GregValiant

@hafeez8 the model has errors . I was able to repair the model using the Mesh Tools plugin and the Fix Normals command. MS 3D Builder is more capable and would also repair it. The model on the left has been repaired by 3D Builder. If you are using Blender or TinkerCad you should always check the models for errors.

There is a lot better chance of developers seeing this on the GitHub page. If you select "New Issue" you will get an option for a bug report or a "Feature Request". Have you tried using "Initial Layer Horizontal Expansion" set to a negative number? I usually have it enabled at -0.2mm. Your build plate temperature can come into play as well. I have an air-conditioning vent above my printer and I had to print a deflector for it to keep the drafts from affecting prints. When I print with PETG I must use an adhesion promoter (hairspray in my case) and I often need to add anti-warping tabs to the models or they will lift.

I'm very, very pleased by the release. 5.1 was reminding me a lot of 4.9 and that is not a good thing.

I was wondering where you've been. So you aren't going to gold plate it for him? How about if it had been for a niece?

My disclaimer: I have a "virtual" dual extruder Ender 3 Pro in Cura that I use for troubleshooting. I have no real life experience with them. When both extruders are enabled and with a model on the build plate you should have the option in the Bed Adhesion section. You can see it in the image below. Next to the Settings Search box is an icon with three lines. Click on it and set the visibility to "All". One thing I've learned about dual extruders is they each have there own settings. I have to be very careful checking all the settings for both extruders by switching back and forth between extruders. It's fairly easy to make a mess.

That looks a lot like a purge tower. In the Dual Extrusion settings you can turn it off. If you happen to be using one extruder for the model but the Build Plate Adhesion is set to the other extruder you will get that. I think if you disable an unused extruder (there is a check box) then it will go away as well.

Here is a snippet from a gcode from your project file. G1 F9000 X100.6 Y100.6 >>Move to the start position over the print G1 F300 Z1.4 ; move back down to resume height G1 F1500 E5 >>Prime to make up for the retraction you asked for in the settings. G1 F922.3 ; restore extrusion feedrate M82 ; switch back to absolute E values G92 E37.72338 I think there is a bug report about this on Github. That line with the E5 should be before the "move to start position" line so any blob occurs where the head was parked and not on the print. This is my system and the 3mf I've attached is what I would use. When filling in the "Pause at Height" dialog leave the "retraction" box at 0. That results in this gcode. Notice that there is no prime move anymore. G1 F9000 X100.6 Y100.6 >>Move to the start position over the print G1 F300 Z1.4 ; move back down to resume height G1 F922.3 ; restore extrusion feedrate M82 ; switch back to absolute E values G92 E37.72338 So the print is running and the pause occurs. You manually pull the filament out, insert the new filament and push by hand until the color changes. THEN pull back 3 to 5mm. Then un-pause the printer. That little hand retraction will relieve the pressure in the nozzle and you should get a clean start with no blob. It may take a couple of practice tries to get the amount of pull-back just right. I've gotten pretty good at it. The best situation you can hope for is that there is some support on that layer because support always prints first so any scar that might occur is in the support rather than in the model. I know, it isn't always possible. That's why you need to practice the hand retraction. I didn't post the 3mf due to power issues here. I'll get to it. It will be the same as yours but with the retraction distance at "0".

The hurricane left me with a mess. It will be a couple of minutes (or weeks) before I can look at that.

Progress. Load that model. Turn off things like "Arc Welder" and "Adaptive layers" since it doesn't need them. After you set up for the slice use the "File | Save Project" command and post the 3mf here.

The Speed and Accel numbers you enter into Cura are the ones used in the calculations. The problem occurs when someone decides to print at 5000mm/sec and at 10000mm/sec² Accel. If that's what you enter in Cura then Cura will happily use those numbers in the calculation. Then the gcode gets read by the printer. The printer may have M201 (Accel) and M203 (speed) set to much lower values. So the printer will refuse to honor the speeds and accels in the gcode file and will limit itself to whatever max values it has. That makes it look like the print time was calculated incorrectly but it's more of a "garbage in and garbage out" sort of thing. If you check the printer's response to M503 it will have those "max" values in it. You can use Pronterface to send and receive info from the printer. I use my own Windows app that I modestly named "Greg's Toolbox".

