GregValiant

Curiosity is a disease. I take solace in the fact that I'm not the only one here with the problem. Up to layer 27. I was able to get the printer running but there aren't any lights around it. I know it's printing but I have no idea how it looks. It's printing by braille.

I looked at the Gcode. Combing tends to run the nozzle all over the place to keep stringing at a minimum but it never has a Z component. It never combs up and down. (You do have Z-hop enabled at a height of 0.6mm.) The last full layer is Layer 68 in the Cura preview. Layer 69 looks correct right on top of it. I would say that the preview is correct and what I expected to see. Within the gcode, Layers start with layer 0. The gcode layers are every .2mm all through the area of interest. Layer 66 is at 13.4 Layer 67 is at 13.6 (this is layer 68 in the Cura preview) Layer 68 is at 13.8 With Gcode layer 68 the Z-hops occur as the nozzle moves from one merlon to the next. Finish with one merlon area, hop up 14.4mm, move to the next area, drop back to 13.8mm. I have a little program I wrote to read gcode files into AutoCad. It allows me to take Cura out of the loop. Unfortunately, I'm revamping my office and then leaving on a vacation (yes, retired guys get vacations too) so it will be a week or more before I can do that part of the analysis. After looking at the gcode with combing turned on (as well as the one with combing turned off) I don't see anything that would relate to a missing layer. The gcode commands are consistent and tell the printer to move to the correct height. The Z-hop command lines are paired as they should be as Z-Hop-up followed later by a Z-Hop-down. @gr5 points out that the print you are using for an example has other issues and I agree it appears to be severely under-extruded. You aren't happy with the maintenance you have had to perform on the machine. Right now I'm thinking that more maintenance is do and specifically on the Z lead screw and Z trolley wheels. There is also a bit of evidence on the print of some light Z banding. My current theory (subject to change when I get my office put back together and the AutoCad computer back up) is that the gantry is hanging up at a Z-hop height and not dropping back down to 13.8 during layer 69. It would not surprise me if this has been an ongoing issue for you but it does surprise me that it is happening on a second printer. Please consider - tens of thousands of people using Cura have not noticed this problem. If it was indeed a problem, it would be at the very heart of what Cura does and surely somebody would have raised their hand and said "hey...wait a minute!!" and Simplify3D might still be in business. EDIT: I plugged in my printer (Ender 3 Pro) and it's printing the "with combing" gcode file now. My curiosity got the best of me. Again.

Not all power supplies can handle a full load on the bed and a full load on the hot end at the same time. That's why people buy the Ender 3 Pro. It has a more robust power supply (and more robust Y beam and better wheels).

OK. Cura does have a definition for a couple of models of LottMax printers and on my install I do have a Shark listed. I think it's probably the V1, but if you have it then it should work. I have customized my installation of Cura and you might not have the Shark but printers run in families and one of the other ones should be OK. The two most important things are the Gcode flavor and the build plate size. Those are both adjustable from within Cura. In Cura, click on Settings and then Printer. Down at the bottom will be "add printer" and click on that. In the next dialog click on "add a non-networked printer". Scroll down the list to "LottMax" and click on it. Select the "Shark" model if it is there, or the SC-20 if it isn't. (If you don't have a LottMax available then choose the Ender 3 from the Creality list as it is close enough) On the right side of the dialog you can name your printer. When you are happy with the name click on the "Add" button. The next dialog has some of the printer settings. The V1 Shark appears to have a build volume of X=235, Y=235, Z=265. Check those numbers against what you printer really is. A couple of boxes below that is the Gcode flavor. The other LottMax printers are Marlin so that is a safe place to start. Don't worry about the numbers on the right side of the dialog box(PrintHead Settings) as they are for printing in a special mode "one at a time". You can play with that later. That should be it. Load a simple STL file like a calibration cube (don't start with a character, they can be tough). Above the Cura Settings is the Setting Search box and to the right of the search box is a dropdown for setting visibility. Select the dropdown and set the visibility to "all". Scroll down and look at all the settings to get and idea of what is there. Make sure your temperatures are correct, set the all the speed settings to 40 and travel speeds to 100 and slice the model. Take a good look at the preview. When you are happy with the way it looks, generate the gcode by clicking on the "Save to Hard Drive / Save to removeable drive" button. Go ahead and print the gcode file. Let us know how you do. Even the Aston Martin drivers here will be curious as to how us Yugo drivers make out.

When errors occur they (usually) get documented. The Cura.log file, your STL file, or a 3mf project file, and sometimes a gode file, may have the clues to a problem. Without any documention we just have some verbiage that may or may not be an accurate description of what is really going on. A problem may occur in an installation, in a model, in a definition, In a user's settings, or in the Cura output. Without a log or 3mf file then diagnosing a problem is like shooting in the dark. People here are certainly willing to help, but nobody really likes to just guess. So if you would - Please post a 3mf file and your Cura.log file.

