GregValiant

Someone here will need a project file ("File | Save Project") to investigate.

This is the UltiMaker Forum so mostly it's about their machines. Have you posted your question on an EasyThreed user site? I think you would get more help there.

https://github.com/Ultimaker/Cura/issues/14036 This keeps coming up.

If you search through the Gcode for "T0" and "T1" you should see where the temps are changed at any tool changes. If you search for "M104" and "M109" you will come across other temperature changes. Between the two you will get a feel for what Cura is doing. On long prints you won't want to be dragging an oozing nozzle around your print so the standby temperature is important.

Thanks @ahoeben. Your fix appears to work as advertised so it's all good now.

"I thought that the temperature was adjusted to the correct level while the opposite core was finishing its layer" It does work that way but it's dependent on "Heat Up Speed" and "Cool Down Speed" which are not exactly consistent (they are affected by a lot of things including flow-rate of material through the nozzle). There is also the question of how long the layer takes to print. For quick layers there may not be enough time for the temp to adjust before the next tool change. The M109 is a safety to insure that the printing temperature is reached. As a side note - A change I made in the PauseAtHeight plugin was to add an option to use either M109 or M104 when the print resumes. If the "Standby" temperature is the same as the "Printing Temperature" then M104 is fine and the print immediately continues after the pause. If the temperatures are different, then the use of M109 is indicated so the printer waits for the new temperature to be achieved before printing resumes. One thing I have noticed is that if the current nozzle temperature is the same as the resume temperature then M109 may or may not cause a 10 second dwell in the print. It appears to be a function of when the M109 appeared in the Printer/Planner queue as to whether a dwell occurs or not. It might have something to do with the clock cycle of the Printer/Planner or whether the reported temperature is slightly above or slightly below the set point temperature. It certainly isn't consistent.

If there are M109 temperature commands (likely) in the gcode then that will usually cause a delay before printing resumes. If both cores are printing at the same temperature, and if the stand-by temperature for both cores is the same as the printing temperature, then you could (if you are brave) use Search and Replace to change all the "M109" lines to "M104"'s. BUT...If the temperatures are not the same, then you need to let the printer adjust temperatures and that will mean a short wait every time there is a tool change.

If your printer is an "Origin at Center" machine and Cura is not set that way then there will be a location problem on the print bed. The opposite is also true. If your printer is NOT an Origin at Center machine but the box is checked in Cura then the print will be off the left front corner of the build plate. Auto-Home your printer, raise the Z a couple of mm's so the nozzle doesn't drag, then move the nozzle to X=0 Y=0. If the nozzle is at the left front corner, then go into Cura to Manage Printers / Machine Settings and make sure the "Origin at Center" box is not checked. If the printer nozzle is at the midpoint of the build surface then the Origin at Center box should be checked. Without any images that's the best I can do.

It's a well rehearsed post. I think I've put that up half a dozen times here and there. There are two things that you should consider here... Use a carpenters square or similar tool and make sure that each axis is at 90° to the other two. If the frame is straight and square your prints will be straight and square. If you calibrate the extruder motor (the "E-steps") then the machine will push the correct amount of plastic into each extrusion. Do not use a "single wall calibration cube" when you calibrate the extruder. Just make sure that when it's told to push 100mm of filament that it actually pushes 100mm of filament. All the "kit" printers need both of those done. Remember that "Just because parts of it were assembled at a factory doesn't mean they were assembled correctly." Check everything, trolley wheel alignment, the hot end is tight, no loose screws, etc.

To say this another way... The virtual build plate in Cura has to match the real build plate of the printer. Leveling takes care of the "Z" and it is the "Home Offset" that takes care of the X and Y. When the printer receives a gcode it will put the X0 Y0 of the print at your Home Offset 0,0 position. If you have never changed the Home Offset then it is the same as the Auto Home position. That is why the print is off. You will need a ruler. (2.5mm is about 1/10".) Your build surface is 235 x 235 but you can't use the whole thing. Creality asks for a very conservative 7.5mm non-printable border (235 - 7.5 - 7.5 = 220) around the build surface. You can make the border smaller than that and increase the printable area. Measure your build plate edge to edge in the X and in the Y. We'll call those Xmeas and Ymeas. Auto Home the printer. Use the LCD and raise the Z axis 5mm or so. Move the nozzle in the X to a point 2.5mm in from the left edge of the build surface. Move the nozzle in the Y to a point 2.5mm in from the front edge of the build surface. Drop the Z back down to "0". On the LCD find "Set Home Offset" (on my older 3 Pro it's under "Prepare") and click on it. Raise the Z 5mm Send the nozzle to Xmeas - 5 and Ymeas - 5. The nozzle should be 2.5mm from the back edge of the build surface and 2.5mm in from the right edge of the build surface. In Cura - goto Manage Printers and then Machine Settings. Make the X(width) = Xmeas - 5 and the Y(depth) = Ymeas - 5. If you find that the nozzle is too far back or too far to the right when you move to the back right corner, then you will need to make an adjustment. If you find that you have to set your Home Offsets with the nozzle 5mm in from the left and 5mm in from the front then you would set Cura up as Xmeas - 10 and Ymeas - 10. When you are happy with how you have set it up find "Save Settings" on the LCD and click on it. That will make your new Home Offset the new default. The midpoint of the Cura build surface should end up matching the midpoint of the actual bed. That will center all your prints.

