bit of time to load) select "Installed" and scroll down to "USB Printing" and make sure it is checked. You can also do a search around here for the same topic but with different printers. The problem does come up once in a while and there might be a couple of other things you can look at.

A printer has a definition file and it tells Cura some max parameters and things like build plate size. Materials have particular print settings and a profile will have further settings that can override the others. Fine, Standard, Coarse are built in profiles and you can add your own custom profiles. Kind of a favorites thing. As long as it is slicing correctly it should stay working.

You see in the "Mesh Fixes" section there is a setting for "remove all holes" and those models are slicing as if it was turned on. Try turning it on - slice, then turn it off and slice again. See if the problem resolves itself. There can be occasions when a setting box is unchecked, but a profile or printer definition loads and the setting variable is enabled in the background but the checkbox isn't updated. It looks like it's turned off but it's on. Fortunately it doesn't happen often and seems to require a specific series of events for the problem to occur. The Cura team looks for those sorts of things in order to fix the problem. Did you happen to have custom profiles and then work with a 3mf file?

This is one of those shapes you need to play with. Models that have hairpin / horseshoe shapes can be tough for combing as the nozzle runs all over the place, traveling up one leg and then down the other to avoid crossing the narrow gap. This is especially true if it is "filling gaps between walls" at the end of each leg. You have combing set to "not in skin" and Cura knows there will be a skin there on the build plate in the future so it generates combing moves to avoid that area. If you move the Z seam to the hairpin turn (left in the 3mf) and change combing to "all" you won't get near the amount of travel. On larger models, those long travel moves can give the nozzle time to ooze and when retraction starts again it can take a few millimeters to get going. As the layers build up, that initial under-extrusion at the same position on each layer can turn into a very noticeable flaw in the finish. I usually turn combing off on those types of models as it can cause more problems than it's worth.

I'm listening. @ahoeben (with 2,000,000 downloads of his work on Cura) is listening. @gr5 (an Ultimaker dealer) is listening. @Torgeir (a well known man-about-town) is listening. We are not a group of kids on Facebook or Reddit but a group of professionals who tear things apart looking for problems. The Cura team needs to know those problems or they can't fix them. I reviewed your claim. I investigated the gcode file itself. I've been working with gcode since 1969. Your gcode file is fine, no problem. The model prints fine using your gcode on a printer that is virtually identical to your own. All I've heard so far is that "it doesn't print right and it can't be my fault." Well, sorry. There is no evidence that the fault lies anywhere else. The pictures may be be blurry and I may have picked a bad color, but I would give my print an "A" and yours an "E". Dark or not, I think it's plain that there are no missing layers. The two loop overhang around the periphery is in place. The raised areas are firmly attached. Go ahead and zoom in. It is my opinion that you need to strive to bring your printers into adjustment. Go back to the CHEP videos and Teaching Tech and straighten your machines out. I'm sure they are capable of making good prints - but not in their current configuration. I'll say this one more time because I don't think I'm being listened to...it's your printer(s). They are poorly adjusted and not calibrated. It isn't Cura. It isn't a firmware problem. The same person put them both together and missed it...twice. I'm sorry if you don't want to believe the evidence. Have a nice day, Greg

I almost forgot... I was going to slice it myself and pass the gcode along but I don't see any reason. Your profile is quite good. For personal preference I would have slowed down to 60 and dropped the Accel to 500 and the Jerk to 8. I typically print at 210 as opposed to 200 but for this I figured 200 was good enough. Your retract speed of 45 might be a bit of the problem with under-extruding. 200 is a bit on the cool side and the plastic is thicker so it can't react as fast to the retraction. You might try 30 and 30 for retract and prime.

So here it is. Besides the color you'll notice that it is significantly different than yours. I took your gcode file, put it on a memory card, and printed it. I made no changes. I broke off the supports but did no other clean up to the print. My printer is an Ender 3 Pro painstakingly assembled and calibrated. It has an 8 bit 1.1.5 silent board and an all-metal hot end. I did add a 5015 cooling fan. I level it with a piece of parchment paper. The problem is not Cura. The problem is that your printer is neither adjusted nor calibrated correctly and if you want good prints from it then you need to go back and re-work it. Get out a carpenters tri-square and make sure the three axis are at 90° to each other. Calibrate the E-steps. Don't try to be a speed demon - just give the little printer it's best shot at making good prints. The problem isn't that they are inherently poor machines but rather that they are each assembled by persons of different skill levels. You talked about Reddit and I spend some time over there. There are a total of about 6 people who give consistently good advice. The rest are talking for the sake of talking and just blowing smoke. Here is the print.

I'd say no. The machine just goes where it's told and the gcode is telling it to take .2mm steps for each layer. That's what the gcode is telling it to do. There is no jump, no strange layer height. I'd be more inclined to say I have to look at my Z rod too. Just so you understand, I have nothing to do with Ultimaker or Cura. I do have a wide skillset and (among other things) I was a forensic investigator. My job was to figure out why something broke, caught fire, fell over, collapsed, etc. Now around here I have found and written up a couple of bugs. The Cura team KNOWS there are bugs and they work hard to fix them. Back to your printer - Z banding is in red. Under-extrusion is blue. There are serious issues with your Z system. It could be a loose coupler or the wheel eccentrics need to be adjusted, or maybe the Z uprights aren't parallel, too much backlash, something isn't right. As for the under-extrusion - did you calibrate the E-steps? If you used a calibration cube throw those results away and just stick with steps/mm. (I can go off on a huge rant about calibration cubes so don't get me started.)