In the Mesh Fixes area of the settings is "remove all holes" and you could give that a try (remember to turn it off when you are done). You also might see a change by making Horizontal Expansion a negative number. Cura can do some things to alter a model but for the most part - you're stuck with the way the artist created the model. If a layer is offset too far from a previous layer then there will be a gap in the XY that you can only see in the Z (which is what you have). You could try a lessor layer height. It's a trigonometry problem. Given a .4 x .2 rectangle under the nozzle - if the angle of a surface is less than (about) 27° from horizontal there is a gap between the extrusions as seen in the Z. It's the "step" distance from one layer to the next. The printer will bridge across the gap if it's small, but there will be a gap. In a case like that, there might not be holes in the model, but there will be holes in a single wall print. Consider the cabin roof of a Benchy if printed as a single wall model. The lines from one layer to the next are far apart in order to describe the slope of the roof. As the angle of a surface approaches horizontal the step distance approaches infinity. That's a big damn gap. I learned this from Pythagoras himself when I was a little guy (that was a couple of years after @Torgeir and @kmanstudios took his class). Either a lower layer height or a larger nozzle will change the geometry. Shown is a .4 nozzle at .2 layer height.

That big gray box on top is a support blocker. It can have different properties and be moved and scaled like any model. In this case I used the button above the support blocker tool "per model settings" and selected "modify settings for overlaps" and then set it to a "cutting mesh" with 0 wall count, 0 top and bottom count, 0 infill, and with support disabled. It becomes a Mesh Modifier and since there isn't anything left to print of the overlapped area, it cuts the model off there. For the top, I would have sunk the model into the base plate and moved the block to an appropriate position. That is a really nice model it just isn't appropriate for FDM printing at a reasonable scale. The flat "floors" that occur up the top of my slice of the model would all need support and that support would have to be removed. Maybe with PVA it would be doable but it would still be very difficult.

There should be a specific command that tells the printer to stop "right now" and for your printer I believe it should be M0. If the command is ignored then there is a problem in the firmware, I suppose if it does pause but then the command won't continue it would also be a firmware problem. I think you would need to get support from AnyCubic for this issue as I am sure Cura is adding the line to the gcode. It's just that the printer isn't enabled for it. You don't need to print a whole file to check on what might work. You could make up a short gcode file just to see if you can pause and resume. If you start a text editor (like Windows Notepad) and enter this: G28 G0 F3000 X100 Y100 Z10 M0 G0 X10 Y10 G0 X100 Y100 M25 G0 X10 Y10 G0 X100 Y100 Then save it as "save as type" = "All Files" and then name the new file as a gcode file - you can print it. M0 works on my Ender but M25 only works when I start a print using M24. Using that example snippet above, my printer will pause at the M0 but blow right through the M25. If you have "Z-Hops" enabled then you can't use "by height" as the search criteria can be confused by Z-hops in the gcode. Using "by layer" works well for me. In the Pause at Height dialog, the bottom setting box is for "gcode after pause". If you put in "G4 S300" then the machine will dwell (a timed pause) for 5 minutes (300 seconds) and then restart by itself. Just make the number of seconds something you are comfortable being able to swap colors in. Practicing is good. A drawback is that you have to be standing there staring at it because it will just go back to work at the end of the time period. There is also no command to make the dwell shorter. If you make the dwell 25 minutes (G4 S1500) and it only takes you 1 minute to change filament, you are going to wait the other 24 minutes for the printer to restart. The maximum "disarm timeout" is 1800 seconds. If your G4 command is more than that then the steppers will lose their position before the print resumes. If you set the "gcode before pause" to M300 there will be a beep from the printer.

It isn't likely a bug in the slicing. The letters aren't connected to the strip below them. A setting like "Initial Layer Horizontal Expansion" that @Smithy is talking about is usually set to a small negative number to reduce elephant's foot and can cause what you see there. If the models had been merged then that wouldn't happen and there would not be "outer walls" between the letters and the line thingy. If you zoom in to the mid-line of the letter "B" in the first screenshot you can see that there are two Outer Walls with no extrusion between them. The same area in the second screenshot shows two outer walls and two inner walls between them. I'm guessing that something was going on with one of the horizontal expansion settings to cause that. It's an effect that shouldn't have been caused by simply going from skirt to brim but a change in profiles could do it.

In Cura use "File | Save Project" and post the 3mf file here. I'll take a look but I ain't makin' no promises.

Got it. The slice was always like that then. It didn't change because you chose a different printer. Line Width is probably the main issue. If you are using a .4 nozzle try dropping the line width to .35 and see if it helps. If you switch to a .2 nozzle (just for a test) and look at the preview do those bad areas get better?

You need to check the settings between your "monitor" (not sure what that means) and the BIQU. Start with Line Width and Layer Heights and turn on "Print Thin Walls". If you post the STL here somebody will take a look. A LOT of scanned and hand modeled character STL's have errors in them. The engineered models don't have near as many problems but it can still happen with them.

There are different temperatures that can be set. You are in the Basic Setting view and can't see them all. Above the settings there is a search box and to the right of search box is a dropdown icon of 3 horizontal lines. Click on that and go down and set the Settings Visibility to "all". You will see the temperature section of Material like this: I looked at the StartUp Gcode in your printer definition file and it looks fine. If you would post one of your "bad" gcode files here @fvrmr or I will take a look and see what is going on.