With nothing to do but wait for hurricane Ian to blow my roof off I decided to try printing the femur. It looks a lot different than your prints. (BTW I converted the file to 1.75 filament so I could print it on my Ender.) The support failed (and then came back to life) but the model itself came out well. I don't know UM printers but I'm pretty good with gcode and I think in this case we can eliminate the gcode as the problem.

It's an Ulttimaker so @gr5 may have a better understanding. I did look at the "bad" gcode and the flow numbers look good. Before you printed the big model that came out OK did you happen to pull out the filament?

If you are printing via the SD card... It may be that the SD card has developed corrupt memory addresses and when your operating system copies files to the SD card the ends of the files can't be read. The memory cards that come from Creality are notorious for this. Re-formatting the SD card will usually fix that. If you have files on the SD that you want to keep, make sure you copy them to your hard drive before formatting. The card needs to be FAT32 and a "quick format" should work. If you are printing some other way (Octoprint or USB) then we would need to know.

No, you have to set a time-out or the printer will just use the default 2 minutes. After experimenting with my Ender I found that 4 hours is the max. If you do that and took 3 1/2 hours till you go home and resumed the print then you would have to let the hot end cool down or the filament will cook off and cause a clog. The max Time-Out allowed by Pause at Height is 30 minutes and it's hard coded in the plugin. If you were to do the pause as we have been talking about, but add the Search and Replace plugin with: Search = M18 S1800 Replace = M18 S14400 Then you would have 4 hours IF your firmware would allow it. Setting a time-out is always temporary and as soon as the steppers disable for any reason (like at the end of a print) the Time-Out goes back to 120 seconds. There is no way to make a permanent change to the firmware without re-compiling the firmware.

No, there is no setting that will do that. The times for the retractions as noted in the Dual Extruder section are included in the time calculation as are the regular retractions and primes. What I have laying around is this post-processor that you may be able to do something with. It displays the time remaining and the layer on the LCD as "91/160 | ET 1H56M" but it includes a Fudge Factor so you can adjust the print time that is displayed. You use the formula "Cura Estimate / Actual Print Time" to calculate the fudge factor. After a few prints I'm sure you would get a handle on the error. I use 1.12 and it is really close to reality. Here is a Zip folder containing the "ShowProgress.py" file if you want to play with it. In Cura 5.x for Windows the .py file goes in the: "C:\Program Files\Ultimaker Cura 5.1.0\share\cura\plugins\PostProcessingPlugin\scripts" folder and becomes available when you add a post-processing script in Cura. To give credit where credit is due, the script was written by a fella named Louis Wooters. I made an adjustment to add an M118 line so it would bounce the same info back to my print server. ShowProgress.zip

So did it Pause and were you able to resume? "It still starts above of what is suppose to..." I assume you mean that there is a second problem. I see two things. In the Pause At Height dialog box set the "Disarm Timeout" to 1800 and set the StandBy Temperature to your Print Temperature. I think what is happening is that the M104 S0 line is allowing the Hot End to cool off while you are changing filament (or inserting a nut, or whatever). That is taking longer than the 120 seconds of the standard Disarm Timeout and so the steppers are losing position. When the print resumes it is at the wrong height. By maintaining the temperature at the Printing Temperature, and by increasing the Disarm Timeout to 1800 seconds (30 minutes) you should finish whatever you are doing in plenty of time. Since the Hot End is at Print Temperature the M109 line that follows will be acted on quickly and the print should resume.

Post a gcode file here and I'll take a look.