There are other places where you need to make changes. The "Mega X" printer inherits the "Mega S" printer which in turn inherits the FDM Printer definition file. Within the override section of the Mega X definition file is: "speed_travel": "maximum_value": 120.0, So you need to alter your definition file and make the maximum_value a higher number. Then you need to copy the file into the Configuration Folder / definition_changes folder so it will carry-over when you upgrade to a new version of Cura. You should probably over-ride the "maximum_value_warning" speed warnings as well as they are all below 250. They won't keep you from slicing but all the boxes will be yellow.

You have the "Walls / Compensate Outer Wall Overlaps" turned off and the "Compensate Inner Wall Overlaps" turned on. If you switch those around you will see that there are artifacts on the outer wall as Cura adjusts the line widths to accommodate that thin wall cross section. So it is still a question of how you set up the slice. This is 4.13.1 but with the "Outer Walls" compensated. You can see that the artifacts re-appear.

An "On-Off" switch for the Arachne Engine has been requested but there currently isn't one. If it is a critical feature I'd go with 4.13.1. This is from PrusaSlicer with Arachne turned on (there is a switch). You can see the same thing happening as in Cura. There is a line width adjustment being made. And here I've flipped the switch and turned Arachne off. I would say this is "altering the 3d geometry".

"Wall Transitioning Threshold Angle" As the inner diameter approaches the exterior wall Cura is making adjustments to the line width. At the default value of 10° - Cura stops extruding, makes a minor adjustment, and then continues with a single extrusion for the narrow part of the wall. That will often leave a mark. With the setting at 25° the situation is different and there is no "stop" to adjust the line width. You can still see some slight variation there. Whether those variations will show up in the print I don't know. Cura is not "altering the geometry" but is making an adjustment to respect the geometry given the settings employed. This is Cura 4.13.1 without the Arachne Engine Variable Line Width. This is likely what you are seeing with Orca.

Good morning @MariMakes, In regards to that model and the alleged problem - this appears to be another clear-cut case of "Everything affects Everything". There does appear to be an interaction between some settings. I don't think Support Horizontal Expansion is one of them. In the end I have to conclude that the "slightly lower" edge that requires support is confusing Cura and that the situation requires the user to closely examine the preview and make adjustments so that the edge (two layers lower) is supported. I noticed that the "unsupported support structure" started at the cross hole on the back side of that large pocket of the model. "Hole Horizontal Expansion" had been set to 0.1. With HHE set to zero, or Max Hole Diameter set to 25, the condition kind of went away. Setting the Support HE to 0.8 changed things, sometimes for the better, but it was conditional on some other settings ("Support Density", and "Support Infill Line Directions" are two of them). This is with both the Support HE and the Interface HE set to 0.8. I'm going to described this as "Wonky". Here I've set "Support Wall Line Count" to 1. The wall is around the periphery of the area requiring support and so it picks up that narrow ledge. Experience tells me that it will also make it harder to remove the supports from the back of that pocket. This is with the Support Line Directions at [90]. Once again the outside is picked up. So this condition does appear to be something that can be "Tuned" and eliminated and seems to be model specific. (That doesn't mean I'm letting the Cura Team off the hook. I'm going to blame all of this on the continued lack of progress on the Cura "Easy" button 🔮 .)

@Mike2481632 Go over to GitHub and fill out a bug report. The gcode generated by 4.13.1 contains the coasting moves throughout the print, but the gcode generated by the 5.x versions only seem to apply coasting to the bed adhesion. So it does appear that coasting might be broken in the 5.x versions. There is a reason why Coasting is in the Experimental section. The problem with that print getting glued together is separate. I would not expect coasting to either fix it, or make it worse.

Maybe I don't understand the problem. As I understood your posts... Printing this model is resulting in the parts getting glued together and you have decided that "Coasting" needs to be used to fix it. We may be talking apples and oranges here. It wouldn't be the first time. I printed this with my own settings. The main differences were: Coasting off, Minimum retract distances to 0.1mm, no Extra Prime, Bridge Settings turned off, Generate Support turned off, The line widths all at .45, the flow for everything at 100%, and I enabled Z-hops at 0.5. I did not use "Random Z-Seam" but for this model it might be a good idea so any blobs are spread out and not in a line. I ended up with three separate pieces. There was some sticktion between the outside piece and the middle piece but it was minor. I suppose it could be more of a problem on a longer model.