Yep, thinking outside the box. I love a good well thought out workaround. (Of course it has to actually work or I'll take away your attaboy.)

Actually, I made it all up. I have no idea if any of that is true or not.🤪 Cura shows the extrusion moves and with coasting enabled there is no extrusion there. The nozzle travels there so that little part is a continuation (vector wise) but there is no E in the line of gcode so the pressure just bleeds off across that distance.

Coasting is usually nice for skins. On walls and with combing turned on, there is the coast distance (during which the pressure in the heat chamber is allowed to fall off) then a retraction followed by the travel motion. All of that means that the prime is not sufficient to get extrusion started right away and I believe that is what we're seeing. This shot is from the Gcode file opened in Cura. That whole corner shows the coasting all the way to the top of the model. BUT within the 3mf file Coasting is not enabled. (You were trying to trick us weren't you.) These are the relevant lines from the gcode file: G1 X99.8 Y98.959 E16.35658 G0 F1080 X99.8 Y99.801 The nozzle extrudes to X99.8 Y98.959 and then coasts to X99.8 Y99.801 which is about 1mm. There is a reason that Coasting is in the Experimental section. Sometimes it has too much of an effect on the resumption of extrusion. Large prints that have a lot of combing moves can have the same problem as the oozing while traveling can make for insufficient prime on resumption.

I had a decent sized "N" gauge layout that I worked on for 25 years and it would have been nice to have the printer then. I don't post a lot of things but I'm supposed to know what I'm doing. This was for a friend. I thought the "glow in the dark" windows were a nice touch. (The gold stripe on the body was a necessity else it would have been an Italian flag instead of the Mexican flag.)

Post the gcode file that shows the hole. With the model loaded in Cura use "File | Save Project" and post the 3mf file here as well. There are certain combinations of settings (coasting, combing, retract at layer change, retract before outer wall) that sometimes don't play well together. Maybe something will stick out.

Wow. You are having a heck of a time. I have no idea why that would happen. Usually something like that is the model, but it's just a calibration cube right? Maybe there was a long combing move before it and that is the start of an extrusion? Too much oozing during a combing move will cause a delay at the start of the first extrusion after the move. You are confident it's not in the preview? (right now I have more questions than answers). I think we can safely rule out a knot hole. That's as far as I'm willing to go right now.

By all means stick with the manufacturers advice. PETG is stringy and I haven't found a way to eliminate all stringing. I avoid Z-hop and print at 245 so the filament is more fluid. That allows it to be retracted faster. At 220 I would think you need to have a slower retract speed since the thicker plastic won't retract as fast. Priming doesn't really effect stringing. I print PETG at 35mm/sec with the outer walls at 30. On real prints the type of Combing you choose will also have an effect. With no z-hop and the nozzle traveling along pervious plastic, the stringing might be there but it's hard to notice until the nozzle crosses over air. Dry PETG is good. It gets even soupier than PLA when it has a high moisture content.

What printer are you using? You didn't mention, but are you printing PETG? Within those settings - the retraction distance does not change but for each level - 2 variables change. For instance, from A to B the retraction speed increases from 25 to 30 and the z-hop goes from 0 to .2. Are you doing other tests where the retraction distance changes? The 4.0 retraction distance would seem to indicate you have a bowden printer. The default retraction distance (for example) of an Ender 3 is 6.5mm. The retraction distance of bowden machines is effected by the amount of "slop" in the bowden system. The tube slides in and out of each coupler, it flexes, the length of filament within the tube during a retract is different than the length during a prime. A retraction distance of 4 with a normal amount of slop and you may be down to 2mm (or less) of actual retraction at the nozzle.

You will need to load the "Printer Settings" plugin from the MarketPlace. One of the settings is "Extruders Share Heater" and make sure that is checked. Materials have a "standby" temperature and you probably want to set that the same as your printing temperature. I don't think you can change the print settings for built-in materials. You might have to make a custom material. I'm also not sure but "Extruders Share Heater" might take the "Standby Temperature" issue out of consideration.

If you could load the model in Cura and set it up they way you think it should work, then go to "File | Save Project" and post the 3mf file here someone will take a look. It's hard to tell what's really going on from a photo.

You can see in the view from Blender that the letters have some depth. The walls look very thin and likely can't be printed. Your outer skin on the model needs some thickness. I don't know Blender but generally any object must exist in three dimensions to print. When you have a single surface it doesn't qualify since it has no Z dimension. Now if you could extrude that surface then you might have something workable.

Yes, it is the Ultimaker Forum but all users of Cura are prospective customers. There is a modification of the definition files that adds an extruder train, then there has to be an extruder file for that new train. Doing it that way will let Cura (any Cura) know that you have multiple extruders. I had already altered the files for a tarantula. The Tornado files are in the zip file. Copy "tevo_tornado.def.json" to the ...\resources\definitions folder. Copy "tevo_tornado_extruder_1.def.json" to the ...\resources\extruders folder tevo_tornado_dual.zip