"(about 30 seconds to retract about 200mm of filament)" If it's taking 30 seconds for 200mm then that's about 7mm/sec. That's really slow. You can set the retract and prime speed for the tool change in the Dual Extrusion settings. At 50mm/sec it should take 4 seconds to retract and another 4 seconds to prime. If the printer has a 10mm/sec limit "maximum E speed" in it's M203 register then no matter what you enter into Cura the printer would use 10mm/sec. You didn't mention, but is that a "multiple-in / one-out" hot end? M109 commands can cause about a 10 second time penalty as the printer processor checks that the temperature is OK. It's something else to look for. If you have "Extruders Share Heater" and "Extruders Share Nozzle" enabled in the Printer Settings then that shouldn't happen though.

Up above is a download for the nozzle files. Download it, extract the files, and put them into the "variants" folder. On my windows computer that is: "C:\Program Files\Ultimaker Cura 4.13.1\resources\variants". If that doesn't work I don't know what to tell you. It's been downloaded 141 times and I haven't received 141 complaints so it must have worked for most folks. Have you tried clicking on the "Empty" in the nozzle size dropdown box? Maybe it needs a kickstart to populate?

Let us know what printer you have. The easiest thing to do is load the model into Cura, set Cura up ready to slice, and then select "File | Save Project". That will create a 3mf file with your entire setup. Post the 3mf file here. Maybe you could post the "bad" Gcode file as well. More information is better for troubleshooting.

Part of what is going on is the variable line width. Here I've multiplied the model and let Cura arrange them. The line width is your 0.4 Here the line width is 0.35 and all the models are filled with skin between the walls. Here the line width is .42 and like magic, it's all good. The walls will fit without any room for skin. This is back to .35 line width but with the top/bottom pattern set to Concentric. So there is flexibility in achieving what you want but 5.1 is different than earlier versions and has to be played with in order to figure out how the new features work.

The threaded brass inserts are the ritz.

Cura is a fine slicer. Every once in a while someone will ask for more features to make adjustments to the model (or in this case an assembly). Cura has a bit of capability in regards to modifying models, but it's rudimentary at best. What I see in this post is similar to others "Here's the model but it isn't what I want, I want it this way instead." There is no functionality in Cura for making large adjustments to the shape of a model. If you want the tires as part of the model of the car body then you need to put an inner wheelhouse in within the CAD software. Another thing Cura isn't good at is aligning two STL models. Cura uses the bounding box of a model. Unless every model has the same bounding box they are tough to align. I have a trick where I make a 1mm thick rectangle just smaller than my build plate and then locate it in the STL file so the top of the rectangle is Z=0 of the actual model itself. The size of the bounding box in the XY is then the size of the plate. Every model gets the same treatment and when they are located at X0 Y0 in Cura and at a Z = -1, they are in the proper relationship to each other and the rectangles don't print. Things like that (fooling Cura) are about all you can do. When you bring in the model you want sliced it's all good. When you bring in a bunch of pieces and try to assemble or adjust them so that you print a different model, then it gets away from what Cura is good at.

If I understand this correctly, you need a 3rd part to fill the gap in such a way that there are no additions to the geometry of the two "real" parts. I agree with @dsp that it wouldn't be difficult. You could then merge the three parts and have your single model to print. Make a 1mm thick part that emulates the lower surface of the top piece. Make a 1mm thick part that emulates the top surface of the bottom piece. "Intersect" those 2 pieces. The resultant shape will fill the gap and not be larger (or smaller) than the virtual intersection of the top and bottom parts. Locate the new piece within the real assy. Merge them into a single part. I merged your STL and my filler STL in MS 3D Builder. This layer is .5mm above the surface of the bottom part. The most time consuming part of this was converting that original STL to a DXF so I could open it in Inventor.

"...all relevant GCodes only work with the short 8.3 file names from the DOS world..." That's the way it works on my Ender. The line below works on my printer. The file is called and upon completion command returns to the calling file. M32 P !MAIN~1.GCO#