Here is your project sliced exactly as it downloaded. This is in 4.13.1 and the only change I made was to turn off "Coasting". This is with 5.5 beta This is with 5.4.0 This cube has a wall that is 0.4mm thick. Coasting is off. This is 5.5beta. Your project file has coasting turned on and the coasting volume is set to 1cubic mm which is a lot. The Cura preview only shows extrusions and there is no extrusion during a "coast" move. There will always be a gap in a preview line if coasting is turned on. @Mike2481632 You can fill in a bug report here on GitHub . Be advised that I do a lot of the bug report triage over there and this sure looks like a setting issue to me. Go to the "Experimental" section and turn off "Enable Coasting". You should see the change in the preview.

The printer definitions come from members of the Cura "open source" community, or from the printer manufacturer. Ultimaker can't be expected to go out and buy one of every printer on the planet on the day they are announced and write definitions for other peoples hardware. They are in business to sell their own printers. In two weeks or so when the stable 5.5 is released, or in 3 or 4 months when a new Cura is released maybe someone will have written and submitted all the definition files for that printer. Then again, maybe not. If you feel that it is a gamble taking a chance on a print hitting the gantry, maybe you should set the printer aside until someone submits a definition for it.

3. Missing supports. This is with normal supports. The outboard supports start abruptly with nothing below except the floor interface. The problem appears to be "Support Infill Layer Thickness" as I often run it at 2 layers high as in the image above. When set to 1 layer high the preview is as I would expect. GV_report 3.3mf

What version of Cura? The second extruder should be there. Different Cura versions can contain different printer definitions because people submit definition changes. Adding an extruder isn't difficult but might require that you copy and alter some files.

If you are splitting a single model at a layer then yeah, layers will start with E1 because it doesn't need E2 until later. Then when E2 comes in it doesn't need E1 anymore so all the remaining layers would start with E2. If you have two models on the build plate and one is set to E1 and the other is set to E2 then I don't see why it would matter which extruder starts a layer because they are both needed every layer. The "efficient" way to do it is to start with one extruder, switch to the other one half way through the layer and then start the next layer with that same extruder and switch back to the first extruder halfway through the layer. effectively you are printing one model twice, them moving to print the other model twice. There is a layer change in there and yes the extruders effectively alternate on which one is active at the start of a layer. Starting every layer with the same extruder means twice as many tool changes. ("tc" is "tool change".) Normal routine: layer 1 E1 tc E2 layer 2 E2 tc E1 layer 3 E1 tc E2 layer 4 E2 tc E1 but starting every layer with the same extruder it would be: layer 1 E1 tc E2 layer 2 tc E1 tc E2 layer 3 tc E1 tc E2 layer 4 tc E1 tc E2 That's a lot of trips to the purge tower.

Post the model and I'll look. It's going to need supports. That indented feature on the backside, or the roof, it's going to require supports no matter how you orient it. You can plan for the supports to not grow on "show" surfaces, or maybe you don't care. You can use tree supports, or normal supports as both have their pluses and minuses. As long as they are easiest to divorce from the print that's about as good as you can do. Supports are part of the deal. A decent set of support removal tools is a necessity. You can get cheap pic sets, micro-files, nippers, and needle nose pliers and a hobby knife at most hardware stores to aid in the removal. The first layer of skin above any support structure is always ugly. I usually run the Support Interface Flow at 95% so they are weaker. If a roof goes down on a cool support interface it won't stick as well. If you make the "Floor Distance" 2 layers tall (the normal air gap is 1 layer tall) then the floors won't stick to a model as well when it needs to grow on the model.

The "Support Overhang Angle" is dependent on the Line Width and Layer Height. For most cases figure that 63° is the highest you can go on that setting. I usually keep it at 55 to 60. When you make a change to the Support Overhang Angle you will see the red areas change size as they are a function of the angle. That lower chamfer looks to be about 45° so setting the Support Overhang Angle above 45 should make that area not required support. Small holes will want support because the tops are essentially at 90° but they are small enough that the printer can bridge across them with no problem. You can use support blockers to keep support out of them if your settings are such that Cura insists on sticking support in them. The underside of that roof will need support. You can try normal supports but they will grow from the floor of the model. Tree supports can grow at an angle and reach into areas like that if they are inboard a reasonable distance. You have a couple of little lips that that are going to need support. Those are tough. You need to set the Support XY distance and the Minimum XY distance to something that will allow support to get to those little overhangs while at the same time not gluing themselves to the model. It can be fussy.

1. Materials are my first problem. There weren't any for my printer and the Preferences dialog does not configure to "Manage Materials". I was able to get the Material list loaded by opening a project file. The dialog is always "whatever the last subject was" rather than Materials. If you look closely you will see that the "Defaults" button is actually displaced from the button below. The amount of displacement varies, but I can always see two (maybe three) buttons on top of each other. 2. AA0.8 print head file was misnamed and Cura wanted me to reset. Changing it from "um_s5_aa0.8_tpu_0.2mm.inst.cfg" to ""um_s5_aa0.8_um-tpu_0.2mm.inst.cfg" seems to have fixed it. An S5 "left" extruder was also a problem. (I open a lot of 3mf files so my config folder may have been incorrect.)